Cover Art. The artistically smoothed graph represents global temperature trends during the past 400,000 

years as determined from fluctuations in oxygen isotope ratios in marine sediment cores. It indicates that 

warmer intervals, such as the present interglacial (the last 10,000 years), are rare and relatively short in 

duration. Intervals significantly warmer than today have not existed for more than 2.5 million years. 
Proceedings of the 

U.S. Geological Survey 

Global Change Research Forum, 

Herndon, Virginia, March 18-20, 1991 

Edited by JOHN A. KELMELIS and MITCHELL SNOW 

USGS Global Change Coordinating Committee (Gang of 12): 

john Kelmelis, Chairman 

Paul Dresler 

linda Stanley 

Robert Hill 

Eliot Christian 

Mary Jones 

Robert Hirsch 

Harry Lins 

Richard Poore 

Milan Pavich 

Gene Thorley 

Lawrence Pettinger 

Office of Assistant Director for Research 

Office of Assistant Director for Research 

Office of Assistant Director for Programs 

Office of Assistant Director for Programs 

Information Systems Division 

Information Systems Division 

Water Resources Division 

Water Resources Division 

Geologic Division 

Geologic Division 

National Mapping Division 

National Mapping Division 

U.S. GEOLOGICAL SURVEY CIRCULAR 1086 
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary 

U.S. GEOLOGICAL SURVEY 

DALLAS L. PECK, Director 

Any use of trade, product, or firm names 

in this publication is for descriptive purposes only 

and does not imply endorsement by the U.S. Government 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1993 

Free on application to 

U.S. Geological Survey, Map Distribution 

Box 25286, Bldg. 810, Federal Center 

Denver, CO 80225 

Library of Congress Cataloging in Publication Data 

U.S. Geological Survey Global Change Forum (1991 - Herndon, Va.). Proceedings of the U.S. Geological Survey Global Change Research Forum I 

Herndon, Virginia, March 18-20, 1991 I editor, John A. Kelmelis ; assistant 

editor, Mitchell Snow. 

p. em. - (U.S. Geological Survey circular; 1086) 

Includes bibliographical references. 

Supt. of Docs. no.: I 19.412:1086 

1. Climatic changes-Congresses. I. Kelmelis, john A. II. Snow, Mitchell. 

Ill. Title. IV. Title: Proceedings of the U.S. Geological Survey Global 

Change Forum. V. Series: Circular (Geological Survey 

(U.S.)) ; 1086. 

QC981.8.C5U516 1993 

551.6-dc20 92-14556 

CIP 
ACKNOWLEDGMENTS 

Organizing an interdisciplinary meeting to review the diverse topics represented in 

global change research is not an easy task. It requires the concerted effort of a large 

number of people. Many arrangements must be made, schedules established, and 

activities coordinated. Budget and personnel restrictions mandate obtaining the best 

possible value for the resources expended. 

It is a very fortunate circumstance that the USGS Global Change Research Forum 

was organized and orchestrated by Linda Stanley, who ably dealt with all the details, large 

and small. She was the real driver behind the Forum and without her it would not have 

happened. Scott Tilley was her able assistant. He helped with the thousands of details 

from contracts to condiments, from abstracts to accommodations. He did an outstanding 

job. 

Mary Fischer and Hannah Sluss provided constant secretarial help, which is a 

difficult task given all the Committee on Earth and Environmental Sciences business and 

other activities constantly underway in the Assistant Director for Research's office. Mary 

Lefler graciously helped throughout the conference. 

Thanks also go to the "Gang of 12" for providing the technical expertise and the 

leverage within the divisions to make the program as comprehensive as it was. The Forum 

participants deserve thanks for providing the many technical presentations and insightful 

discussions throughout the meeting. And thank you to all of the others, who, through my 

oversight, I have not mentioned. All of you have made the job of putting this Forum 

together very much easier. 

John Kelmelis 

Coordinator 

USGS Global Change Research Program 

Editor's Note: The submissions by non-USGS employees have not been cleared 

through the USGS Director's Review process and may not reflect USGS style. 

Acknowledgments Ill 

CONTENTS 

Acknowledgments III 

First General Session 1 

Welcome and Introductory Remarks, by Stephen Ragone 1 

The Committee on Earth and Environmental Sciences: Its Role in Federal 

Research, by Dallas Peck 3 

U.S. Global Change Research Program, by Robert Corell 5 

U.S. Department of the Interior/U.S. Geological Survey Global Change 

Research Program, by John Kelmelis 9 

Interagency Working Group on Data Management for Global Change, by Eliot 

Christian 12 

A Fragile Seam of Dark Blue Light, by Jack Eddy 15 

Second General Session 23 

Earth System History and Global Change, by R.Z. Poore 23 

Climate, Hydrology, and Water Resources, by Harry F. Lins 27 

Terrestrial Implications and Uncertainties in the Atmospheric Carbon Dioxide 

Budget, by Eric T. Sundquist 33 

Land Data and Information Management, by Donald T. Lauer 37 

Developing a Sound Basis for National Policy, by Allan Bromley 40 

The Receding Threat From Global Warming, by Patrick J. Michaels 43 

Third General Session 51 

Pliocene Climates, by Tom Cronin, R.Z. Poore, H.J. Dowsett, and R.S. 

Thompson 51 

Desert Processes, by C.S. Breed 53 

Satellite Image Atlas of Glaciers of the World, by Richie S. Williams, Jr., and 

J. G. Ferrigno 55 

Sensitivity of Water Resources in the Delaware River Basin to Climate Change, 

by Gregory J. McCabe, Jr., D.M. Wolock, G.D. Tasker, M.A. Ayers, 

and L.E. Hay 56 

A Strategy for Large-Area Land Characterization: The Conterminous United 

States Example, by Thomas R. Loveland 63 

Breakout and Poster Sessions 68 

A Distributed Visualization Modeling Environment for Methane Flux, by W. 

Acevedo, L.A. Morrissey, and G.P. Livingston 68 

Long Climatic Records From Sediment Cores in Western North America: 

Results and Prospects, by D.P. Adam 68 

Transects of Long Climatic Records, by D.P. Adam 69 

Late Cenozoic Climates of Alaska and Yukon: A Joint U.S. Geological SurveyGeological Survey of Canada Global Change Research Project, by T.A. 

Ager 69 

Sustainable Development: Focus for Department of the Interior Global Change 

Human Interactions Experiment, by R.H. Alexander 70 

Using Spatial Statistics to Improve Estimates of Regional Methane Emissions 

From Tundra Ecosystems, by S.P. Benjamin, G.P. Livingston, and R.E. 

Rossi 71 

Reconstructing Climate of the Great Basin for the Past 25,000 Years: Completed 

and Ongoing Research, by L.V. Benson 71 

CoMents V 
VI Contents 

From Fire to Flood: Pacific Climate and Southwestern Watershed Management, 

by J.L. Betancourt 72 

Soil Interpretations for Global Change Modeling and Impact Assessment, by 

N.B. Bliss 72 

A 3-Million Year Terrestrial Climate Record and the Variable Character of the 

Marine-Terrestrial Climate Connection, by J.P. Bradbury 73 

Arctic Ocean Winter Polynya Zones During 1978-87, by W .J. Campbell and 

P. Gloersen 73 

Global Change Data Management, by D.M. Carneggie 74 

Late Cenozoic Arctic Climatic Change, by L.D. Carter 75 

"Cool" vs. "Warm" Winter Precipitation and its Effect on Surface Hydrology in 

the Western United States, by D. Cayan 76 

Data Management Planning, by E. Christian 76 

Climatic Change Inferred From Borehole-Temperature Measurements, by G.D. 

Clow and A.H. Lachenbruch 77 

Interrelations Between Gas Hydrates of Northern Alaska and Atmospheric 

Methane, by T.S. Collett and K.A. Kvenvolden 77 

Stratigraphy of Climatic Change in Large Lakes, by S.M. Colman 78 

Rates of Holocene Climate Change-Evidence From Varved Lake Sediments, by 

W.E. Dean and J.P. Bradbury 79 

Varve Chronology or 14C Dating-Which Do You Believe? by W.E. Dean 79 

Multiscale Characterization of Land Cover Complexity in Colorado, by 

L. De Cola 80 

Description of Interdecadal Trends in Surface Temperatures of the Sierra Nevada 

and Gunnison River Areas Using Singular-Spectrum Analysis, by M.D. 

Dettinger 80 

Pliocene Marine Climate Records, by H.J. Dowsett, L.B. Wiggs, and R.Z. 

Poore 81 

Climate, Lakes, and Ostracodes, by R.M. Forester 81 

The Effect of Climate Change on the Hydrology of Glacier Regions, by 

A.G. Fountain 82 

Report of a Workshop on the Correlation of Marine and Terrestrial Records of 

Climate Changes in the Western United States, by J.V. Gardner, A.M. 

Sarna-Wojcicki, D.P. Adam, W.E. Dean, J.P. Bradbury, and H.J. 

Rieck 83 

Assessing the Human Impact of Global Change in Western United States and 

Alaska, by L.J. Gaydos 83 

Role of Volcanic Emissions in Global Change, by T.M. Gerlach 84 

Climatic and Paleo-Oceanographic History of the Canada Basin, Arctic Ocean, 

by A. Grantz, R.L. Phillips, S.D. May, M.W. Mullen, R.Z. Poore, and 

H.J. Rieck 84 

The Effect of Changes in Data Resolution on Hydrologic Response, by 

C.A. Hallam 85 

Coral Fluorescence as an Index of Runoff in South Florida, by R. B. Halley 86 

Seawater Temperature and Coral Bleaching in the Florida Keys: No Relation to 

Global Warming ... Yet, by R.B. Halley and J.H. Hudson 86 

The Old Crow Tephra: A Stratigraphic Marker for the Last lnterglaciation in 

Alaska? by T. D. Hamilton 87 

Nutrient and Carbon Dynamics in Soil Systems, by J.W. Harden, R.K. Mark, 

D.H. Showalter, E.T. Sundquist, and R.F. Stallard 88 

Estimation of Precipitation Patterns in the Delaware and Gunnison River Basins, 

by L.E. Hay and W.A. Battaglin 88 

Lake Baikal, Southeastern Siberia: Prospects for Paleoclimate Research, by P.P. 

Hearn, Jr., S.M. Colman, E.B. Karabanov, and D.F. Williams 89 

Geomagnetism and Climate, by D.C. Herzog 89 
Modeling the Late Pleistocene Paleohydrology of the Great Basin, by S.W. 

Hostetler 90 

Large-Area Digital Elevation Data and Their Derivatives, by S.K. Jenson 90 

Satellite Passive Microwave Observations of Snow Conditions in the Upper 

Colorado River Basin, by E.G. Josberger, W.J. Campbell, P. Gloersen, 

and A.T.C. Chang 91 

Planar Pattern of Delayed Postglacial Uplift in New England: A Datum for 

Measuring Late Glacial Sea-Level Changes, by C. Koteff and G.R. 

Robinson 92 

Permafrost and Gas Hydrates as Possible Sources of Atmospheric Methane at 

High Latitudes, by K.A. Kvenvolden and T.S. Collett 92 

Paleoclimate Reconstructions From Alaskan Ice Records: Teleconnections 

Between Pacific-North American (PNA), Reverse PNA, and El 

Nino-Southern Oscillation (ENSO) States, by G.P. Landis, J.J. 

Fitzpatrick, T.K. Hinkley, and R.O. Rye 93 

HCDN (Hydro-Climatic Data Network): A U.S. Geological Survey Streamflow 

Data Set for Climatological Analysis, by J .M. Landwehr and 

J .R. Slack 93 

Stochastic Analysis of 8180 and 813C Time Series Found in a Continuous 

500,000-Year Climatic Record From Great Basin Vein Calcite, by J.M. 

Landwehr, I.J. Winograd, T.B. Coplen, A.C. Riggs, K.R. Ludwig, and 

B.J. Szabo 94 

Water, Energy, and Biogeochemical Budgets in the Luquillo Mountains, Puerto 

Rico, by M.C. Larsen, P.D. Collar, and R.F. Stallard 94 

Investigation of Climate-Hydrology Interactions Using Coupled Atmospheric and 

Hydrologic Models, by G.H. Leavesley 95 

Land Characterization Using Remotely Sensed Data and Artificial Neural 

Networks, by G.P. Lemeshewsky 96 

Biogeochemical Cycling of Carbon and Related Elements in Estuarine Wetlands, 

by J.S. Leventhal, L.L. Jackson, K.S. Smith, L. Balistrieri, and 

K. Walton-Day 96 

Monitoring the Dynamics of the Antarctic Coastline With Landsat Images, 

by B.K. Lucchitta, L.M. Bertolini, J.G. Ferrigno, and R.S. 

Williams, Jr. 97 

Glacier Growth and Shrinkage Related to Climate Variations and Nonclimatic 

Factors in Alaska, by L.R. Mayo 97 

Photogrammetry and Global Change, by R .. B. McEwen 98 

Continental Hydrology and Global Climate, by P.C.D. Milly 99 

Glacier Monitoring for Global Change-Three Case Studies, by B.F. 

Molnia 99 

Monitoring Land Surface Responses to Social and Economic Pressures in 

Sahelian Africa, by D.G. Moore, G.G. Tappan, and M.E. Wehde 100 

Quantification of Information Contained in Outputs of General Circulation 

Models, by M.E. Moss 101 

Late Quaternary Sea Level History of the Pacific Coast of North America: A 

Detailed Record of the Last Glacial/Interglacial Cycle, by D.R. Muhs, 

J.F. Whelan, G.L. Kennedy, and T.K. Rockwell 101 

History of Desertification on the Great Plains: A Holocene History of Eolian 

Sand Movement, by D.R. Muhs, H.T. Millard, Jr., R.F. Madole, and 

C.J. Schenk 102 

The Global Land Information System, by L.R. Oleson 103 

Methane in Mono Lake, California, by R.S. Oremland 103 

Assessment of Effects of Potential Climate Change on the Hydrology of the 

Gunnison River Basin, by R.S. Parker and W.A. Battaglin 104 

Contents VII 
VIII Contents 

The Panola Mountain Research Watershed: Hydrologic and Biogeochemical 

Process Research, A Watershed Approach, by N.E. Peters, R.P. 

Hooper, and T.G. Huntington 105 

Climatic Variability in the San Francisco Bay Estuarine System, by D.H. 

Peterson and D.R. Cayan 105 

Phosphate and Trace Metals in Cenozoic Phytoplankton: A Signal of Changing 

Ocean Chemistry, by D.Z. Piper, V.G. Mossotti, and D.J. Bukry 106 

Potential Effects of Climate Change on the Surface-Water Resources of the 

Carson, American, and Truckee River Basins, by A. Pupacko 107 

Development of Land Data Sets for Studies of Global Climate Change, by F.G. 

Sadowski and A.H. Watkins 107 

Use of Ash Layers in the Reconstruction of Earth System History: Correlation 

and Age Calibration of High Resolution Stratigraphic-Climate Records 

in the Oceans and on Land, by A.M. Sarna-Wojcicki, C.E. Meyer, and 

E. Wan 107 

Water, Energy, and Biogeochemical Budgets at Sleepers River, Danville, 

Vermont, by J.B. Shanley and E.T. Sundquist 108 

Baseline Studies for Monitoring Global Climate Change in the Arctic 

Environment: A Remote Sensing-Spatial Data Base Approach, by 

M.B. Shasby 109 

Sulfur Isotope Geochemistry of Paleoclimate Change in Lake Baikal, Siberia, by 

E.C. Spiker and A.L. Bates 109 

Examination of Biogeochemical Processes in Tropical Watersheds of Puerto Rico 

and Panama, by R.F. Stallard 110 

Developing Land Surface Characterization Requirements for Water and Energy 

Exchange Models, by L.T. Steyaert 111 

Consumption of Atmospheric Methane in Unsaturated Soils, by R.G. 

Striegl 111 

A Monthly Water Balance Model to Study Possible Impacts of Climate Change 

in the Delaware River Basin, by G.D. Tasker, M.A. Ayers, D.M. 

Wolock, and G.J. McCabe, Jr. 112 

Paleobotanical Evidence of Population Dynamics and Paleoclimatic Fluctuations, 

by R.S. Thompson and P.J. Bartlein 112 

Some Anticipated and Measured Responses of Glaciers to Global Change in 

Alaska, by D.C. Trabant 113 

Banded Corals as Indicators of Tropical Pacific Paleoclimate, by G.W. Tribble 

and C.D. Hunt, Jr. 114 

An Investigation of the Water, Energy, and Biogeochemical Budgets of Loch 

Vale and Other Rocky Mountain Watersheds, by J.T. Turk, N.E. 

Spahr, and D.H. Campbell 114 

Some Recent Advances in Statistical Analysis of Spatial Random Processes, by 

A.V. Vecchia 115 

Hydrologic and Biogeochemical Budgets in Temperate Lakes and Their 

Watersheds, Northern Wisconsin, by J.F. Walker, D.P. Krabbenhoft, 

and J.F. Elder 115 

Assessment of the Potential Effects of Climate Change on Salinity Intrusion in 

Delaware Bay, by R.A. Walters 116 

Synoptic-Scale Climate and Mass Balance Interactions in Western North 

America, by R.A. Walters 116 

Modeling the Spatial Distribution of Solar Radiation Incident on the Land 

Surface, by R.D. Watts 117 

Relations Between Upper-Air Flow Patterns, Climate, and Hydrologic 

Variability in the Red River of the North Basin in North Dakota, South 

Dakota, Minnesota, Manitoba, and Saskatchewan, by G.J. Wiehe, J.L. 

Knox, and L.E. Welsh 118 
Arctic Data Interactive: Demonstration of a Hypermedia System, by D.A. 

Wiltshire 118 

Carbon Dioxide Contributions of the Terrestrial Biosphere to the Global Carbon 

Cycle, by B.E. Wright 119 

Author Index 120 

Contents IX 
X Acronym List 

Acronym List 

AAP average annual precipitation 

AA T average annual temperature 

ADI Arctic Data Interaction 

AFFP average frost free period 

AMS accelerated mass spectrometry 

ARC Arid Regions Climate project 

A VHRR Advanced Very High Resolution Radiometer 

BAHC Biological Aspects of the Hydrologic Cycle 

BATS Biosphere-Atmosphere-Transfer Scheme 

BCNM Barro Colorado Nature Monument 

CD ROM compact disk read-only memory 

CEES Committee on Earth and Environmental Sciences 

CNN Cable News Network 

CNO California-Nevada-Oregon 

CRREL (U.S. Army) Cold Regions Research and Engineering Laboratory (in Hanover, 

N.H.) 

DCW Digital Chart of the World 

DEM digital elevation model 

DIC dissolved inorganic carbon 

DOD Department of Defense 

DOE Department of Energy 

DRI Desert Research Institute 

DSDP Deep-Sea Drilling Project 

EDC EROS Data Center 

ENSO El Nino-Southern Oscillation 

EOF empirical othogonal function 

EOS Earth Observing Satellite 

EPA Environmental Protection Agency 

ERBE Earth Radiation Budget Experiment 

ESDD (USGS) Earth Science Data Directory 

FAO (United Nations) Food and Agricultural Organization 

FCCSET Federal Coordinating Council for Science, Engineering, and Technology 

GCIP GEWEX Continental-Scale International Project 

GCM general circulation model 

GEWEX Global Energy and Water Cycle Experiment 

GFDL Geophysical Fluid Dynamics Laboratory 

GIS geographic information system 

GISP II Greenland Ice Sheet Project 

GISS Goddard Institute for Space Studies 

GLIS Global Land Information System 

GPS global positioning system 

GSC Geological Survey of Canada 

HCDN Hydro-Climatic Data Network 

HCN Historical Climate Network 

HDGEC Human Dimensions of Global Environmental Change 

ICSU International Council of Scientific Unions 

IGBP International Geosphere-Biosphere Program 
IGCA International Global Atmospheric Chemistry Program 

IGF A International Group of Funding Agencies 

IGY International Geophysical Year 

INST AAR Institute for Arctic and Alpine Research 

IPCC Intergovernmental Panel on Climate Change 

ISSS International Society of Soil Sciences 

IWG Interagency Working Group (on Data Management for Global Change) 

JGOFS Joint Global Ocean Flux Study 

LDGO Lamont-Doherty Geological Observatory, Palisades, New York 

LEF Luquillo Experimental Forest (in Puerto Rieo) 

LTER long-term ecological research 

MARS Mitigation and Adaptation Strategies 

MHD magnetohydrodynamic 

MLRA Major Land Use Resource Area 

MMTS maximum minimum temperature system 

MSS (Landsat)Multispectral Scanner 

NAS National Academy of Sciences 

NASA National Aeronautics and Space Administration 

NATSGO National Soil Geographic data base 

NAWQA National Water Quality Assessment program 

NCAR National Center for Atmospheric Research 

NCDC National Climate Data Center 

NDVI normalized difference vegetation index 

NHAT Northern Hemisphere air temperature 

NOAA National Oceanic and Atmospheric Administration 

NOS National Oceans Service 

NRC National Research Council 

NRSC National Remote Sensing Center (in Great Britain) 

NSF National Science Foundation 

NTIS National Technical Information Service 

OCt Old Crow tephra 

ODP Ocean Drilling Project 

OMB Office of Management and Budget 

OSTP Office of Science and Technology Policy 

PAGES Past Global Changes 

PC personal computer 

PCAST President's Council of Advisors of Science and Technology 

PMRW Panola Mountain Research Watershed 

PNA Pacific North America 

PNV potential natural vegetation 

PRISM Pliocene Research, Interpretation, and Synoptic Mapping 

RBV (Landsat) Return Beam Vidicon 

RES radio echo sounding 

SAR synthetic aperture radar 

SCAR Scientific Committee on Antarctic Research 

SI Smithsonian Institution 

SiB Simple Biosphere model 

SMMR Scanning Multichannel Microwave Radiometer 

SO Southern Oscillation 

Acronym List XI 
SOl Southern Oscillation Index 

SOWR sensitivity of water resources 

SCS Soil Conservation Service 

SOTER Soil and Terrain date base 

SPECMAP spectral mapping 

SSA single-spectrum time-series analysis 

SST sea-surface temperature 

ST ATSGO State Soil Geographic data base 

STRI Smithsonian Tropical Resources Institute 

TDR Time-domain reflectometry 

TOGA Tropical Ocean-Global Atmosphere 

TM (Landsat) Thematic Mapper 

UCAR University Corporation for Atmospheric Research 

UKMO United Kingdom Meterological Office 

UNESCO United Nations Educational, Scientific, and Cultural Organization 

USCGC U.S. Coast Guard Cutter 

USDA U.S. Department of Agriculture 

USGCRP U.S. Global Change Research Program 

USGS U.S. Geological Surv3ey 

USSR Union of Soviet Socialist Republics 

WCRP World Climate Research Programme 

WEBB (USGS Global Change Project of) Water, Energy, and Biogeochemical 

Budget 

WGGC Working Group on Global Change 

WOCE World Ocean Circulation Experiment 

xtl Acronym List 
Proceedings of the U.S. Geological Survey 

Global Change Research Forum, Herndon, 

Virginia, March 18-20, 1991 

Edited by John A. Kelmelis and Mitchell Snow 

First General Session 

Welcome and Introductory Remarks 

Stephen Ragone, Assistant Director for Research 

U.S. Geological Survey 

Earth sciences information and understanding are 

essential components to solving many of society's problems. Within the last decade, the U.S. Geological Survey 

(USGS) has embarked on several programs to help solve 

such problems. Let me mention a few of them to establish 

the theme for this meeting. 

A study that is representative of the kinds of programs 

the Survey has been getting into in the last 10 years is the 

investigation of contamination of the Kesterson National 

Wildlife Refuge. The USGS, along with other Department 

of the Interior bureaus, initiated a program to identify the 

nature and extent of irrigation-induced water-quality problems in the Western United States. Results of the program 

significantly contributed to the understanding of the location and factors affecting the occurrence of arsenic ~and 

selenium in the environment. 

Those of you from California might be familiar with 

the earthquake insert that was included in the San Francisco 

Bay Sunday papers in September 1990. Recently, I visited 

my son who lives in the Marina District, and I was happy to 

see how valuable USGS information was to the public. This 

is another example of how Survey investigations can 

contribute to the well-being of society. 

My research was formerly in the Toxic Waste 

Hydrology Program. The program just held its fifth technical meeting, which now draws 200 to 300 people. The 

program provides information about the fate of contamiManuscript approved for publication March 26, 1992. 

nants moving through surface and ground water. Such 

information is relevant to the mission of several Federal 

agencies--EPA, DOE, and DOD particularly-and to the 

States. This program has demonstrated how essential Earthsciences information is to solving the point-source contamination problems facing our Nation today. 

The Survey is also playing a major role in the 

President's agricultural initiative on water quality. As one 

of several Federal agencies, the Survey is studying what 

happens to agricultural chemicals after they have been 

applied to our farmlands. We're working ann-in-arm with 

USDA and EPA in the field in the Midwest, sharing our 

expertise and developing some understanding of the processes that move the chemicals. Such interagency partnership will lead to the development of farming practices for 

mitigating the effects of agriculture on water quality. 

Finally, I want to mention the National Water Quality 

Assessment (NA WQA) program, which is just getting 

underway. NA WQA represents a major example of how the 

Survey is providing information that will help decisionmakers protect and enhance the Nation's water quality. 

The U.S. Global Change Research Program provides 

the Survey an opportunity, once again, to demonstrate the 

importance of the broad disciplines that constitute the Earth 

sciences in addressing a major societal problem. The scope 

and scale of the Global Change Program make it unique. In 

this context, there is some good news and some bad news 

about the Global Change Program. The good news is that 

the Global Change Program is a highly visible, socially 

relevant, interdivisional, interbureau, interagency, interdisWelcome and Introductory Remarks 
ciplinary effort. The bad news is that the Global Change 

Program is a highly visible, socially relevant, interdivisional, interbureau, interagency, interdisciplinary effort. 

Although the program provides us an opportunity to demonstrate the relevance of the Earth sciences, its high degree 

of visibility and the broad social and political implications 

of the program may require some accommodations on our 

part. Researchers may encounter additional demands to 

show relevance or timeliness of the results of their studies. 

Researchers may be expected to demonstrate how well their 

work is coordinated with other researchers, not only within 

the Survey, but within other bureaus and agencies, and even 

internationally. These demands are not necessarily bad. It 

really is a matter of balance. 

In the final analysis, however, the responsibilities of 

the researchers in the Global Change Program are simple. 

First and foremost, they are to carry on the tradition. of 

excellent research. One of the things that the bureau and 

division technical managers have to do is ensure that the 

USGS research community remains a research community. 

The second responsibility is to keep in mind the larger 

overall technical picture in which our research is being 

conducted. Global change research is interdisciplinary 

research, and we have to ensure that the technical relevance 

of our work is conveyed outside traditional boundaries. 

Likewise, we have to be receptive to the research information becoming available to us from nontraditional sectors, 

including the political scientists and economists. Finally, 

we must remember the societal context in which the 

research is being conducted. We must strive to make the 

2 Proceedings of the U.S. Geological Survey Global Change Forum 

results of the research available as soon as possible and in a 

format that is useful to decisionmakers. 

We also have to ask ourselves how best to get our job 

done. The fact is that there are not enough resources and 

people to do everything that we feel should be done under 

the banner of global change. Thus, the divisions and the 

bureau coordinators have a major responsibility to ensure 

that the research being conducted represents a balanced, 

integrated, efficient, and comprehensive effort, within the 

constraints of funding and staff. 

This meeting will provide us with a conceptual 

framework for the research, and for the data collection and 

management activities that constitute the USGS Global 

Change Program. It will describe the major scientific and 

information issues that are being addressed, as well as the 

geographical context in which the research and datacollection activities are being conducted. As you look 

through the abstracts, you will see the seeds of some very 

exciting opportunities for research and for coordination 

between the people in this room and other researchers in the 

scientific community at large. 

The charge to us this week is to listen to the 

presentations with a view to both their scientific relevance 

and their relevance to the U.S. Global Change Program. 

Constructive criticism is welcome. Identify the value of 

your research to others with regard to the kind of information you are obtaining, the type, scale, and intensity of data 

being collected, and how it might be used in other studies. 

Use the opportunity of this meeting to work with others to 

ensure that no essential understanding or data are missing. 
The Committee on Earth and Environmental Sciences: 

Its Role in Federal Research 

Dallas Peck, Director 

U.S. Geological Survey 

This meeting is a first. It's a mixture of people from 

different disciplines and different divisions working 

together on a very important program. I have hoped all 

along that this would be a program to bring together the 

different elements of the Survey and the Department of the 

Interior in a spirit of cooperation. This is a testament that 

we're making some progress. This could be a catalyst for 

making it happen. 

It's particularly a pleasure to have the representatives 

from the other Interior bureaus. We're looking forward to 

working together with you through this program. 

I look forward to hearing about your research and 

asking questions. It's important that we get to know each 

other so that we can develop teams and work together to 

solve problems. The need for cooperation and the importance of building and maintaining partnerships are key 

elements. Understanding the context within which your 

specific research fits means understanding what the whole 

program is all about. 

I'm going to talk a little bit today about global change 

and then discuss the Committee on Earth and Environmental Sciences. I hope that's the last bureaucratic talk you'll 

hear. I'm looking forward to hearing some science for a 

couple of days-instead of budgets and bureaus. 

We are scientists. We know the world changes. It was 

a little chillier 18,000 years ago than it is now. So we know 

that the climate changes in a natural sort of way. However, 

there are indications now that the environment, and particularly the climate, may be changing as a result of man's 

influence. We've been a rider on the train for all these 

millions of years, but now we have access to the train's 

steering mechanism. 

The ozone hole over the Antarctic is a particularly 

good example of a phenomenon that seems to reflect the 

impact of man's activities. The same thing is true with the 

very famous curve indicating the increase in C02 at the 

summit of Mauna Loa. The Earth would be 30° cooler 

without the greenhouse gases, but C02 concentrations have 

increased 0.5 percent per year since 1958. 

This fact summarizes why we're here. There's an 

increase in trace gases that may cause global warming and 

may change all sorts of things. That's going to have 

tremendous impacts on you and me and society as a whole. 

Changes in the Earth's climate, both natural and manmade, 

may have profound implications for the future of our 

Nation. They can affect our economic well-being, our 

competitive position in world markets, and the health and 

safety of our people. That same statement is true of the 

world as a whole. 

Important decisions are going to be made nationally 

and internationally over the next few years. They're going 

to be poor decisions if we have a poor understanding of 

what's going on. So it's important to get that understanding. 

That helps provide a focus and a way to establish priorities. 

A word that I like to use around town these days is 

"paradigm." It's the "in" word. But the message is more 

important than the word-that science is an integral part of 

the policy process in areas like global change. 

The problem is that the global system is comprised of 

a variety of interactive parts: the atmosphere, the oceans, 

the solid Earth, and the land surface, including soils, water, 

and biota. There are so many complex interacting aspects of 

this that it's pretty hard to understand. We need a better 

understanding of these processes if we are to predict the 

consequent impacts of global change. 

The carbon cycle is a good example of the uncertainties that we face. The flux related to man's activities is 

about 6 billion tons of C02 . Now, of that, we don't know 

where 21f2 billion tons goes. It may be in the oceans. It may 

be in the midlatitude biosphere, including the soils. We 

have to learn where the carbon is and understand the cycle 

a little better. 

The Committee on Earth and Environmental Sciences, as well as the group of you here, is working to 

develop the science of global change-to make the observations, develop the understanding, and form a predictive 

understanding of global change-and then hand that information to policymakers. The Domestic Policy Council and 

the President, working through Allan Bromley, the present 

science adviser, will use our input for the policy decisions 

that will be made domestically and around the world. 

The handoff will be made through the Federal Coordinating Council for Science, Engineering, and Technology 

(FCCSET). FCCSET has been in existence since 1976, but 

it was raised to prominence by Allan Bromley. Allan 

Bromley was the first science adviser to have cabinet-level 

status; in other words he's at the same rank as the Secretary 

of the Interior. Today FCCSET meets in the Roosevelt 

Room of the White House. Most of the chairmen are 

Assistant Secretaries, Under Secretaries, or Secretaries. 

There are seven different committees, all of which 

have been very active. One of them is the Committee on 

Earth and Environmental Sciences (CEES). It was formed 

out of the old Oceans and Atmospheres Committee about 4 

The Committee on Earth and Environmental Sciences: Its Role in Federal Research 3 
years ago. Tony Calio was the first director of CEES, and, 

for the last 3lf2 years, I've been chairman. 

The work really gets done thfough a whole series of 

working groups. One of the most active and successful has 

been the Working Group on Global Change that Bob Corell 

heads. He's going to be talking to us later about that. 

Another very important one has to do with research on 

mitigation and adaptation strategies, the so-called MARS 

Subcommittee. That had been headed by John Kelmelis, but 

now it's headed by Gary Evanson of the Department of 

Agriculture. We have a number of other kind of important 

subcommittees tackling things like water resources, coastal 

oceans, and atmospheric sciences. The subcommittees 

under the committee have been very successful. We also 

interact informally with another very successful group, the 

Interagency Working Group on Data Management for 

Global Change headed by Tom Pyke of the National 

Oceanic and Atmospheric Administration (NOAA). 

Why CEES? The basic point is that we need coordination. We need to identify what the gaps and missing 

elements are. We need to relate to international science 

programs. We need to coordinate with ourselves and with 

the policymakers. I think we've been successful in doing 

that. 

One of the good things over the last year is that we 

have new active participants-the Department of Transportation and the Smithsonian. And the Department of Defense 

is a far more active participant than it has been in the past. 

We have to maintain a partnership. That's a particularly important element of the success we've had in this 

program. We're all in it together, and we're all partners. 

We have to focus on the interdisciplinary science aspects as 

well as the international aspects. We have to do the 

planning and carry out the program at the same time. We 

have to guide the process with priorities. Setting those 

priorities and developing a good, crisp goal statement has 

been an important part of reaching this goal. 

It has taken a lot of effort and a good partnership 

between the many Federal agencies to develop this program. We have moved very quickly. What might have 

taken 5 to 7 years, we carried out in about 18 months. 

Through all the Federal agencies, we work with 

scientists at universities. In the Federal laboratories we also 

4 Proceedings of the U.S. Geological Survey Global Change Forum 

work with international programs like WOCE, the World 

Ocean Circulation Experiment, and TOGA, the Tropical 

Ocean-Global Atmosphere program. 

We work with the National Academy Committee on 

Global Change to lay out the main science elements. 

Through the National Academy, we work with the International Geosphere-Biosphere Program of the International 

Council of Scientific Unions (ICSU). Along with the World 

Climate Research Program, it is the international analog of 

our domestic Global Change Research Program. 

Our good working relationship with the Office of 

Management and Budget (OMB) is enormously important. 

Dr. Jack Fellows of OMB is a hydrologist and a good 

science partner in planning these programs. He has helped 

guide us and prepare documents. He has been very effective. Working with him in identifying budget priorities, we 

have moved the program's budget from somewhat over 

$100 million in 1989 to the President's request of almost 

$1.2 billion in 1992. 

It is through the Office of Science and Technology 

Policy-through the present science adviser, Allan Bromley-that we reach into the Domestic Policy Council and 

other parts of the White House policy apparatus. 

The CEES Federal research strategy for global 

change accompanied the President's budget in January 

1989. Since then, we've prepared similar documents laying 

out the details of the program in far more detail, including 

the budget priorities. 

In our original document, we laid out the research 

program goal-that is really important. It's something to 

focus on in our discussions today. There are a lot of aspects 

of the world, all the way from the core to the atmosphere, 

that have changed over its millions and billions of years. 

This program is to gain an understanding of the complex 

interactions that predict these changes so that we can 

establish a scientific basis for national and international 

policy formulation decisions. 

Our objectives break down into three parts: documenting, observing, or monitoring; gaining understanding 

through research; and developing models-both conceptual 

models and predictive models-so we can predict what the 

implications and the impacts would be. 
U.S. Global Change Research Program 

Robert Corell, Assistant Director for Geosciences 

National Science Foundation and Chairman, 

Working Group of Global Change 

I want to share some perspectives on the U.S. Global 

Change Research Program circa 1991, where we hope to go 

and what the forces are. 

We are interested in the total Earth system. The U.S. 

Global Change Research Program is intended to cover a 

fairly broad spectrum of scientific interest. There would 

have been a propensity for us to focus on physical, 

biological, geological, and chemical sciences-the traditional parts of the natural sciences-but we've made an 

explicit reference to social processes because potential 

anthropogenic changes-changes the come from people-are what bring us to the table. We need to know more 

about the evolution of societies, about the way we invest 

our resources as a civilization, and about the way those 

investments affect our environment. 

These concerns intermesh with an international and 

national policy framework. And we, in the Earth sciences, 

for the first time, at least from my perspective, have moved 

from the quietude of our laboratories to front and center. 

We're on the agenda at the Paris Economic Summit. Our 

science can no longer be done in the isolation that it was in 

the past. Science results now are placed on the policy tables 

of heads of state. 

When Margaret Thatcher was the Prime Minister of 

Great Britain, she became interested in global change. She 

asked for, and received, briefings. Every 2 weeks she spent 

half a day sitting in Number 10 Downing Street with key 

scientists who tried to help her understand the driving 

scientific questions that make global change important to 

her nation and the other nations around the world. She 

became very, very knowledgeable about the subject. She 

would get into the questions of what's in the model and the 

roles of the various component parts and processes. That's 

a different level of interest by policymakers from what 

we've been exposed to throughout most of our professional 

lives. 

Most of us gathered here, and certainly the Committee on Earth and Environmental Sciences (CEES), tend to 

be working on the scientific underpinning of global change, 

the processes in question. This research sits in a larger 

context, particularly in the Departments of the Interior, 

Energy, or Agriculture-what I call the Earth-based mission agencies. Those agencies have strong needs for understanding the impacts of global change on the terrestrial 

environment and the political outcome of these projected 

changes. It is that interaction between scientific research 

and policy information needs that must be well coordinated 

to help the policy process solve some major problems now 

and in the future. 

If we're going to say something about how science 

fits into the policy process, we must separate out Earthsystems elements that are normal and natural-driven by 

the way the climate functions and has functioned over the 

millennia-from those elements that are induced by humans 

around the world. That will help us understand the changes 

that we can and cannot influence. 

We've tried to drive the U.S. Global Change 

Research Program from fundamental scientific issues and 

questions. Yet, we are part of the policy process. Our job is 

to somehow link science and policy, to speak the language 

of policymakers. For example, when we talk about biogeotechnical processes, most people on Capitol Hill won't 

know what we are talking about. We must put that into a 

context that lets them understand that it has something to do 

with the carbon cycle and that the carbon cycle is important. 

The U.S. Global Change Research Program is organized across government to bring together the resources of 

all of the participating agencies. We're hard pressed to find 

an agency of government that is not involved. The policy 

process is handled through the Domestic Policy Council, 

which consists of those members of the Cabinet who have 

domestic policy responsibility, augmented, in this case, by 

two science agencies that were not there before: NASA and 

NSF. At this time the research activities are conducted by 

DOC/NOAA, DOD, DOE, DOl, EPA, NASA, NSF, SI, 

and USDA. 

PCAST, the President's Council of Advisors of 

Science and Technology, came into existence roughly a 

year ago. It is made up of people appointed by the President 

from outside the government. It is patterning its organization after the IGFA process, so there are direct clones in the 

CEES. Three members of the council have been designated 

as liaisons to CEES, and they are in fact expanding their 

membership to work more closely with us. 

The U.S. Global Change Research Program has 

worked to build linkages between these groups. There are 

many examples demonstrating how this work is paying off. 

If you look at the 1991 economic report the President sent 

to Congress, you'll see, for the first time, a major section on 

the environment-written largely by the CEES community 

and our partner agencies around the government. This is an 

example of the results of the linkages among agencies that 

this program has created. These linkages are not perfect. 

U.S. Global Change Research Program 5 
They need to be expanded, but the framework is there, and 

we seem, in my judgment, to have gotten off to a decent 

start. 

I'd like to suggest that the United States has one of 

the best organized programs for global change research; it 

is, by a long shot, better organized than global change 

research programs in virtually any other country in the 

world. Our ability to use our organization, our structure, to 

get the job done for our people will be the true test. 

Our program goal has three priorities: to support the 

broad U.S. and international scientific effort; to identify 

natural and human-induced changes; and to focus on interactions and interdisciplinary science. Nothing is in the U.S. 

Global Change Research Program unless it serves at least 

one of these priorities, and we hope it serves more than one. 

The program is designed to evaluate the Earth system. To use a medical metaphor-to identify the Earth's 

vital signs. What makes it tick? We need to measure those 

key parameters and keep track of them over time. This 

should help to truly expand our knowledge of the critical 

processes, and that leads to a conceptual enhancement of 

understanding. 

I think it's tremendously important that we all 

enhance our conceptual understanding of the Earth's lifesustaining functions; then we can worry about model 

development, prediction, or assessment. Without that fundamental knowledge, the programs to predict changes are 

likely to fall short of the long-term program goal. What is 

that goal? Ultimately, to help us better assess-if you will, 

predict-the future so that sound management and policy 

decisions can be made. 

No matter what is done, human-induced variability 

must be separated from natural variability. Understanding 

must be enhanced so that there is some predictive capability. But trying to fit the U.S. Global Change Research 

Program into a framework has become controversial at 

times. 

Nevertheless, the framework has been immeasurably 

helpful to us as we have tried to work our way through the 

budget process. It does have an impact on the actual budget. 

Budget policymakers who don't come from science-decisionmakers at the White House and Capitol Hill- understand that we have brought a priority process to bear and can 

better understand that the funding increases we request are 

being generated as part of a carefully crafted priority 

structure. 

The framework is a living document. It should be 

changed. It's had a few modifications in the year and a half 

of its existence and will have more in the out-years. 

Enough background. The program and the budget for 

fiscal year 1992, the one that is before the Congress, 

represents about a $230 million increase over the 1991 

budget. That's a little less than a 25 percent increase. This 

virtually doubled the program since 1990. 

6 Proceedings of the U.S. Geological Survey Global Change Forum 

What were the guiding principles used in developing 

the budget? What is the difference between the strategy of 

1990 and the strategy of 1989? 

In 1989, the agencies that make up CEES said to the 

Administration and the Congress, "We recommend that you 

wrap this program up in about 3 years with about a 60 

percent increase each year. Thereafter, a committee of the 

agencies will manage those resources. Some programs will 

fade out and new programs will emerge as the objectives are 

amended." That was agreed to for 2 years. 

The budget summit has forced us to rethink that 

approach. Instead of 50 to 60 percent increases, what we 

can expect is much less than that. It will be significant 

growth nonetheless. 

In putting forth the 1992 budget, we were asked by 

the Office of Management and Budget (OMB) to take a 

good look at the long-range targets, timetables, and goals 

and objectives. The CEES is in the middle of developing 

these. It's a tough job to put milestones on a scientific 

research program, and yet we're spending over a billion 

dollars, and congressional and White House people want to 

know where that money is going, when the goals will be 

met, and what useful results will be produced as we proceed 

toward the goals. These are valid concerns. 

This is not simply a climate program. The word 

"climate" is used frequently, because that's the topic that 

has the political clout at the moment. It's the topic people 

understand. Words like "greenhouse gases" are constantly 

in the newspaper. But we're concerned about more than just 

climate. We need to know how this planet ticks, what 

makes it function, what the controlling processes are. We 

are trying to ensure that over the long term we have the 

capacity to track how the earth functions. Because of the 

visibility of the climate aspects, we chose to highlight some 

of those things that will move us forward on the climate 

question a little more rapidly and slow down the growth of 

some of those other parts of the program. That is a fact; 

however, there is no less of a commitment to the other 

elements of the program over the long term. They will 

probably grow a little more slowly. 

How did we decide that? We decided to introduce 

some new ideas. As most of you know, in the early work of 

the committee, we had to think about integration. We had to 

bring together the component parts, disciplines, and resources of people and ideas to eventually get an integrated view 

of the system. We ended up using the idea of the integrating 

theme, which moves us to truly integrating all of the 

component parts. 

We chose to do three or four themes. These are the 

areas in which there was substantial budget growth. We 

lead with climate modeling and prediction as precursors to 

integrated persistent modeling. Modeling, prediction, and 

assessment provide an integrated force for working across 

the disciplines. This not only allows us to deal with what 

you might call a classical view of climate modeling from the 
physical perspective but also forces us to worry about the 

ethnogenic element-the biological and social sciences 

aspect. 

It also forces us to ask questions about the past, about 

paleoclimate, and about fundamental Earth systems processes. That's our strategy. We think it will help us move 

toward our goals and will ensure a sound program in the 

long run. 

There are also three additional focal points: global 

water and energy; global carbon; and ecological systems 

and population dynamics. Let me say a word or two about 

each of them. 

• Climate modeling and prediction. The goal of this 

element is to develop improved predictive capability of 

the Earth as a global system and to enhance our capacity 

to predict global climate at regional levels. 

This is a very challenging objective. It is going to 

take years to meet it. But we think that setting that as a 

target, as a precursor to integrative Earth system modeling, is a desirable feature. It means getting at things like 

the climate process and all of its component parts. It also 

has implications for ocean science and the atmospheric 

research community. 

We see ourselves improving integrated predictive 

capability versus merely building the models. That has 

three implications: to make predictions, to support the 

assessment process on the science as well as the policy, 

and to provide input to improve our modeling capability. 

There are a number of key component parts that 

we're working on: to ensure that data sets fit into and 

feed the modeling process; to enhance process understanding so that the component parts are a more realistic 

picture of what's really taking place in the Earth's 

environment; and to increase computational capability 

not only in new machines but, more important, with 

algorithms to do the complex analysis more effectively 

and efficiently. 

It is estimated by the modeling community, not by 

CEES alone, that we need roughly three orders of 

magnitude of increased computer capacity. We will have 

that at our disposal within the next 5 to 8 years. That 

makes it possible to start conducting modeling at regional 

resolutions. 

• Global water and energy. In my view, this is the first 

really truly integrated piece of scientific research that we 

are conducting across disciplinary, system, and scale 

boundaries. Its first expression, certainly not its only 

expression, is the Global Energy and Water Cycle 

Experiment (GEWEX) program. 

GEWEX is a world climate research program initiative. GEWEX was born conceptually a number of 

years ago but is now ramping up very rapidly. Its first 

major pilot staging program is for the continental United 

States. 

The international community decided that the continental United States provided a unique opportunitywe have a massive data set. It brings in the hydrologic 

cycle at the highest level of our conceptual notion of that 

idea. The international office for GEWEX is here in 

Washington. It is chaired by a U.S. scientist. So the 

United States has shown substantial leadership in developing this effort. 

• Carbon Cycle. The carbon cycle is not just C02 ; it 

consists of all the carbon elements in the system. This has 

very strong biological implications. Many of the processes that move carbon around and sequester it have both 

terrestrial and oceanic biological implications. 

Our level of knowledge about the carbon cycle is 

remarkably poor. For at the moment, we can't account 

for 25 percent of the carbon sequestration process. 

Conventional wisdom is still that it's not in the ocean but 

somewhere in the terrestrial biosphere. Hardly a month 

goes by that Nature or Science or another major semipopular journal doesn't address it. The science requirements here are really broad. 

The Earth sciences research community in general 

and USGS in particular have contributed significantly 

over time to paleostudies. These studies have helped set 

the groundwork for understanding the carbon cycle. We 

now need to expand that to understanding the large 

carbon cycling process in the terrestrial environment. 

This will be a valuable contribution. 

• Ecological system population dynamics. The Department 

of the Interior has important resources and you here in 

USGS have unique abilities that allow the ecological 

system and population dynamics part of the program to 

expand because of your interest in the terrestrial system. 

I would be irresponsible if I didn't say something 

about some of the other parts of the program. Those 

integrating areas that have substantial impact on the solid 

Earth processes, paleoclimate, and other Earth systems 

history issues are particularly important. I want to point out 

that we have asked the Academy to set up special panels to 

review these and other areas. We expect those reports out 

this year. They might substantially alter the out-year projections for our investment in research. 

For the next 4 years, the overarching goal is establishing the program that will build an integrated system 

model with regional resolution. We think that that's going 

to come into being say by 2010. A companion to that 

modeling effort is a global observing system. The Earth 

Observing System (EOS) is not a global observing system. 

It is a research tool that allows us to get to the global 

observance. In the Earth sciences there are many observing 

systems. They have taken decades to put into place. Once 

stream gauges, for example, are in place, they're a vital part 

of evaluating how your science is doing and how your 

policy is functioning and can become part of a global 

observing system. 

U.S. Global Change Research Program 7 
Those are the far, far distant goals and objectives. To 

reach them, we're going to be working in the early part of 

the program, first by building a sound scientific and 

programmatic footing in the early part of the 

1990's-focusing on climate, moving toward predicting 

climate, and then integrating our Earth system modeling at 

increasingly finer resolutions until regional scale predictions can be made with a good understanding of their 

reliability. 

In passing, I need to mention something about computer resources. As many of you know, there is a companion FCCST program in the advanced scientific community 

known as the High Performance Computing and Communications Program. The two are working side by side. CEES 

is worried about program-specific aspects of computing, 

and the high-performance computing initiative is concerned 

about the generic issue of computing resources. So that 

program, for example, is driving very hard toward massively parallel computer architectured software and the 

supporting hardware. 

The people who are really working on that problem 

think they will have a crossover on vector-based computing-massively paralleled computing-in 2 years. That's 

significantly earlier than was originally anticipated. For us, 

that's exciting because when you start to think about 

massively paralleled computation, you start to think about 

two to three orders of magnitude more power. And that 

translates into resolution of the kind we need to meet our 

goal of predictions at the regional scale. 

There are many problems that we're going to run on 

workstations or other computing resources as they exist 

today. This we'll continue. We're not done with vectorized, 

parallel, and Cray-like machines. But for certain problems 

there will be major improvements. 

I also want to say a word about international cooperation. This is a complex picture, but it has a very simple 

message. Many of the component parts of the U.S. Global 

Change Research Program have global implications and 

therefore involve as many nations of the world as are 

willing to participate. In thinking about that, we've come up 

with a strategy for developing the ideas, the commitment, 

the resources, and the methods of implementation. 

By and large, the CEES is relying on the scientific 

community to do the fundamental science. That involves 

scientists in government agencies and elsewhere but not 

through the CEES per se. So we rely heavily on the U.S. 

National Academy of Sciences (NAS). We rely heavily on 

the workshop processes that produce science plans and 

scientific implementation programs. But largely they're 

8 Proceedings of the U.S. Geological Survey Global Change Forum 

known through the International Council of Scientific 

Unions (ICSU) or its national equivalent, such as the NAS. 

With respect to facilitating and implementing these 

programs internationally, we rely to a large measure on the 

intergovernmental bodies of the United Nations, such as the 

World Meteorological Organization or UNESCO, because 

they have the membership and the access to the international research community. And to do many of these 

terrestrial research programs, access to field programs 

requires participation from the international sphere. 

Last summer we formed an international equivalent to 

CEES. It's called IGFA, the International Group of Funding 

Agencies for Global Change Research. It brings together 

the CEES-like bodies from around the world to coordinate 

to the best of our ability the timing of assets that are put on 

the problem so that we don't decide to put all our money in 

the United States on one set of programs while other 

countries make other decisions. 

I want also to say a word or two about something that 

is very close to home but has broad international implications. At the White House conference last spring, the 

President invited other nations to join the United States in 

establishing regional research institutes that address 

regional and global research efforts. Since that time, there 

have been task forces appointed under the CEES. There's a 

special group now called the Working Group on International Programs and Development that has the responsibility 

to work with the Office of Science and Technology Policy 

(OSTP) and other bodies of the government to establish an 

institute for the Western Hemisphere. The first major 

expression of that will be a science-level planning meeting 

in Puerto Rico in mid-July. And within the 1992 budget, 

there are resources to kick this off in the Western Hemisphere. 

If you would like to track the philosophy that is 

inherent in the U.S. approach to global change research, I 

urge you to read Report Number 15 of the International 

Geosphere-Biosphere Program [Global Change System for 

Analysis, Research and Training (START)] . It lays out the 

conceptual framework for these regional research institutes. 

In summary, the U.S. Global Change Research Program presents the scientific community with some very 

substantial challenges: to reduce uncertainties about our 

understanding of how the planet ticks, to make predictions 

about what future environments are likely to be, and to 

reduce the uncertainty of our predictions-to give us the 

capacity to feed into the policy process. The long-term goal 

of CEES is to know about the Earth and what makes it 

function. Out of that knowledge, the other matters will fall 

into place. 
U.S. Department of the Interior/U.S. Geological Survey 

Global Change Research Program 

John Kelmelis, Coordinator, 

USGS Global Change Research Program 

U.S. Geological Survey 

Thank you all for coming to the first USGS Global 

Change Research Forum. The term "forum" was chosen 

carefully. A forum is an open exchange of ideas, and it is 

ideas that make research happen; of course, funding money 

helps too. The forum is somewhat more structured than 

we'd like it to be. But structure is necessary so that as many 

research topics as possible can be presented in the short time 

we have available. 

I hope that all of you here will take the opportunity to 

talk with other scientists and to make contacts across 

divisions and across disciplines to help with your research. 

Listen to the discussions on topics that are not your usual 

areas of interest; surprising new and innovative research 

efforts may result. 

You might ask why the Department of the Interior is 

involved in a scientific research program that is often 

characterized as climate change research. And the answer is 

simple; it is stewardship. 

The Department of the Interior is the steward of 500 

million acres of managed and unmanaged lands and of 

natural resources in the United States that span the physical, 

biological, and social spheres, without which large segments of the population would suffer incredibly and without 

which large segments of the economy would crumble. It is 

imperative that we know how global change affects the 

management of that land and those resources and how those 

lands and resources will affect global change. 

The U.S. Global Change Research Program is far 

more than climate change. While the climate change question is one of the major issues, other issues are critical as 

well-all are linked to the climate system, but all have 

causes and effects outside of the climate system. All are 

critical to policymaking, whether the climate is actually 

changing or whether it's merely varying. 

These issues include, among many others, sea level 

rise; coastal changes; biodiversity and population dynamics; 

desertification; water availability, both quantitative and 

qualitative; and land use changes and their social and 

economic impacts. These are all areas in which the USGS 

and the rest of the Department of the Interior have scientific 

and management interest. 

Since its beginning in 1879, the U.S. Geological 

Survey has conducted global change research. Of course, it 

was not called global change research at the time; that is 

new terminology. The USGS has had a long tradition of 

studying the Earth's past. 

Studying the Earth's past is critical for mineral 

exploration, and one of the earliest charges of the Geological Survey was to inventory the mineral resources of the 

land. 

Characterizing the present has been a basic staple of 

the USGS research since its inception. A monumental effort 

lasting more than a century has provided environmentalist 

and engineer alike with maps of the land's surface so that 

efficient and sound use could be made of our limited 

resources. We are only now beginning to realize how 

limited and fragile some of those resources are. 

The processes that have changed the past to the 

present have also been studied since the Geological Survey's beginning. It is the basis of science to understand 

processes. It is only by understanding the many Earth 

processes that we can ever expect to make wise choices on 

the use of the resources or wise decisions on the hazardousness of a place. 

All of this research has produced immense amounts 

of data. The USGS has learned how to manage that data for 

the benefit of all. The USGS is still learning and will learn 

more as research and operational activities produce new 

data, new types of data, and new demands for data. 

Responding to this challenge will expand our technology, 

our management capabilities, and even our philosophy of 

data management. 

Thus, the USGS is unique in its expertise and desire 

to examine the past, characterize the present, and develop 

an understanding of the processes that have changed the 

past to the present-and that will change the present to the 

future. 

The USGS, with our sister bureaus at the Department 

of the Interior, brings a unique perspective to the U.S. 

Global Change Research Program. It is the perspective of 

those who must manage the resources of our lands. We 

work at the scale of laboratory experiment, at scales at 

which managers must make decisions, and at global scales. 

These are not just spatial scales; they're temporal scales as 

well. Because of this, we have already achieved results that 

are useful to resource managers and to other scientists in the 

U.S. Global Change Research Program. 

It is now our job to deliver results, not just make 

plans. And so a sample of our 1991 results includes the 

publication of the final report of the 3-year Delaware River 

Basin Sensitivity Study. This report will contain information on climate and weather scenario development; on 

U.S. Department of the Interior/U.S. Geological Survey Global Change Research Program 9 
hydrologic and water resources response to climate, both 

contemporary and potential future; on response to the 

Delaware estuary, both physical and chemical, to climate 

change; and potential changes in drought in the basin. 

Also, a pilot study to estimate the sea surface temperatures in the North Atlantic Ocean for the Pliocene, the 

last time the Earth's climate was significantly warmer than 

at present, will be completed. The pilot study will demonstrate the capacity to reconstruct environmental conditions 

on a scale suitable for testing general circulation model 

simulations of warmer climates. 

Digital files of global vegetation cover and global 

soils maps have been produced. Vegetation greenness and 

classification maps at national and continental scales will be 

developed. Initial efforts will concentrate on the United 

States and North America. This will help identify spacial 

and temporal boundaries of evapotranspiration and other 

biologic processes. 

A prototype of the Global Land Information System 

will become operational. This system will provide a method 

to access metadata (information about information) for 

scientists seeking sources of information about the Earth's 

land surfaces. This will help scientists studying global 

changes and other topics to locate the existing terrestrial 

data they need to conduct their research. 

During the next couple of days we will hear in much 

greater detail about these and many other accomplishments 

of the USGS Global Change Research Program and the 

progress in new and ongoing research efforts. These accomplishments are important. This is a program driven by 

stewardship, management, and policy needs, and many of 

those needs cannot wait until the ultimate question of 

whether, or by how much, climate is changing is answered. 

The Committee on Earth and Environmental Sciences 

(CEES) Working Group on Global Change (WGGC) is 

developing a milestone chart at the moment. It shows a 

global climate model capable of reliable predictions as the 

ultimate goal. Producing such a model of the climate will 

probably take 30 to 40 years. To achieve that goal, many 

intermediate milestones must be met. Complicating the 

achievement of those milestones is the iterative nature of 

scientific advancement, with understanding in one field 

nourishing advances in the other. 

Fitting into the effort are hundreds of small contributing programs that contribute pieces to the puzzle. No one 

agency, even focusing all of its efforts, can hope to 

accomplish this on its own; however, all of the agencies 

together contribute parts, which makes the entire project 

realizable. 

If we were to carry the chart showing the milestones 

of the U.S. Global Change Research Program to the project 

level, the chart would be totally unintelligible. There would 

be tens of thousands of projects across many agencies over 

the life of the U.S. Global Change Research Program. 

10 Proceedings of the U.S. Geological Survey Global Change Forum 

Obviously, the chart will have to be updated frequently as 

new, and sometimes unexpected, results and interpretations 

occur. 

We, the U.S. Geological Survey, are part of the 

overall national and international global change research 

effort, a valuable part without which I believe the effort 

would falter, if not fail. Our programs cut across six of the 

seven science elements outlined in the research plan of the 

U.S. Global Change Research Program. Of course, these 

programs focus on our areas of greatest expertise, making 

critical contributions to the interdisciplinary science elements of climate and hydrologic systems, biogeochemical 

dynamics, Earth systems history, and solid Earth processes. 

We're also active in the study of ecological systems and 

dynamics and in human interactions. 

The U.S. Global Change Research Program has 

evolved from the former climate program established in 

1979, 10 years before the U.S. Global Change Research 

Program started, to 11 elements funded at $28.2 million in 

fiscal year 1991. And in fiscal year 1992, the President's 

budget requests $32.5 million. The number of elements of 

the program will certainly fluctuate over the years as our 

understanding of portions of the Earth system increases and 

objectives of the U.S. Global Change Research Program are 

met. Fluctuations will also take place as the realities of the 

nation's budget affect programs all across government. 

The programs currently funded span the interests of 

global change. Some are global in nature, such as interactions of climate and hydrologic systems, biogeochemical 

exchanges, paleoclimates, and land characterization. Others 

examine sensitive regions. These are sensitivity of water 

resources, coastal erosion and wetlands processes, volcano 

emissions, climates of arid and semiarid regions, and cold 

region studies. The land data and extramural grants programs provide broad support to the other work. I won't 

describe the details of these programs. You'll learn more of 

them throughout the meeting over the next few days. 

When the programs of the other bureaus of the 

Department of the Interior are included, a broad-based 

study of the terrestrial system becomes apparent. It is 

imperative that any global change research effort we propose to do not only meet the needs of the U.S. Global 

Change Research Program but also provide useful input to 

the stewardship mission of the Department of the Interior, 

and we have to ensure that any proposals we make identify 

that input. 

That our research will be applied to important problems of the day is in keeping with many years of performing 

basic research and data acquisition in support of policy 

decisions. I expect that results from our program will be 

useful long before the question about global change is 

ultimately answered. 

I was told that I had to say something about the 

process by which decisions are made within the USGS on 

global change research, so bear with me. There's a round-
table group. In fact, we meet around a round table in the 

Information Systems Division conference room every 

week. That group discusses all of the issues of the USGS 

Global Change Research Program. 

That group is called the "Gang of 12." All of the 

divisions are represented, as are the Assistant Director's 

office for programs and the Assistant Director's office for 

research. 

The Gang of 12 discusses each program element that 

is proposed and attempts to agree on a total package that can 

be supported by the divisions while meeting the overall 

goals of the U.S. Global Change Research Program, the 

Department of the Interior, and the USGS. We have an 

external panel of experts, most of whom are here at this 

forum. They help us with the review process. Also, we 

must attempt to assess the viability of the program in the 

Office of Management and Budget (OMB) and Congress. 

In addition, the Committee on Earth and Environmental Sciences has developed the unique ability to generate phenomenal amounts of paperwork for the member 

agencies. And that's not really a negative statement. The 

work is necessary to build and run a complex program like 

the U.S. Global Change Research Program. 

Much of the work is short turnaround- on the order 

of days, or even hours, and it's needed to keep the wheels 

of both the executive and legislative branches greased and 

responsive to the requirements as varied as the continued 

availability of Landsat data and the expansion of the 

terrestrial-based research in a program that is often conceived of as simply climate change by many outside of the 

research community. 

The Gang of 12 helps provide the necessary responses 

and is constantly dealing with these short turnaround 

efforts. Exhausting as it is, it helps keep our fingers on the 

pulse of the program. 

The program, as agreed upon by the Gang of 12, is 

presented to the division chiefs for their approval. And, of 

course, negotiations have to take place there. Then it's 

presented to the Director, who must weigh it against the 

other priorities within the bureau and within the Department. 

Within the Department, there are two working 

groups: the Global Change Research Working Group, of 

which Steve Ragone is the Executive Director and to which 

I am the USGS representative, and the Policy Working 

Group, which is at the Assistant Secretary's level. 

The Research Working Group acts for the Department much like the Gang of 12 acts for the USGS. It is 

through the Department's Global Change Research Working Group that programs are presented to the CEES. 

Through a system of agency reviews, working group 

reviews, and specialist task group reviews, a balanced 

program is arrived at by the CEES. This includes suggesting 

increases in the types of research that are inadequately 

supported to meet the goals of the program and suggesting 

decreases in oversupported programs. Once the recommended balanced program is planned, it is proposed to the 

OMB. 

There is another track as well, and that is through the 

normal budgetary process. There the research programs are 

presented to be included in the Department's budget 

request. Thus, there are two independent tracks. Both tracks 

lead to OMB; both tracks must be satisfied for the program 

to make it to the President's budget request to Congress, 

and then Congress must be satisfied. Members of the Gang 

of 12 often get involved at various levels of this process as 

well. 

That's enough about process. It's science that we 

came here to talk about. 

We will strive to maintain our tradition of objective 

scientific research while we step beyond our traditional 

disciplinary boundaries and make interdisciplinary, interdivisional, interagency, and international links to significantly expand our understanding of a changing world. 

Please participate, interact, exchange" ideas, make new links 

among each other, and help make this forum and the U.S. 

Global Change Research Program one of the most dynamic 

scientific efforts that the USGS has ever engaged in. 

U.S. Department of the Interior/U.S. Geological Survey Global Change Research Program 11 
Interagency Working Group on Data Management for Global Change 

Eliot Christian 

Information Systems Division 

U.S. Geological Survey 

The Interagency Working Group on Data Management for Global Change, usually known as simply the IWG, 

focuses on data needed for global change research, and its 

activities are as relevant to global change researchers as to 

data managers. Although its role is one of coordination, not 

implementation, the IWG does have a record of making 

things happen. 

Through the IWG, the Federal research agencies help 

set the tone for global change science. As you know, global 

change research is not driven solely by the traditional 

agenda of the natural science agencies, and the Survey 

viewpoint needs to be actively expressed. The Survey does 

have a strong voice in the IWG, in part because the 

Survey's Land Data Management Program is second in size 

only to NASA's program. 

In addition to influencing global change research on a 

broad scale, what the IWG does can affect your project on 

the operational level. For example, the IWG may influence 

how your proposal is evaluated, how easy it is for you to 

find other global change data and information, and what 

you might pay for data. If you let your needs and preferences be heard through the IWG, your research could 

benefit directly. 

The U.S. Government efforts in global change 

research are focused through the Committee on Earth and 

Environmental Sciences, the CEES, chaired by Dallas 

Peck. A continuing theme of the U.S. Global Change 

Research Program is that data management is an integrating 

priority. That means it's crucial to the success of all of the 

other program elements. 

The current IWG grew out of informal coordination 

in 1987 among Ray Watts of the USGS, Dixon Butler of 

NASA, and Francis Breatherton, then at the National 

Center for Atmospheric Research. Launched as an ad hoc 

group under the CEES, the IWG works closely and shares 

membership with the CEES Working Group on Global 

Change, especially its "Earth Systems Measurement and 

Data Management" task group and its "International Coordination and Development" task group. 

To support its coordination role, the IWG today has a 

modest budget made out of contributions by the participating agencies-NOAA, NASA, EPA, NSF, Navy, and the 

Departments of Energy, Agriculture, State, and the Interior. 

With active interagency participation, the IWG has been 

effective in raising policy recommendations to the CEES 

and in tackling practical data management problems. 

12 Proceedings of the U.S. Geological Survey Global Change Forum 

Now, you might be wondering why data management 

becomes such an issue in the global change context. Sure, 

the U.S. Global Change Research Program is big, but the 

technologies available for data management are still 

advancing explosively. Why don't we just scale up our 

current data management practices to handle global change 

data and information? 

We all know that global change research will generate 

data in unprecedented volume and that researchers will need 

that data organized in many different ways. Although the 

sheer size of the data management problem presents a 

massive technical challenge, there are more basic reasons 

why global change data management requires a new 

approach. 

The need for comparable data in very long time series 

requires that data be archived and documented well enough 

to be useful long after the original research, 20 years later at 

least. Also, global change research, as a program, is driven 

by public policy issues rather than purely scientific curiosity. This need for policy relevance implies a strong emphasis on interdisciplinary perspectives and on interagency 

projects. 

The Survey's mission has always involved historical, 

interdisciplinary, and interagency data issues. Each of our 

mission programs has long established data management 

practices and its own coordination with other programs. 

However, global change research spans many programs, so 

the inconsistencies that exist become very troublesome. 

One striking example is the lack of an interagency agreement on how to document data to be useful over time and 

across science disciplines. 

The IWG is now coordinating agency plans to resolve 

some of these major inconsistencies, including a framework 

for a global change data and information system. The 

concept of this system is evolving away from that of being 

a new supersystem that would bring together everything 

you'd want to know about global change-the major thrust 

is now to emphasize the prerogatives of the separate 

researchers and a very decentralized flow of information. 

The original charge given to the IWG is very simple: 

to make it as easy as possible for the scientific community 

to access and use data needed to study global change. It 

should be clear here that the IWG is focused on the needs of 

the scientific community, not on helping data managers find 

new ways to do data management. 

The National Science Foundation (NSF) continues to 

be a very active member of the IWG, and the Committee on 
Geophysical Data of the National Academy of Sciences is a 

continuing source of scientific guidance. In fact, the IWG 

commissioned the Committee on Geophysical Data to 

document a U.S. strategy for global change data and 

information management. The strategy document is still 

awaiting official publication, but draft copies were widely 

reviewed and are in active use now. 

The IWG also sponsored the University Corporation 

for Atmospheric Research, UCAR, to hold a 3-day forum 

on data management for global change. At that forum, the 

IWG met with 65 representatives of the scientific community to explore their perspectives on data management 

problems and possible approaches. Another forum is 

planned for later this year. 

In addition to periodic meetings and forums, the IWG 

coordinates several ongoing activities and has supported 

pilot projects by member agencies. One ongoing activity is 

the development and operation of a global change master 

directory. This joint venture maintains a catalog of global 

change data sets across agencies and data centers. 

There is also an ongoing IWG activity handling 

international exchange issues and another activity that looks 

at various agency mechanisms that are in use for ordering 

and billing for data products. 

The IWG recently started a new activity to address 

data and information management standards issues, which 

includes informal and emerging standards. As chairman for 

that standards activity, I tried to draft a charter to encourage 

any level of input or participation from researchers and data 

managers. I look forward to working with many of you in 

this IWG standards activity. 

The IWG sponsored the International GeosphereBiosphere Program's Global Change Diskette Project, 

which focused on the need for cost-effective tools and data 

for developing countries. The project's PC-based geographic information system used Africa data sets such as 

vegetation cover. It's now being widely used for training in 

global change study techniques. 

Another pilot project is the Survey's recently completed "Arctic Data Interactive." ADI serves as a prototype 

for an electronic science journal incorporating hypermedia 

techniques. 

The IWG is always looking for additional pathfinder 

projects or other ideas. The general guidelines for proposals 

are that the project be short term, 1 to 2 years, and that it 

address data management problems of wide interest to 

agencies in the global change research community. To be 

appropriate to the IWG, the proposal ought to be outside of 

the normal responsibilities of any one agency so that IWG 

sponsorship is directed toward projects for which there is no 

other usual source. Please call me directly or go through 

your division channels if you would like to raise an idea to 

the IWG. 

In the policy area, the IWG developed a set of seven 

principles of data management to be applied to the overall 

U.S. Global Change Research Program and to be used as 

criteria to evaluate project funding proposals. These principles were approved by the CEES and are receiving wide 

exposure internationally, throughout the Federal Government, and within agencies. The Global Energy and Water 

Cycle Experiment, GEWEX, has incorporated these principles as part of its science plan. And through division 

representatives, the Survey is seeking to apply these principles to all of its programs, not only global change 

research. 

The two most relevant principles to researchers here 

are probably the principle of designating an archive for the 

data and the principle that data be made available as soon as 

they are widely useful. Now, setting a short time for 

exclusive use of data is probably a sensitive point. I would 

point out that for the Earth Observing System (EOS), the 

plan is that data will be available to all researchers at the 

same time as they are made available to the principal 

investigator. 

Ultimately, these data management principles must 

be applied in actual projects. As you may know, an explicit 

data management plan is already required in applications for 

NSF grants. When global change project proposals are 

reviewed by the CEES, they are now evaluated in part on 

how the projects propose to address these principles. 

In practice, the specific mechanisms you might use to 

manage project data can range from fairly simple to very 

complex. At the project description level though, expressing your data management plan ought to be very straightforward. So I'd like to take a look at what that would consist 

of. 

Within a global change research project description, 

the data management plan should address these four points: 

1. Identify- what data or information will be gathered or 

derived; 

2. Document-how and where the data will be documented; 

3. Archive-which established archive will house the data; 

and 

4. Distribute-when and how the data will be made accessible. 

The data management plan in a one-page project 

description might be stated in two or three sentences. For 

example, a complete data management plan might be 

written like this: "The primary data product is a derived data 

set produced by a computer model of global change. The 

data will be accessible at the USGS in Menlo Park when the 

model is published. It will be documented in the Earth 

Science Data Directory." 

Another example might be: "This project will generate Arctic groundwater observations, which will become 

part of the USGS National Water Information System data 

base. Once the report has been published, the data will be 

identified in NA WDEX and referenced in the Global 

Change Data and Information System." 

Interagency Working Group on Data Management for Global Change 13 
This second example also illustrates that project data 

management will often need to mesh with broader mission 

programs such as those that are managed at the division 

level. Please call me at any time if you'd like to talk about 

a project plan and how you can identify, document, archive, 

or distribute your project data. 

Before I finish, I'd like to give you a feel for how you 

might envision the Global Change Data and Information 

System as a tool for your global change research. 

Let's say you have an idea for a new global change 

research project. As you develop your project description, 

the Global Change Data and Information System shows you 

related projects already completed, in progress, or proposed. This information allows you to see opportunities for 

collaboration and to avoid unnecessary overlap with other 

projects. 

The system also allows you to see the current research 

priorities as expressed in the overall U.S. Global Change 

Research Program plan, so you can tailor your project 

description to highlight its relevance. In writing your 

project description, you include a data management plan 

that tells how you will identify, document, archive, and 

distribute the project data. In this case, your new project 

data may not be part of an existing mission program, so you 

14 Proceedings of the U.S. Geological Survey Global Change Forum 

check with your Division's data management office to 

determine which established archive will house the data. 

The Global Change Data and Information System describes 

the procedures for requesting services from that data center 

and helps generate an electronic message requesting data 

archive services. The data center then responds with the 

electronic input form you will use to identify and document 

your data set. 

The Global Change Data and Information System 

directory helps you to find or even browse through related 

data sets that may be useful in your project. Of course, once 

your own project is funded and completed, the system 

provides the mechanism for you to describe your project 

data so that they can be used by other researchers across 

agency and scientific discipline boundaries. 

In summary, the Survey is working through the IWG 

to improve access to USGS data and information by outside 

global change researchers and access to outside sources by 

USGS global change researchers. 

I hope you've seen that there are things afoot in the 

IWG that you may want to explore further or to influence. 

To the extent that you let me know what works for you, we 

can help the IWG shape the future for global change data 

management. 
A Fragile Seam of Dark Blue Light 

jack Eddy, Director 

Office for Interdisciplinary Earth Studies 

University Corporation for Atmospheric Research 

Some years ago, I met with a number of astronauts 

who were preparing to man the Spacelab module, which 

was to be carried on one of the space shuttle flights. In the 

group was a young German scientist named Ulf Merbold. 

Later, after their successful mission, he had this to 

say about what he saw when he first looked down on the 

Earth from the vantage point of space: "For the first time in 

my life, I saw the horizon as a curved line that was 

accentuated by a thin seam of dark blue light, our atmosphere. Obviously, this was not the ocean of air I had been 

told it was so many times. I was terrified by its fragile 

appearance." 

Science, in recent years, has focused more and more 

on the Earth as a planet, one that for all we know is 

unique-where a thin blanket of air, a thinner film of water, 

and the thinnest veneer of soil combine to support a web of 

life of wondrous diversity in continuous change. What is 

more, living and nonliving parts of the system are by nature 

entwined and interconnected. 

"When one pulls up any part of it," wrote the 

naturalist John Muir, "he finds its roots entangled with all 

the rest." I think the mystic poet Francis Thompson may 

have said it better in 1893, when he wrote, "All things by 

immortal power, near or far, hiddenly, to each other linked 

are; that thou canst not stir a flower without troubling of a 

star." 

I don't think anyone doubts these connections-least 

of all, any of you here. We're here for a global change 

research forum, a scientific enterprise that's driven by 

environmental concerns serious enough to have inspired the 

kind of scientific crusade that, as Bob Corell showed us, is 

going to extend halfway through the next century, and it's 

focused on impending global changes. 

Yet the world is everchanging and always has. How 

do the modem changes rank in perspective? Ask yourself 

this question: What are the most drastic global changes that 

the Earth has known in its long history? 

My own list, in the long run, would include probably 

first the acquisition of an atmosphere and the oceans; the 

birth and the spread of life; the repeated annihilations of life 

that seem to go on with the destruction of species, as at the 

boundary of the Cretaceous and the Tertiary 65 million 

years ago; and surely the drifting and gnashing of the 

continents that give us our present geography and all the 

action in geology today. 

If asked to describe the most drastic global changes of 

the last 1 or 2 million years, I think I would put only two on 

that list: the recurrent ice ages that signaled a drastic change 

in the tempo of Pleistocene climate, and the rise of man, 

whose whole history has been played out in the shadow of 

the last of these. And from all of these, life has recovered, 

apparently through interactive processes that make it resilient to environmental change. 

What about the last 100 years? What is the most 

drastic global change of this period? Although the Earth has 

warmed by 0. 6°C, that global warming cannot qualify as a 

drastic change, nor can wars. It is surely, instead, the 

complete ascendancy of man on the planet, now numbering 

about 5 billion, or about 34 per square kilometer of the land 

surface of the Earth. 

We get an erroneous impression of the crowding of 

the planet in our own country, a very large one, where the 

population of about 25 per square kilometer is significantly 

less than the world average. In China, where a quarter of the 

Earth's people live, the density of people is now 108 per 

square kilometer. In the United Kingdon and India, in the 

latter of which one-seventh of the Earth's population lives, 

there are over 200 people per square kilometer; in Japan and 

the Netherlands, there are over 300; in Taiwan, there are 

513; and in Hong Kong, there are 5,000. 

I think the marks of this many people are now on the 

planet: marks that were at first subtle and for millennia 

insignificant in any global view. But that is no longer the 

case and never will be. 

We see them most easily at night, as in the montage 

of modem dark Earth views from space put together about 

10 years ago by Woody Sullivan and already out of date. 

Only the curved arc of the aurora borealis that is seen there, 

caught by chance above Norway, is natural, a reminder of 

how the world was but a century ago. 

The world at night is now so bright that cities on the 

northeast coast are indistinguishable in the glowing blur of 

a megapolitan BosWash. Puerto Rico is an island of light, 

as is the whole south of India and Southeast Asia, where so 

many now live and will live. 

More than 1 percent of the Earth's surface is urban. 

More than 10 percent of the land surface is now under 

cultivation. More than 30 percent is today under active 

management for the purposes of mankind. 

I think more pervasive and much more troubling in 

1991 are the changes we have wrought in but the last 

seconds of geologic time in the essential chemistry of the 

planet. I don't think I need to tell any of you about it, about 

how permanent it is and about how when you drove here 

A Fragile Seam of Dark Blue Light 15 
today, as I did, you put carbon dioxide into the atmosphere 

that will be here long after any of us in this room are on the 

planet. 

Inadvertently, we have initiated, indeed, a global 

experiment whose ultimate outcome is at present unknown. 

And in so doing, we may have driven Ulf Merbold' s fragile 

seam of dark blue light-in which is all of life-beyond its 

range of natural repair. Perhaps we have done this at a time 

when we must prepare the planet for a doubling of the 

present world population, most of it in the less developed 

world. The Earth is changing at a rate faster than it has ever 

known and at a time when a change in any part of it affects 

all the rest. 

There's nothing new or particularly sinister about 

global change; it happens all the time. The Earth is a 

dynamic planet, as you all know and have seen. It is only in 

our minds that time or conditions are ever frozen and only 

our short lifetimes that make anything seem fixed. On 

repeated occasions, since man has walked upright, the 

planet has been held in the icy grip of major ice ages, as in 

the time of Cro-Magnon man, when all of Canada, on 

another continent, lay under 2 miles of ice for more than 

20,000 years. 

"The whole history of humankind," wrote the historian Norman Pounds, "has been lived in the shadow of an 

ice age." And in a world of global change. 

When Columbus was a boy, the Earth fell again into 

a period of prolonged cold, called the Little Ice Age, that 

lasted for 400 years through the middle of the 19th century, 

when global temperatures dropped something less than 1 °C. 

And the Earth recovered. 

What is different today is the rate of anticipated 

change. 

The Little Ice Age, so far as we know it, was 

characterized by a rate of change of about 0. 5°C per century 

in global mean surface temperature. The rate of greenhouse 

warming in the most conservative models of climate is at 

least ten times faster, about 0. 5°, not per century but per 

decade, which will drive the temperature, so far as we 

know, in 50 to 100 years to levels higher than any that have 

been reached in the last 30 million-since the early Tertiary 

Period. 

There is something else that is new and, to me, 

troubling about these predictions of future climate change. 

It is the first time in human history that we, as individuals 

or a society, have been allowed to look clearly at the face of 

the future. Never before have we known tens of years in 

advance what awaits us, and it is a real experiment to see 

how society responds to being able to look ahead. It makes 

one wonder: Did God ever want us to be able to look ahead? 

Much of the responsibility of what we do about it rests with 

people like us and with organizations like the Survey. 

Is all this I have told you another "cranberry crisis" 

that will soon go away? I don't think so. What makes it 

seem different to me is that now it's based on solid scientific 

16 Proceedings of the U.S. Geological Survey Global Change Forum 

information. And in a sense, it's now accompanied by a call 

from policymakers at the highest level. 

The reason I decided to invest my life in this crusade 

7 years ago was it seemed to me that these were problems 

that not only were real- and they bother me as they do all 

of you-but were only going to be made worse with time, 

that the pressures of population were always going to keep 

these problems before us. 

Can we count on continued funding at the level that 

Bob Corell showed us today, or not? I think for sure we can. 

These problems are going to be there, and they're going to 

get worse. To me, that makes it a rather safe gamble of 

one's time, plus something we should all work toward. 

It is a difficult problem for several reasons. To 

Senator Gore, the reasons were these: We deal with 

long-term problems in a short-term world. We deal with 

"uncertainties" that will always abound, as in the classic 

case of the association between tobacco and health. There 

will always be enough uncertainty there to make some 

people unsure even though the great weight of evidence is in 

another direction. We need to decide using incomplete 

information. There is a science fiction nature to the threat. 

And the options are expensive and socially revolutionary. 

Still, I think the current level of national and international awareness of the problem still should amaze us; it 

does me. 

In the past, there were only voices out of the 

wilderness. One of them was Andrei Sakharov, the Soviet 

dissident physicist who died in 1989. In the 1970's, when 

he was fighting a political system from within, he defined 

what he saw as the four threats to mankind, and he put them 

in the order of perceived danger. I think it's a pretty good 

list. The first was nuclear war; the second was hunger; the 

third was problems of the environment; and the fourth 

shouldn't surprise us coming from someone there: "the 

stultifying effects of mass culture." 

The war danger seems to be passing. Hunger has 

always been there. And the environment will always be a 

major problem. 

Today environmental consciousness worldwide has 

reached a peak unequaled in all the past. The notion of an 

endangered Earth, driven largely by concerns of ozone 

depletion and impending climate changes, has now 

appeared in almost everything we watch or read and is or 

has been high on the agendas of heads of state. In the last 4 

years, global environmental concerns have taken the covers 

of all the major magazines, the titles of television series, 

and even an episode of "Saturday Night Live." 

Global environmental change has been the subject of 

conferences called personally by the President of France, 

the Prime Minister of England, the President of the Soviet 

Union, the President of the United States, and even the 

Pope, in an encyclical issued a year ago at Christmas 1990. 

The Second World Climate Conference held in Geneva a 
few months ago focused the attention of an entire planet on 

impending problems of climate and global change. 

I think we're ready to do something about it, and 

that's why you're here. The dilemma that we face is 

knowing what to do, which requires knowing how the 

system works. 

A number of years ago, that bad boy of science, 

Wally Broecker, told me this story that now seems apt to 

describe the situation we have all felt when we're asked, as 

scientists, what we should do about all these problems. 

Wally said it's not unlike being dropped down, totally 

uneducated, to take charge of a major oil refinery-and 

forget for a moment the fires of Kuwait, but think about a 

big working oil refinery. You're plopped down in the chair 

of the director-as the one who is supposed to know. 

Then people start coming in your door and saying, 

"Something's wrong. The stuff that used to come out of the 

pipe down there on LE56 that used to be clear is now all 

black. There are continual fires breaking out over here on 

this side of the refinery, the electric power keeps failing, the 

heating doesn't seem to work, and the supply system seems 

to be breaking down." 

As these problems come in, you would say, "Now, 

wait a minute; hold it. Show me the plans. Put the plans to 

the refinery on the table here, and we can track down what 

the problem is." 

They look at you and say, "But we don't have any 

plans. We don't know how it works." 

That is the situation with the Earth: we work here, but 

God never gave us the plans that go with the place. 

Moreover, we're like the guys in the refinery: we've got 

pipe fitters and electricians and plumbers and welders, but 

we don't have any total system "refinerists," or whatever it 

would be. And we somehow, in a great hurry, have to find 

them, or make them, and in the meanwhile re-create the 

plans of a working system. 

I think it is a crisis, and I think, as in the case of a city 

under siege, there is a need to organize and mobilize, if not 

to put out fires, at least to understand the nature and extent 

of the environmental threat. 

What is it now that we must do? I have a personal list 

of six actions that seem to me imperative. As we talk about 

the program, you'll see that most of them are well covered 

in the program we are building, but here's my personal list. 

• The first is to put the Earth in intensive care. We've got 

to monitor the vital signs of the planet. We must put in 

place, as fast as we can, systems to detect global changes 

in what are to our best knowledge the most vital signs. 

And we must continue to track them indefinitely into the 

future. 

This we owe to future generations, and it is a task 

neither started nor yet fully defined. What we now know 

best of long-term global changes concerns trace gas 

abundances and, to a lower level of certainty, surface 

temperatures. The scattered readings of other parameters 

now in hand are not enough to diagnose a system as 

complex and as interconnected as the Earth. 

And if you agree with me that this must be high on 

our list, that helps you understand why in a budget that's 

never big enough, but still big, for global change, so 

much of it goes to NASA. 

It's expensive business, but we've got to start doing 

it. And it's up to you and me as non-NASA persons to 

make sure that the vital signs that EOS and other space 

and nons pace systems monitor are the right ones. 

The challenge is to anticipate wisely, so that when 

the youngest among us are asked 20 years from now what 

vital parameters have changed in the last 20 years, we 

shall have given them the means to answer. I think it very 

sad that we didn't start that earlier and that the process is 

being delayed as much as it is now. 

You should ask yourself what you would put on the 

list, knowing we can afford to monitor only a limited 

number. The comparison with health is, I think, a pretty 

good one. We're like physicians in an intensive care 

ward, with a patient, just admitted, on whom we can put 

on only so many monitors. We have only suspicions as to 

what is wrong. What is it we should monitor? We've got 

to come to agreement on that, soon, and start. That was 

number one. 

• Number two on my list is to begin a crash effort to 

recover the history of global changes. What happened the 

last time that temperatures reached the levels that we 

expect? How did the natural Earth respond to carbon 

dioxide and methane levels as high as we see them going 

now? I don't need to remind you, as people in the 

Survey, that that is the stock and trade of the geological 

sciences, who do it very well. 

It is also, I think, one of the great intellectual 

achievements that through such reading of natural diaries, we were able to recover the lost fact that there were 

once ice ages. Humans are very poor sensors of these 

changes as they happen, surreptitiously, in real time. 

It has always amazed me that we endured and forgot 

an ice age at a time when there were intelligent CroMagnon people walking around Europe and people in 

this hemisphere, yet nothing came down to us at all about 

it in legends. We have a story in the Old Testament about 

a flood and some other catastrophes that were probably 

local events, but nothing at all about a global ice age. I 

think we were designed to forgive and forget, which is 

good, but it makes us the worst possible detectors of 

gradual change. 

We must use whatever tricks we can to read nature's 

diaries, and we must do it faster than we are now. We 

know very little of past climate. There's now a debate, as 

you know, regarding the warming of even the last 

century. In a few months, a conference will convene in 

Japan to debate whether there was a Little Ice Age. 

A Fragile Seam of Dark Blue Light 17 
All that we know in good detail about the really long 

temperature history of the Earth and about the corresponding changes in atmospheric greenhouse gases 

comes from a number of ice cores that you can count on 

the fingers of one hand, and you wouldn't need all five 

fingers. These dangerously few cores have provided our 

only clues to how the Earth works as a biogeochemical 

system. Other records like them from other places are 

needed now for prediction and for the validation and 

testing of models. 

In some cases we shall be doing something like what 

other scientists now call "salvage archeology." 

Salvage archeology, as you know, comes in when, 

for example, the Corps of Engineers, which I think is 

about to put in a dam in southern Colorado, and archaeologists are called in to quickly dig up the past before it 

is forever lost. We face a similar call in the case of 

old-growth trees, which are going very fast, and a 

number of threatened lacustrine and other sedimentary 

records. 

We must recognize that we have to work faster and 

to secure greater funding to recover the history of the 

past, which, in many cases, is no longer a subject of only 

academic interest. The world is watching and waiting and 

looking over our shoulders, depending on us as scientists 

to answer such questions as the phasing between past 

changes in carbon dioxide and surface temperature. 

Which comes first? How much of a lag is there, and 

why? 

• The third imperative is to develop an Earth system 

science. I think we have started on that at last, and 

you've heard that talked about today. In doing this, we 

go against the grain of history. For 100 years, science has 

been specializing, going in exactly the opposite direction. In the courses of study that universities taught 100 

years ago, for example, there were no detailed science 

subjects like today. Geology is a rather late invention, as 

are oceanography, hydrology, and atmospheric physics. 

It is our nature to specialize; we need those also who will 

bring it back together. 

If you were to ask the Earth-if it could speak-

"How is your biosphere today?" or "How is your geology?", it would say, "My what?" 

It's all hooked indistinguishably together. These are 

artificial names that we have invented in order to study it 

or to grant diplomas, and we somehow have to find a way 

to look at the whole. This does not take from the need for 

continued, strong disciplinary studies, but we need to add 

to our agenda for research the study of system processes 

and of global processes. 

• The fourth imperative is to begin now to develop Earth 

system models. Bob Corell gave us today a very visionary look into the next 50 years that called for the 

development of models and the need to get them in place 

18 Proceedings of the U.S. Geological Survey Global Change Forum 

so that we can begin to make reliable predictions. They 

will require the missing set of plans for the refinery. 

I think the goal should be operable models, capable 

of tests within 10 years and capable of reliable prediction 

within 20. And, if this seems like a long time 

away-A.D. 2000 or 2010-think about how short a 

time ago 1980 or 1970 was. Usable models must include 

all coupled elements of the system. They will be crude at 

first-toy models, if you will-but I think we ought to 

get going on them with some speed. 

• The fifth imperative is to put in place a global data and 

information system: a challenge in which the Survey has 

many roots and many present activities. The system must 

be one that makes environmental data, both past and 

current, available to everyone, instantly, among all fields 

of study. We must make it easy to ship biological data to 

meteorologists, to ship meteorological data to biologists, 

and to ship data between countries, even new ones like 

Lithuania. 

Why is it necessary? Because the problems are 

interconnected and data connect disciplines. And because 

we need all the manpower we can get. And to accommodate, intelligently, a vast new stream of Earth system 

data. 

We must also put an end to the concept of proprietary data, and that's a case where EOS is really leading 

the way. When I started out as an astronomer, it was the 

way you worked, that you got your own data and for a 

while, sometimes a long while, you kept it very close to 

your chest. Only then, and sometimes never, was it 

shared. Those days are passing. 

Data and information systems may sound boring to 

some. A voice from the room today pointed out that data 

always comes up last and gets talked about last and 

funded last, and we somehow have to reverse that. Here 

is where our nation's big investment in the Earth Observing System may help us out, because that system is trying 

to put in place a global data and information system that 

can serve as an example. 

• The sixth and last imperative is to enlist and train a new 

army of scientists who are needed to create the set of 

plans that God never gave us and to provide the responsible policy advice that will be called for ever more 

loudly in the future. Gene Rasmusson asked about that 

earlier today from the floor: Where are the people who 

are going to do this? 

We must build a cadre of scientists and technicians 

needed to keep the promises that you and I have made 

through efforts in education at all levels. The challenge is 

to recruit and educate a new and larger generation of 

scientists to work in the environmental and related 

sciences and to make these challenging jobs attractive. 

We must also involve, much more than we have, the 

talents of scientists from the undeveloped world. We 

must do this for three reasons. The first is that we need 
them. There aren't enough people if we don't involve 

them. 

A second reason is that we need to know about their 

parts of the world, and we're not going to get that kind of 

information unless we involve those who live and work 

there. 

The third reason, sometimes forgotten, is that to 

provide responsible policy advice that might make a 

difference in this world you cannot expect nations to 

respond or alter policy if they haven't been involved from 

the start. 

In spite of past efforts, the present international 

effort at global change is at present still very heavily an 

activity of scientists of the Northern Hemisphere and 

Australia, leaving out about half the globe, and this must 

be redressed. 

In particular short supply are regional and global 

ecologists and regional and global hydrologists. Another 

shortage I came across last week at an international 

meeting on past global changes are the people who model 

paleodata, who develop climate and other environmental 

models of the past. There are so few of them that if you 

get them, all three of them, at a meeting, then all the 

work stops. 

It's not unlike the situation in the early days of radio 

astronomy- a new subdiscipline that burst upon the 

scene at the end of World War II-as a very exciting new 

field. It was so new that there was almost no one to work 

in it. The story was that whenever two radio astronomers 

got together, the first thing they did was to try to hire 

each other. 

As I said earlier, we need hydrologists who work at 

scales larger than the watershed. And we need some kind 

of hermaphroditic scientists who can work with one foot 

in the natural sciences and the other in the social 

sciences, to address what is probably the biggest 

unknown in the whole system, which is the human 

element of global change. 

How well does the U.S. Global Change Research 

Program (USGCRP) fit this list? 

The good news is that much of what I've said is now 

being done. 

For one thing, the U.S. Global Change Research 

Program that you heard described so well today by Dallas 

and by Bob Corell and others now stands as a "paradigm" to 

the world. It has set an example for many other countries. 

It has broken ground that we never thought possible several 

years ago. I think we should feel happy about the amount of 

funding that Congress has given us at a time when there are 

many competing demands. 

I don't think we heard enough today, even from 

Dallas, who is such a big player in it, or Bob, about the 

tremendous achievements of the Committee on Earth and 

Environmental Sciences. The Committee is still not a 

perfectly happy family, of course, but its members have 

done what was never done before in bringing agencies 

together and in looking at each other's budget books. They 

are even finding ways to live with the hardest of all 

organisms to live with-which is the National Academy of 

Sciences-to try to work with the Committee on Global 

Change. These are tremendous accomplishments. 

At the same time, there are still problems in our own 

U.S. program. One of them is that while there are lots of 

closet environmentalists out there, in academia and elsewhere, the reaction of much of the academic community is 

not altogether positive to an organized program of the sort 

that we're here cheering on tonight. 

Their objections deal with fears of big science versus 

little science, a scientific psychosis that will probably never 

go away. We customarily get around that by saying we've 

got to do both and that, yes, not all science is going to be in 

the U.S. Global Change Research Program, not in any 

field. We may indeed take all the paleomodelers-all three 

of them-but there may be only a small fraction of the 

people in any field that will be working centrally in this, and 

there will still be room and money for a scientist's own 

individual investigations. 

I think there's a general distrust of any program-I'll 

have to say it-that is run by the Feds. My God, you're 

going to let USGS and NASA and NOAA run this thing? So 

we have some more selling to do to show them how sage 

and trustworthy you all are. But that's out there. 

There's also a danger of diffusion that worries me. 

Some research institutions I won't mention have developed 

unilateral initiatives, reinventing for their own ends, programs that we've organized, we've fought for, and we 

believe must be done collectively. They arise as a way to 

win without getting in the game or even suiting up. I look 

upon it as in a bicycle race where, yes, there's lots of them 

back there winding on us, but that's okay so long as we get 

to the needed end. 

There's the question of sufficient manpower that I 

mentioned earlier and the question of adequate funding. 

Have we yet made the case to Congress about what we're 

doing in this program? 

I was asked also to tell you about the international 

program in which the U.S. Global Change Research Program is a part and more than a part as an example and a 

leader. What's going on in the rest of the world? 

The International Geosphere-Biosphere Program has 

been in the planning stages now for 8 years. Would you 

believe it? It is going into the implementation stage this 

year, in 1991. It now involves on the order of 50 nations, of 

which about 40 now have national committees for global 

change research like our own. Included are all the major 

countries of the world. China and the Soviet Union are very 

big players. The ones we've yet to bring on board are 

largely in Africa. 

The IGBP is sponsored by the International Council 

of Scientific Unions and is now organized by a secretariat in 

A Fragile Seam of Dark Blue Light 19 
the Swedish Academy of Sciences in Stockholm. Sweden 

now pays far more than its share of administrative costs; 

many other countries, including the United States, also 

contribute. 

The IGBP now collaborates very closely with the 

World Climate Research Program, and that collaboration 

gets closer and closer all the time. Many of us wish that the 

two will someday merge into an international global change 

program that would have the climate elements of the World 

Climate Research Programme and the nonclimate elements 

of the IGBP working essentially together. 

The core research projects that are now established in 

the IGBP define the way that that program will run. They 

comprise a federation of allied research projects that do a 

pretty close job of matching the major tombstones, if you 

will, in the U.S. Global Change Research Program: the 

major science priorities. 

There are now five of those federated projects that 

together make up the IGBP. One of them is the International 

Global Atmospheric Chemistry Program, IGAC. It now has 

a core project office in Cambridge at MIT that is funded by 

the United States. It brings together a lot of international 

effort, and it fits in with the U.S. thrust toward biogeochemical dynamics. 

The second core project is JGOFS, the Joint Global 

Ocean Flux Study. It has a core project office established in 

Germany, in Kiel, funded by Germany. It will look at the 

marine side of biogeochemistry. Problems of the carbon 

cycle are highlighted also in the 1992 U.S. Global Change 

Research Program. 

The third of these projects, less known, just opened a 

core project office in the last year in Australia, in Canberra. 

It's the Global Change and Terrestrial Ecosystems project, 

which includes impacts on agriculture and forestry. It is a 

very close match to the U.S. priority element on ecological 

systems and dynamics. 

The PAGES project will soon open a core office in 

Switzerland that we hope will be co-funded by Switzerland 

and the United States to look at past global changes, where 

that acronym-that very fitting acronym-comes from. It 

corresponds to the U.S. effort in Earth system history. 

Biological Aspects of the Hydrologic Cycle, BAHC, 

is an IGBP core project that will introduce more biology, 

more life science, into what is now the Global Energy and 

Water Cycles Experiment (GEWEX) program of the 

WCRP. It has its core project office now in Berlin. 

There are now in place five major international 

projects of the IGBP. They each rank as the equivalents of 

the World Ocean Circulation Experiment (WOCE), the 

Tropical Ocean-Global Atmosphere program (TOGA), 

GEWEX, and even the IGY, if you will; five of them are 

going, and a few others are under discussion. The really 

good news is that the IGBP is now closely associated with 

the World Climate Research Program, with strong connec20 Proceedings of the U.S. Geological Survey Global Change Forum 

tions to GEWEX, WOCE, and TOGA. I think it would be 

a good idea to band all these together even more formally. 

The IGBP has also a built-in design to mesh with a 

third part of the international global change program that 

corresponds to the U.S. thrust in the human dimensions of 

global change; internationally, that will be taken care of by 

a separate program run by the International Social Sciences 

Council, called Human Dimensions of Global Environmental Change (HDGEC). 

These three, IGBP, WCRP, and HDGEC, I think 

you'll see working closely together in future years, providing the international counterpart of the research activities 

that we will be working on in this country. 

They have worked together already in laying out the 

newest step you heard Bob Corell talk about today: the 

establishment of regional research centers around the world, 

an effort meant largely to entrain the less developed 

countries into the job of monitoring global change, understanding it, modeling it, and handling the data. 

That will be done if plans proceed as now envisioned 

by setting up global change research centers that will, in 

effect, divide the world into 14 parts. One will encompass 

northern South America, another southern South America. 

Others envisioned among them are the Caribbean, the 

Mediterranean, and the Arctic. One will encompass the 

Antarctic. You can figure out some of the rest. 

In each of them there will be sited a regional research 

center. In each of them will be regional research sites that 

are linked to this center. The centers will intercommunicate 

and talk to each other and deal with the major elements of 

the international program. 

That's a very fast and acronym-filled survey of what 

seems to me a very healthy sign that countries of the world 

are banded together, much like the United States is within, 

to tackle global change research. There is now as well an 

international funding organization for global change 

research that Bob Corell has put together to coordinate 

international funding for these activities. Indeed, if you are 

a scientist who is worried about big science versus little 

science, maybe you should be worried, but I think again 

when a city is under siege, as I think the Earth is, you 

needn't get too upset about that. 

I'm going to end with a thought about the level of 

funding that is now going into the USGCRP, the time that's 

going into it, and something about the challenge. 

The U.S. Congress has authorized, in an era of severe 

constraints, almost a billion dollars in fiscal year 1991 for 

focused research in this program, a number that's within a 

factor of three of what was envisioned a number of years 

ago when this program was first thought up. Indeed this 

year's $900 and some million is not yet enough for what 

must be done, but it's still a lot when measured in terms 

with which we're more familiar. 

How does that compare with other big numbers that 

we may know about? The total world economic output, the 
sum of the gross national products of all countries, is now 

about $18 thousand billion, or $18 million million. 

The gross national product of the United States is $5 

thousand billion, more or less. The U.S. national debt is $3 

thousand million: there's another big number for you. The 

President's budget for fiscal year 1992 is $1,450 billion, 

$218 billion of which is allocated to all of the things that 

you and I are interested in. The savings and loan bailout will 

cost us $100 billion. 

I read in the New York Times the other day that the 

estimated Iraqi reparations to Kuwait are about $100 billion. The cleanup costs of U.S. nuclear plants also come in 

at that level. Star wars was estimated a couple of years ago 

at $41 billion. The annual U.S. foreign aid is $12 billion. 

The United States contributes $1.8 billion to the World 

Bank each year. The cost of a shuttle spacecraft is $1.2 

billion. The U.S. Global Change Research Program is big 

enough to appear in such a list: the President's request for 

fiscal year 1992, as you know, is about $1.2 billion. 

How is that to be spent? You probably know. Most of 

it goes to NASA for the simple reason that we've got to get 

the vital signs monitored, and it costs a lot to get instruments started and kept in place. 

What about the international costs? The estimated 

annual budget for each of the core projects, when they get 

up to full speed, is on the order of $100 million per year. 

The estimated annual budget of a Regional Research Center, of the 14 I told you that might be established, is $10 

million. We now put about $2 million into administering the 

international program. 

The fiscal year 1991 budget for the USGCRP is 

around $950 million. How much is that? 

Toward the close of a thought-filled book, The 

Farther Shore, Don Gifford puts such incomprehensible 

figures into a more personal perspective. If you or I were 

personally given the U.S. Global Change Research focused 

budget for fiscal year 1991 to spend on ourselves, and we 

were given that in the year that Christ was born, invested 

none of it, and spent it at the exorbitant rate of $1 ,000 a day 

through all the months and years of history that have since 

passed by, we would still have enough left today to last 

another 621 years. A billion dollars is a lot of money. 

I think a more appropriate comparison may be found 

in the fractional increases granted to the program over the 

last 3 years, which confirms, to me, that Congress is ready 

to bring this program up to the visible level. 

The point I should like to leave you last is that most 

of the work of the broad global change program lies ahead 

of us. Moreover, like Babe Ruth at the plate, we scientists 

have pointed to where, in deep center field, we're going to 

place a hit, inviting a world of watchers to see that it is 

done. Promised are not singles, or doubles, but home runs 

in the form of pragmatic assessments and predictions 

sufficiently specific to be of use to policymakers. It is a very 

big challenge that we have taken on; it will require a lot of 

challenging research across a broad front, a lot of innovation, a lot of new methods of doing things. 

I think we have to keep the message heard that 

prudent decisions regarding the global environment require 

first that we know what, if anything, is changing and why. 

And that the cost of the focused research to provide updated 

answers to these very real questions is the most prudent 

investment one can make in the environmental future; that 

the rush to legislate, which is always the first resort of 

policymakers, cannot outdistance knowledge nor supplant 

the need for better understanding. 

Support of the focused science that makes up the 

broad global change program needs to be sustained at a 

level in this country several times higher than today. In 

time, this investment in knowing must surely be acknowledged by those who govern as a necessary fee for living on 

a planet so benign. 

The total international cost of the broad global change 

program, in the United States and all other countries, will 

probably reach the level of $5 to $10 billion per year, or 

roughly 0.05 percent of the world's present economic 

output, and that is a very small insurance premium. 

I think we have to keep reminding ourselves and 

others that, as Bob Corell said today, global change is 

more, I would say much more, than climate change or 

global warming. Most would agree that the global changes 

that will strike the hardest blows on people or other living 

things in the next 20, 50, or 100 years will not be those of 

climate change. 

If the world is in environmental extremis today, it is 

more through the rapidly changing chemistry of the air and 

soils and water, through the inexorable and wide-reaching 

pressures of urbanization and intensive agriculture and land 

use. Impacts of a changing climate driven by the enhanced 

greenhouse effect are not unlinked to these other concerns, 

and because of them they will become even more serious. 

We must never tie the support that's needed to 

understand a changing planet to some expected unequivocal 

announcement that, "Aha, the Earth is warming, and it's 

fitting this predicted curve." 

Although it is the most widely publicized facet of the 

problem, climate is also surely the most fickle. It can vary 

only surreptitiously. It will always be hidden from human 

perception behind masks of short-term extremes and local 

or regional weather that will always far exceed in magnitude 

any underlying trend. 

Climate change can be seen only in retrospect. And if 

we take the past as a guide, it can be recognized best from 

the perspective of at least 100 years removed. We don't 

dare wait for that. 

In spite of all that I have said about how good an 

organized program is and how we have to address global 

change through big science, I want to end with this 

A Fragile Seam of Dark Blue Light 21 
quotation to remind us of reality. It comes from Samuel 

Langley, a name you know. He was an American scientist 

who died in 1909, and he was, among other things, 

president of the American Association for the Advancement 

of Science. 

In his retiring address as president in 1889, he had 

this to say, which I always try to keep in mind if I get too 

excited about big programs: "We often hear the progress of 

science likened to the march of an army toward some 

definite end. But this, it has seemed to me, is not the way 

science usually moves, but only the way it seems to move 

in the view of the compiler, who probably knows almost 

nothing of the real confusion, diversity and retrograde 

motion of the individuals that comprise the body." 

22 Proceedings of the U.S. Geological Survey Global Change Forum 

He went on to say that although this comparison is 

often used, the one he liked better for the march of science 

is that of a pack of hounds. In the long run perhaps, the pack 

catches its game, but in the course of the hunt, it nevertheless, behaves in a random fashion. When in doubt, each 

individual goes his own way, by scent, not by sight, some 

running back and some forward. In some times of doubt, 

the louder voiced members of the pack convince many to 

follow them, though when they do, it's nearly as often 

down a wrong path as down a right one. In other times of 

doubt, the entire pack has even been known to move off 

bodily on a false scent. Nevertheless, it still seems to get 

its game. 
Second General Session 

Earth System History and Global Change 

R.Z. Poore 

Geologic Division 

U.S. Geological Survey 

The Earth is constantly changing, and the geologic 

record contains the evidence of past climate change and the 

effects of change on Earth systems, including the biosphere. 

Climate varies naturally on time scales of decades to 

hundreds of thousands of years. Documenting and understanding the record of natural variability is very important 

for differentiating between natural changes and those that 

may be occurring because of man's activities. 

Public concern about climate change is growing 

because man's activities are increasing the concentration of 

greenhouse gases in the Earth's atmosphere. But we know 

from the study of ice cores that atmospheric concentrations 

of C02 and other greenhouse gases have varied naturally in 

the past. Figure 1 shows a detailed record of oxygen isotope 

variations and C02 content of air bubbles trapped in the 

Greenland Dye 3 ice core. The oxygen isotope variations 

reflect changes in local air temperatures at the ice core site 

with more negative values representing colder temperatures. The C02 measurements reflect C02 content of the 

atmosphere. The analysis illustrates close correlation in the 

variability of C02 content of the atmosphere and air 

temperature and shows that significant changes occurred 

over time scales of decades to centuries. Further work is 

needed to determine if the C02 changes lead or lag the 

temperature changes. However, it is clear from this and 

from other ice core records, such as the 160,000-year record 

from the Vostok ice core in Antarctica, that both climate 

and atmospheric concentrations of greenhouse gases (C02 

and CH4) varied significantly and on relatively short time 

scales in the past. Understanding the causes and impacts of 

these past variations can help us understand and predict 

future change. 

PALEOCLIMATE STUDIES 

By studying the geologic record we can observe the 

response of Earth systems to climate change, gain insights 

into the mechanisms and causes of climate change, and 

determine links between different components of the climate system. We can use paleoclimate studies to build and 

refine climate models by testing the ability of climate 

models to hindcast the past. Specifically, our confidence in 

the ability of climate models to predict possible future 

changes will be increased if climate models can accurately 

simulate climates that actually occurred in the past. 

DYE3 

A depth below surface (meters) 

1,860 1,870 1,880 1,890 

[ppm] CD.2 Concentration 0 

250 

200 

28,000 

B 1,860 

(0/oo] 

-32 

-34 

-36 

28,000 

0 

0 

31,350 34,650 

years before present 

depth below surface (meters) 

1,870 1,880 

31,350 34,650 

years before present 

0 

38,000 

1,890 

38,000 

Figure 1. C02 and oxygen isotope values from a 30-meter 

section of Greenland Dye 3 ice core. The section from 

1 ,860 to 1 ,890 meters below the top of the core represents 

about 10,000 years ranging from 28,000 to 38,000 years 

before present. Panel (A) shows concentrations of C02 

measured from air bubbles trapped in the ice. Open 

circles give individual measurements. Solid line connects 

mean values for samples from the same interval of the ice 

core. More negative values indicate colder temperatures. 

Note close correlation between local air temperature and 

concentration of C02 • Figure modified from Oeschger 

and others, 1985. 

Earth System History and Global Change 23 
CORE SU 81-18 

0 

50 

100 

s 150 

£ 

£ 

p. 200 Q) 

Q 

250 

300 

350 

3.0 2.0 1.0 0.0 

glacial 

&180 

interglacial 

Figure 2. Oxygen isotope record from foraminifers in 

Core SU 81-18 taken off Portugal. The record represents 

the transition from glacial conditions at the bottom of the 

core to interglacial conditions at the core top. In this 

figure more positive values (heavy values) represent glacial conditions and more global continental ice volume 

whereas smaller values (light values) represent interglacial 

conditions and less global continental ice volume. Note 

rapid reversal toward glacial conditions that is labeled 

"Younger Dryas." The abrupt reversal of the transition to 

interglacial conditions, known as "Younger Dryas event," 

took place over a few decades. Figure taken from Fairbanks, 1989. 

Providing information on past climates on the scale 

and scope needed to help understand and model future 

global change represents a major challenge to Earth historians. Substantial, coherent, and quantitative data sets are 

needed in a relatively short period of time. In order to meet 

the needs of global change research, resources have to be 

concentrated on well-selected problems and questions, and 

interdisciplinary approaches have to be more widely used. 

Recognizing the need for a more organized research effort, 

the National Research Council's committee on global 

change (National Research Council, 1990) has formulated a 

research plan for Earth system history that involves three 

major initiatives focused on the Holocene, on late Quaternary glacial-interglacial "cycles," and on longer term major 

climatic changes (discussed below). Investigations under 

this plan will explore both the conditions and the variability 

during these periods. In addition, particular attention will be 

placed on periods of abrupt transitions, which may provide 

insights into potential Earth systems responses to rapid 

changes and possible nonlinear responses to climate forcing 

anticipated over the next century. 

The first NRC initiative is aimed at producing an 

integrated set of globally extensive records of the Holocene 

as a frame of reference for comparison of greenhouse gas 

24 Proceedings of the U.S. Geological Survey Global Change Forum 

induced warming. This initiative would essentially detail 

the natural variability of the current climate state, which 

must be known before anthropogenic changes can be 

identified with certainty. For example, average global 

temperature has varied by 1.0 to 1.5°C during the Holocene. Thus, the change of +0.5°C in global average 

temperature estimated for the last century is within the 

range of natural variability of the current climate state. 

The second initiative is to understand glacialinterglacial fluctuations of the Quaternary. Special concerns 

in this initiative include delineating systems response to 

known orbital forcing, detailing interactions among different components of the climate system, and documenting 

instabilities in the climate system. 

The third initiative is to examine system response to 

large changes. Primary concerns in this initiative include 

insights into warm climates, the development of paleoenvironmental data sets to test model simulations of different 

climate states, and the response of the biosphere to large 

perturbations. 

As mentioned above, paleoclimate studies document 

a number of extreme states and abrupt transitions in the 

Earth's climate. We must be able to explain and model 

these extreme states and transitions in order to understand 

and make credible predictions of future changes. For 

example, at the end ofthe last major glaciation, rapid global 

warming was abruptly reversed at about 11,000 years ago, 

and large portions of the Northern Hemisphere returned to 

almost full glacial conditions within a time span of decades 

to a century (fig. 2). Then after a few hundred years, the 

climate again abruptly changed and rapidly warmed to the 

present interglacial climate. The abrupt reversal of global 

warming at about 11 ,000 years ago may be related to 

fundamental changes in deep-ocean circulation (Broecker, 

1990), but the forcing and mechanisms for the change are 

still unknown. An example of an extreme warm event is 

provided by the Kap K0benhavn Formation in Greenland. 

This unit contains wood and other plant remains that show 

that trees were growing at the northern tip of Greenland 

about 2 million years ago. The growth of trees at 82°N 

latitude indicates winter temperatures in northern Greenland 

2 million years ago were 15° to 20°C warmer than present 

winter temperatures (fig. 3). Much additional work is 

needed to document the duration and geographic extent of 

the 2-million-year warming episode and understand the 

cause for this large climate perturbation. 

Several common themes run through all three initiatives. These themes include (1) abrupt transitions, (2) 

climates of warm periods, (3) system response to known 

forcing, (4) biotic response to climate change, and (5) links 

between different components of the geosphere and biosphere with emphasis on the carbon cycle. These themes 

will guide the overall Federal global change research effort 

and provide the context for USGS investigations. 
Figure 3. Location of Kap K0benhavn at northern tip of 

Greenland, location of modern tree line, and modern 

distribution of Thuja occidentalis. Trees including Thuja 

occidentalis were growing at Kap K0benhavn about 2 

million years ago. This northward migration of the tree 

line suggests winter temperatures in northern Greenland 

2 million years ago were 15° to 20°C higher, and precipitation was at least double modern values. Figure modified 

from Funder and others, 1985. 

Earth System History and Global Change 25 
REFERENCES 

Broecker, Wallace S., 1990, Salinity history of the Northern 

Atlantic during the last deglaciation: Paleoceanography, v. 5, 

p. 459-467. 

Fairbanks, Richard G., 1989, A 17,000-year glacio-eustatic sea 

level record: influence of glacial melting rates on the Younger 

Dryas event and deep-ocean circulation: Nature, v. 342, p. 

637-642. 

Funder, Svend, Abrahamsen, Niels, Bennike, Ole, and FeylingHanssen Rolf, W., 1985. Forested Arctic: Evidence from 

North Greenland. Geology, v. 13, p. 542-546. 

26 Proceedings of the U.S. Geological Survey Global Change Forum 

National Research Council, 1990, Research strategies for the U.S. 

Global Change Research Program, National Academy Press, 

Washington, D.C. 291 pp. 

Oeschger, H., Stauffer, B., Finkel, R., and Langway, C.C., Jr., 

1985, Variations of the C02 concentration of occluded air 

and of anions and dust in polar ice cores, in Sundquist, E. T., 

and W.S. Broecker, eds., The Carbon Cycle and Atmospheric C02: Natural Variations Archean to Present (Geophysical Monograph 32): Washington, D.C., American Geophysical Union, p. 132-142. 
Climate, Hydrology, and Water Resources 

Harry F. Li ns 

Water Resources Division 

U.S. Geological Survey 

Perhaps the most significant of all the effects of 

global climate change are those related to hydrology and 

water resources. Potential effects in the agricultural, forestry, and urban sectors, although of justifiable concern, are 

actually derivative problems stemming from the climate 

change effects on water availability. Clearly, potential 

changes in the distribution, quantity and quality of, and 

demand for water form one of the most central issues in the 

current worldwide efforts to understand and deal with 

climate change. Both nationally and internationally, a 

reliable water supply is an essential base for social, economic, and political stability. 

The issue would be troublesome enough if it were 

merely a matter of estimating future hydrologic conditions. 

However, when considering water resources, it is also 

necessary to incorporate social and economic dynamics. 

During the first assessment of the Intergovernmental Panel 

on Climate Change (IPCC), scientists participating in the 

working group that investigated the potential impacts of 

climate change realized that producing an estimate of 

agricultural, water resources, human settlement, and other 

conditions extant within a climate that may exist 40 or 50 

years in the future would be misleading at best and 

unrealistic at worst, unless estimates of concomitant social 

and economic conditions likely to exist in these future 

decades were also prepared. Thus, to acquire estimates of 

future water resource conditions appropriate for planning 

and policy formulation, consideration must be given to ( 1) 

physical changes likely to occur in the climate and hydrologic systems associated with both human-induced and 

nonhuman influences, (2) social and economic changes not 

affected by climate, and (3) social and economic changes 

that may occur in response to climate and that may, in tum, 

produce their own effect on the climate. 

This presentation focuses primarily on the physical 

aspects of the linked climate-hydrology-water resources 

theme. This subject lies within the mission of the Geological Survey's Water Resources Division, and it is, in many 

respects, more tractable than those aspects associated with 

the dynamics of social and economic behavior. Two diverse 

components of the subject will be discussed: fundamental 

process research (including modeling) and the estimation of 

the sensitivity of water resources to climate variability and 

change. 

We will look first at fundamental processes. For 

decades, hydrologists have begun seminars of broad hydrologic issues by considering the hydrologic cycle. Given the 

/ / / 

Roots 

Vegetation ...,. __ -t Soil 

Runoff 

Aquifer 

/ 

/ 

/ 

Runoff 

Pump 

Drain Pump 

Pump 

Drain 

Open water 

Pump 

Humanity 

Figure 1. The global hydrologic cycle (Waggoner and 

Revelle, 1990). 

theme of this forum, global change, it is equally appropriate 

to follow that tradition here. However, I will depart from 

the typical illustration of the hydrologic cycle (the block 

diagram showing land, ocean, and atmosphere, with snow, 

vegetation, and rivers) and use a more contemporary 

graphic that appears more like the plumbing in a water 

system (fig. 1). In this illustration, from Waggoner and 

Revelle (1990), the large rectangle at the top represents the 

water in the atmosphere. The smaller squares beneath the 

rectangle represent the water in vegetation, in the soil 

reached by roots, in the aquifers below, and in open bodies 

of water. The square marked humanity represents the water 

in ourselves, pipes, dishwashers, and so forth. Arrows 

represent the fluxes between reservoirs. Valves are placed 

on three fluxes to show that they are controlled by C02 . 

Carbon dioxide directly affects transpiration from foliage by 

increasing it through faster photosynthesis and by narrowing leaf pores. Indirectly, C02 warms the air temperature, 

Climate, Hydrology, and Water Resources 27 
GLOBAL 

1QOOOKm 

1.000Km 

100Km 

10Km 

1Km 

LOCAL 

~--~--~--r---r---~TKm---+---+-

1 

DRAINAGE T---+---+---N~~ 

FORMATION 

MOISTURE EROSION I ~--~--r---1-"-"-=t-'-----t ~:t~ 

WATER 

CIRCULATION 

SEC MIN DAY YEAR CENTURY ONE MIWON ONE BIWON 

YEARS AGO YEARS AGO 

Figure 2. Spatial and temporal scales of selected atmospheric and hydrologic processes (National Research 

Council, 1991). 

enhancing the evaporation from vegetation, soil, and open 

water. Faster evaporation, of course, decreases the water 

that runs off to bodies of water or into aquifers, increases 

pumping to irrigate soil, and even raises humanity's 

demands. The arrows from the atmosphere down to the 

vegetation, soil, and open water boxes represent the flux by 

precipitation. Water resources (in the context of human 

consumption and use) exist in the open water and aquifer 

boxes. 

From this perspective, it is possible to begin defining 

critical climatic-hydrologic research needs in a global 

change context. Three of the most notable needs are 

presented here: improved process models, enhanced data 

collection, and coordinated field experiments and campaigns. Modeling and data collection are not independent 

processes. Ideally, each drives and directs the other. Better 

models illuminate the type and quantity of data that are 

required to test hypotheses. Better data, in tum, permit the 

development of better and more complete models and new 

hypotheses (National Research Council, 1991). 

Clearly, model development and improvement have 

become pivotal aspects of the U.S. Global Change Research 

Program. The adequate parameterization of variables representing the terrestrial phase of the hydrologic cycle 

remains a major weakness of existing general circulation 

and mesoscale climatic models. As a recent report of the 

National Research Council (1988) notes, 

"Treatments of runoff in climate models do not adequately represent the realities of catchment-scale 

hydrology, such as the highly nonlinear, almost threshold, relationships between rainfall and runoff as well 

as the dependence on terrain, soil heterogeneity, and 

subgrid-scale statistical structures of rainfall patterns. . . . Improvements in modeling the linkages 

28 Proceedings of the U.S. Geological Survey Global Change Forum 

between surface hydrology and climate require better 

understanding of evapotranspiration from diverse terrestrial vegetation, other land covers, and lakes; infiltration of water through the unsaturated zone with 

consequent improved understanding of aquifer 

recharge; the conversion of precipitation to streamflow, including the role of topography at a variety of 

scales of catchment and storm patterns; and the processes of snow accumulation, transformation, redistribution, and melting." 

Hydrologists have developed a number of finer resolution basin-scale models of hydrologic processes. It 

remains to be seen if these relatively successful basin-scale 

modeling efforts can simply be scaled up to work in the 

coarser atmospheric models. The usefulness of microscale 

knowledge of plant physics, soil physics, lake thermal 

structure, and other processes in estimating the required 

model parameters of a general circulation model (GCM), 

given the diversity of land characteristics in a given cell, is 

unknown. Approaches to modeling the land surface processes in the GCM's that account for the fact that moisture 

conditions within a grid cell are highly variable need to be 

explored. Finally, the importance of lateral movements of 

water on or beneath the land surface (either as ground-water 

flow or by diversion, storage, and application to the land in 

large irrigation projects) to the climate system has not been 

explored. The present GCM's assume that water moves 

only vertically between the land and the atmosphere or 

directly from the land to the oceans and that there is no 

spatial redistribution of moisture within the cell or between 

cells. The issue of scale is critical in any effort to model 

climatic and hydrologic processes, because the range of 

dynamics involved varies spatially from a point up to 

the globe and temporally from a second up to millennia 

(fig. 2). 

Data also represent a major need in the climatichydrologic research arena. Advances in the atmospheric and 

hydrologic sciences are dependent upon the success with 

which investigators are able to integrate reliable, largescale, long-term data sets (National Research Council, 

1991). Such data are particularly needed to initialize, 

validate, and prescribe boundary conditions for the process 

models described earlier. The data sets required for these 

tasks are highly varied and include topography, land use 

and cover, vegetation, soil moisture, humidity, temperature, precipitation, wind velocity, and runoff. 

It is also important to recognize that models are not 

going to provide answers to all of the questions associated 

with global change. Data need to be used for monitoring the 

global environment and for conducting diagnostic or retrospective studies. An example of such use is evident in the 

subdiscipline of hydroclimatology, where large-scale interactions between the atmosphere and the hydrosphere are 

determined by statistical associations. Hydroclimatology 

has both diagnostic and prognostic elements and is a strong 
complement to the deterministic process models of climate, 

especially with respect to processes for which the underlying physics are poorly defined. 

This leads us to the third critical need, coordinated 

field experiments and campaigns. It is now generally 

accepted that further progress in the development of the 

needed parameterizations of land surface fluxes of energy 

and water in climate dynamics and hydrology must be based 

on new comprehensive experiments conducted, and with 

field data collected, at broader scales than those customary 

in the past (National Research Council, 1991). One of the 

most visible and comprehensive signs of the recognition of 

this need is the incipient Global Energy and Water Cycle 

Experiment (GEWEX) of the World Climate Research 

Programme. 

The goal of GEWEX is to determine global distributions of water and energy fluxes from observations and to 

compute their values from predicted atmospheric properties, for the purpose of quantifying the energetic processes 

of the Earth's climate system and the atmospheric forcing 

on the ocean, land, ice, and vegetation (World Climate 

Programme, 1990). The initial phase of GEWEX is focusing on the establishment of a GEWEX Continental-Scale 

International Project (GCIP) to study the water and energy 

budgets of an extensive geographical area of the earth for 

which there is a large volume of accessible data. The 

objectives of GCIP are (1) to determine the time/space 

variability of the hydrologic and energy budgets over a 

continental scale; (2) to develop and validate macroscale 

hydrological models, related high-resolution atmospheric 

models, and coupled hydrological-atmospheric models; (3) 

to develop and validate information retrieval schemes incorporating existing and future satellite observations coupled 

with enhanced ground-based observations; and (4) to provide a capability to translate the effects of a future climate 

change into impacts on water resources on a regional basis. 

The Mississippi River basin has been selected as the 

GCIP study area. The meteorological and hydrological 

networks covering the continental United States, enhanced 

by new Doppler radars, wind profilers, and automatic 

weather stations being implemented as part of the upgrade 

of the U.S. observing network, provide the best opportunity 

for collecting the data sets essential for ( 1) the determination of precipitation, wind fields, and other climatic variables and (2) the validation of estimations based on 

remotely sensed data. Equivalent data sets are not likely to 

be available in other continental areas within the same time 

frame, that is, the mid-1990's. 

The general strategy for implementing GCIP is illustrated in a time-phase schedule commencing in the early 

1990's with a series of contemporaneous planning studies, 

proceeding through to a buildup observational period, and 

then to a fullS-year intensive observing period (fig. 3). The 

timing of the buildup period and start of the intensive 

observing period will be determined to some extent by the 

speed with which some of the new key observing systems 

planned for the Mississippi River basin can be implemented. Currently, it is estimated that the intensive observing period could begin around 1995 and continue through to 

the end of the decade, when it is anticipated that several 

new satellite-borne remote sensing systems will be in 

operation. Diagnostic, modeling, and water assessment 

studies will proceed throughout the life of GCIP, making 

use of each new data set as it becomes available. 

We tum now to the second aspect of the climate, 

hydrology, and water resources theme to be addressed in 

this presentation, that is, the sensitivity of water resources 

to climate variability and change. Although a totally comprehensive analysis of the climatic effects on water resources requires consideration of numerous specific scientific 

issues, only a few of the most important ones are discussed 

here. One of the more critical and controversial issues 

relates to the use of climate scenarios. In order to estimate 

the hydrologic and water resource effects of climatic 

change, a regionally specific forecast of future climatic 

conditions is necessary. Precipitation, air temperature, 

cloud cover, wind speed, and humidity are the most 

important conditions. Unfortunately, reliable forecasts of 

regional climate changes are currently unavailable. In their 

absence, various approaches are used to develop "scenarios" of future climatic conditions. These include (1) hypothetical, or prescribed, climatic conditions; (2) general 

circulation model output; (3) recent historical analogs; and 

(4) paleoclimatic reconstructions (fig. 4; Gleick, 1989; Lins 

and others 1990). 

Purely hypothetical scenarios have been widely used 

in recent years to assess the response of watersheds to future 

changes in climate. Frequently referred to as "what if' 

scenarios, this method of generating climatic values is easy 

to develop and apply and affords a useful means of testing 

the sensitivity of a watershed to a range of climatic 

conditions. In practice, the method involves prescribing, for 

example, a +2°C or +4°C temperature increase, along with 

a percentage change in precipitation, such as +5 or -10 

percent. Admittedly, such scenarios may not be very 

realistic. They are valuable, however, in facilitating the 

study of the effect of a range of climatic values without 

specifying the likelihood of one set of conditions versus 

another. Thus, emphasis is placed on identifying under 

what combination of climatic conditions a water system 

experiences stress, as opposed to attempting to "forecast" 

future water system conditions. 

A second type of climate scenario is based on the 

output from general circulation models (GCM's). Modelsimulated atmospheric values, such as temperature and 

precipitation, are then used as input to hydrologic models. 

General circulation models are the most sophisticated class 

of climate models. They are detailed, time-dependent, 

three-dimensional numerical simulations that include horizontal and vertical atmospheric motions, heat and moisture 

Climate, Hydrology, and Water Resources 29 
GCIP IMPLEMENTATION PHASES 

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 

I~ATDtl 

~F-II INTENSIVE OBSERYIHO PERIOD 

iCONnNENTAL SCALE WATER AND ENERGY CYCLES I 

MODEL DEVELOPMENT & VALIDATION 

iwATER RESOURCES IMPACTS I 

I DATA COLLECTION I 

DATA MANAGEMENT I 

I ENERGY AND WATER BALANCE 

DATA ANALYSIS & ASSlMII.AllON 

Figure 3. The GEWEX Continental-Scale International Project (GCIP) implementation phases. 

exchanges, and interactions between the land, ocean, ice, 

and atmosphere (Manabe and Wetherald, 1980; Washington 

and Meehl, 1984; Wilson and Mitchell, 1987). Presently, 

GCM' s provide the most comprehensive simulations of the 

climatic effects of increasing concentrations of greenhouse 

gases. 

Despite their complexity, however, general circulation models suffer from two major limitations when used to 

provide data for evaluating hydrologic and water resources 

consequences of climatic change. First, the spatial resolution of GCM's, typically several degrees of latitude by 

several degrees of longitude (that is, hundreds of thousands 

of square kilometers), is too coarse to provide information 

detailed enough to be of hydrologic significance. Hydrologists generally focus on processes occurring at catchment 

scales (tens to hundreds of square kilometers). To be of use 

from a hydrologic perspective, therefore, GCM output must 

be disaggregated from the low-resolution grid scale to the 

more detailed high-resolution catchment scale. The development of methods for disaggregating GCM-generated 

estimates of precipitation and temperature is currently a 

very active area of research. A major contribution to this 

endeavor has recently been made by a team of Geological 

30 Proceedings of the U.S. Geological Survey Global Change Forum 

Survey investigators using a technique based on classifying 

weather pattern types affecting streamflow in the Delaware 

River basin (Hay and others, 1991). Weather types permit 

the identification of weather conditions associated with 

varying frequencies, intensities, and amounts of precipitation. Weather-type frequencies were used to stochastically 

simulate precipitation for Philadelphia and to produce 

estimates that statistically match observed precipitation. A 

new method was then developed that derives weather-type 

RUNOFF AND SOIL TEMPERATURE AND 

MOISTURE SCENARIOS PRECIPITATION SCENARIOS 

Hypothetical Data Hypothetical Data 

Historical Analog Data Historical Analog Data 

Paleohydrologic Data Paleoclimatic Data 

GCM Data GCM Data 

l 

I HYDROLOGIC MODELS 

~ I WATER MANAGEMENT MODELS I 

Figure 4. Methods for estimating the hydrologic and water 

resource impacts of climatic change (Gieick, 1989). 
frequencies from GCM-generated climate change scenarios 

to simulate future precipitation. 

Second, the parameterization of terrestrial hydrologic 

conditions in general circulation models is very rudimentary 

and typically does not provide regional simulations that are 

realistic enough for water resources planning. Parameterization refers to the expression of the statistical effects of 

various detailed, high-resolution (subgrid scale) transport 

processes in terms of the more coarse, low-resolution (grid 

scale) variables explicitly resolved by the model (Global 

Atmospheric Research Program, 1975). Because of the 

wide range of scales of interacting atmospheric processes in 

relation to the limited spatial resolution of GCM grid cells, 

it is technically and economically impractical to observe or 

explicitly calculate the effects of subgrid scale processes in 

detail. These subgrid processes are, however, extremely 

significant in their effects on climate, and it is necessary to 

relate their statistical effects to measurable or computable 

conditions at more general scales. Because the arbitrary 

specification of detailed effects does not accommodate full 

interaction with the broader scale resolvable state of the 

atmosphere, parameterization is required. As a consequence, the representation of many atmospheric and terrestrial conditions (such as evapotranspiration and soil moisture) in GCM's are generally poor and unrealistic. 

Although general circulation models are internally 

consistent characterizations of the climate system, accounting for most of the important components and interactions, 

they are still very crude representations of the natural 

system and do not produce realistic forecast information at 

regional scales. It is very important to be cognizant of this 

fact when using GCM simulations of future climatic conditions to estimate potential future hydrologic conditions. 

Because GCM' s produce quantitative estimates of future 

conditions, hydrologic analyses based on such estimates 

give the appearance of being more "realistic" than they may 

actually be. Readers of such reports must remember that the 

descriptions of "future hydrologic conditions" are only as 

good as the model predicted climatic conditions, and these 

are not very good at all. 

A third method for producing scenarios of future 

climatic conditions, historical analogs, is based on the use 

of data from the recent observational record. This procedure 

involves searching for periods in recent history when 

climatic conditions were similar to those that are believed 

will accompany a doubling of atmospheric C02 • In most 

regions, hydrologic conditions associated with these anomalous climatic conditions are known, so it is possible, 

therefore, to develop insights into the vulnerability of water 

systems to climatic change. The strength in this method is 

that it draws on human experience. On the other hand, this 

method has a serious weakness. In many regions, the 

magnitude of estimated changes in climate is greater than 

most natural historical variations. Thus, it may not be 

possible to find an appropriate analog in the systematic 

record or, if such a variation exists in the record, it is 

unlikely that it lasted for a long enough period of time to 

obtain a reliable (in the context of future conditions) 

estimate of its hydrologic effects (Karl and Riebsame, 

1989). 

The fourth method of producing scenarios of future 

climatic conditions is based on analyses of variations in 

climatic conditions over periods spanning millennia, as 

recorded in the geologic record. By observing such variations and attempting to identify periods that may be similar 

to future greenhouse conditions, that is, paleoclimatic 

analogs, it is possible to identify where significant changes 

in water availability may appear. Paleoclimatic scenarios 

are limited by several things, however, in their usefulness 

for evaluating the impacts of future climatic changes on 

hydrology and water resources (Gleick, 1989). First, the 

farther back in time one goes, the more difficult it becomes 

to recover hydrologic data. Second, the reasons for climatic 

fluctuations through geologic time may differ significantly 

from the human-induced changes anticipated in the coming 

decades. Third, because these paleoclimatic changes generally predate human activity, there is no evidence of how 

they might affect society. 

Significantly, the ability to assess hydrologic and 

water resource impacts of climatic change is predicated on 

satisfying several important requirements. First, it is necessary to understand how hydrologic systems respond to 

meteorological and climatological conditions. Notably, the 

current capability for meeting this requirement is only fair. 

Second, one needs estimates of regional meteorological 

conditions attendant to a potential future climate. This is the 

"water supply" side of the impacts equation. From the 

preceding discussion of scenarios it should be clear that the 

ability to produce an accurate regional forecast of climatic 

conditions decades, years, or even months into the future is 

currently very poor. Third, estimates of the regional social 

and economic conditions likely to exist contemporaneously 

with a future changed climate are necessary. This is the 

"water demand" component of the impacts equation. As 

with climate forecasting, the current ability to accurately 

forecast regional social and economic conditions is poor. It 

is noteworthy that studies of the accuracy of socioeconomic 

forecasts in general, and water use forecasts in particular, 

have shown that the majority of such forecasts during the 

past 30 years have been substantially in error (Osborn and 

others, 1986). 

Although in recent years there has been an increased 

interest placed on understanding how worldwide water 

resources would be impacted by long-term climate change, 

little attention has focused on the fact that our current 

understanding of how water resources respond to short-term 

climate variability is seriously deficient. Significantly, it is 

only by first improving our knowledge of the latter shorter 

term processes that it will be possible to answer questions 

associated with the former longer term process. Thus, 

Climate, Hydrology, and Water Resources 31 
increased understanding of relations between climatic variability and hydrologic response must be developed. Such 

work should include the development of methods for 

translating climate model information into a form that 

provides relevant data for watershed and water resource 

system models. 

One of the most important outcomes of the Intergovernmental Panel on Climate Change (IPCC) Impacts 

Assessment (Tegart and others, 1990) was the recognition 

that physical and social scientific understanding is not yet at 

a level where water resources impact assessments are 

practical. Significantly, though, it is now feasible to identify river basin sensitivities to both climate and socioeconomic change. Clearly, such identification is essential to 

the development of reasoned and beneficial planning and 

policy-making activities. 

Lins and others ( 1990) suggest that in the absence of 

a true impact assessment capability, a number of beneficial 

tasks should be undertaken in order to develop useful 

planning and policy formulation information. For example, 

improved analytical tools for characterizing climate effects 

on water resources and water resource systems can be 

developed. Considerable work has already been initiated in 

this regard. Also, techniques and tools specifically designed 

for planning and managing water resource systems assuming a nonstationary climate can be developed. Such methods are critical inasmuch as the traditional procedures for 

water resources planning unrealistically assume stationary 

climatic conditions. Moreover, water system managers can 

test and evaluate alternative operating procedures and rules 

for making their systems more robust (less sensitive) to 

climate variability and change. Having taken such steps as 

these, as regional climate and socioeconomic forecasts 

begin to improve, an adequate scientific and technical basis 

will then exist to define the effects of climate change on the 

physical hydrologic system as well as the issues of water 

demand and water use. 

REFERENCES 

Gleick, P.H., 1989, Climate change, hydrology, and water 

resources: Reviews of Geophysics, v. 27, no. 3, p. 329-344. 

Global Atmospheric Research Program, 1975, The physical basis 

of climate and climate modeling: GARP Publication Series 

No. 16, 265 p. 

32 Proceedings of the U.S. Geological Survey Global Change Forum 

Hay, L.E., McCabe, Jr., G.J., Wolock, D.M., and Ayers, M.A., 

1991, Simulation of precipitation by weather-type analysis: 

Water Resources Research, v. 27, p. 493-501. 

Karl, T.R., and Riebsame, W.E., 1989, The impact of decadal 

fluctuations in mean precipitation and temperature on runoff: 

A sensitivity study over the United States: Climatic Change, 

V. 15, p. 423--447. 

Lins, H., Shiklomanov, 1., and Stakhiv, E., 1990, Hydrology and 

water resources, in, Tegart, W.J.McG., Sheldon, G.W., and 

Griffiths, D.C., eds., Climate change: The IPCC impacts 

assessment: Canberra, Australian Government Publishing 

Service, p. 4-1-4-42. 

Mana be, S. , and W etherald, R. T. , 1980, On the distribution of 

climate change resulting from an increase in COrcontent of 

the atmosphere: Journal Atmospheric Science, v. 37, p. 

99-118. 

National Research Council, 1988, Toward an understanding of 

Global Change, National Academy of Sciences, Washington, 

D.C., 213 p. 

---1991, Opportunities in the hydrological sciences. National 

Academy of Sciences, Washington, D.C., 348 p. 

Osborn, C., Schefter, J., and Shabman, L. 1986. The accuracy of 

water use forecasts, Water Resources Bulletin, v. 22, p. 

101-109. 

Tegart, W.J. MeG., Sheldon, G.W., and Griffiths, D.C. (eds.), 

1990, Climate change: The IPCC impacts assessment: Canberra, Australian Government Publishing Service. 

Waggoner, P.E., and Revelle, R.R., 1990, Summary, in, Waggoner, P.E., ed., Climate change and U.S. water resources. 

Report of the American Association for the Advancement of 

Science Panel on Climatic Variability, Climate change and 

the Planning and Management of U.S. Water Resources, 

John Wiley, New York, p. 447-477. 

Washington, W.M., and Meehl, G.A., 1984, Seasonal cycle 

experiment on the climate sensitivity due to a doubling of 

C02 with an atmospheric general circulation model coupled 

to a simple mixed-layer ocean model: Journal of Geophysical 

Research, v. 89, p. 9475-9503. 

Wilson, C.A., and Mitchell, J.F.B., 1987, A doubled C02 

climate sensitivity experiment with a global ~limate model 

including a simple ocean: Journal of Geophysical Research, 

v. 92, p. 13,315-13,343. 

World Climate Programme, 1990, Scientific Plan for the Global 

Energy and Water Cycle Experiment. WCRP-40 (WMO/ 

TD-No. 376), World Meteorological Organization, Geneva, 

83 p. 
Terrestrial Implications and Uncertainties in the Atmospheric Carbon 

Dioxide Budget 

Eric T. Sundquist 

Water Resources Division 

U.S. Geological Survey 

Atmospheric C02 is one of the smallest carbon 

reservoirs in the global carbon cycle (fig. 1). Because of its 

relatively small carbon content, the atmosphere is very 

sensitive to changes in the larger carbon reservoirs with 

which it exchanges. This sensitivity spans a broad spectrum 

of time scales, depending on the rates of C02 exchange 

between the atmosphere and the other global carbon reservoirs (fig. 1). Of particular concern is the historical acceleration of C02 production caused by human consumption of 

fossil fuels and destruction of vegetation. These activities 

produce so much C02 that the potential greenhouse effect 

due to anthropogenic C02 is several times that due to any 

other greenhouse gas (fig. 2), even though C02 is not the 

most efficient greenhouse gas on a per-molecule basis. 

Accordingly, anthropogenic C02 has been the focus of most 

TIHIIE GlOBAl CAIRIBOINI CYCliE TIME REQUIRED 

TO AFFECT 

ATMOSPHERE 

(IN 

RESERVOIRS: GIGATONS CARBON 

FLUXES: GIGATONS CARBON/YEAR 

YEARS) 

10 

6 

10 

420 

ATMOSPHERE 590 

740 

}6 T t-3 

FOSSIL TERRESTRIA 

FUELS BIOSPHER 

560 

4,000 

ACTIVE 

SOILS 

1,100 

OLD SOILS 

500 

EARTH'S CRUST 

t 5,000 YEARS AGO 

300 YEARS AGO 

TODAY 

I 6o 10 1 

O SURFACE 

-c 900 

E 

A 

DEEP 

36,000 N 

10.6 l 0.4 

REACTIVE 

MARINE 

SEDIMENTS 

3,000 

l 0.2 0.2 1 

90,000,000 

Figure 1. A representation of the principal reservoirs and 

fluxes in the global carbon cycle. Vertical placements 

relative to scale on left show approximate time scales 

required to affect atmospheric C02 • 

Table 1. Approximate historical budget for anthropogenic 

carbon dioxide for the years 1850 through 1990 

[See text for sources of data. Uncertainties of sums are calculated as 

square-roots of sums of squares of individual uncertainties. Units: gigatons 

carbon] 

Sources and sinks 

Fossil fuels ................................. . 

Nonfossil sources ............................ . 

Total anthropogenic input .................... . 

Ocean uptake ............................... . 

Atmospheric increase (from 288 to 352 ppm) .. . 

Net budget "imbalance" (terrestrial sink?) ..... . 

GtC 

220±25 

125±40 

345±45 

-135±25 

-140±5 

70±50 

of the concern for potential global warming caused by an 

increase in the greenhouse effect. 

Ironically, the increased research focus on C02 has 

not resolved one of the most fundamental questions: Where 

does the anthropogenic C02 go? It has long been known 

that the atmosphere retains only about half of the C02 

produced by burning fossil fuels. The fate of the other 

half- and the fate of the C02 generated by the destruction 

of terrestrial vegetation-has been the most intensely 

debated topic among C02 researchers for decades. While it 

is clear that the oceans are capable of absorbing much of the 

"missing" C02 , the absorption of C02 on land appears to be 

a necessary but very perplexing component in balancing the 

global C02 budget. 

The most powerful constraint on the C02 budget of 

the last 250 years is provided by the historical record of 

atmospheric C02 concentrations. This record can be assembled from analyses of air trapped in polar ice cores (Neftel 

and others, 1985) and, since the late 1950's, monitored 

directly at sites remote from industrial areas (Keeling and 

others, 1989a). Industrial C02 emissions can be estimated 

from production statistics (Keeling, 1973; Marland, 1989). 

Emissions from vegetation and soils can be estimated from 

land use records (Houghton and Skole, 1990). Estimates of 

ocean uptake must be based on models that integrate 

simulations of air-sea gas transfer, seawater chemistry, and 

ocean circulation. A variety of ocean models indicate 

uptake of about 30 to 50 percent of added C02 (Sundquist, 

1985; Siegenthaler and Oeschger, 1987). A C02 budget for 

the period 1850 to 1990 can be estimated (table 1) by 

subtracting the oceanic uptake and atmospheric increase 

from the sum of the fossil-fuel and nonfossil emissions. 

Although the uncertainties in the budget are large and 

Terrestrial Implications and Uncertainties in the Atmospheric Carbon Dioxide Budget 33 
A 

DECADAL INCREMENTS OF GREENHOUSE FORCING o, 

CFCs. 

G 

!. 

... -·

s 

0.08 

o, 

CFCs. 

str . 

H,O 

o, 

CFCs. 

str. 

HaO 

:·./.··: 

. t . : . . 0.04 

o, 

CFCs. 

co. :··#··: co. Fn 

NaO 8.2 

ppm 

0 CH. 

1980's 

IPER DECADEt 

B 

0.20 

12.8 

N,O ppm 

CH. 

1970's 

CH. 

15.6 

ppm 

CH. 

1980's 

DECADAL INCREMENTS OF GREENHOUSE FORCING 

11990-20301 

. :·····: . : o, : 

o, 

:cFcs.: 

: str. : 

G CFCs. ....... : H,O: str. . . !. • o, • . . -· 

H10 :cFCs.: . .... ··i··· : str • . s . . . . . . . : HaO: . . . . . co • . co. 

co. 

27.8 

20.8 23.9 ppm 

ppm ppm 

CH. CH. CHe CH. 

0 

1990's 2000's 2010's 2020's 

Figure 2. Incremental greenhouse forcings attributed to anthropogenic trace gases, 

by decade. These forcings do not include feedbacks of the global climate system, 

and therefore represent only a fraction of the total expected global temperature 

effect. Future forcings are based on a scenario of future gas emissions that assumes 

simple extrapolation of early 1980's growth rates. From Ramanathan and others 

(1985, Figure 15-22, p. 874). A. 1850-1980. B. 1990-2020. 

difficult to quantify (table 1 assumes-arbitrarily-a sumof-squares relationship among the uncertainties of individual terms), the net imbalance appe¥s to require a significant 

terrestrial carbon "sink." The identity of this sink is 

unknown. 

A similar imbalance is apparent in estimates of the 

annual C02 budget for recent years. Three estimates based 

on datafrom the 1980's are shown in table 2. Each estimate 

implies a terrestrial sink analogous to that inferred from 

table 1. Like the long-term historical budget, the annual 

C02 budget is affected by large uncertainties. For example, 

34 Proceedings of the U.S. Geological Survey Global Change Forum 

different estimates of the annual atmospheric C02 increase, 

such as those apparent in table 2, may be attributed to real 

interannual variations, which amounted to about ±25 percent (standard deviation) during the 1980's (Keeling and 

others, 1989b, table 6). 

Table 2 also shows more significant uncertainties in 

the large discrepancy between the ocean C02 uptake estimate of Tans and others (1990), which is based on ocean 

surface C02 measurements, and the ocean uptake estimates 

of Keeling and others ( 1989b) and Watson and others 

(1990), which are based on ocean models. This discrepancy 
Table 2. Three scenarios for annual carbon dioxide budgets from the 1980's 

[The budget of Keeling and others (1989b, table 10, p. 352) is from their 

summary of mean annual fluxes as of January 1, 1980. The budget of 

Watson and others (1990, p. 13), which is part of the Scientific Assessment of the Intergovernmental Panel on Climate Change (IPCC), is their 

summary estimate for the decade 1980-1989. "Scenario 6" of Tans and 

others (1990, table 4, p. 1437) is based on atmospheric C02 data for 

1981-1987 and ocean surface C02 measurements for 1972-1989. The net 

budget "imbalance" in each case is thought to represent terrestrial C02 

uptake. units: gigatons carbon per year] 

Sources and sinks Reference 1 Reference 2 

Fossil fuel burning ......... 5.3 5.4±0.5 

Nonfossil sources .......... 1.8 1.6± 1.0 

Atmospheric increase ....... -2.8 -3.4±0.2 

C>cean uptake .............. -2.2 -2.0±0.8 

Net budget "imbalance" .... 2.1 .6±1.4 

Reference 1: Keeling and others, 1989b, 1980 scenario 

Reference 2: Watson and others, 1990, IPCC scenario 

Reference 3: Tans and others, 1990, "Scenario 6" 

Reference 3 

. 3 

1.4 

-3.0 

-0.7 

--

3.0 

has direct implications for the terrestrial component of the 

C02 budget because the much smaller ocean uptake estimate by Tans and others requires a much larger terrestrial 

sink. Moreover, the location of the discrepancy can be 

specified by analysis of the latitudinal gradient of atmospheric C02 concentrations. Anthropogenic C02 accumulates in the Northern Hemisphere atmosphere more rapidly 

than it can be mixed southward (fig. 3). The resultant 

north-to-south atmospheric C02 gradient, combined with 

estimates of the rate of interhemispheric atmospheric 

exchange, constrains the rate at which C02 reaches the 

Southern Hemisphere via the Northern Hemisphere atmosphere. This constraint applies to a large fraction of anthropogenic C02 because nearly all of it is produced in the 

Northern Hemisphere. 

Both Keeling and others ( 1989b) and Tans and others 

(1990) concluded from such calculations that there must be 

a large C02 sink in the Northern Hemisphere (table 3). 

Without such a sink, the buildup of C02 in the Northern 

Hemisphere would be much higher and the latitudinal 

gradient would be steeper. Table 3 shows that Keeling and 

others attribute this sink primarily to ocean uptake, whereas 

Tans and others attribute it mainly to terrestrial uptake. 

Both budgets are defensible: Keeling and others constrain 

their simulations using atmospheric 13C as well as C02 

data, while Tans and others do not use 13C data. On the 

other hand, Tans and others show that the Northern Hemisphere ocean uptake suggested by Keeling and others does 

not appear to be consistent with the most extensive data set 

available for estimating net ocean surface C02 exchange. 

Both budgets suggest that the global biosphere is a net C02 

sink, in spite of the significant quantities of C02 released by 

deforestation. The budgets differ in their estimates of 

the magnitude of this sink, particularly in the Northern 

Hemisphere. 

Table 3. The latitudinal distribution of carbon dioxide 

uptake according to two of the scenarios summarized in 

table 2 

[The specified equatorial latitude ranges are 15.65"N-15.65°S for Keeling 

and others (1989b) and 15°N-15°S for Tans and others (1990). Negative 

sign denotes net uptake from the atmosphere; positive sign denotes net 

release to the atmosphere. units: gigatons carbon per year] 

Latitude and environment 

Extratropical Northern Hemisphere: 

C>cean ....................... 

Biosphere .................... 

Total ...................... 

Equatorial: 

C>cean ....................... 

Biosphere .................... 

Total ..................... 

Extratropical Southern Hemisphere: 

C>cean ....................... 

Biosphere .................... 

Total ...................... 

All Latitudes: 

C>cean ....................... 

Biosphere .................... 

Total ...................... 

Keeling and 

others, 1989b 

1980 scenario 

-2.6 

-0.5 

-3.1 

1.4 

0.3 

1.7 

-1.0 

-0.1 

-1.1 

-2.2 

-0.3 

-2.5 

Tans and 

others, 1990 

"Scenario 6" 

-0.6 

-2.6 

-3.2 

1.3 

1.0 

2.3 

-1.4 

0.0 

-1.4 

-0.7 

-1.6 

-2.3 

Tables 1 through 3 illustrate the extent to which the 

atmospheric C02 budget remains fundamentally unresolved. Best estimates of both industrial-era and annual 

C02 budgets suggest a net imbalance equivalent to approximately 30 to 60 percent of the production of C02 from 

burning fossil fuels. The imbalance appears to require 

uptake of an amount of C02 approaching (in the industrialera budget) or possibly exceeding (in some recent annual 

2 

II. 

.!!:. 

z 

e z 

~ z 

~ 1 

8 

(\} 

0 

u 0 

90s 60 30 0 

LATITUDE 

30 60 90 N 

Figure 3. Seasonally adjusted atmospheric C02 concentrations vs. latitude for May 1984, january 1968, January 1962. 

The curves are cubic spline fits of data from ships and 

fixed-island and coastal stations. All curves are plotted as 

differences relative to the contemporaneous atmospheric 

C02 concentration at the South Pole. From Keeling and 

others (1989a, figure 32, p. 184). 

Terrestrial Implications and Uncertainties in the Atmospheric Carbon Dioxide Budget 35 
budgets) the amount released from the biosphere by deforestation and other changes in land use. 

The inference of a terrestrial C02 sink has persisted 

through decades of carbon-cycle modeling and research, yet 

the specific identity of this sink remains elusive. Efforts to 

balance the C02 budget by direct monitoring require determining small differences between large sources and sinks. 

For example, net terrestrial C02 uptake might be calculated 

from the difference between estimates of net primary 

productivity and heterotrophic respiration. These fluxes are 

more than an order of magnitude greater than the hypothesized net uptake. The resolution of such differences is 

inherently limited by uncertainties arising from spatial and 

temporal variability of large sources and sinks. Global 

monitoring of net C02 exchange with the biosphere is not 

yet feasible. The studies by Tans and others and by Keeling 

and others show how monitoring of oceanic and atmospheric C02 uptake may constrain net biospheric C02 

exchange at least as accurately as direct monitoring of the 

biosphere. However, the history of C02 research suggests 

that atmospheric C02 budgets will not be widely accepted 

unless they can be related to specific identifiable C02 

exchange processes. 

REFERENCES 

Houghton, J.T., and others (eds.), 1990, Climate change: The 

IPCC scientific assessment: Cambridge: Cambridge University Press. 

Keeling, C.D., 1973, Industrial production of carbon dioxide from 

fossil fuels and limestone: Tellus, v. 25, p. 174-198. 

Keeling, C.D., and others, 1989a, A three-dimensional model of 

atmospheric C02 transport based on observed winds: 1. 

36 Proceedings of the U.S. Geological Survey Global Change Forum 

Analysis of observational data, in Peterson, D.H., ed., 

Aspects of climate variability in the Pacific and the Western 

Americas: Geophysical Monograph 55, Washington, American Geophysical Union, p. 165-236. 

---1989b, A three-dimensional model of atmospheric C02 

transport based on observed winds: 4. Mean annual gradients 

and interannual variations, in Peterson, D.H., ed., Aspects of 

climate variability in the Pacific and the Western Americas: 

Geophysical Monograph 55, Washington, American Geophysical Union, p. 305-363. 

Marland, G., 1989, Fossil fuels C02 emissions: three countries 

account for 50% in 1986: CDIAC Communications (Carbon 

Dioxide Information Analysis Center, Oak Ridge National 

Laboratory), Winter 1989, p. 1-3. 

Neftel, A., Moor, E., Oeschger, H., and Stauffer, B., 1985, 

Evidence from polar ice cores for the increase in atmospheric 

C02 in the past two centuries: Nature, v. 315, p. 45-47. 

Ramanathan, V., and others, 1985, Trace gas effects on climate, 

in Atmospheric Ozone 1985: World Meteorological Organization, Global Ozone Research and Monitoring Project, 

Report Number 16, v. 3, p. 821-893. 

Siegenthaler, U., and Oeschger, H., 1987, Biospheric C02 

emissions during the past 200 years reconstructed by deconvolution of ice core data: Tellus, v. 39B, p. 140-154. 

Sundquist, E. T., 1985, Geological perspectives on carbon dioxide 

and the carbon cycle, in Sundquist, E.T., and Broecker, 

W.S., eds., The carbon cycle and atmospheric C02 : natural 

variations Archean to present: Geophysical Monograph 32, 

Washington, American Geophysical Union, p. 5-59. 

Tans, P.P., Fung, I.Y., and Takahashi, T., 1990, Observational 

constraints on the global atmospheric C02 budget: Science, 

v. 247, p. 1431-1438. 

Watson, R.T., and others, 1990, Greenhouse gases and aerosols, 

in Houghton, J.T. and others, eds., Climate Change: The 

IPCC Scientific Assessment: Cambridge, Cambridge University Press, p. 1-40. 
Land Data and Information Management 

Donald T. Lauer 

National Mapping Division 

U.S. Geological Survey 

Science-we'll use adjectives-it's interesting, it's 

exciting, it's challenging, it's rewarding, and it's important. 

Data management, it's ... um, it's ... well, it's important. 

Our attitude truly has to change, and my attitude has. 

I don't know if I'm a scientist anymore, and I'm certainly 

not a data manager, but I do see the challenges. These 

challenges are evident to all of us as we do our research in 

a different context than we've done in the past. 

Let me ask you five questions. Think about them. 

First, are you sure, when you set out to do your 

research, that all the available data in your topical area or 

region are readily available to you? Are you sure that you 

can determine what data exist? Are you satisfied with the 

availability of current data? 

Second, what makes you sure that you have access to 

all the data that might be available in your area of interest? 

Is there a chance that you know data are available, but you 

can't access the data? 

Third, how about the information about the data you 

seek? This introduces a new term, "metadata," or information about data. Are you fully satisfied with the way the data 

that you seek from other sources are identified and characterized? 

Fourth, how about your data? Are your data available 

to the science community? You'd probably say "Yes, my 

partner here works with me; the data are available." How 

about the metadata that describe your data so that this data 

could be more readily available to other scientists? I'm not 

talking about your close colleagues. If you are a geologist or 

a hydrologist, are your data available to a forester? a 

biologist? a social scientist? Are the data that you worked 

with and the metadata about the data readily available and 

documented in a manner so that someone in a totally 

different field of study can access and fully understand the 

data? Could someone in a different field acquire your data 

for their studies on Earth systems and global change? 

Fifth, what about the mechanisms that you use to 

ensure that your data are available? These data can be in the 

form of reports or hand-recorded field information, or the 

data might be on floppy disk, hard disk, or magnetic tape. 

What mechanisms are you using to ensure that there's ready 

access- not necessarily to the results of your work but to 

the data? 

Clearly, we are facing some serious challenges in the 

area of data and information management. The Survey is a 

partner in this national research program, and we must 

make a commitment together to improve our attitude toward 

data management. 

The scientific objectives of the Nation's global 

change research program are to measure the health of the 

planet, to improve our understanding of Earth system 

processes, and to make predictions for the future. Furthermore, there is a commitment to have open access to much 

of the data, eventually all of that data, that contribute to 

carrying out these objectives. 

Policies are emerging because of the importance of 

data management. One important policy is a commitment to 

data preservation, starting now. We have an early commitment to maintaining and preserving data. 

A policy of easy access is also important-which gets 

back to my five questions. We need to pay more attention to 

data commonality in the area of data access. The way we, 

in our discipline areas of hydrology, mapping, and geology, 

exchange either data or metadata with scientists in other 

disciplines will lead to the establishment of data standards. 

Often, as researchers, we don't like to follow standards, but 

they are essential if we expect to provide data access with 

any degree of efficiency. 

Another important policy is to make data available at 

the lowest possible cost so that researchers throughout the 

world can have access to this data without having to spend 

a large part of their research budget on acquiring the data. 

These policies point to the fact that the way we 

manage our data now may be unacceptable. In a single 

discipline, we take a single data set, and we share it only 

with our closest colleagues. In the future, we must develop 

new techniques, new infrastructures, and new capabilities 

for handling increasingly large volumes of data. We used to 

talk about kilobytes of data, then megabytes, now 

gigabytes, and next is terabytes; it just kind of flows off the 

tongue. What is 1,000 terabytes? A petabyte. I really don't 

know how many that is. All I know is that it's a lot of those 

little hummers. These are the terms that we're starting to 

use as we look to the future. 

We've started some new initiatives within the Survey 

in the last 12 to 18 months. 

The first one on the list is Landsat data maintenance 

and conversion. I won't say too much about this job other 

that it's big, and, unfortunately, among NASA, NOAA, 

and the Survey, it has not been done very well. 

The second initiative is called data set development. 

The purpose of this activity is to roll up our sleeves and get 

Land Data and Information Management 37 
some experience with new and different types of data that 

are regional, continental, and global in scale. 

The third initiative is to develop a global land 

information system-to help understand what's available, 

who has it, where it is, how to process it, how to get it into 

digital form, how to enter it into an information system, and 

maybe how to create some derivatives from it. 

Let's take these new initiatives in ascending order. 

The global land information system-here we're 

looking at a conceptual plan for building an information 

system but of a different type than we're accustomed to. 

Our plan is to look at the information systems within our 

own organization; to look at what NASA, NOAA, and EPA 

have done; and then to glean the good from each of these 

existing systems to conceive a land information system that 

deals with nontraditional types of data. I'rri talking about 

metadata, an information system that contains metadata and 

only metadata but a system that contains different types of 

metadata and that has improved query, access, and network 

efficiencies. 

The types of data that you would want in a global land 

information system would include land cover, terrain, soils, 

and satellite observations. Only in a few cases would the 

data actually reside in the Survey. Most often, the data 

would reside someplace else. But we have a congressionally 

mandated responsibility to conceive an information system 

that will provide access to a wide variety of data held by 

different organizations. 

There are basically three levels of query in the global 

land information system, starting with a very general 

directory-like the Survey's Earth Science Data Directory 

and NASA's Master Data Directory-where someone can 

log into the system and say, "I'm interested in soils data of 

the world. What's available?" The directory could point to 

work done by the United Nations Food and Agricultural 

Organization (FAO), by the International GeosphereBiosphere Program, or by the Soil Conservation Service. 

The directory gives quick, generalized information. 

The second level of query is the guide, sometimes 

called a catalog. If you were searching for FAO soils data, 

you might ask "What is this data? How were the data 

acquired? What kind of instrumentation was used? How 

reliable are the data?" Answers to these questions are found 

in the guide. 

Inventory information is contained in the third level 

of query. Here one can find the detailed parameters associated with the data and what geographic areas are covered. 

Instructions on how to access the data also are included in 

the inventory. 

Anybody in the Survey or another government agencyand eventually anybody in the world -can log into the 

global land information system through INTERnet, 

ETHERnet, NASAnet, GEOnet, or other existing "nets." 

Connection to the information system can be made with a 

38 Proceedings of the U.S. Geological Survey Global Change Forum 

terminal, PC, or workstation, providing real-time access to 

the metadata files. 

In some cases, the information system will be 

extended to include not just text files but also graphic 

displays, particularly with image data. When we are dealing 

with satellite images, often someone will want to know 

what the data look like. If there are clouds in the data, they 

will want to know where the clouds are located. 

The satellite images can be sampled by selecting a 

portion of the total number of picture elements in the 

original image. The sampled data form a coarse resolution 

image that easily can be stored, retrieved, and displayed 

along with the metadata that describe the image. Thus, a 

person can perform searches by geographic area and then 

display the images of interest-taken during periods of high 

rainfall, snowfall, whatever-and actually see at least 

sampled portions of the image. 

That's just a quick introduction to the first activity 

that is part of the new data management initiatives within 

the Survey. 

The second data management initiative is called 

global data set development. Global data set development 

provides an opportunity to gain some experience with very 

large data sets. But first, we need to know who wants what. 

Who are these Earth system modelers, and what kind of 

data do they need? From the literature and from one-to-one 

conversations with modelers, we know that information 

about physical parameters, rates of processes, nominal 

classifications of the landscape, rates of change, and types 

of change is the kind of data needed, but at regional, 

continental, and global scales. 

We searched for several global data sets. 

The first was vegetation. What's the best vegetation 

data set available in the world? We didn't find much. Elaine 

Matthews, at the Goddard Institute for Space Studies, 

created a global vegetation map from a variety of sources. 

Part of our effort is to characterize that data, with her help, 

and to make sure that the data and the metadata are available 

in an information system like the global land information 

system I just described. 

Another global data set describes the world's ecosystem. J.S. Olsen, J.A. Watts, and L.J. Alison have done this 

kind of work at Oak Ridge National Laboratories in Oak 

Ridge, Tenn. Again, interpretations were compiled using a 

variety of source material. Soils interpretations have been 

made by Leonard Zobler (Columbia University, New York, 

N.Y.) from the FAO's global soils map. 

Global elevation data-this material goes way back if 

you track its original source-can be acquired from 

NOAA's National Geophysical Data Center in Boulder, 

Colo. These data are referred to as ETOP05 and have 

5-minute grid cell spacing, which is about the best we have 

of the entire globe. 

Land use and land cover mapping are areas of 

expertise within the Survey. What's available of the world? 
Probably the best product has been generated by the 

Soviets. We are working with the University of New 

Hampshire to convert the Soviet maps to digital form, to 

show the data in various map projections, to compile the 

attribute files after digitization, and to make the data 

available to the science community. 

What about satellite data? One example of Earth 

observation data is that acquired from the polar-orbiting 

NOAA satellites using the Advanced Very High Resolution 

Radiometer. That sensor system provides data at about 

1-kilometer resolution. Multiple passes are acquired each 

day across the country. These passes are mosaic ked, geometrically corrected, and then registered on each successive 

day, one image after another. A normalized difference 

image is calculated to obtain an index of the condition of the 

vegetation or a measure of greenness-the difference 

between the red and the infrared channels, divided by the 

sum of the two, provides an index image that closely 

approximates the condition of vegetation occurring on the 

Earth's surface. 

An interesting aspect to using satellite images for 

assessing vegetation condition is that it can be done in 

1-week, 2-week, 3-week, or monthly intervals throughout 

an entire growing season with today' s computer processing 

facilities. In fact, we're doing this on 12-year-old V AXes. 

It sometimes takes a long time, particularly to merge the 

vegetation index data with other data sets and to do more 

complex processing tasks, but these satellite data provide a 

new way of looking at the Earth and its temporal cycles. 

Clearly, Earth observations from space will help us 

measure the health of the planet, especially when the 

satellite data are merged with other data sets that may or 

may not come from the Survey, such as elevation models, 

digital line graphs, major land use areas, land cover, 

ecoregions, and climatic zones. 

We are doing everything in our power to identify data 

sources of the world and to make those data available to the 

science community. I'm excited about combining the technologies of satellite image processing and geographic information systems to develop a data base that can be used to 

characterize the landscape. 

We now have an agreement with the Canadian 

government to expand this work from the conterminous 48 

States to all of North America. We'll work with the 

Canadians on creating a comprehensive land surface characterization data base for the entire continent. And then, 

wouldn't it be nice if we could do this for the globe? I think 

this is within reach when we're talking about a long 

program of 15 to 20 years. 

Part of this effort is to make these regional, continental, and global data sets available to the science community 

at the lowest possible cost. Right now, the time-sequence 

greenness data over the conterminous United States for the 

1990 growing season, all of those multiple data sets, can go 

on five CD-ROM's. You can get three gigabytes of data for 

$160. 

The preservation of Landsat data is the third data 

management initiative being addressed by the Survey. First 

of all, does the Earth science community care whether 

Landsat data are properly maintained? Some scientists do. 

Scientists being trained in graduate school todayscientists who are going to reach their prime in 15 to 20 

years-might want to know, for example, what Kuwait City 

looked like in January 1991 as the Iraqis pulled out. Using 

Landsat imagery, you can count between 600 and 1,000 

fires burning out of control near Kuwait City. The science 

community, particularly the United Nations Environment 

Program, is worried about the impact these fires are having 

on the environment. They're worried about oil spills in the 

Persian Gulf. They're worried about disturbances to the 

desert varnish. 

Preserving that data is difficult. If you think it's 

difficult to store your data on floppy disks or on hard disks, 

visit the Landsat data archive. Some of the data are on 

lf2-inch tapes-tens of thousands of high-density tapes. 

The first 400,000 scenes of Landsat data, acquired 

between 1972 and 1978, were delivered to us from NASA. 

There's no system available today that can even process 

these data. The computers built by NASA in the late 1960's 

to process these data are gone. The people of the United 

States have paid more than $1.5 billion to fly Landsats 1 

through 5. More than 1 million Landsat scenes are archived 

at the EROS Data Center, 40 percent of which cannot come 

out of the plastic storage bags because the systems to 

process these data don't exist anymore. We're not even sure 

these data can be read. 

Our priority activity is to preserve the most recent 

Landsat data-the thematic mapper data acquired since 

1982. 

The experience we are gaining with Landsat data will 

serve us well when managing satellite data acquired by 

future space systems, such as the planned Earth Observing 

System (EOS). The Survey is a partner with NASA for 

EOS. The EROS Data Center will be a distributed active 

archive center for land data acquired by EOS-which is 

another example ofthe Survey's commitment to a long-term 

program of data and information management. 

In summary, the Survey is taking the subject of data 

and information management very seriously. In this presentation, I have touched on the global land information 

system as an example of a prototype system for managing 

information about data, called metadata. I have talked about 

data set development in support of climate change research, 

about the Landsat data preservation problem, and about the 

Survey's anticipated role in EOS. When carrying out 

current responsibilities associated with data management, 

we have found both challenges and rewards. But I think we 

do not need to change our attitudes. I've certainly changed 

mine. 

Land Data and Information Management 39 
Developing a Sound Basis for National Policy 

Allan Bromley 

Assistant to the President for Science and Technology 

It is indeed a pleasure to be here with you in this first 

of the interdivisional workshops on the interagency U.S. 

Global Change Research Program. These last few years 

have represented a remarkable achievement in terms of 

coordinating and developing the program. The President 

and all of us in the Bush Administration are very much 

indebted to your director, Dallas Peck, for the leadership 

that he has provided. 

A remarkable cross section of agencies, 19 in all, 

have been brought together-and I think it represents a first, 

both inside and outside of government-in a cooperative, 

collegial spirit to put together a program that represents 

something of which the nation can be proud. It is a coherent 

and integrated program rather than just a heterogeneous 

combination of 19 different programs that happened to boil 

up through 19 different agencies. 

Those of you who have ever been involved in 

coordinating anything among quite independent agencies 

understand what an accomplishment this represents. Agencies have been convinced to go back home and recraft their 

programs so that they fit into a national program rather than 

furthering a particular private aim of somebody in the 

bowels of that particular agency. In the years ahead, the 

success of this program is going to depend critically on the 

efforts of a great many of our agencies working together 

with the same kind of cooperation, understanding, and, in 

fact, trust. 

We will keep looking to the Geological Survey to 

provide the major leadership, not only in the overall 

program but in the special areas of hydrology, hydrologic 

systems, Earth systems history-particularly having to do 

with paleoclimates, paleohydrology, and paleoecology-solid Earth processes, land characterization, and land 

data management. 

I want to take this opportunity to emphasize the 

importance that all of us back in the White House place on 

data management, because that's going to be one of the very 

key elements of your work in the years ahead. You're 

fortunate that the U.S. Global Change Research Program 

has at its disposal the EROS Data Center, and someday 

somebody is going to tell me exactly what the EROS Data 

Center contains. My misspent youth had enough Greek and 

Latin to make this a fascinating question. 

One of the important things to keep in mind is that 

data management is a very real problem. When EOS-A is 

functioning as we expect it to function, it will deliver data 

equivalent to the entire Library of Congress every 4.8 days. 

Unless we have made some major steps in the high 

40 Proceedings of the U.S. Geological Survey Global Change Forum 

performance computing and communications program that 

is one of the President's initiatives this year, we will be 

swamped by all these data. 

We have an opportunity, however, to develop our 

information-handling capabilities in parallel with the work 

that you're involved in. When the need arises, we'll be in 

great shape to digest, analyze, and present these huge 

amounts of data in fashions that use the remarkable ability 

of the human to sense patterns and to develop hypotheses 

based on graphical information. 

A useful piece of information is that 75 percent of 

whatever fraction of your brain happens to be working is 

devoted to visual processes. I would not dare to guess at 

what that fraction is. 

Visual processing is something that we have not taken 

nearly as much advantage of as we should have in the past. 

But with the new supercomputers that are now available to 

us, for the first time we can build the interface between vast 

amounts of data and human perceptions and analytic abilities in an entirely new way. 

I don't think I need to tell anyone in this room that, 

over the past century and a little more, we have been 

engaged in what is unquestionably the largest unplanned 

experiment that our species has ever attempted on the 

planet. 

We've altered the face of the Earth in irretrievable 

fashion by clearing forests, building cities, and converting 

wild lands to agriculture. We've changed the composition 

of the Earth's atmosphere; in fact, the carbon dioxide that 

we've put into our atmosphere represents the largest single 

impact that our species has had on the planet. 

It is not surprising that we have now reached a point 

where we have to face the possibility that those changes can 

lead to unpleasant consequences. They may be large or 

small; we're not sure yet what their magnitude or timing 

might be. But it's clearly a global problem that can be 

addressed only at a global level with a vast amount of 

goodwill. And those of you who have been attending the 

meetings of the framework negotiating session just recently 

completed will recognize that we have some distance to go 

in developing goodwill in the international global change 

arena. 

One of the things that would make our life vastly 

easier would be if there were any sort of clear, unequivocal 

understanding of the phenomena that we're dealing with. If, 

for example, it were possible to associate the warmer-thanaverage years of the 1980's with a greenhouse effect, then 

the policy decisions that we would have to make to respond 
to that effect would be vastly simpler than they are in the 

present situation, where it is far from obvious what is cause, 

what is effect, and exactly where we're headed. 

It is also true that the global circulation models-the 

major computer models that we have come to depend on to 

predict the future of climate change-are not nearly as 

complete or as fine grained as we would like them to be or 

as they will need to be if we are to use them as the basis for 

sound national policy. 

It is very important for us, as people making policy, 

to remind ourselves from time to time about what we do 

know about the system and what we do not know about the 

system. We know, for example-and none of this is going 

to come as great news to many of you in this room, but it's 

worthwhile simply listing some of these things-that for the 

past 100,000 years, global average temperatures and atmospheric carbon dioxide have risen and fallen together, at least 

on a large scale. We also know that the atmospheric loading 

of carbon dioxide has increased by about 25 percent since 

preindustrial times. 

We have excellent measurements from the Mauna 

Kea equipment that allows us to average over much of the 

Pacific basin. We also know that other greenhouse gases, 

like the chlorofluorocarbons and methane, have increased 

much more rapidly. In the case of methane, we don't fully 

understand why this is happening, and our monitoring and 

measuring techniques are not as good as they might be. 

We know, too, that the global circulation models 

predict an average surface temperature increase of between 

1.5°C and 4.5°C for a doubling of the equivalent carbon 

dioxide loading. I say equivalent to take into account all of 

the greenhouse gases on a comprehensive equivalent basis. 

Finally, I think most of you in the room and most 

scientists anywhere would agree that the average temperature of the planet has increased by somewhere between 

0.3°C and 0.6°C over the past century. 

Each of those statements is the result of hard-won 

evidence obtained by people like yourselves working in 

your own special fields. It's been difficult, and the most 

difficult part of all is the fact that there is still a tremendous 

number of uncertainties associated with many of these data. 

Let me mention just a few of them. 

Regarding the warming of the last century, I think 

you would all agree that it is not scientifically possible to 

associate in an unambiguous way the warming that we 

believe we see with a specific greenhouse effect. 

First of all, the behavior of the warming doesn't agree 

with what you'd expect from a simple greenhouse phenomenon. The systematic decrease in the global temperature 

from about 1940 to 1970 is certainly not something you 

would expect as you increase the flux of greenhouse gases 

into the atmosphere. 

One of the things we have to keep in mind is that we 

know from our measurements that the global temperature 

does fluctuate. Either we could be observing a fluctuation, 

or a fluctuation could be masking a much larger increase, 

because of a greenhouse effect, than we have thus far seen. 

We have to find out which of these is the case. 

Regarding the paleoecological connection between 

carbon dioxide and temperature, it is enormously important 

to be able to say with certainty which is the leading 

phenomenon. Does the temperature increase result because 

of an increase in carbon dioxide, or does the carbon dioxide 

result in an increase in temperature? Despite a number of 

claims that this question has been resolved, I think the jury 

is still out; we really do not know which is which. 

As far as the general circulation models are concerned, remarkable progress has been made. It remains the 

fact, however, that of the six major global circulation 

models, three predict that if we were to double the equivalent greenhouse gases, the American Midwest would get 

hotter and drier, and the other three say it would get colder 

and wetter. That's the kind of fundamental scientific information that is extraordinarily helpful as you try to make 

policy decisions. 

What we have to do, clearly-and one of the major 

challenges for you and the research program that you and 

the Committee on Earth and Environmental Sciences have 

pulled together-is to try to improve this regional predictive 

capability. In the absence of regional predictions, it's well 

nigh impossible to apply economics to the situation, and in 

the absence of economics it's extremely difficult to make 

sensible policy. 

It's also a little startling to those who are not experts 

in the field to realize that over the past 18 months we appear 

to have lost a quarter of all the carbon in the global carbon 

cycle. As you well know, we have always thought and 

taken as an article of faith that 50 percent of the carbon 

dioxide that goes into the atmosphere is immediately 

absorbed by the oceans, leaving 50 percent in the atmosphere. Over the last 2 years, however, the actual measurements of carbon dioxide partial pressure in the Earth's 

oceans, primarily by U.S. and British ship instrumentation, 

have shown that the fraction is much nearer to 25 percent. 

Where is the other 25 percent? There are many 

hypotheses. Perhaps the increased carbon dioxide has fertilized plant life in the temperate zones and the missing 

carbon is in the biomass in the temperate latitudes. We 

don't know, and it's something that we have to find out. 

We also know that passive microwave radiometry 

from satellites has given us the ability to do precise 

temperature measurements from satellites over long periods. This is surprising, because I don't think anyone 

believed that the calibrations would remain fixed. Still, 

there are mysteries left even when we have these precise 

measurements. For example, the fact that the average global 

temperature, measured over the entire planet rather than in 

just a few isolated measuring locations, did not increase at 

all from 1979 to 1989, during a period of major increase in 

greenhouse loading, is a puzzle. 

Developing a Sound Basis for National Policy 41 
Another remarkable new development is the ideas 

that Broecker and his colleagues have produced to the effect 

that the global circulation in our oceans may not be as 

permanent as we have thought. There may be more than one 

stable configuration. A suggestion has been made, for 

example, that when the North American mid-continent sea 

broke into the Atlantic through the Saint Lawrence waterway, it flipped the circulation in a major way and turned off 

the Gulf Stream, producing fundamental changes in climate 

worldwide. We don't know whether that happened or not, 

but it's a fascinating idea and deserves a tremendous 

amount of additional study. 

The last thing I would mention is that Intergovernmental Panel on Climate Change (IPCC) documents suggest 

that if we are to achieve the goals that the IPCC finds 

appropriate, we should make something like a 60- to 

80-percent reduction in anthropogenic carbon dioxide emissions. That's going to make a significant difference in the 

ways we do business and live our lives. It bears emphasis, 

however, that the anthropogenic fluxes are slightly less than 

one-twentieth of the natural fluxes. A 2- to 3-percent 

change in a natural sink could therefore have the same 

overall effect as this 60-percent change in anthropogenic 

emissions. Conceivably, this could be done with much less 

turmoil and difficulty for our society. It obviously merits 

study. 

But if anybody tells me he is about to grind up a 

battleship and sprinkle it around Antarctica, I'm going to be 

very uneasy until a number of bathtubs have been filled up 

with ground-up battleship to see just what else happens 

when you do this. It's a marvelous idea to fertilize and 

increase the level of biological material that, at least on the 

basis of our present information, we believe to be limited by 

the availability of iron. But it certainly needs some study 

before we plunge ahead. We have tended to take the 

approach in the past of "damn the torpedoes" -if there's a 

technology, let's implement it. We have learned that this 

can lead to some very unhappy situations. 

Given all these uncertainties, how best can we, as a 

Nation, approach this issue of greenhouse warming? Obviously, this is an area where we are looked to by much of the 

rest of the world for leadership, although we have been 

accused of dragging our feet by some nations. We have 

been accused of not wishing to exert leadership. We have 

been accused of a great many things. 

42 Proceedings of the U.S. Geological Survey Global Change Forum 

One of the most important things we can do is 

represented by the U.S. Global Change Research Program. 

Understanding the system a lot better than we do now is a 

major challenge. I think the coordinated multiagency program that Dallas and his colleagues have put together is 

something of which we can be proud. Since the President 

took the first program plan with him to the economic 

summit in Paris and delivered it to all the other heads of 

state, it has been considered a prototype for a proper 

national program in many fields of activity. 

The program, as Dallas has spelled it out, has three 

fundamental objectives: to document the Earth's system 

through coordinated, integrated observations; to improve 

our scientific understanding on the basis of these data; and 

to develop the capability to predict what is going to happen 

both in the short-term and in the long-term and both in the 

global sense and in the regional sense. 

We are, I hope, about to see major progress in the 

development of both the space-based and ground-based 

components of this program. Very large systems like EOS, 

the Earth Observing System, a key part of Mission to Planet 

Earth, get more press and more attention than do the equally 

important developments that are taking place on the surface. 

But it is only by putting both space- and surface-based 

activities together that we can hope to answer the fundamental questions. 

I want to conclude by again complimenting the 

Committee on Earth and Environmental Sciences for the 

remarkable accomplishment that this U.S. Global Change 

Research Program represents. It is something that even a 

few years ago people would not have believed possible. It is 

something that business schools are talking about making 

into a case study. That's the ultimate measure of success. 

The most important thing is the translation of good 

science, good technology, and good economics into good 

policy. That's the challenge for all of us in the Federal 

Government, and it's one toward which we're making 

progress. 

It is a pleasure to have been here with you to ensure 

that you get your lunch and also to talk to you about the 

remarkable job that all of you have done. It's an activity of 

which you can be justly proud. No other nation has anything 

like the group of people who are represented in the room 

today. We count on you for a tremendous amount of the 

understanding on which we will build a very important part 

of our future. 
The Receding Threat From Global Warming 

Patrick J. Michaels 

Department of Environmental Sciences 

University of Virginia 

One popular and apocalyptic vtswn of the world 

influenced by increasing concentrations of infraredabsorbing trace gases is that of ecological disaster brought 

about by rapidly rising temperatures, sea level, and evaporation rates. This vision was developed from a suite of 

climate models that have since considerably reduced their 

estimates of prospective warming. Observed temperatures 

indicate that much more warming should already have taken 

place in the Northern Hemisphere and that night, rather than 

day, readings in that hemisphere show a relative warming. 

A high-latitude polar night warming or a general night 

warming would be either benign or beneficial. Further, a 

large number of plant species show both increased growth 

and greater water use efficiency under enhanced carbon 

dioxide. 

An extensive body of evidence now indicates that 

anthropogenerated sulfate emissions are mitigating much of 

the warming and that increased cloudiness as a result of 

these emissions will produce primarily night, rather than 

day, warming. These observations could drastically alter 

the debate on global warming in favor of less interventionist 

policies. 

Virtually all scientists directly involved in research on 

climatic change believe that the Earth will undergo some 

warming as a result of the increase in anthropogenerated 

emissions that absorb infrared radiation or enhance the 

"greenhouse effect." However, within certain broad limits, 

how much the world warms is irrelevant. Rather, the critical 

policy question is how the world will warm, because the 

real effect will be expressed by its regionality, seasonality, 

and distribution within the day-night cycle. As a result of 

these factors, there are now several compelling lines of 

evidence that indicate that the chance of an ecologically or 

economically disastrous global warming is becoming more 

remote. These findings are at considerable variance to what 

might be referred to as one vision of apocalyptic warming: 

global temperature change of approximately 4°C, pronounced sea level rise because of the melting of major areas 

of land ice and thermal expansion of water, and starvation 

and civil strife resulting from ecological chaos. 

It is interesting to note that the 19th-century calculations of Arrhenius, which projected a net global warming of 

approximately 5°C for a doubling of carbon dioxide, are 

usually cited as an argument for the robustness of the 

apocalyptic vision, inasmuch as projected warming by 

much more complete general circulation climate models in 

the mid-1980's gave roughly the same answer. What was 

usually neglected in this citation is that Arrhenius also 

wrote, in the same paper, that the warming would be greater 

in winter than in summer, that it would tend to occur at the 

high latitudes (and therefore concentrate in polar night), and 

that a primary effect would be to diminish the temperature 

range between day and night-that is, that night temperatures would be those primarily affected. For reasons 

described below, this is hardly the formula for the climate 

disasters implied in the apocalyptic vision. 

While that vision is accommodated by more lurid 

interpretations of the recent Intergovernmental Panel on 

Climate Change (IPCC) Policymakers Summary (1990), it 

is not even characteristic of the median range of climate 

impacts suggested in that report. Rather, that vision became 

prominent because of two synergistic events. The first was 

the publication of a generation of general circulation model 

(GCM) climate simulations in the mid- to late 1980's: These 

predicted a mean global warming of 4.2°C with winter 

warming of as much as 18°C for the North Polar regions 

(Hansen and others, 1984; Manabe and Wetherald, 1980; 

Mitchell, 1983; Schlesinger, 1984; Washington and Meehl, 

1983). The second was the congressional testimony of June 

23, 1988, that there was a "high degree of cause and effect" 

between current temperatures and human greenhouse alterations (Hansen, 1988). 

Nowhere in that testimony, and to my best knowledge 

nowhere else, did NASA's James Hansen ever state that the 

anomalously warm summer of 1988 in the United States 

was caused by human alterations of infrared-absorbing trace 

gases. Nonetheless, the press and the public concluded 

otherwise: 70 percent of the respondents to a subsequent 

CNN (1988) poll agreed with the statement that the 1988 

drought was in fact caused by "the greenhouse effect." 

There is little doubt that such unanimity in fact does reflect 

a commonly held vision. 

In the light of that vision, we examine here the 

problems of ( 1) global and hemispheric temperature histories and trace gas concentrations, (2) artificial warming 

from urban heat islands, (3) high latitude and diurnal 

temperatures, (4) more recent climate models, (5) direct 

effects on vegetation of an increase in carbon dioxide, and 

(6) compensatory cooling from other industrial products. 

Also included at the end is a personal projection based on 

my interpretation of these findings. 

The Receding Threat From Global Warming 43 
TRACE GAS CONCENTRATIONS AND 

TEMPERATURE HISTORIES 

Although there are several infrared-absorbing trace 

gases that have increased as a result of anthropogeneration, 

almost all of the current radiative forcing is associated with 

(in descending order), carbon dioxide, methane, nitrous 

oxide, and chlorofluorocarbons. As a result of their infrared 

absorption and the concentration of these species in the 

lower atmosphere, an increasing, but very small, fraction of 

energy that would normally escape to space is redirected 

toward the Earth's surface, resulting in increased warming. 

The sensitivity of the current mean surface temperature is 

thought to be about 1 oc for every additional w/m2 of 

downward-directed radiation. 

Continuous instrumental records of C02 concentration date from the late 1950's at Mauna Loa Observatory, 

where the 1958 annual average was 315 ppm. The concentration now is near 354 ppm. "Preindustrial" (circa 1800) 

concentrations were initially assumed to be in the range of 

295 ppm (Schlesinger, 1982), giving a change between 

1800 and the mid-1980's (level: 335 ppm) of 14 percent. 

Assuming that change alone accounts for a change in total 

radiative forcing of approximately 0.7 w/m2

, the observed 

warming of approximately 0.5°C in the last 100 years 

certainly seemed consistent with the changes in trace gases 

that were assumed in the early 1980's. 

Since then, estimates of the background C02 concentration have dropped somewhat, and the calculated contributions by other anthropogenerated infrared-absorbing 

gases have increased dramatically. Initial ice-core studies 

gave a background of 270 to 290 ppm, with a most likely 

value of 279 ppm (Neftel and others, 1985). Another 

analysis obtained a lower bound of 260 ppm (Raynaud and 

Barnola, 1985). The Soviet/French work on the long 

Vostok core seems to corroborate the lower values (Lorius 

and others, 1987), which, if assumed to be 270 ppm, results 

in an anthropogenerated rise of 31 percent to date. This 

would increase the flux of downwelling radiation by 

approximately 1.5 w/m2 , which would have increased 

global mean temperature approximately 1.5°C if other 

factors were not either delaying or mitigating the warming. 

Other greenhouse gases, notably methane, nitrous 

oxide, and the chlorofluorocarbons, have also increased 

considerably. The current climate forcing of methane is 

nearly 40 percent of the effect of increased C02 (Craig and 

Chou, 1982). The radiative effect of all of the non-C02 

trace anthropogenerated greenhouse enhancers is approximately an additional 80 percent of that caused by a change 

in C02 alone. Thus the current effective C02 concentration 

is approximately 420 ppm, or 151 to 161 percent of the 

background range of 260 to 279 ppm. The IPCC (1990) 

corroborates this by stating that "greenhouse gases have 

increased since pre-industrial times ... by an amount that is 

44 Proceedings of the U.S. Geological Survey Global Change Forum 

radiatively equivalent to about a 50 percent increase in 

carbon dioxide," which gives a current effective value of 

390 to 420 ppm. By all calculations, we have already 

proceeded more than halfway to an effective doubling of the 

background C02 concentration. 

While the citation is often made that the history of 

global temperature as "at least not contradictory to" the 

mid-1980's climate model projections (MacCracken and 

Kukla, 1985), those models produce an expected equilibrium warming for this trace gas change of approximately 

2.5°C, while a least-squares fit of the entire set of Jones and 

Wigley global data gives a rise of 0.45±0.10°C in the last 

100 years (Balling and Idso, 1990). Further, virtually all of 

the warming of the northern hemisphere was prior to the 

major postwar emissions of the trace gases (Jones, 1988). 

This discrepancy is further compounded by the fact that the 

"water" (southern) hemisphere, which should warm up least 

and slowest, in fact shows the more "greenhouselike" 

signal. 

Least-squares analyses of the Jones and Wigley 

global record demonstrate that fully 90 percent of the 

warming of the global record took place prior to 1945. At 

this time the actual C02 concentration was in the range of 

307 ppm and the effective concentration was approximately 

322 ppm. This is only one-third of the total forcing to date 

and implies that there has been very little warming during 

the period in which the majority of the radiative forcing has 

taken place. 

Oceanic thermal lag may not in fact account for the 

difference. Wigley (1987) calculated, using liberal estimates of the lag, that the hemisphere should still have 

warmed l°C (primarily after 1950), and the net global 

warming since then is in fact approximately 0.30°C. Sea 

surface temperature analyses of Bottomley and others 

(1990) and Oort and others (1989) demonstrate very little 

lag between that record and land readings. 

URBAN HEAT ISLANDS AND LONG-TERM SITE 

BIAS 

Localized warming related to urban buildup has long 

been recognized as a confounding factor in regional and 

global temperature analyses. While causes include changes 

in the surface energy balance, local wind flow, and amount 

of open sky, precise calculations on the various components 

of the "urban effect" are not available. However, Karl and 

others (1988) have found in the United States that the effect 

is statistically detectable at population levels of 2,500 and 

up, and Balling and Idso (in press) note the effect at 

population levels as low as 500. The temperature record is 

further confounded by the fact that exponential population 

increases suggest the urban warming bias should be of the 

same functional form as enhanced greenhouse forcing and 

will therefore contaminate the latest years of temperature 
measurement. In other words, it would be striking if the last 

years in the record weren't the warmest. 

Karl and others (1988) have created a deurbanized 

"Historical Climate Network" (HCN) of 492 stations that 

have been checked for instrumental and location changes 

and adjusted for population. While this record applies only 

to the coterminous United States and is therefore not 

necessarily representative of global trends (that is, it shows 

a slow but unsteady cooling for much of the last 50 years), 

it serves as an important check on other global records 

because they can be compared over this limited region. 

Karl and others found an artificial warming of0.10 to 

.15°C in the global temperature records. Curiously, the bias 

appears greatest in the U.S. portion of the record. A similar 

analysis of an analogous Soviet Union record shows no 

overall urban bias (Jones, in press), although urban stations 

are in fact cooler than surrounding rural ones from 1953 to 

1967. There is no difference between the two through 1980, 

and then there is some apparent urban warming after 1980. 

A similar negative urban effect is observed in the 1960's in 

mainland China (Wang and Karl, in press). It therefore 

seems that the global urban bias is currently not appreciably 

more than 0.10°C, but it should be noted that it will be more 

pronounced at the end of the record, which shows the 

warmest temperatures. Because of the urban effect, it 

appears that the true global warming during the last 100 

years is 0.35 to 0.40°C. 

Urban contamination compromises our estimates of 

historical temperature change. In an attempt to determine 

the reliability of the various long-term climate records, 

Spencer and Christy (1990) correlated satellite-microwave 

sensed temperatures with Karl's United States HCN and the 

hemispheric records of Jones and Wigley and the Hansen 

and others (1984) record that formed the basis of the June 

1988 congressional testimony. The HCN is the most correspondent (R2 =0.77), Jones and Wigley's record was almost 

as reliable (R2=0.72 and 0.66) for the Northern and 

Southern Hemisphere, while the NASA record of Hansen 

and Lebedeff in the Southern Hemisphere was much less 

reliable (R2

=0.27). This last record, which is the "warmest" of the global records, has the majority of its warming in 

that hemisphere. Spencer and Christy's (1991) temperature 

record from 1979 through 1990 shows a global trend of only 

+0.04°C/decade, and the coefficient of determination (R2

) 

between the U.S. HCN and the 1979-1990 data is now 

0.86. 

We calculated annual departures from the 1979 

through 1990 mean period in the Jones and Wigley data set 

and subtracted from them anomalies in the Spencer and 

Christy data. When these are plotted as function of time 

(beginning in 1979), it is apparent that there is a dramatic 

relative warming of the Jones and Wigley data, compared to 

the satellite, in the Southern Hemisphere; no similar effect 

occurs in the Northern Hemisphere. The very high correlation between the satellite data and the U.S. HCN suggests 

that the measurements are accurate and therefore that there 

is a great deal of spurious warming in the recent Jones and 

Wigley data for the Southern Hemisphere. If this is the 

case, than global warming in the land-based records is much 

lower than 0.4°C, perhaps as low as 0.2°C. 

An additional, and more insidious, problem may be 

introduced into long-term land-based climate records by a 

general site bias. Over what was the "developing world" of 

the late 19th century, the longest standing records have 

tended to originate at points of commerce. Because of the 

predominance of water power during that era, it is likely 

that the longest records are in fact at sites that are preferential for cold air drainage. Such locations may be buffered 

from nighttime warming. 

Several attempts have been made to compensate for 

both population and general biases, usually involving temperatures in the free atmosphere. These can be determined 

from combinations of barometric readings and weather 

balloon ascents, and therefore cannot suffer from the urban 

effect on thermometers. Angell (1990), using the atmospheric layer from 850 to 300mb, found a net warming of 

0.24°C in the last 30 years after adjusting for El Nifio 

warming and volcanic cooling. This is quite consistent with 

the global land record. A recent extension shows 1990 as 

the warmest year (by 0.04°), but this is not replicated in the 

Spencer and Christy data. The Spencer and Christy data 

correlated very well with Angell's data up to 1990. 

Michaels and others (1990) used the depth of the 

bottom half of the atmosphere over North America back to 

the beginning of systematic balloon observations in 1948 

and a statistical surrogate back to 1885 and concluded that 

the observed secular variability in surface temperatures 

calculated from this record was approximately three times 

larger than that measured from ground-based thermometers. 

The rise in the first half of the 20th century and the 

subsequent fall through the mid-1970's was in fact concurrent with that of the ground-based record, although the 

magnitude was again greater. Notably, the rise in early 

20th-century temperatures calculated by this method (of 

1. 8°C) does not differ appreciably from the expected 

regional greenhouse warming calculated by GCM' s for the 

next century. It is unknown whether this magnitude is 

related to noise in the statistical transfer functions between 

the cyclone frequency record used to calculate the 500 mb 

height from 1885 to 1948 or whether it truly reflects 

free-atmosphere temperature variability. 

Weber (1990) also examined the same layer over the 

entire Northern Hemisphere since 1950 and found warming 

in the Northern Hemisphere tropics and subtropics but 

cooling in the higher latitudes, with no overall hemispheric 

warming or cooling between the 1950's and the 1980's. 

This signal is opposite what would be expected from most 

climate models that suggest enhanced high-latitude warming and minimal tropical warming. 

The Receding Threat From Global Warming 45 
HIGH-LATITUDE AND DAILY TEMPERATURE 

REGIMES 

In the climate simulation of Manabe and Wetherald 

(1980), which is quite representative of the mid-1980's 

generation of climate models (Hansen and others, 1984; 

Manabe and Wetherald, 1980; Mitchell, 1983; Schlesinger, 

1984; Washington and Meehl, 1983), the difference 

between 2 x C02 and 4 X at high northern latitudes is twice 

the difference between 1 x and 2 x (8°C), suggesting that 

for the currently effective 1.5 x there should be considerable Arctic warming, even with oceanic thermal lag. 

Nonetheless, the Elsaesser and others (1986) compendium 

of temperature records indicates a rapid rise in Arctic 

temperatures prior to the majority of trace gas emissions and 

concurrent with the rise in the Northern Hemisphere average. In most records the rise is followed by a decline, from 

the 1930's to the mid-1970's, of similar proportion. 

All general circulation climate models suggest that 

the polar warming will be magnified in winter. Nonetheless, there has been a substantial secular decline in winter 

temperatures over the Atlantic Arctic since 1920 (Rogers, 

1989), and there has been no change in polar night 

temperatures at the South Pole- a station that surely has no 

urban warming or cold air drainage (Sansom, 1989). 

Kalkstein and others (1990) have documented that, 

although there has been no net warming of the North 

American Arctic, the coldest air masses, whose mean 

surface temperatures are approximately -40°, have warmed 

some 2°. Thus the most severe air mass in North America 

may be undergoing some mitigation that is consistent with 

an enhanced greenhouse. 

The very negative vision of future climate is not 

supported by recent studies on daily temperature regimes. 

Karl and others (1988) examined maximum and minimum 

values from the U.S. HCN and found that the daily range 

(difference between the two) has declined precipitously 

since 1950 and is now two standard deviations below the 

mean for the century. In that record, maximum values have 

actually declined, while minimum values have risen. It is 

worth noting, however, that a measurement bias toward a 

lower daily range has recently been introduced by the 

replacement of the traditional mercury-in-glass thermometer with the electronic MMTS version, although the magnitude of the bias only explains about one quarter of the 

decline in range (R.G. Quayle, National Climate Data 

Center, Asheville, N.C., 28801, pers. commun.). 

This behavior of the HCN is consistent with an 

enhanced greenhouse combined with the increases in cloudiness (of 3.5 percent) and reduced sunshine that have been 

documented across the coterminous United States (Angell, 

1990). Weber (1990) has also documented a decline in 

sunshine in Germany and notes that the effect is enhanced in 

the mountains, which implicates stratocumulus-the low46 Proceedings of the U.S. Geological Survey Global Change Forum 

altitude cloud type most effective at surface cooling-as the 

cause. Warren and others (1988) have also found increasing 

cloudiness at most marine locations around the globe, 

although the shipboard observations used are subject to 

substantial observer and scale biases. Nonetheless, the 

cloud type that shows the most increase is again the 

low-level stratocumulus and again in the Northern Hemisphere. The finding of a decline in ultraviolet radiation at 

the low elevations (Scotto and others, 1988), in combination with increased values at heights greater than 10 km 

(Bruhl and Crutzen, 1989), is also consistent with an 

increase in low-level cloudiness. 

Subtraction of maximum and minimum temperature 

curves for the other Northern Hemisphere locations in the 

IPCC chapter on observed temperature (Folland and others, 

1990) gives the same result: a considerable narrowing of the 

daily range since 1950 that is mainly a result of a rise in 

night temperatures. Rural data for the Soviet Union, not 

included in the report exhibit the same behavior (T .R. Karl, 

National Climate Data Center, Asheville, N.C. 28801, 

pers. commun.). 

If anthropogenerated warming takes place primarily 

at night, the negative vision of future climate is probably 

wrong. Evaporation rate increases, which are a primary 

cause of projected increases in drought frequency (Rind and 

others, 1990), are minimized. The growing season is 

longer, because that period is determined primarily by low 

night temperatures. Finally, many plants, including some 

agriculturally important species, will show enhanced 

growth with increased moisture efficiency (Sionit, 1980) 

because of the well-known "fertilizer" effect of C02 • Night 

warming also minimizes polar melting because mean temperatures are so far below freezing during winter that the 

enhanced greenhouse is insufficient to induce melting. Thus 

"how" the world has warmed already appears to be beneficial. If this is indeed the expression of the altered greenhouse, the Earth will have to reverse a course it has already 

embarked upon to get to an enhanced greenhouse disaster. 

Curiously, none of the analyzed Southern Hemisphere temperature ranges are declining (Folland and others, 1990; T.R. Karl, National Climate Center, Asheville, 

N.C., 28801, personal communication citing doctoral dissertation of J. Salinger, University of East Anglia). Such an 

important interhemispheric differential in one of the prime 

components of diurnal energy could be very important, as 

the most likely cause would be an increase in Northern 

Hemisphere cloudiness with less change in the Southern 

Hemisphere. One prime candidate for causation is therefore 

anthropogenerated sulfate, which both reflects solar radiation directly and brightens clouds by serving as condensation nuclei. Anthropogenerated sulfide is produced in much 

lower volume in the Southern Hemisphere and has a 

residence time from days to months, so that very little 

diffuses from the Northern to the Southern Hemisphere. 
MORE RECENT CLIMATE MODELS 

An earlier generation of GCM's calculated a mean 

equilibrium warming for a doubling of atmospheric C02 of 

4.2°C, with maximum warming of as much as l8°C during 

North Polar winter and less significant warming (approximately 2°) over tropical oceans (Hansen and others, 1984; 

Manabe and Wetherald, 1980; Mitchell, 1983; Schlesinger, 

1984; Washington and Meehl, 1983). 

Major shortcomings in these calculations included 

unrealistic ocean dynamics and ocean-atmosphere coupling, 

inadequate cloud paramaterization (prior to the ERBE 

analysis even the sign of the temperature forcing by the 

earth's cloud cover was unknown and debatable; it is now 

thought to be negative) (Ramanathan and others, 1989), and 

the usual use of stepwise (instantaneous) doubling of C02 

rather than the low-order exponential increase that exists in 

the real world. 

With a modified ice-water interaction between 

clouds, projected warming in the United Kingdom Meteorological Office (UKMO) dropped from 5.2° to 1.9°C 

(Mitchell and others, 1989). With a coupled ocean and 

climate general circulation model, the net warming in the 

National Center for Atmospheric Research (NCAR) model 

dropped to 1. 6°C for 30 years after a shock doubling, 

compared to 3. 7°C in an earlier equilibrium calculation 

(Washington and Meehl, 1989). Manabe and others (in 

press) reports a net equilibrium warming for a doubling with 

a coupled atmosphere-ocean model of 1.8°C, compared to 

4.3°C in a more primitive version. The net warming 

projected for the Southern Hemisphere is approximately 

1.0°C, with 2.5°C projected for the Northern Hemisphere. 

The observed behavior of the last 50 years-in which the 

Southern Hemisphere shows a more "greenhouselike" 

warming than the Northern Hemisphere-seems inconsistent with this model projection unless there has been some 

mitigation of Northern Hemisphere warming by other 

means (such as from sulfate aerosols) not included in the 

modeling process. 

In each of these models, estimates of global warming 

for a doubling of C02 have been considerably reduced. The 

mean of these three runs is 2.0°C, down over 2° from the 

previous mean. This substantially reduced warming is 

calculated with either altered cloud or ocean parameters. It 

therefore seems logical that a combination of the two will 

produce even less net warming. 

The NCAR calculation with the coupled land and 

ocean GCM for 30 years after a shock doubling shows that 

areas of warming of greater than 4 oc have been dramatically reduced, and in fact there are no areas of warming in 

either hemisphere for June-August. 

Because maximum warming in all GCM' s tends to 

concentrate at high latitudes, use of this Mercator or related 

projections presents a highly distorted view of model results 

that serves to overemphasize areas of warming. In terms of 

actual area of the globe, on an annual basis, the area of 

greater than 4 oc of warming in the illustrated model is less 

than 5 percent. Because almost all of that warming is 

confined to latitudes higher than 60° in the Northern 

Hemisphere, virtually all of the strong warming is now 

projected for either twilight or night, which is consistent 

with what has been observed in the U.S. HCN. 

It is tempting to view the unanimity of these newer 

models as a sign of reliability, but that is not the case. In a 

version of the NCAR model that increases greenhouse gases 

by a realistic 1 percent per year (as opposed to the "shock 

doubling" used in the model cited above), calculations 

based upon its results show that the current land temperature 

should be 1.4°C above the 1950 mean (Washington and 

Meehl, 1989); in fact the rise has been on the order of 

0.3°C. Thus, even the most conservative climate model 

appears to have grossly overestimated global land warming. 

This version also predicts very unrealistic regional temperatures for the current greenhouse enhancement. The distribution of December-February temperature in the 5-year 

average of years 26 to 30 in the 30-year transient run, 

roughly speaking, should be analogous to a 5-year aggregate in the period 1975-1985 (years 26-30 beginning in 

1950). The most significant projected anomalies are the 

2-4° warming of the northern half of North America and the 

3-6° cooling of the North Atlantic. Neither occurred, 

although Atlantic temperatures may have dropped some. 

This projected cold anomaly does not appear in later years 

of this transient model (G .A. Meehl, National Center for 

Atmospheric Research, pers. commun., September 13, 

1990). 

THE RESPONSE OF VEGETATION TO AN 

INCREASE IN C02 

It has long been known that many plants show 

increased growth rates when subjected to increasing concentrations of C02 • In fact, this response may be an 

expression of plant evolution, inasmuch as virtually all 

terrestrial plant species evolved when the atmospheric C02 

concentration was higher than it is today. Many plants show 

this enhanced growth at concentrations higher than 3,000 

ppm, some 10 times greater than late-19th- century values. 

Ellsaesser (1990) has noted that, in the last ice maximum, 

the Earth's atmosphere was within 100 ppm of being unable 

to support plant life because of a lack of carbon dioxide. In 

fact, during the last 100 million years, the Earth has 

undergone a general cooling associated with a reduction in 

atmospheric C02 that has only been reversed by human 

industrial activity. 

Enhanced atmospheric C02 appears to stimulate plant 

growth both by increasing the rate at which carbon is fixed 

and by increasing plant water use efficiency. Thus we can 

expect that plants of the 21st century, on the average, will 

The Receding Threat From Global Warming 47 
grow more rapidly per unit of moisture consumed. If the 

climate of that era is going to be dominated by night 

warming-which will lengthen the growing season without 

substantially increasing the natural evaporation rate-we 

may therefore expect a profound "greening" of the planet. 

Atmospheric C02 has increased some 33 percent 

since the Industrial Revolution. Is there any evidence that 

this greening has begun? Woodward (1987) has indicated 

that plant specimens from the British Museum collected in 

the mid- 19th century (prior to the major C02 input) have 

more stomata than members of the same species collected 

today. These are the pores through which gases exchange 

and are the major pathway for loss of moisture. This verifies 

laboratory experiments that demonstrate that plants grown 

under enhanced C02 have fewer stomata than those grown 

under ambient concentrations. Consequently, both laboratory and field studies indicate that plants have already 

become more water-efficient as a result of the increase in 

C02 . 

Several "real world" surveys also indicate that vegetative growth is accelerating as a result of the increase in 

carbon dioxide. The effect has been noted in montane 

species in the Western United States, in a virgin forest plot 

being carefully monitored by the Oak Ridge National 

Laboratory, and in the northern forests of Scandinavia 

(Idso, 1989). In all these studies the growth responses have 

been dramatic and appear to be unexplainable by any 

conventional weather variable. Further, they have occurred 

at a time when forest growth is ostensibly being retarded by 

acid precipitation. Thus, while the same mechanism that 

causes acid rain may be preventing a disastrous warming 

(see below), the same gas that could cause warming (C02) 

could be enhancing growth that more than compensates for 

any putative losses of forests to acid rain. 

There is some other evidence for large-scale vegetation expansion. Brush surveys in the State of Texas indicate 

a change in the area infested by woody plants from 88 

million acres in 1963 to 106 million in 1983. Idso (1989) 

quotes a 1988 study by Veblen and Markgraf concerning "a 

dramatic invasion of the (Patagonian) steppe by tree species ... as well as many species of tall shrubs." This change 

has occurred in spite of purposeful deforestation by European settlers and without any demonstrable climate change. 

In fact, these and other changes have prompted two 

rangeland specialists to comment that "an experiment 

assessing the consequences of increased C02 levels has 

already been conducted on a global scale, and we should 

consider the possibility that the recent increases in abundance of woody plants on rangelands is its most visible 

result" (Mayeux and Johnson, 1986). 

COMPENSATORY COOLING FROM OTHER 

INDUSTRIAL PRODUCTS 

It is clear that human activity, besides enhancing the 

greenhouse effect, also produces substances that can serve 

48 Proceedings of the U.S. Geological Survey Global Change Forum 

to counter that effect. These include particulates, which 

serve to scatter radiation, and sulfur dioxide, which when 

oxidized to sulfate can nucleate clouds. 

Mayewski and others (1990) recently demonstrated 

that the anthropogenerated sulfate load in the Northern 

Hemisphere atmosphere now is equivalent to the maximum 

loading from the Tambora volcano, which has been associated with a 2°C cooling of short duration. Hansen and 

Lacis ( 1990) suggest that current global forcing from 

aerosols may be as much as 1.5 w/m2 . Because anthropogenerated sulfates are produced and reside primarily in the 

Northern Hemisphere, we may therefore be equaling or 

overcompensating for current greenhouse forcing (1.5-2.5 

w/m2

, depending upon estimate) with actual negative forcing in the hemisphere that contains most of the world's 

population. Recent calculations by Charlson and others 

(1990) quantitatively demonstrate this phenomenon. 

Idso ( 1990) recently compared Northern and Southern Hemisphere temperature histories and found a striking 

difference that appears to be associated with the onset of 

world industrialization after World War II. Beginning in the 

mid-1950's, Northern Hemisphere temperatures stopped 

rising at the rate that characterized the 20th century, while 

those in the Southern Hemisphere continue to rise at the rate 

that characterized the first half of this century. 

In fact, if anthropogenerated sulfates were mitigating 

enhanced greenhouse warming, we would expect to see the 

following: 

1. Night warming from an increase in both clouds and 

greenhouse forcing, 

2. A counteraction of daytime warming by the greenhouse 

forcing because of an increase in clouds, 

3. A decrease in daily temperature range, 

4. Concentration of these effects in the industrial (northern) 

hemisphere, and 

5. Enhanced brightening of low-level clouds near sulfate 

source regions. 

Previous sections of this paper detail evidence for the 

first four. With regard to the fifth, Cess (1989) analyzed a 

limited set of satellite data and found an increase in 

brightness in ocean-surface stratocumulus that was heightened near the source regions of Asia and North America. 

The effect, in which reflectivity was increased by as much 

as 8 percent, persisted for thousands of miles downstream 

from the source regions. A "clean" swath of the South 

Pacific Ocean served as a "control" and showed no brightening. Finally, German and United States records showing 

a decrease in sunshine (Angell, 1990; Weber, 1990) and the 

diminution of ultraviolet radiation at low altitudes (Sansom, 

1989) coupled with enhancement at high elevation (Kalkstein and others, 1990) argue for some type of increase in a 

low-altitude reflectant. 
CONCLUSION 

One apocalyptic vision of the world influenced by an 

enhanced greenhouse is that of ecological disaster resulting 

from rising temperature, evaporation rates, and sea level. 

Several lines of observational and model evidence show that 

this scenario is becoming increasingly improbable. 

The Northern Hemisphere, which should warm first 

and most, shows little net change in the last half-century. 

Repeated measurements now show relative warming at 

night, which may in fact be beneficial. The amount of 

global warming is clearly less than it should be according to 

the earlier GCM's, given the fact that we are already 

halfway to an effective doubling of C02 . The only highlatitude signal that seems consistent with a greenhouse 

alteration is a 2°C warming of air masses whose average 

surface temperature is approximately -40°, which is a 

slight modification of the air mass type that is most 

inhospitable in North America. Other anthropogenerated 

compounds may be mitigating the warming. New climate 

models partition almost all of the warming of more than 4 oc 

to polar twilight or night, which will have a minimal effect 

on ice melting. 

If this is the course the Earth has embarked upon in 

response to human insults of the atmosphere, that response 

is primarily benign. And if human sulfate emissions are 

indeed the cause of this benign greenhouse, what are the 

implications for environmental policy? 

A PERSONAL PROJECTION 

World population and the ambient C02 concentration 

are profoundly linked, with an explained variance of 

approximately 99 percent between the two variables over 

the last 200 years. Any attempt to forcibly change this linear 

relationship will therefore involve disturbance of a highly 

coupled system and is therefore not likely to be particularly 

successful. 

I believe that both the observed and theoretical 

evidence for mitigation of greenhouse warming by anthropogenerated sulfates is compelling and that it certainly 

serves to explain several disparate measurements that 

seemed counter to a simple greenhouse enhancement. If this 

is indeed true, the dimensions of the policy debate on global 

change have changed dramatically. 

Two arguments should now surface. One group will 

argue, as did Hansen and Lacis (1990), for an advanced 

timetable to drastically reduce or eliminate fossil-fuel combustion, because the much longer residence time of C02 

means that a substantial warming pulse already has been 

hidden by sulfates and that that pulse will emerge soon after 

so2 emissions are reduced. 

The counterargument will be that we may have 

inadvertently discovered a control technology against 

greenhouse warming. The acid-rain effects of that technology can be minimized by concentrating fossil-fuel-based 

power generation on the eastern margin of continents, while 

using nonfossil dense energy sources inland. 

Is a sulfate-mitigated warming reason to limit fossilfuel combustion immediately, or does it argue that coal, 

whose reserves can last for centuries, should continue as a 

primary fuel? The former point of view now acknowledges 

both economic and ecological disruption as usage is curtailed, while the latter viewpoint will continue to increase 

the C02 content to the atmosphere dramatically. Will we 

purposefully produce a significant near-term disruption, or 

will we hope that the intellectual capital generated by 

nondiminished economic activity will, over the next 200 

years, provide a nondisruptive solution to the global warming problem? That is the environmental question of the 

1990's. 

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and cloud type amounts over the ocean: U.S. Department of 

Energy Publication DOE/ER-0406, 42 p., maps. 

Washington, W .M., and Meehl, G .A., 1983, Journal of Geophysical Research, v. 88, p. 6600. 

---1989, Climate Dynamics, v. 2, p. 1-38. 

Weber, G.R., 1990a, International Journal of Climatology, v. 10, 

p. 3. 

---1990b, Theoretical Applications of Climatology, v. 41, p. 

1-9. 

Wigley, T.M.L., 1987, Climate Monitor, v. 16, p. 14. 

Woodward, F.l., 1987, Nature, v. 327, p. 617. 
Third General Session 

Pliocene Climates 

Tom Cronin, R.Z. Poore, H.j. Dowsett, and R.S. Thompson 

Geologic Division 

U.S. Geological Survey 

The PRISM (Pliocene Research, Interpretation, and 

Synoptic Mapping) project is an interdisciplinary, coordinated investigation of Pliocene climates. Knowledge of the 

climate and environmental conditions during this youngest 

of the sustained warm intervals in Earth history will be used 

to explore numerical model simulations of past warm 

climate episodes and to provide insights into the impact of 

such climateg on the biota and other aspects of Earth 

systems. PRISM operates through three core projects, 

Table 1. PRISM External Collaborators 

which focus on pelagic marine, ocean margin, and terrestrial records. PRISM members collaborate with researchers 

at the national and international levels (table 1) to increase 

expertise and geographic coverage. A steering committee 

provides overall planning and scheduling of activities. 

PRISM has two principal objectives. The first is to 

construct a synoptic paleoclimate map of the Northern 

Hemisphere for a much warmer interval than today or the 

last interglacial. The components of the map will include 

International 

Group/Organization 

Working Group VIII U.S.-Fonner Soviet Union 

Bilateral Agreement on Environment Protection, 

Institute of Geography, Moscow 

Geological Survey of Canada 

University of Iceland 

Institute of Earth Sciences, Wales 

Shizuoka University, Japan 

Geological Institute, Moscow 

Tongii University, China 

Smithsonian Tropical Research Institute (STRI), 

Panama 

Subject or Area 

Pliocene Reconstruction 

Canadian Arctic 

Pliocene, Iceland 

Modem and Pliocene, NE Atlantic, SW Pacific 

Late Neogene, W Pacific 

Late Neogene, Bering Sea-Arctic Basin 

Late Neogene, W Pacific 

Late Neogene, Central America, 

Isthmus of Panama 

National 

Group/Organization 

National Center for Atmospheric Research 

(NCAR), Boulder 

Goddard Institute for Space Studies, New York 

Institute for Alpine and Arctic Research 

(INSTAAR), Boulder 

University of Alaska, Fairbanks 

University of Massachusetts, Amherst 

Lamont-Doherty Geological Obervatory 

Columbia University, Palisades 

Northern Illinois University 

University of Maine 

University of Oregon 

University of Florida 

University of Texas, Austin 

University of Delaware 

Ohio State University 

Byrd Polar Research Center 

Subject or Area 

Modeling 

Late Neogene, Arctic 

Late Neogene, Pacific 

North Atlantic 

Oxygen/carbon isotopes 

Technique development 

Pliocene, Florida 

Pliocene, Gulf of Alaska 

Pliocene, Atlantic Coastal Plain 

Antarctic ice volume changes 

Pliocene Climates 51 
!l Modern Effective Moisture 

D II 

!l Modern Temperature oc ~ -1 +1 +3 +5 ?.7 

Dryer Same Wetter lelei®IOIOI 

Cold Season 

Figure 1. Environmental estimates from 3 million years ago. 

estimates of precipitation, sea surface temperature, biota, 

and other aspects of Earth systems response to global 

warming. The reconstruction will provide a quantitative 

data set to calibrate and test numerical model attempts to 

simulate warmer climates. The reconstruction will be especially important for evaluating model simulations of 

regional-scale effects because current model simulations 

show gross differences on regional scales. The second 

PRISM objective is to document climate variability during 

the Pliocene with particular emphasis on the interval from 

3.5 to 2.0 million years ago. This interval brackets the first 

major continental glaciation of the Northern Hemisphere at 

about 2.5 million years ago and represents a large, abrupt 

transition in Earth systems. Documentation of climate 

variability during the Pliocene will lead to better understanding of the mechanisms, forcing functions, and impacts 

of this major climate shift. 

Initial PRISM activities include (1) delineation of 

Pliocene climate variation, (2) identification and evaluation 

of Pliocene records, (3) chronological refinement at key 

52 Proceedings of the U.S. Geological Survey Global Change Forum 

sections, and ( 4) development and refinement of techniques 

to quantify environmental parameters. A major warm episode at or about 3 million years ago is the first target for 

synoptic reconstruction. Estimates of sea surface temperatures (SST) and of precipitation for localities at 3 million 

years ago are shown on figure 1. Those results show that 

SST near the eastern coast of the United States, in the 

northeast Atlantic, and in the Arctic Ocean were much 

higher during this interval. SST in equatorial regions and 

off the southern tip of Greenland were similar to modem 

values. Precipitation was generally higher both in the 

Western United States and in the Canadian Arctic. 

We tentatively conclude that the warming at 3 million 

years ago (fig. 1) involved increased transport of heat 

northward by the Gulf Stream and North Atlantic Drift. Sea 

ice must have been substantially reduced or even absent in 

large parts of the Arctic Ocean during this interval. Future 

work will involve testing and refining our preliminary 

interpretations by analyzing more sites to give broader 

geographic coverage to our reconstruction and by comparing our data to model simulations. 
Desert Processes 

C.S. Breed 

Geologic Division 

U.S. Geological Survey 

U.S. Geological Survey (USGS) research in deserts 

has traditionally been focused on understanding how certain 

types of sedimentary rocks (eolian sandstones) were built by 

wind in ancient deserts, because the structures formed by 

wind deposition have later influenced the migration of oil 

and gas. New demands on the USGS-to provide better 

understanding of the geological causes and effects of global 

change-require research into the role of desert processes, 

especially wind erosion, in changing land surfaces and 

resources in response to changes in climate or in human 

activity. The erosional effectiveness of wind varies very 

rapidly with changes in land surface climatology (precipitation, wind regimes, soil moisture, vegetation) and with 

human activity (farming, grazing, construction, war). Wind 

erosion provides an almost immediate signal of a changed 

environment in the form of deflating surfaces, migrating 

dunes, or dust emission, and it provides evidence of past 

episodes of aridity in the paleoclimatic records of dunes and 

of dust infiltrated into ice cores, lake and marine sediments, 

and soils. 

Wind erosion has occurred episodically at least since 

the Cambrian on all continents on Earth. It also occurs on 

other planets (Mars and Venus). Wind erosion at present 

may remove as much as 1 billion tons of sediment (including soils) per year from North America. Saltating sand 

destroys crops, abrades property, and generates dust palls 

(aerosols) that affect the global radiation budget in ways 

that are still poorly understood, possibly even having 

feedback effects on climate. The recognition of eolian 

components in marine sediments, glacial ice, and soils 

worldwide has coincided with the perception, based on 

satellite tracking of dust storms, that wind is capable of 

transcontinental and even global transport of vast amounts 

of fine sediment. The sources, sinks, and rates of erosion 

and transportation of airborne sediment, past and present, 

are still poorly known. More reliable data are needed for 

inclusion in global climate models (GCM's), for forecasting 

adverse effects of wind erosion on vulnerable land surfaces 

such as the semiarid American West, for detecting and 

assessing variations in eolian activity that may be early 

warning signals of global change, and for calibrating 

paleoclimatic reconstructions. 

Where, in the one-third of the Earth's land surface 

that is desert, should studies of global change be focused? 

The hyperacid core deserts are ideal "natural laboratories" in 

which to study wind processes unhindered by surface 

moisture and vegetation, but they are not the most critical 

areas in which to focus studies on the detection and societal 

consequences of global change. The key areas are the 

adjacent semiarid to subhumid regions, where climatic 

conditions are marginal and surfaces are inherently susceptible to wind erosion wherever they become destabilized. 

Eighty percent of the world's grazing lands and most of the 

irrigated farming are in these climate-sensitive transitional 

zones. 

Vulnerability of the dry parts of the continental 

interiors to wind erosion is a global problem, exacerbated 

by the recent tendency to exploit these regions for grazing 

and farming. The result of this pressure has been "desertification" -the degradation and loss of biological productivity, whether due to climate change or human activity. The 

presently arid to subhumid regions in the continental United 

States and southern Canada, central Asia, central Australia, 

parts of central South America, southern Europe, central 

southern Africa, and the southern margin of the Sahara 

(Sahelian zone) all are surfaced largely with eolian materials (dunes and sand sheets or loess) deposited during 

Quaternary episodes of greater aridity. Their surfaces are 

now "fixed" to some extent by vegetation, but, like the 

Sand Hills of Nebraska, they remain chronically vulnerable 

to reactivation, "preconditioned" to remobilization by wind, 

given a return to greater aridity or removal of the native 

vegetation. 

Although years of effort have been applied to studies 

of erosion and sediment transport by running water, only 

recently have we begun to define the basic geologic and 

climatic controls on erosion, transport, and deposition of 

sediment by wind under natural (field) conditions. Past 

neglect of wind as a geologic agent was due in part to the 

absence of reliable equipment capable of long-term monitoring in the abrasive, often difficult environments where 

eolian processes are most active; hence, most early studies 

of wind erosion relied on the collection and analysis of 

proxy data or on wind-tunnel experiments. Rates of wind 

erosion inferred from previous studies may be wildly 

inaccurate; preliminary results recently acquired by field 

instruments suggest that calculations derived from windtunnel experiments and theoretical considerations differ by 

an order of magnitude or more from calculations derived 

from field measurement under real conditions. The reason 

for this difference is that the standard wind-erosion equations are based on ideal conditions in wind tunnels and on 

certain characteristics of farm fields. These equations do not 

Desert Processes 53 
work well for natural surfaces with variable soil moisture 

and uneven topography or for different types of vegetation 

and surface sediments. 

Systems now are in place to obtain field measurements of climatic and surface geologic conditions concurrently with real-time measurements of eolian sediment flux. 

Automated "Geomet" stations are presently operating in 

several types of desert sites in the American Southwest that 

range in climate from hyperarid to semiarid. Ground surface 

and atmospheric conditions recorded at these sites provide 

data on the "normal" climatic variability under which eolian 

54 Proceedings of the U.S. Geological Survey Global Change Forum 

processes are active and eventually will provide data for 

calculating rates and amounts of eolian sediment transport 

that actually occur under monitored sets of land surface/ 

climatic conditions. Once the boundary conditions for 

modem eolian activity are more precisely defined, the 

modem analogs should be used to better calibrate models of 

the paleoclimatic conditions inferred from eolian deposits. 

In addition, the long-term Geomet records will provide a 

baseline of present climatic variability in areas typical of the 

American Southwest, against which future effects of 

changes in climate and human activity may be assessed. 
Satellite Image Atlas of Glaciers of the World 

Richie S. Williams, Jr., and j.G. Ferrigno 

Geologic Division 

U.S. Geological Survey 

Of all the expected impacts of the predicted global 

warming on the geosphere and biosphere, the greatest 

potential for economic disruption of human population is by 

accelerated melting of glacier ice (net loss of global glacier 

volume) and a concomitant rise in sea level. The cryosphere 

(glacier ice, sea ice, snow cover, ground ice, and permafrost) is the most sensitive component of the geosphere to 

seasonal and longer term changes in global surface temperature. During the past two decades, satellite sensors have 

recorded variations in the areal extent of sea ice, snow 

cover, and glaciers. Only by using satellite sensing technology may systematic and repetitive regional and global 

measurements of changes in area or other remotely sensed 

characteristics of the cryosphere be accomplished. 

The realization that one element of the Earth's cryosphere, its glaciers, was amenable to global inventorying 

and areal-change monitoring with Landsat images led to the 

decision, in 1978, to prepare an 11-volume U.S. Geological 

Survey Professional Paper 1386 (A-K), Satellite Image 

Atlas of Glaciers of the World, in which Landsat 1, 2, and 

3 multispectral scanner (MSS) and return beam vidicon 

(RBV) images are used to inventory the areal occurrence of 

glacier ice on our planet within the spacecraft's orbital 

coverage (between about 81° north and south latitudes). 

Between 1979 and 1981, optimum Landsat images were 

distributed to an international team of 54 scientists (from 25 

nations, representing 42 different institutions), who each 

agreed to author a section of the Professional Paper concerning either a geographic area or a glaciological topic. In 

addition to analyzing images of a specific geographic area, 

each author was asked to summarize up-to-date information 

about the glaciers within the area and to compare the present 

areal distribution of glaciers with historical information 

about their past extent (for example, from published maps, 

reports, and photographs). Because of the limitations of 

Landsat images for delineating or monitoring small glaciers 

in some geographic areas (for example, inadequate spatial 

resolution, lack of suitable seasonal coverage, or complete 

absence of coverage), information on areal distribution is 

sometimes necessarily derived from ancillary sources. 

Completion of the atlas by 1993 will provide an accurate 

regional inventory of the areal extent of glaciers on our 

planet within a relatively short time (1972 to 1982). This 

global "snapshot" or "benchmark" of glacier extent already 

is being used for comparative analysis with previously 

published maps and aerial photographs and with new maps, 

satellite images, and aerial photographs to determine the 

areal fluctuation of glaciers in response to natural or 

culturally induced changes in the Earth's climate. For 

example, sequential Landsat images have documented 

many major changes in the coastal regions of Antarctica. 

Chapter A of the atlas is a general introduction, 

including a discussion of the physical characteristics, classification, and global distribution of glaciers. The next nine 

chapters, B through J, are arranged geographically and 

present glaciological information from Landsat and other 

sources of data on each geographic area: Chapter B, 

Antarctica (Swithinbank, 1988); Chapter C, Greenland; 

Chapter D, Iceland; Chapter E, continental Europe (except 

for the European part of the USSR); Chapter F, USSR, 

China, India, Nepal, Afghanistan, and Pakistan; Chapter G, 

Turkey, Iran, and Africa (Kurter and others, 1991); Chapter 

H, Irian Jaya (Indonesia) and New Zealand (Allison and 

others, 1989); Chapter I, South America; and Chapter J, 

North America. Chapter K presents related glaciological 

topics. 

Satellite Image Atlas of Glaciers of the World 55 
Sensitivity of Water Resources in the Delaware River Basin 

to Climate Change 

Gregory J. McCabe, Jr., D.M. Wolock, G.D. Tasker, M.A. Ayers, and l.E. Hay 

Water Resources Division 

U.S. Geological Survey 

The U.S. Geological Survey began a study of the 

effects of climate change on water resources in the Delaware River basin in 1988. As part of this study, a hydrologic model of the basin was developed that included the 

operation of reservoirs and diversions. The basin hydrologic 

model was used to examine the sensitivity of water resources in the basin to prescribed changes in temperature, 

precipitation, and the stomatal resistance of plants to 

transpiration. 

Results of simulations made using the model indicated that within the ranges of the prescribed changes in 

precipitation (-20 percent to + 20 percent) and temperature 

(0 to +4°C), streamflow and reservoir contents were more 

sensitive to changes in precipitation than to changes in 

temperature. In contrast, irrigation demand was more sensitive to changes in temperature than to changes in precipitation. The results also indicated that all water-resource 

components of the basin were very sensitive to prescribed 

changes in the stomatal resistance of plants to transpiration. 

Because of current reservoir operating rules, simulation results indicated that the New York City reservoirs are 

more sensitive to climate changes than are other waterresource components of the basin, such as streamflow at 

Trenton, N.J., and the position of the salt front in the 

Delaware River estuary. Storage in the reservoir system acts 

as a buffer to changes in unregulated streamflow caused by 

climate changes, and to changes in the upstream movement 

of the salt front in the estuary caused by sea-level rise. 

Natural climate variability has a large effect on 

estimates of future hydrologic conditions in the Delaware 

River basin. The estimated effects of natural climate variability were as large as the modeled effects of the prescribed 

climate changes. Because natural climate variability causes 

such large changes in basin water resources, it could mask 

any effects of long-term trends in climate change. 

INTRODUCTION 

Scientists have estimated that increasing concentrations of atmospheric carbon dioxide (C02) may cause 

global warming and changes in temporal and spatial patterns of precipitation (Bolin, 1986; Lins, 1988). Some 

research also has shown that the stomatal resistance of 

56 Proceedings of the U.S. Geological Survey Global Change Forum 

plants to transpiration is increased in a C02-enriched 

atmosphere thereby decreasing transpiration rates (ldso and 

Brazel, 1984). Such changes in temperature, precipitation, 

and plant transpiration may have important effects on water 

resources. 

In 1988, the Water Resources Division of the U.S. 

Geological Survey initiated an interdisciplinary study of the 

sensitivity of water resources in the Delaware River basin to 

climate change (Ayers and Leavesley, 1988). Certain 

aspects of the basin's water resources were of particular 

concern: (1) changes in streamflow, (2) changes in water 

storage in the New York City and other basin reservoir 

systems, (3) maintenance of prescribed minimum streamflow requirements, (4) the upstream movement of saline 

water in the Delaware River estuary caused by changes in 

freshwater inflows, and (5) changes in irrigation demand. 

This paper presents the results of a sensitivity analysis of the 

basins water resources to climate change. 

THE DELAWARE RIVER BASIN 

The Delaware River basin, which lies along the east 

coast of the United States, encompasses about 30,000 km2 

(fig. 1). The region has a humid, temperate climate with a 

mean annual temperature oflabout 12°C and a mean annual 

precipitation near 1 ,200 mm. Soils and topography vary 

considerably within the basin. Soils range from thick 

sandy-loam soils to thin clayey soils, and topography varies 

from low relief in coastal areas to the Appalachian mountains in the northern part of the basin. 

The Delaware River basin provides water for an 

estimated 20 million people within and outside the basin 

(Albert, 1987). Water availability is enhanced by a system 

of reservoirs, wells, and diversions. Two large diversions 

out of the basin are through the New York City aqueduct 

system and the Delaware and Raritan Canal (D & R Canal) 

(fig. 1). Releases of water from the reservoirs are managed 

to maintain specified minimum flows at important points in 

the river. These minimum flows keep saline water downstream of important freshwater supplies. 

The objective of the Delaware River basin study was 

to examine the sensitivity of the water resources in the 

Delaware River basin to climate change under existing 

water management policy and infrastructure. 
N E 

z 

z 

Ul 

10 20 30 40 MILES 

I I I 

I I I 

0 20 40 KILOMETERS 

Base from Delaware River Basin Commission, 1986 

Figure 1. The Delaware River basin. 

Sensitivity of Water Resources in the Delaware River Basin to Climate Change 57 
HYDROLOGIC MODEL OF THE DELAWARE 

RIVER BASIN 

To examine the sensitivity of the water resources in 

the Delaware River basin to climate change, a hydrologic 

model of the basin was developed that included the existing 

management policy and infrastructure. The model was 

based on a monthly time-step water balance within the 

basin. The basin water-balance model was a modification of 

the Thornthwaite water-balance model, which is a waterbudget bookkeeping procedure that accounts for soil moisture, evapotranspiration, water deficit, snowmelt, and surface runoff (Thornthwaite and Mather, 1955; McCabe and 

Ayers, 1989). 

The basin water-balance model estimates unregulated 

streamflows based on climate inputs (monthly mean temperature and monthly precipitation) and a few simple 

parameters such as soil field capacity (see McCabe and 

Ayers (1989) for a detailed description of the water-balance 

model). 

Unregulated streamflow estimates were made at several key nodes in the basin, such as the sites of reservoirs 

where critical management decisions are made. Basin 

operation rules then were applied at these key nodes and 

reservoir storage, regulated streamflow, and the position of 

the salt front in the Delaware River estuary were estimated 

for every time step in the simulation. The length of the time 

that the basin was in a state of drought for a given 

simulation was computed as the number of months when the 

simulated reservoir storage or regulated streamflow dropped 

below some specified level. 

The basin water-balance model also was adapted to 

estimate annual irrigation demand as a function of temperature, precipitation, and soil characteristics. Irrigation 

applications were based on the soil-moisture content estimated by the model. 

SCENARIOS OF CLIMATE CHANGE 

General circulation models (GCM's) of the atmosphere commonly are often used to estimate the effect of 

increasing atmospheric C02 on climate. There is an inherent scale problem, however, in interpolating estimates from 

GCM' s to areas the size of the Delaware River basin. GCM 

nodes are spaced on a grid about 4 o of latitude by 5° of 

longitude. The size of the Delaware River basin measures 

only about 3° of latitude by 1 o of longitude. Thus, the basin 

is smaller than the area outlined by four GCM modes, and 

estimates of climate conditions from such spatially coarse 

models for areas the size of the Delaware River basin are 

unreliable (McCabe and Ayers, 1989). 

In an attempt to overcome the spatial incompatibility 

between GCM's and the Delaware River basin, surface 

weather patterns, such as frontal passages and high-pressure 

58 Proceedings of the U.S. Geological Survey Global Change Forum 

systems, simulated by GCM's were compared to observed 

weather patterns over the basin. The spatial size of weather 

patterns (about 10° of latitude by 10° of longitude) is large 

enough to be estimated reasonably by GCM's, and knowledge of weather-pattern frequencies and characteristics in 

and around the Delaware River basin allows for adequate 

estimates of temperature and precipitation. 

GCM simulations of weather patterns (for both current and doubled-C02 conditions) were analyzed and compared to observed weather patterns [a detailed description of 

GCM weather-pattern analysis is given in Hay and others 

(1992)]. Although GCM-simulated weather pattern frequencies for current conditions matched well with observed 

weather-pattern frequencies, the weather-pattern frequencies computed for doubled-C02 conditions matched 

observed data equally well. Changes in weather-pattern 

frequencies from current to doubled-C02 conditions were 

hoped to be the primary driving force of changes in 

temperature and precipitation simulated by the GCM's; this 

would have provided a scale-appropriate means of estimating future temperature and precipitation without relying on 

GCM simulations of changes in precipitation and temperature. The GCM results indicated, however, little or no 

changes in weather-pattern frequencies from current to 

doubled-C02 conditions. 

Given the inability to use weather patterns to generate 

appropriate climate-change scenarios for doubled-C02 conditions, and the lack of confidence in using GCM simulations directly, prescribed changes in precipitation and temperature were used in the analyses presented in this paper. 

The range in prescribed changes represented the range of 

GCM estimates of precipitation and temperature changes 

reported in the literature (Schneider and others, 1990). 

Because of the speculation that increasing concentrations of C02 may increase the stomatal resistance of plants 

to transpiration, prescribed changes in a conceptual 

stomatal-resistance factor were included in the climatechange scenarios (Idso and Brazel, 1984; Rosenberg and 

others, 1990; Wolock and Hornberger, 1991). The range in 

prescribed changes in stomatal resistance reflect the range 

reported in the literature for doubled-C02 conditions 

(Rosenberg and others, 1990). In addition, prescribed 

increases in sea-level also were incorporated as a component of climate change. As temperatures increase with 

increasing concentrations of atmospheric C02 , sea-level 

also is estimated to increase due to thermal expansion of the 

oceans as they warm, and due to the melting of glacial ice. 

Increased sea-level may have important effects on the 

position of the salt front in the Delaware River estuary and 

the intrusion of salt water into freshwater aquifers. 

The prescribed temperature and precipitation changes 

were used with simple stochastic equations to generate 

multiple time series of temperature and precipitation that 

were subsequently input to the Delaware River basin 

hydrologic model. Temperature and precipitation time 
Table 1. Median drought frequency1 in the Delaware River 

basin derived from 50 30-year simulations for various 

prescribed changes in temperature and precipitation 

Temperature Precipitation Change2 

Change2 No 

-20% -10% Change +10% +20% 

No change .............. 79 29 6 1 0 

2°C warming ........... 90 50 13 3 0 

4 oc warming ........... 96 70 29 7 1 

1 Drought frequency is defined as the percentage of months during a 

30-year simulation the basin is in drought conditions based on contents of 

New York City reservoirs. 2 Change from current mean annual temperature and precipitation 

(1895-1988). 

series developed from the succhastic equations were used to 

study the effects of long-term transient changes in climate 

on water resources, as well as the effects of steady-state 

changes. The time series of temperature and precipitation 

estimates also were used to evaluate the effects of prescribed changes in temperature and precipitation on water 

resources amid natural climate variability. Even with prescribed long-term changes in precipitation and temperature, 

natural climate variability creates a wide range of climate 

conditions that potentially may occur. 

RESULTS OF MODEL SENSITIVITY ANALYSES 

Effects of Changes in Temperature and 

Precipitation 

Streamflow and drought conditions (defined by 

streamflow or reservoir storage) were sensitive to the 

prescribed changes in precipitation and temperature. For 

example, the median drought frequencies derived from 50 

30-year simulations for various climate changes are given in 

table 1. Drought frequency is the percentage of months 

during a 30-year simulation that the basin experienced 

drought conditions based on the contents of the New York 

City reservoirs. Drought occurred approximately 6 percent 

of the time for current climate conditions, but increased to 

13 percent of the time for a warming of 2°C with no change 

in precipitation, and increased to 29 percent of the time for 

a warming of 4°C with no change in precipitation. For the 

2°C warming scenario, drought frequency increased to 90 

percent for a 20 percent decrease in precipitation, but 

decreased to 0 percent for a 20 percent increase in precipitation. 

Within the ranges of precipitation and temperature 

changes used in this study, drought frequencies were more 

sensitive to precipitation changes than to temperature 

changes (table 1). Assuming a 2°C temperature increase, 

drought frequencies varied from 0 to 90 percent, depending 

on the assumed change in precipitation. In contrast, assumTable 2. Annual irrigation demand (in millimeters) for 

various prescribed changes in temperature and precipitation based on 50 100-year simulations 

Temperature 

Precipitation Change 1 

Change1 No 

-20% -10% Change +10% +20% 

0°C warming ........... 212 192 174 158 145 

2°C warming ........... 278 256 236 217 201 

4°C warming ........... 357 331 309 289 269 

1

Change from current mean annual temperature and precipitation 

(1895-1988). 

ing a 10 percent decrease in precipitation, drought frequencies ranged from 29 to 70 percent, depending on the 

prescribed temperature change. The sensitivity of drought 

to precipitation, coupled with uncertain GCM precipitation 

estimates for a C02-enriched atmosphere, made the estimation of C02 effects on drought difficult. 

Irrigation demand estimated by the basin model also 

was sensitive to the prescribed changes in temperature and 

precipitation (table 2) based on 50 100-year simulations. 

The estimated annual irrigation demand was 174 mm for 

current climate conditions, 236 mm for a warming of 2°C 

with no change in precipitation, and 309 mm for a warming 

of 4°C with no change in precipitation. Annual irrigation 

demand was 278 mm for a 2°C warming combined with a 

20 percent decrease in precipitation, and 201 mm for a 2°C 

warming combined with a 20 percent increase in precipitation. 

Within the prescribed ranges of precipitation and 

temperature changes, irrigation demands were more sensitive to temperature changes than to precipitation changes 

(table 2). Assuming a 2°C temperature increase, annual 

irrigation demand varied from 201 to 278 mm, a range of 77 

mm depending on the change in precipitation. In contrast, 

assuming no change in precipitation, irrigation demand 

varied from 174 to 309 mm, a range of 135 mm depending 

on the prescribed temperature change. Temperature has a 

strong effect on soil moisture and irrigation demand through 

its effect on potential evapotranspiration. 

Sensitivity analyses also indicated that increases in 

temperature can affect the timing of streamflow in areas 

where winter snow accumulation and spring snowmelt are 

currently important components of the annual water budget. 

Increased temperatures cause a greater proportion of winter 

precipitation to fall as rain, and therefore allowed more of 

the available precipitation to run off during the winter and 

reduced the snow accumulation and the snowmelt runoff 

during spring. 

The various water-resource components of the Delaware River basin differed in their degree of sensitivity to 

climate change due, in part, to the current management 

policies practiced in the basin. Drought as defined by the 

contents of the New York City reservoirs was more sensiSensitivity of Water Resources in the Delaware River Basin to Climate Change 59 
Table 3. Effects of prescribed changes in temperature and 

precipitation on changes in water-resource components 

based on 50 30-year simulations 

Change in temp. 1 

Change in precip. 1 

Percentage of time in 

drought (based on 

stream flow at 

Trenton, N.J.) ........ . 

Percentage of time in 

drought (based on 

contents of New York 

City reservoirs) ....... . 

Position of salt front 

(river mile) ........... . 

No change +4°C +4°C 

No change No change -10 percent 

3 9 20 

8 30 73 

75 77 79 

1

Change from current mean annual temperature and precipitation 

(1895-1988). 

tive to changes in precipitation and temperature than was 

drought as defined by streamflow at Trenton, N.J. (table 3). 

Similarly, the position of the salt front in the Delaware 

River estuary was less sensitive to changes in climate than 

was drought as defined by the contents of the New York 

City reservoirs. This difference in sensitivity resulted 

because the New York City reservoirs are the primary 

mechanism used to maintain minimum flows in the Delaware River, and to maintain the position of the salt front 

below river mile 100 where water is withdrawn from the 

river by the city of Philadelphia, Penn. Storage in the 

reservoir system acts as a buffer to changes in unregulated 

streamflow caused by changes in temperature and precipitation. If requirements of reservoir releases from the New 

York City reservoirs are reduced, then the sensitivity of the 

various water-resource components changes. For example, 

if target flow requirements are reduced, reservoir storage in 

the New York City reservoirs becomes less sensitive to 

climate changes and the position of the salt front in the 

Delaware River estuary becomes more sensitive (table 4). 

Table 4. Model simulations of the percentage of time New 

York City (NYC) reservoir storage is at zero (less than 1 

percent of storage capacity) and the salt front in the 

Delaware River estuary is at or above river mile 100 for a 

4°C increase in mean annual temperature (1895-1988) and 

a 10 percent decrease in mean annual precipitation 

(1895-1988), and for various reductions in required reservoir releases (target flows) 

Percentage of time 

NYC reservoir storReduction in target flows (percent) 

0 10 20 30 40 50 60 

age reaches zero . . . . 4.0 3.0 2.0 1.5 1.0 0.5 0.0 

Percentage of time salt 

front reaches river 

mile 100............ 0.0 0.0 0.0 0.0 0.5 2.0 5.0 

60 Proceedings of the U.S. Geological Survey Global Change Forum 

Table 5. Percentage of time the New York City (NYC) 

reservoir storage reaches zero (less than 1 percent of 

storage capacity) and the position of the salt front in the 

Delaware River estuary reaches river mile 100 for a 4°C 

increase in mean annual temperature 1895-1988) and a 10 

percent decrease in mean annual precipitation (1895-

1988), and for various prescribed upstream shifts in the 

mean monthly position of the salt front 

Percentage of time NYC 

reservoir storage 

reaches zero ........... 

Percentage of time salt 

front reaches river 

mile 100 ............... 

Prescribed upstream shift in mean 

monthly position of salt front 

miles 

kilometers 

0 

0 

4 

0 

5 

8 

5 

0 

10 15 

16 24 

6 6 

2 5 

Effects of Sea-Level Rise 

The effects of potential sea-level rise on the water 

resources of the Delaware River basin were examined by 

prescribing shifts in the mean monthly position of the salt 

front in the Delaware River estuary and observing changes 

in the percent of time New York City reservoirs reached 

zero storage (less than 1 percent of storage capacity) and the 

percent of time the salt front reached river mile 100. Model 

results indicated that even for large increases in temperature 

and decreases in precipitation large upstream shifts in the 

mean monthly position of the salt front only caused the salt 

front to reach river mile 100 a small percentage of the time 

(table 5). For example, a shift in the mean monthly position 

of the salt front 10 miles (16 km) upstream resulted in the 

salt front reaching river mile 100 only 2 percent of the time 

for a 4°C increase in temperature and a 10 percent decrease 

in precipitation. To produce a 10 mile (16 km) upstream 

shift of the salt front would require a sea-level rise of almost 

1 m, which is more than twice the current estimates of 

sea-level rise for doubled-C02 conditions (Robin, 1986; 

Titus, 1986). 

The percentage of time the New York City reservoirs 

reached zero storage increased as the mean monthly position of the salt front was shifted upstream because current 

operating rules require releases from the reservoirs to 

maintain the salt front below river mile 100. 

Potential effects of sea-level rise on salt-water intrusion into coastal aquifers also was considered. Examination 

of coastal aquifers along northern Delaware indicated that 

the location and extent of inundation caused by sea-level 

rise has a great effect on salt-water intrusion into many 

aquifers along the Delaware River basin. Inundation causes 

saline water to move inland past silty confining units and to 

more readily intrude into the aquifer. The lack of detailed 

topographic maps (with a 30 to 50 em contour interval) and 
Table 6. Effects of prescribed changed in temperature, 

precipitation, and stomatal resistance on annual irrigation 

demand (in millimeters) based on SO 100-year simulations 

A. No change in temperature 1 

Change in 

Precipitation 1 

Change in Stomatal Resistance 

No change .... . 

-10% ........ . 

No Change 

174 

192 

B. + 2°C increase in temperature 1 

+20% 

91 

103 

+40% 

26 

32 

Change in 

Precipitation 1 

Change in Stomatal Resistance 

No Change ... . 

-10% ........ . 

No Change 

236 

256 

+20% 

133 

149 

+40% 

48 

58 

1

Change from current mean annual temperature and precipitation 

(1895-1988). 

detailed description of the silty confining units limited 

research of this problem. At this point, because the intrusion of salt-water into many aquifers along the Delaware 

River are sensitive to the location and extent of inundation, 

reasonable estimates of the effects of sea-level rise on 

salt-water intrusion into coastal aquifers along the Delaware 

River are not possible. 

Effects of Changes in Stomatal Resistance 

The results of the sensitivity analyses performed in 

this study indicated that the water resources of the Delaware 

River basin were very sensitive to changes in stomatal 

resistance, and that changes in stomatal resistance could 

offset the effects of increases in temperature and decreases 

in precipitation (table 6). With a 2°C increase in temperature and no change in precipitation, annual irrigation 

demand was 236 mm, an increase of 62 mm over estimated 

current irrigation demand (174 mm) (table 6). With 

increases in stomatal resistance of 20 and 40 percent, 

however, annual irrigation demands were 133 and 48 mm, 

respectively, which represented decreases of 41 and 126 

mm from the estimated current demand (174 mm) (table 6). 

The reduction in transpiration caused by increased stomatal 

resistance more than offset the increase in potential evapotranspiration resulting from increased temperature. 

In a similar manner, increases in stomatal resistance 

offset decreases in precipitation. With no change in temperature and a 10 percent decrease in precipitation, annual 

irrigation demand was 192 mm, an increase of 18 mm over 

estimated current annual irrigation demand (table 6). With 

increases in stomatal resistance of 20 and 40 percent, annual 

irrigation demands were 103 and 32 mm respectively, 

which represented decreases of 71 and 142 mm from the 

estimated current demand (table 6). Even for a 2°C increase 

Table 7. Range of drought frequency1 derived from SO 

30-year simulations of current climate conditions and 

conditions resulting from prescribed changes in temperature and precipitation2 

[T, current mean annual temperature (1895-1988); P, current mean annual 

precipitation (1895-1988)] 

Climate 

scenario 

Current climate 

T+4°C 

T+4°C, P-10% 

T+4°C, P+10% 

P-10% 

Drought frequency (percent) 

0 10 20 30 40 so 60 

----------------+ 

------------------------+ 

-------------------------------------+ 

----------------+ 

------------------------------+ 

1 Drought frequency is defined here as the percentage of months 

during a 30-year simulation the basin is in drought conditions based on 

contents of New York City reservoirs. 2

Change from current mean annual temperature and precipitation 

(1895-1988). 

in temperature and a 10 percent decrease in precipitation, 

annual irrigation demand was less than estimated current 

demand when stomatal resistance was increased (table 6). 

Effects of Natural Climate Variability 

Natural climate variability was a major factor affecting the estimation of the effects of climate change on water 

resources in the Delaware River basin. For a given expected 

future climate, natural variability created a wide range of 

climate conditions that potentially may occur. The range in 

climate conditions that may be realized due to natural 

variability can mask the effects of long-term changes in 

temperature and precipitation. Table 7 gives a range of 

drought frequencies due to natural climate variability for 

several climate-change scenarios. Each scenario had a suite 

of possible drought frequencies; for instance, drought frequency ranged from 1 to 20 percent for current climate 

conditions and from 4 to 36 percent for a 4°C increase in 

temperature and no change in precipitation. The overlap in 

these distributions implies that natural climate variability 

can mask the effects of estimated long-term climate 

changes. Even if accurate estimates of long-term changes in 

mean temperature and precipitation can be made, a wide 

range of drought frequencies is possible because of natural 

short-term variability in precipitation and temperature. 

SUMMARY AND CONCLUSIONS 

A hydrologic model of the Delaware River basin was 

developed that included the operations of reservoirs and 

diversions based on current management policy and infrastructure. The basin hydrologic model was used to examine 

the sensitivity of the water resources in the basin to climate 

Sensitivity of Water Resources in the Delaware River Basin to Climate Change 61 
change. Because of a large amount of uncertainty in 

estimates of climate change by GCM's, a range of prescribed changes in climate was used. 

Changes in streamflow and reservoir contents were 

more sensitive to changes in precipitation than to changes in 

temperature within the ranges of prescribed changes in 

temperature and precipitation used in the study. In contrast, 

changes in irrigation demand were more sensitive to 

changes in temperature than to changes in precipitation. The 

water resources of the Delaware River basin also were very 

sensitive to changes in stomatal resistance of plants to 

transpiration, which may offset the effects of increases in 

temperature and decreases in precipitation. 

The current infrastructure and reservoir operating 

rules cause the various water-resource components of the 

basin (for example, New York City reservoir storage, 

streamflow at Trenton, N.J., and the position of the salt 

front in the Delaware River estuary) to have differing 

sensitivities to climate changes. By changing the reservoir 

operating rules, the sensitivity of the various water-resource 

components to climate changes can be altered. 

The potential effects of climate change on water 

resources in the Delaware River basin are uncertain for 

several reasons. First, GCM estimates of the effects of 

increasing C02 on regional precipitation are unreliable, and 

basin water resources are very sensitive to changes in 

precipitation. Second, the basin water resources are sensitive to assumptions about the effects of C02 on stomatal 

resistance of plants to transpiration. Finally, the effects of 

natural climate variability are as large as those due to the 

prescribed temperature and precipitation changes. Natural 

variability in precipitation and temperature, therefore, may 

mask the effects of long-term climate trends on water 

resources. 

REFERENCES 

Albert, R.C., 1987, Damming the Delaware: University Park, 

Pennsylvania, The Pennsylvania State University Press, 

202 p. 

62 Proceedings of the U.S. Geological Survey Global Change Forum 

Ayers, M.A. and, Leavesley, G.H., 1988, Assessment of the 

potential effects of climate change on water resources of the 

Delaware River Basin-Work Plan for 1988-90: U.S. Geological Survey Open-File Report 88-478, 37 p. 

Bolin, B., 1986, How much C02 will remain in the atmosphere? 

in Bolin, B., Doos, B.R., Jager, J., and Warrick, R., eds., 

The greenhouse effect, climate change, and the ecosystem: 

New York, John Wiley, p. 93-155. 

Hay, L.E., McCabe, Jr., G.J., Wolock, D.M., and Ayers, M.A., 

1992, Use of weather types to disaggregate general circulation model predictions: Journal of Geophysical Research, v. 

97' p. 2781-2790. 

ldso, S.B., and Brazel, A.J., 1984, Rising atmospheric carbon 

dioxide concentrations may increase streamflow: Nature, v. 

312, p. 51-53. 

Lins, H.F., Sundquist, E.T., and Ager, T.A., 1988, Information 

on selected climate and climate-change issues: U.S. Geological Survey Open-File Report 88-718, 26 p. 

McCabe, Jr., G.J., and Ayers, N.A., 1989, Hydrologic effects of 

climate change in the Delaware River basin: Water Resources 

Bulletin, v. 25, p. 1231-1242. 

Robin, G., 1986, Changing the sea level: projecting the rise in sea 

level by warming of the atmosphere, in Bolin, B., Doos, 

B.R., Jager, J., and Warrick, R., eds., The Greenhouse 

Effect, Climate Change, and the Ecosystem: New York, John 

Wiley, p. 323-362. 

Rosenberg, N.J., Kimball, B.A., Martin, P., and Cooper, C.F., 

1990, From climate and C02 enrichment to evapotranspiration, in Waggoner, P.E., ed., Climate change and U.S. water 

resources: New York, John Wiley, p. 151-175. 

Schneider, S.H., Gleick, P.H., and Mearns, L.O., 1990, Prospects for climate change, in Waggoner, P.E., ed., Climate 

Change and U.S. Water Resources: New York, John Wiley, 

p. 41-73. 

Thornthwaite, C.W., and Mather, J.R., 1955, The water balance: 

Publications in climatology: Centerton, New Jersey, Laboratory of Climatology, v. 8, p. 1-104. 

Titus, J.G., 1986, The basis for expecting a rise in sea level, in 

Hull, C.J.H., and Titus, J.G., eds., Greenhouse Effect, 

Sea-level Rise, and Salinity in the Delaware Estuary: EPA 

230-05-86--010, Washington, D.C., U.S. Environmental 

Protection Agency, p. 3-14. 

Wolock, D.M., and Hornberger, G.M., 1991, Hydrological 

effects of changes in levels of atmospheric carbon dioxide: 

Journal of Forecasting, v. 10, p. 105-116. 
A Strategy for Large-Area Land Characterization: The Conterminous 

United States Example 

Thomas R. Loveland 

National Mapping Division 

U.S. Geological Survey 

We need an accurate descriptive and quantitative 

understanding of the characteristics of the land surface to 

derive parameters needed in global and mesoscale climate 

models. 

An inspection of the characteristics of global land 

data sets shows that we do not have consistent, comprehensive data bases of vegetation conditions at spatial resolutions required for the next generation of global climate 

models. 

The Matthews land cover data base is considered the 

best global vegetation, land cover, and land use data base 

(Matthews, 1983). The Matthews data base was assembled 

from approximately 70 vegetation maps and 40 land use 

maps covering portions of the globe-augmented where 

necessary with Landsat imagery. The result is a representation of the Earth's land surface characteristics at a spatial 

resolution of 1 o of latitude by 1 o of longitude. Although this 

is the best data base for representing the global land surface, 

there are inconsistencies in the data set because of the 

difficulty of consolidating the more than 110 source maps 

with different classification systems, interpretation methods, and accuracy levels into a single global coverage. 

Considering the growing importance of mesoscale or 

regional land process models, we must begin building land 

characteristics data bases that provide a more detailed look 

at spatial patterns of the landscape. We must also start 

assessing a broader range of land surface characteristics if 

we are to contribute data to models that adequately address 

biosphere, atmosphere, and hydrosphere interactions. 

To address this problem, U.S. Geological Survey 

staff at the EROS Data Center (EDC) initiated an investigation in late 1990 to develop a large-area land characterization to start filling the gaps caused by unavailable or 

inadequate land surface data. 

Remote sensing can help solve this problem. For 

example, the National Center for Atmospheric Research 

recently concluded that normalized difference vegetation 

index (NDVI) data provide a better definition of both what 

is on the land surface and where the boundaries of different 

land cover types are than other global data sets (HendersonSellers and others, 1986). NDVI data are derived from 

Advanced Very High Resolution Radiometer (A VHRR) 

data collected onboard National Oceanic and Atmospheric 

Administration (NOAA) polar-orbiting satellites. NDVI 

measures several land surface properties including primary 

production, leaf area, evapotranspiration, canopy resistance, and surface heat flux. In its basic form, however, 

NDVI is difficult to interpret and incorporate directly into 

existing models. 

Our large-area land characterization research is 

focused on the development of methods for classifying 

remote-sensed data such as 1-kilometer (km) resolution 

A VHRR imagery to produce large-area land characteristics 

data bases. We are developing a prototype data base for the 

conterminous United States that can be evaluated as an 

alternative to current data sets. 

Our experimental methods and prototype product 

definition are guided by several design considerations that 

were developed at the onset of the research: 

• The methods must be repeatable over large areas. In most 

cases, the larger the area the more complex the analysis 

will be. 

• Significant seasonal, ecological, and cultural variations 

in the landscape must be dealt with. 

• The procedures must be efficient even with large data 

volumes. This requires simple rather than elaborate, 

complex approaches. If, for example, it takes several 

years to map land cover for a small part of the Earth's 

surface, the value of the results will be greatly reduced. 

• Data of varying quality must be usable. Some source 

materials will be reliable, some inaccurate. We need 

methods that will use the strengths of various types of 

data in order to create a single integrated data base of 

land characteristics. 

• The results must have the flexibility to be tailored to a 

range of applications. The user community for large-area 

land characteristics data bases includes the environmental 

monitoring and land management communities, in addition to global change scientists. 

Figure 1 illustrates the conceptual approach we are 

using to produce the land characteristics data base. Our 

analysis is based on a combination of remote sensing and 

other multisource Earth science data in an integrated classification framework. A time series of 1-km NDVI data 

provides a means to classify land cover based on the 

seasonal characteristics of vegetation communities. Other 

climate, elevation, and ecosystem variables are used to 

stratify selected remote sensing derived classes into homogeneous categories. 

The prototype land characteristics data base contains 

both spatial and attribute components. The spatial component is a set of seasonally distinct land cover regions, which 

A Strategy for Large-Area Land Characterization: The Conterminous United States Example 63 
ANALYSIS DATA BASE APPLICATIONS 

Temporal 

RemoteSensed 

Parameters 

NDVI (1) 

ALBEDO (1) 

NVDI (2) 

ALBEDO (2) 

NDVI (3) 

ALBEDO (3) 

• 

• 

LAND MANAGEMENT 

~ g~-

' I Forest Cover 

Land Characteristics Data Base Contents 

I Agricultural Statistics 

CLIMATE MODELING 

• Land Surface Regions 

• Land Cover/Vegetation Descriptions 

• Seasonal Growing Conditions - Greenness Onset - Peak Green Period Albedo 

- Season Length l Carbon Cycling 

• Seasonal Albedo Values I Surface Roughness 

ENVIRONMENTAL MONITORING • Summary Terrain Parameters 

• Summary Climate Parameters 

Related 

Earth 

• Ecological Components 

o~~ Science 

and 

Climate 

Parameters 

Land Surface Change 

I Resource Condition 

I Ecological Vulnerability 

Figure 1. Conceptual framework for large-area land characterization research. 

are consistent in their floristic composition and their physiognomic characteristics. (The density and height of the 

communities are constant within the regions.) Equally 

important, however, is that each region has consistent 

seasonal characteristics, so that we can look at the temporal 

variations in factors such as leaf area or albedo. 

Each region is described in terms of land cover and 

vegetation components (community composition and life 

form). Also included are quantitative biophysical data 

pertaining to seasonal parameters of land cover (onset of 

greenness, peak green period, duration of green period, and 

relative biomass amounts). Additional properties, such as 

physical measures of albedo, evapotranspiration, primary 

production, and leaf area index, may be added to the data 

base as research defining acceptable procedures for their 

calculation are completed. 

Finally, the data base includes summary site characteristics that describe the local context of each region. These 

site characteristics include the ecological setting, terrain 

characteristics, and climate conditions of the various 

regions. 

64 Proceedings of the U.S. Geological Survey Global Change Forum 

Collectively, the regions and attributes data base must 

be flexible enough to be tailored to a variety of applications. 

We can view this as a spreadsheet of land parameters that 

can be translated or interpreted to yield variables or classes 

of data needed for specific models or applications. This may 

include production of land cover maps, or perhaps the 

spatial distribution of carbon. Our strategy is to provide 

enough descriptive and quantitative detail so that users have 

a dynamic source of needed data. 

The data required to produce the land characteristics 

data base are based largely on remote sensing and, in 

particular, A VHRR data from the NOAA polar-orbiting 

series of satellites. The NDVI transformation derived from 

A VHRR provides a useful means for looking at the seasonality of land cover and permits classification of the different 

vegetation communities that form land cover regions. 

Various characteristics of A VHRR data make this 

type of data useful for understanding global vegetation 

patterns. A VHRR data provide an appropriate resolution 

(approximately 1 km) over the entire globe. A single 

A VHRR scene is about 2,600 km wide. The A VHRR 
Conterminous U.S. NDVI Statistics 

Selected Agricultural Classes 

0.7 

0.6 

0.5 

> 0.4 

0 

z 0.3 

0.2 

0.1 

3/16 4/13 5/11 6/8 7/6 8/3 8/31 9/28 

Start of Composite Period 

• 30-Spring Wheat + 35-Winter Wheat * 43-Row/Mixed Crop 0 44-Row Crops 

Figure 2. NDVI temporal characteristics for selected agriculture and range land cover clases. 

sensor views the same land, area every day. With two 

operational satellites, we receive imagery of the Earth twice 

a day. This provides data about landscape conditions at any 

given date. When we accumulate the daily observations and 

use simple transformations like NDVI, we can get a good 

picture of the patterns of vegetation dynamics. 

The NDVI is considered sensitive to differences in 

standing green biomass. Thus, over time, it provides a 

profile of annual vegetation phenology (Justice and others, 

1985). For the conterminous United States, EDC is producing NDVI composites every 2 weeks (Eidenshink and 

others, 1991; Sadowski, 1990). The NDVI composites for 

1990 show patterns of greenness caused by changes in 

regional temperatures and precipitation. 

NDVI data for March through October 1990 were 

processed using image classification techniques to identify 

the seasonally distinct land cover regions in the United 

States. We overlaid 17 biweekly AVHRR greenness images 

of the conterminous United States, creating eight sequential 

monthly composites. These composites were evaluated 

using unsupervised classification methods to segment the 

data into seasonally distinct land cover regions. 

Figures 2 and 3 illustrate the relationship between 

temporal NDVI values and selected land cover types. The 

graphs display selected classes and the NDVI means from 

the eight monthly composites. Because NDVI time-series 

data capture the seasonality of vegetation, the data are 

diagnostic of the form and the floristic characteristics of 

vegetation communities found across the country. 

The NDVI curve for rangeland in figure 2 (class 5) 

represents the Basin and Range region of the United States. 

If we assume that the value of 110 is the approximate start 

of green-up, we can infer that this class represents coolseason vegetation with low primary production. Therefore, 

through a convergence of evidence, we can interpret this 

category as representing sagebrush steppes with cool-season 

grasses. 

The curve for class 30 represents North Dakota. The 

start of the growing period is in April, and the peak of green 

is in June. This phenology of vegetation development leads 

A Strategy for Large-Area Land Characterization: The Conterminous United States Example 65 
Conterminous U.S. NDVI Statistics 

Selected Forest Classes 

0.7 

> 

00.4+---~----~~--------------------------------+-~ 

z 

0.1 

3/16 4/13 5/11 6/8 7/6 8/3 

Start of Composite Period 

8/31 9/28 

• 53-Decid/Conifer + 54-Deciduous * 61-Deciduous 0 70-Con iter 

Figure 3. NDVI temporal characteristics for selected forest land cover classes. 

to the conclusion that this class represents a spring wheat 

region. 

Class 44 displays a later start and peak of greenness 

and a higher overall amount of greenness (or relative 

biomass). The shapes of the curves for classes 30 and 44 are 

similar, but their seasonal traits are different. We can 

interpret class 44 as row crops, and in particular, corn and 

soybeans in the corn belt. 

Figure 3 displays greenness curves for several types 

of forest vegetation. Class 53 represents northern hardwood 

regions of Minnesota, Wisconsin, and Michigan (maple, 

birch, and beech) and has a late green-up. Class 61 

represents oak and hickory forests in southern Appalachia 

and in the Boston Mountains, the Ozarks, and the Ouachita 

Mountains. Although both classes represent deciduous forests, they are in separate classes because of different timing 

of green-up and green-period duration. 

Class 70 is found in the Pacific Northwest and is 

composed of conifer forest types (fir, spruce, hemlock, and 

cedar). Note the dip in greenness in early May-an example 

of the impact of clouds and haze on NDVI. In this case, the 

66 Proceedings of the U.S. Geological Survey Global Change Forum 

high amount of atmospheric interference was a diagnostic 

characteristic that aided in the interpretation of this class. 

Finally, class 69 represents a mixed forest community 

in the southern United States, a combination of oak, 

hickory, and southern pine. 

This classification is the starting point and represents 

our results to date. Even though we can identify many 

significant land cover relationships, there are several classes 

that correspond to multiple, disparate land cover types. We 

are currently in the process of improving these classes 

through the incorporation of multisource data. 

An important tool in understanding our preliminary 

classes is the Major Land Resource Area (MLRA) data base 

produced by the Soil Conservation Service. The MLRA' s 

include descriptive information that helps calibrate the 

contents of the classes. 

For class 30, found primarily in North Dakota, we see 

that about 60 percent of the class falls in three MLRA's: 

Central Black Glaciated Plains, Central Dark Brown Glaciated Plains, and Red River Valley of the North (fig. 4). 

The land use attributes for the three MLRA' s indicate that 
Class 30 Name Central Black Glaciated Plains 

Percent 24.5 Land use Dryland Wheat/Small Grains 

(70 percent); Range/Woodland 

(25 percent) 

Elevation 300-600m 

Topography Level to Undulating Till Plains/ 

Kettles, Kames, Moraines 

AAP 400-500mm 

AAT 4-7°C 

AFFP 120-140 Days 

Soils Borolls 

PNV Natural Prairie (Wheatgrass, 

Needleandthread, Needle grass) 

Class 30 Name Central Dark Brown Glaciated 

Plains 

Percent 17.3 Land use Dry land Spring Wheat ( 65 

percent); Range/Grazing 

Elevation 500-600m 

Topography Rolling Till Plains with Kettles, 

Kames, Moraines, Lakes 

AAP 350-425mm; Majority in Growing 

Season 

AAT 1-7°C 

AFFP 110-130 Days 

Soils Borolls 

PNV Natural Prairie (Wheatgrass, 

Needleandthread, Needle grass) 

Class 30 Name Red River Valley of the North 

Percent 17.2 Land use Dryland S.Wheat/S.Bean/Potato/ 

Beet/Com (80 percent); Wooded 

(10 percent) 

Elevation 200-300m 

Topography Nearly Level Glacial Lake Plain 

AAP 475-550mm; Majority in Growing 

Season 

AAT 2-7°C 

AFFP 105-135 Days 

Soils Aquolls 

PNV Natural Prairie (Bluestem, 

Switchgrass); Oak/Elm 

Figure 4. Major land resourc~ areas and their characteristics found in class 30. 

dryland spring wheat makes up about 70 percent, 65 

percent, and 80 percent, respectively, of the three MLRA's. 

This suggests that class 30 likely has dryland spring wheat 

as the dominant land use. In addition to providing an 

indication of dominant land use, the MLRA data bases give 

a profile of other characteristics such as terrain conditions, 

precipitation, temperature, and annual frost-free periods 

that help interpret seasonally distinct land cover regions. 

Digital elevation data also provide insights into land 

cover characteristics. Elevation has a significant impact on 

vegetation and land cover and, thus, can be used both to 

understand vegetation types and to divide regions represented by two or more land cover types into homogeneous 

classes. For example, several similar classes are found both 

in the southwestern United States and in the northern Rocky 

Mountains. In the southwest, the vegetation is desert 

grassland with biomass production in midsummer following 

July rainfall. In the Rocky Mountains, the vegetation is 

alpine tundra; here temperature (as influenced by elevation) 

controls the production of biomass. This is an example 

where decision rules based on elevation can sort similar 

classes into separate seasonally distinct land cover regions. 

We are developing decision rules for using such 

ancillary variables as elevation, climate, MLRA's, and 

ecosystems to stratify the mixed classes into homogeneous 

land cover classes. We will then complete the development 

of the descriptive and quantitative attributes for each of the 

final regions. The attributes will serve as spreadsheets of 

characteristics that correspond to different, seasonally distinct land cover regions. Derivatives from the land characteristics data base will include maps of seasonal parameters 

(onset of greenness, peak green period, duration of green 

period, and NDVI). We also plan to provide linkages to 

existing land cover classification systems (such as the 

USGS Anderson system), so that continental patterns of 

land cover can be better understood. 

Our immediate plans are to solicit critical reviews of 

our prototype work. We will then improve and test the 

methodology in different environments (such as Arctic 

regions). Ultimately, we plan to expand our work to include 

all of North America. Our goal is to develop a prototype 

data base containing the detail users need to tailor data to 

their specific application. 

REFERENCES 

Eidenshink, J.C., Burgan, R.E., and Haas, R.H., 1991, Monitoring fire fuels conditions by using time-series composites of 

Advanced Very High Resolution Radiometer data, in 

Resource Technology International Symposium on Advanced 

Technology in Natural Resource Management, Second, 

Washington, D.C., November 1990, Proceedings, p. 68-82. 

Henderson-Sellers, A., Wilson, M.F., Thomas, G., and Dickinson, R.E., 1986, Current global land-surface data sets for use 

in climate-related studies: National Center for Atmospheric 

Research Technical Note 272+STR, Boulder, Colorado, 

110 p. 

Justice, C.O., Townshend, J.R.G., Holben, B.N., and Tucker, 

C.J., 1985, Analysis of the phenology of global vegetation 

using meteorological satellite data: International Journal of 

Remote Sensing, v. 6, p. 1271-1318. 

Matthews, E., 1983, Global vegetation and land use: new high 

resolution databases for limited studies: Journal of Climatology and Applied Meteorology, v. 22, p. 474-487. 

Sadowski, F.G., 1990, Prototype land data sets for studies of 

global change, in International Geoscience and Remote 

Sensing Symposium, lOth, Washington, D.C., May 1990, 

Proceedings: New York, Institute of Electrical and Electronics Engineers, Inc., v. 2, p. 1235. 

A Strategy for Large-Area Land Characterization: The Conterminous United States Example 67 
Breakout and Poster Sessions 

A Distributed Visualization Modeling Environment for Methane Flux 

William Acevedo, National Mapping Division, U.S. Geological Survey 

L.A. Morrissey and G.P. livingston, TGS Technology, Inc. 

An interactive, distributed modeling environment for 

the analysis of methane flux at local and regional seasonal 

scales is under development. The modeling environment 

will use distributed processing and visualization technology 

to provide the tools to develop an ecosystem model for 

arctic Alaska. A collaborative effort with National Aeronautics and Space Administration (NASA) was established 

to develop the model, whose descriptions of methane 

fluxes, environmental parameters, and temporal dynamics 

are based on quantitative surface and satellite remotely 

sensed observations. 

A distributed modeling capability will allow near 

real-time control of model simulations and analysis of both 

input and output data. The application of visualization 

techniques for analysis will exploit the inherent power of 

the human visual system. The interactive nature of the 

modeling environment will enhance understanding of the 

many variables that control methane emission rates. System 

development will involve the design and implementation of 

a prototype flux model on the NASA Ames Research Center 

supercomputer. Model control, visualization, and analysis 

activities will be handled by a high-performance graphics 

workstation. The system will be designed as a distributed 

workstation application that can run the actual model on the 

supercomputer. Visual tools, such as time-series animation 

and 3-D perspective transformations, will be developed to 

convey critical elements, spatial patterns, and interactions 

among the environmental variables contributing to methane 

emission. Land surface characterization parameters 

required by the model will be generated from remotely 

sensed data. Digital data sets of vegetation and land cover, 

elevation and its derivatives, thaw depth, water depth, soil 

temperature, precipitation, and leaf area index will be used. 

Long Climatic Records From Sediment Cores in Western North America: 

Results and Prospects 

D.P. Adam 

Geologic Division 

U.S. Geological Survey 

Most of the continuous Quaternary paleoclimatic 

records now available from North America span the past 

10,000-20,000 years; only rarely do records span more than 

100,000 years. Few deposits east of the Cordilleras are 

suitable for long-term climate records, but many sedimentary basins of considerable antiquity are present in the 

western part of the continent. Previous work by the USGS 

has described long records at Clear Lake (130 ,000 years 

ago), Searles Lake (about 3.2 million years ago), and 

Tulelake (3 million years ago), all in California. 

The USGS is well positioned to pursue other long 

records in Western North America by virtue of its institutional stability and access to drilling equipment. Sediment 

cores represent a significant investment and require proper 

curation. Parallel studies of particular cores demand careful 

systematic core sampling and sample tracking. A good 

model exists in the DSDP/ODP core library system; we are 

implementing a similar system for cores from continental 

68 Proceedings of the U.S. Geological Survey Global Change Forum 

sites. We also plan to adopt the Deep-Sea Drilling Project/ 

Ocean Drilling Project (DSDP/ODP) practice of recovering 

many cores while reserving detailed studies for the best 

ones. 

Many suitable sites for long climate records in westem North America have been identified. Further work will 

begin in 1991 in south-central Oregon, where several sites 

will be cored to obtain at least 100 thousand year records 

that can be correlated with marine cores taken from the 

Gorda Rise. Some of these records should also include older 

sediments. The tephra record should be well preserved in at 

least some of these sites, allowing direct links to the marine 

record and permitting study of phase relationships between 

marine and continental climate records. We also hope to 

recover a detailed and continuous record from deposits at a 

forested site that is correlative with deep-sea oxygenisotope Stage 5. This will allow comparison with the pollen 

record from Clear Lake. 
Work planned for 1992 includes recovery of a long 

core from Fort Yukon, Alaska, which should provide a 

record of climatic change spanning several million years at 

high latitudes. Other prime candidates for long cores are 

Mono Lake and Owens Lake. Studies of these cores will 

involve both academic and USGS researchers from many 

disciplines. 

Continuous continental climate records spanning 105

-

106 years will permit us to assess aspects of global change 

Transects of Long Climatic Records 

D.P. Adam 

Geologic Division 

U.S. Geological Survey 

Long climatic records (more than 100,000 years) are 

as yet relatively rare from continental environments. Each 

such record provides a history of the climate at a particular 

site through time, but a detailed understanding of the 

dynamics of the climate system through time will require 

study of multiple sites distributed across major climatic 

boundaries of regional significance. 

The scarcity of long records from continental environments results in part from the lack of suitable deposits in 

many parts of the world. In the extensional tectonic regime 

of the Western United States, however, closed basins are 

common enough to permit strategic selection of sample sites 

for long records. A nested sampling strategy will permit 

independent evaluation of various factors whose effects 

cannot be separated at single sites. 

Here I describe a potential California-Nevada-Oregon 

(CNO) transect of long records across major regional 

climatic boundaries in the northwestern Great Basin, 

e~tending from the ancient lake basins of the upper Feather 

River drainage north of Lake Tahoe to the Malheur Basin of 

that are not accessible through studies of only the past 

20,000 years, including the nature of transitions from 

interglacial to glacial periods and the character of jumps 

between modes of long-term behavior. Neither abrupt 

climatic changes nor long-term modal shifts are well understood as yet (particularly as they affect continental records), 

but such understanding may be of critical importance for 

evaluating how the climate system could change in response 

to anthropogenic forcing. 

east-central Oregon. The boundary zone between regions 

dominated by Pacific vs. continental airmasses passes 

through the middle of this transect. Because the volcanoes 

of the southern Cascades have produced many Quaternary 

tephra layers in this area, detailed correlations between 

cores will be possible. 

Among the factors that can be studied over long-time 

intervals within the context of the CNO transect are the 

positions of major airmass boundaries through time, vegetation behavior of the eastern vs. western sides of the Sierra 

Nevada, behavior of drainage basins at several different 

latitudes, paired studies of neighboring pluviated vs. unpluviated basins, and studies of the filling of pluvial lakes 

through multiple cores within a given pluvial system. 

Prospects are good for recovering suitable cores from 

many sites along the CNO transect. Detailed studies may 

not be appropriate for all cores, but each will contribute to 

a regional stratigraphic framework that can later be 

extended to cover much of the Western United States. 

Late Cenozoic Climates of Alaska and Yukon: A Joint U.S. Geological SurveyGeological Survey of Canada Global Change Research Project 

T.A. Ager 

Geologic Division 

U.S. Geological Survey 

This interdisciplinary paleoclimate research project 

involves scientists from the USGS, Geological Survey of 

Canada (GSC), Agriculture Canada, and several universities in Canada and the United States. Its objectives are (1) 

to improve understanding of the history of climate and 

environments in Alaska and Yukon during the past 17 

million years; and (2) to improve late Cenozoic biostratigraphic and chronologie frameworks needed to interpret the 

surficial and subsurface geology of Alaska and northwest 

Canada. The research specialties involved in the project 

Breakout and Poster Sessions 69 
include sedimentology, stratigraphy, isotope geology, paleomagnetism, palynology, paleobotany, paleoentomology, 

and paleopedology. 

The project began with a joint USGS-GSC planning 

workshop held in Menlo Park, Calif., in November 1989. 

The first joint field season was carried out in August 1990, 

when a team of nine scientists studied and sampled Miocene 

fossil-bearing deposits exposed along the valley walls of the 

Porcupine River in northeastern Alaska. Preliminary results 

indicate that between about 17 to 15 million years ago the 

climate of interior Alaska was far more temperate and 

substantially less continental than is today's rigorous subarctic climate. During middle Miocene time, forest vegetation included taxa such as Pinus, Tsuga, Metasequoia, 

Abies, Ulmus, Pterocarya, Carya, !lex, and Diervilla. 

None of those taxa grow in interior Alaska today. The 

second field season will be held in June-July 1991 in 

interior Alaska and northern and central Yukon. The 1991 

field season will involve a team of 12 scientists, and field 

objectives include examination and sampling of deposits of 

Miocene, Pliocene and early Quaternary age. In 1992 the 

project will attempt to obtain a ca. 350 m sediment core 

from Yukon Flats in interior Alaska. If successful, the 

drilling effort will provide a rare opportunity to obtain a 

nearly continuous record of late Cenozoic climate and 

environmental changes in interior Alaska. The information 

derived from this project will contribute significantly to 

understanding how past global climate changes have 

behaved at high latitudes in the Northern Hemisphere. 

General circulation models suggest that global warming is 

most dramatic in those regions. 

Sustainable Development: Focus for Department of the Interior Global Change 

Human Interactions Experiment 

R.H. Alexander 

National Mapping Division 

U.S. Geological Survey 

A Department of the Interior collaborative experiment is proposed to illustrate how a regional sustainabledevelopment approach might help mitigate future disasters 

and, at the same time, maintain a healthy regional economy 

and promote interactions with other regions. Sustainable 

development is defined as "development that meets the 

needs of the present without compromising the ability of 

future generations to meet theirs" and "development that 

takes account of social and ecological factors as well as 

economic ones" by the World Commission on Environment 

and Development and the International Union for Conservation of Nature and Natural Resources, respectively. 

Experiments in Colorado, California, and Alaska 

would be based on collaboration among groups sharing 

regional concerns and responsibilities. Scenarios would be 

developed to determine how those concerns could be 

integrated into specific resource management decisions. 

Teams would comprise three components: research, management, and a regional observatory. 

70 Proceedings of the U.S. Geological Survey Global Change Forum 

The research component would consider models of 

land-use change processes, their environmental and socioeconomic consequences, and efficacy of various adjustment 

strategies. The management component would examine 

land management policies and actions of the Interior 

bureaus, other Federal agencies, and State and local governments in relation to a sustainable-development model. 

The regional observatory component would monitor and 

interpret trends by collecting_ or inventorying relevant data 

bases, such as land-use/land-cover and land-capability data 

bases. 

Liaison would be maintained with other global 

change programs; for example, in Colorado, the Long-Term 

Ecological Research sites program, the proposed new Colorado Man and the Biosphere. regional site program, the 

emerging University of Colorado Global Change program, 

and the prospective National Science Foundation LongTerm Regional Research Sites program for global change/ 

human interactions. 
Using Spatial Statistics to Improve Estimates of Regional Methane Emissions 

From Tundra Ecosystems 

S.P. Benjamin, National Mapping Division, U.S. Geological Survey 

G.P. Livingston and R.E. Rossi, TGS Technology, Inc. 

Spatial statistical methods, in particular geostatistics, 

are used to estimate quantities when data are not regularly 

sampled and to estimate the errors of interpolation for each 

point. Remote sensing technology, geostatistics, geographic information systems, and in situ approaches are 

integrated to modify estimates of midsummer methane 

emissions from tundra ecosystems on the North Slope of 

Alaska that are being made in a companion project sponsored by NASA. Based on ground coordinates of sampling 

sites and recorded methane emissions, geostatistical analysis has been used to test underlying sampling assumptions. 

Spatial interpolation and random simulation techniques are 

being used to generate methane emission and error surfaces. 

Using geographic information system analysis, the scientists will combine data on error surfaces with data on 

vegetation strata derived from Landsat multispectral scanner classifications, and with calculated strata emission 

means and variances, to produce flux estimates adjusted for 

sampling locations. Analysis is underway at three scales: 

Local-small areas about the size of a single multispectral 

scanner pixel (50 m2); Meso-the land portions of the 

Beechey Point and Barrow 1:250,000-scale quadrangles; 

and Regional-the entire 196,000 km2 of the North Slope. 

These analyses use tundra methane flux measurements from 

Prudhoe Bay, Point Barrow, and other Alaskan sites along 

the coastal plain and in the foothills of the Brooks Range. 

Reconstructing Climate of the Great Basin for the Past 25,000 Years: 

Completed and Ongoing Research 

LV. Benson 

Water Resources Division 

U.S. Geological Survey 

During the last few years a study of arid regions' 

climate has been undertaken to understand the magnitude 

and timing of changes that occurred in the hydrologic 

balance of the Great Basin during the past 25,000 + years. 

The Arid Regions Climate (ARC) project also has attempted 

to suggest hypotheses of climatic change that explain 

variation in the size of Great Basin lakes and glaciers and 

the timing of ground-water recharge. Our current hypothesis follows the suggestion of Ernst Antevs that, during an 

Ice Age, the polar jet stream (a source of increased 

precipitation and decreased evaporation) is located over the 

American Southwest during the entire annual cycle. In an 

effort to test the efficacy of the jet-stream hypothesis, 

numerical simulations of the effects of the introduction of 

(1) a jet-stream climatology, (2) ice cover, and (3) lakeeffect processes on lake-size have been performed (see 

abstract by S . Hostetler). 

In addition, we have been testing the ability of 

various sediment-based chemical parameters (e.g., carbonate chemistry, mineralogy, and stable-isotope content) to 

serve as proxy indicators of lake-size change. Ongoing 

research includes extension of the lake-size chronology of 

the western Lahontan basin through integrated studies of 

outcrop and cores from various altitudes in the Pyramid and 

Winnemucca Lake subbasins. This interdisciplinary 

research effort is being jointly conducted by members of the 

Geological Survey's Water Resources and Geologic 

Divisions, the academic community (University of Colorado, University of California-Berkeley, University of 

California-Davis, Western Washington State University, 

Calgary University, University of New York-Binghamton, Kent State University, Imperial College, University of 

Michigan, University of New Mexico, and Columbia University) and other research institutions (INSTAAR, NCAR, 

LDGO, NOAA, DRI). In addition to extending the chronology of Lake Lahontan, this study will test methodologies 

of paleolake-size determination. Members of the project 

will also attempt to formulate an optimal set of sampling 

and analytical procedures for the determination of lake-size 

change in large closed-basin lake systems common to the 

Great Basin. 

Breakout and Poster Sessions 71 
From Fire to Flood: Pacific Climate and Southwestern Watershed Management 

j.l. Betancourt 

Water Resources Division 

U.S. Geological Survey 

Fire and flood regimes integrate weather phenomena 

over space and time and thus offer a less equivocal measure 

of climatic variability than point rainfall. Pacific climate, 

specifically the Southern Oscillation (SO), exerts a strong 

influence in the Southwestern United States, where fires 

and floods are primary concerns of watershed management. 

Two diagnostic studies are presented in which climatic 

effects were considered to improve forecasts of large fires 

and to challenge indiscriminate use of standard methods for 

estimating flood frequencies. 

Ponderosa pine forest is the predominant vegetation 

in the upper watersheds of the Rio Grande and Colorado 

River basins. Due to a policy of suppression, fire regimes in 

these forests have shifted from frequent (2- to 10-year 

intervals) surface fires in early historic times to occasional 

stand-replacing crown fires in the modem era. Such large 

fires cannot only yield large sediment pulses in critical 

watersheds, but they also can affect local and global 

climates by injecting greenhouse gases and aerosols into the 

midlatitude troposphere. The climatologies of these fires are 

only now being linked to large-scale and highly variable 

features of the climate system such as the Southern Oscillation. Fire scar and tree growth chronologies (1700 to 

1905) and fire statistics (since 1905) from Arizona and New 

Mexico show that large areas bum after dry springs associated with the high phase of the SO (La Nifia). Because fire 

regimes lag teleconnections one or more seasons, the 

relation between SO and fires could have forecasting value 

and thus important implications for both fire and watershed 

management (Swetnam and Betancourt, 1990). 

Flood-frequency analyses typically yield inconsistent 

results for rivers in southern Arizona, a phenomenon 

commonly attributed to watershed changes (urbanization of 

floodplains, channel evolution, etc.) rather than climate; 

however, climatic effects are manifested by dramatic differences between flood-frequency estimates for different 

storm types, for different time periods, and for El Nifio 

conditions. For example, on the Santa Cruz River at 

Tucson, increasing flood magnitudes since 1960 were 

accompanied by a shift in annual flood seasonality, with 

more floods occurring during fall and winter. This shift 

reflects greater meridionality in the upper air westerlies and 

more frequent El Nifio conditions after 1960. Questions are 

raised about the validity of standard methods of floodfrequency analysis in regions where mixed populations of 

floods affect flood magnitude and frequency (Webb and 

Betancourt, 1992). 

REFERENCES 

Swetnam, T.R., and Betancourt, J.L., 1990, Fire-southern oscillation relations in the southwestern United States: Science, v. 

24, p. 1017-1020. 

Webb, R.H., and Betancourt, J.L., 1990, Climatic variability and 

flood frequency of the Santa Cruz River, Pima County, 

Arizona: U.S. Geological Survey Water-Supply Paper 2379, 

40 p. 

Soil Interpretations for Global Change Modeling and Impact Assessment 

N.H. Bliss 

TGS Technology, Inc. 

Global soil data bases are being developed from 

source maps at three scales for use in assessing global 

change. These will initially be used for evaluating the 

storage and dynamics of water and carbon in the soil. The 

data bases will be adapted for use as inputs to general 

circulation models of the atmosphere and for assessing the 

impacts of alternative scenarios of climate change and 

human activity on agriculture and forestry. Physical, chemical, and biological changes in soil as a global natural 

resource will also be evaluated. Soil scientists in the Soil 

72 Proceedings of the U.S. Geological Survey Global Change Forum 

Conservation Service, the Environmental Protection 

Agency, the National Aeronautics and Space Administration, and the International Society of Soil Science are 

collaborating on the interpretations. 

An initial set of interpretations will be developed for 

a digitized and edited global soil map at 1:25,000,000 scale. 

The polygons are being classified to the suborder level of 

soil taxonomy and according to soil temperature regime. 

The initial interpretations will be completed within 6 

months. 
More detailed interpretations will be developed for a 

digitized and edited global soil map at 1:5,000,000 scale. 

The polygons are being classified to the great group level of 

soil taxonomy, with the two most important great groups 

being indicated for each polygon. The soil temperature 

regime is also encoded. By relating the soil taxonomy to 

other data bases that contain information on soil properties, 

a more rigorous definition of the soil properties on a global 

scale is possible. The additional data bases include the State 

Soil Geographic (STATSGO) and the National Soil Geographic (NATSGO) data bases in the United States, which 

are linked to the Soil Interpretations Record. Data bases 

from field and laboratory analyses of soils (pedons) will be 

used worldwide. Maps of slopes and surface texture can be 

produced at the present time. Additional data base connections and interpretations will be completed within 1 to 3 

years. 

Participation in international efforts to develop global 

soil data bases and derivative maps at the 1:1,000,000 scale 

includes testing proposed data base structures in a geographic information system. Maps have been developed for 

the North American test site of the Soil and Terrain 

(SOTER) digital data base of the world. The effort at the 

1:1,000,000 scale is longer term and will require extensive 

international coordination. 

A 3-Million Year Terrestrial Climate Record and the Variable Character of the 

Marine-Terrestrial Climate Connection 

J.P. Bradbury 

Geologic Division 

U.S. Geological Survey 

The 3-million year paleolimnological diatom record 

from Tule Lake, northern California, reflects climatic 

changes that relate to the interaction of continental ice 

sheets and low-pressure air systems in the North Pacific. 

This record clearly defines the transition from warmer and 

equable Pliocene climates to "Pleistocene-style" climates of 

high variability. Lacustrine variation occurred largely as a 

result of changes in effective moisture and seasonality of 

precipitation. 

In the Pliocene and the warm intervals of the early 

Pleistocene, algal productivity was dominated by Aulacoseira, a diatom that prospers in warm, freshwater lakes. 

Glacial climates in the late Pliocene, 2.6 to 2.4 million 

years ago, caused a decrease in effective moisture; but 

cooler climates allowed freshwater marshes to persist 

throughout the year in this region. After 900,000 years ago, 

marsh environments, reflected by an abundance of Fragilaria species, recurred at about 100-thousand year intervals, 

approximately coinciding with the even-numbered marine 

oxygen isotope stages. 

During the Mid-Brunhes Climatic Event, recorded as 

reduced dust flux in the North Pacific, Tulelake became 

very shallow and alkaline to saline, perhaps as low thermal 

gradients and weak wind systems failed to deliver sufficient 

moisture to northern California. 

Late Pleistocene climatic changes at Tulelake are of 

different character than those that occurred earlier, possibly 

reflecting different circulation patterns in the Pacific Ocean 

as observed in marine diatom records. 

Arctic Ocean Winter Polynya Zones During 1978-87 

W.j. Campbell, Water Resources Division, U.S. Geological Survey 

Per Gloersen, National Aeronautics and Space Administration 

The Scanning Multichannel Microwave Radiometer 

(SMMR), which operated on board the Nimbus-7 satellite 

from October 1978 to August 1987 (the longest interval of 

observation ever accomplished by a satellite-borne passive 

microwave instrument), obtained continued sequential synoptic observations of the entire Arctic sea ice cover every 2 

days during all weather and solar illumination conditions. 

This unique, almost decade-long data set gives the first 

reliable information on the distribution and size of polynya 

zones (areas of reduced ice concentration due to the creation 

of leads, parallel-sided cracks, and amorphously shaped 

openings) that occur throughout the Arctic Ocean during 

winter. The occurrence of large polynya zones during 

winter is of great significance for the arctic heat balance 

Breakout and Poster Sessions 73 
because the flux of heat and water vapor through a given 

area of open water is 2-3 orders of magnitude greater than 

through the ice. The SMMR record shows that an average 

of 0.17 X 106 km2 of open water, about 2.4 percent of the 

area of the Arctic Ocean, occurs throughout each winter. 

Thus, the polynya fluxes dominate the heat and vapor 

exchanges between the Arctic Ocean and its atmosphere. 

During the SMMR period, large(> 104 km2

) polynya zones 

formed in various parts of the ocean throughout each 

winter. The distribution patterns of the polynya zones vary 

interannually, but there are three mesoscale areas where 

Global Change Data Management 

D.M. Carneggie 

National Mapping Division 

U.S. Geological Survey 

The interdisciplinary, interagency, and international 

aspects of global change studies, together with their longterm view, pose unprecedented challenges to the data 

management community. Traditional land data management practices are inadequate to bridge the tremendous 

volumes of historical and future global change observations 

and scientific understanding. The majority of global change 

observations required by researchers are acquired by spaceborne sensors; however, existing satellite data are in 

immediate jeopardy because of deteriorating storage media, 

and data inquiries cannot be made easily because index and 

catalog systems are outdated or do not exist. An example is 

Landsat data, which provide the longest and most consistent 

global record of the Earth's condition; however, Landsat 

data are being lost because magnetic storage tapes are 

deteriorating and processing systems to retrieve some of the 

data are inoperable or unavailable. 

Current data management problems will be compounded in the future unless improved technologies are 

applied now. The acquisition rate and volume of landrelated data to be collected by satellite systems in the 1990's 

and beyond will increase enormously, and effective data 

management systems must be in place. For example, the 

National Aeronautics and Space Administration's Earth 

Observing System program alone will generate more than 

74 Proceedings of the U.S. Geological Survey Global Change Forum 

they repeatedly occur: (l) southern Beaufort Sea adjacent to 

the Alaska coastline; (2) north of zone 1, centered along 82° 

north; and (3) Chukchi Sea along the transpolar drift stream. 

Most polynya events are remarkably persistent, lasting for 

periods of several weeks to several months. Because it is 

doubtful that wind forcing can maintain open polynyas for 

such lengthy periods, it is postulated that they are driven by 

ocean forces, namely relatively stationary surface water 

divergence patterns formed by upwelling associated with 

tides or internal waves. 

10,000 terabytes of data over 15 years. Data from current 

and future U.S. and international satellites, in addition to 

the ground-based data stored at numerous locations, must 

be available to global change research programs. Data 

directories, catalogs, and inventories, linked by communications networks, are needed to help identify and order 

data. Capabilities to develop, process, and distribute land 

data sets are needed to ensure that the data are readily 

available in user-compatible formats. Meeting these data 

management requirements is essential to an integrated, 

comprehensive long-term program of documenting the 

Earth system on a global scale. 

The U.S. Geological Survey's global change data 

management activities began in fiscal year 1990. Current 

efforts are concentrated in three areas: (1) Land Data 

Directory, Catalog, and Inv~ntory Systems Development, 

to provide on-line systems containing land information and 

data to the global change science community, with interfaces to the Global Change Data and Information System; 

(2) Landsat Data Maintenance and Conversion, to convert 

Landsat data to a stable storage medium and improve 

Landsat data processing capabilities; and (3) Data Set 

Development, Processing, and Distribution, to develop and 

implement techniques for organizing, producing, and making available land data sets. 
Late Cenozoic Arctic Climatic Change 

L.D. Carter 

Geologic Division 

U.S. Geological Survey 

This investigation began in fiscal year 1990 and 

initially was composed of two parts. The objective of Part I 

was to establish the character and chronology of major late 

Cenozoic climatic changes in northern Alaska. This part of 

the investigation was terminated after the first year of 

funding. Fortunately the research was founded on a solid 

base of geologic mapping and associated stratigraphic, 

geomorphic, geophysical, geochemical, and paleontological studies carried out over the past 15 years that facilitated 

several significant accomplishments from this single year of 

work: (1) Stratigraphic and paleomagnetic studies with 

J.W. Hillhouse (Branch of Western Regional Geology) 

determined an age of 2.48 million years ago for the Pliocene 

Bigbendian marine transgression of northern Alaska. 

Knowing the age of this high sea level event is important for 

the synoptic reconstruction of Pliocene warm intervals, 

which is an integral part of the National Global Change 

Research Plan. Also, determining the age of the Bigbendian 

transgression permitted calculation of a generalized ground 

temperature for the past 2.48 million years using measurements of the extent of amino acid diagenesis in the shells of 

Bigbendian mollusks. The calculated ground temperature is 

about -15°C, which suggests that permafrost has been 

present nearly continuously since the Bigbendian transgression. (2) Stratigraphic and palynological studies with R.E. 

Nelson (Colby College) determined that Arctic Slope vegetation during the Pliocene Colvillian marine transgression, 

which occurred sometime between 3.0 and 2.48 million 

years ago, was boreal forest or spruce-birch woodland with 

scattered pine and rare fir and hemlock. Climate was much 

warmer than at present and slightly warmer than during the 

succeeding Bigbendian transgression, which was characterized by an absence of permafrost and sea ice. (3) Results 

from oxygen-isotope analyses by J.F. Whelan (Branch of 

Isotope Geology) show that marine mollusk shells from 

deposits of the last two eustatic high sea level events along 

the Beaufort Sea coast, which include the last interglacial 

highstand (125,000 years ago), have higher 8180 values 

than modern shells. Our initial interpretation is that this 

enrichment in part indicates less extensive summer sea ice 

than occurs during modern summers. Continuing this 

research could provide information regarding the response 

of the Arctic Ocean to warming during the last interglacial, 

which is one goal of the Earth System History element of 

the National Global Change Research Plan. 

The objective of Part II, which began this fiscal year, 

is to determine the details of climatic change on the Alaskan 

arctic slope during the latest glacial-interglacial cycle 

through a multidisciplinary study of ancient eoliandominated sedimentary systems. Emphasis will be placed 

on the warm period that peaked about 10 or 9 thousand 

years ago as a possible analog for a phase of the warming 

that is expected to result from the buildup of anthropogenic 

greenhouse gases in the atmosphere. Research will concen- , 

trate on eolian sand, interdunallake sediments, and loess on 

the western part of the Arctic Coastal Plain, because studies 

have demonstrated that these now-stabilized eolian sediments and their intercalated paleosols are sensitive indicators of climatic change, and that they formed over the latest 

glacial-interglacial cycle. This research will include morphological and sedimentological studies that can provide 

information about wind directions, surface moisture conditions, and snow cover; studies of fossil lacustrine ostracodes 

by R.M. Forester (Branch of Paleontology and Stratigraphy) that will indicate water temperature-hydrechemistryclimate relations; measurements of oxygen isotopes in fossil 

and active ice wedges by D. E. Lawson (U.S. Army Cold 

Regions Research and Engineering Laboratory) that can 

provide paleotemperature information; and pollen analyses 

by R.E. Nelson that will show changes in vegetation 

through time. This research will link climatic change to 

physical processes on the Earth's surface in the climatically 

sensitive Arctic, which are goals of the Earth System 

History and the Solid Earth Processes elements of the 

National Global Change Research Plan. 

Breakout and Poster Sessions 75 
"Cool" vs. "Warm" Winter Precipitation and its Effect on Surface Hydrology in 

the Western United States 

Dan Cayan 

Climate Research Division 

Scripps Institution of Oceanography 

In this study, the winter precipitation in the Western 

United States is stratified into "warm" and "cool" groups, 

which are decided on the basis of regional temperature 

anomalies. Consideration of the temperature in association 

with the precipitation may provide a means for better 

identifying distinct precipitation-bearing atmospheric circulation types. Temperature has an impact on surface hydrology: when storms are cool they deposit more precipitation 

as snow than when they are warm. Finally, an investigation 

of historical winter variations of precipitation/temperature 

should be useful in discriminating natural climate fluctuations from possible future global warming effects. 

Local anomalies and their spatial patterns of pertinent 

variables were composited for the four categories (cool/wet, 

warm/wet, cool/dry, warm/dry) at selected watershed 

regions. Variables considered include atmospheric circulation, precipitation, temperature, streamflow, and snow 

water content. Although the cases entering the composites 

are chosen on the basis of the precipitation and temperature 

in a specific basin, the anomalies of all of these variables 

extend well beyond the basin; often the centers are fairly 

remote, and there are opposite-sign teleconnections downstream. Characteristic monthly atmospheric circulation 

anomaly patterns occur for each of the two wet categories. 

The cool/wet pattern has great southward meridional flow 

of cold air into the eastern Pacific, while the warm/wet 

pattern is dominated by strong southerly displaced zonal 

flow over the eastern North Pacific basin. Circulation 

patterns of individual storms from the cool/wet and warm/ 

Data Management Planning 

Eliot Christian 

Information Systems Division 

U.S. Geological Survey 

This session will include practical guidance on 

writing a data management plan into a research project 

description-describing how the researcher will identify, 

document, archive, and distribute the project data. Specific 

information will be provided on using the USGS Earth 

Science Data Directory (ESDD) as a means for documenting USGS data sets. Those entries in the ESDD relevant to 

global change are forwarded to the Global Change Master 

76 Proceedings of the U.S. Geological Survey Global Change Forum 

wet classes confirm that the storms themselves, not simply 

the intervening between-storm periods, produce those circulation anomaly patterns, and thus exert a major influence 

on the surface temperature as well as the precipitation 

during these months. 

Concerning runoff, the impact of temperature as well 

as the timing of precipitation during the water year is 

illustrated by compositing the monthly temperature and 

precipitation according to the late spring fraction of annual 

streamflow in rivers flowing out of California's Sierra 

Nevada mountains. A relatively late peak in streamflow is 

favored by later winter and spring precipitation and cool 

winter and spring temperatures, while a low fraction of 

spring/early summer streamflow is produced by heavy early 

winter and light spring precipitation and warm winter and 

spring temperatures. 

The cool vs. warm classification also provides insight 

into anomalously dry spells as well as wet cases along the 

West Coast. While the circulation for both the cool/dry and 

warm/dry categories along the West Coast is dominated by 

high pressure anomalies near and upstream of a watershed, 

the pattern for the cool/dry case is displaced farther to the 

northwest, inducing a southward penetration of cold air 

from the Gulf of Alaska and the interior of North America 

to the coastal regions. The hydrological warm dry case 

appears to have the harshest impact on water supplies in the 

West, as evidenced by anomalies of snow water content and 

streamflow. 

Directory. Sponsored by the Interagency Working Group on 

Data Management for Global Change, the Global Change 

Master Directory catalogs global change data sets across 

agencies and science disciplines. This session will demonstrate a personal computer version of the Global Change 

Master Directory and provide information on access to the 

online version. 
Climatic Change Inferred From Borehole-Temperature Measurements 

G.D. Clow and A.H. Lachenbruch 

Geologic Division 

U.S. Geological Survey 

Analysis of meteorologic records indicates that the 

global temperature of the Earth has increased ~o. soc 

during the past century. Presently it is unknown what 

fraction of the observed warming is due to the anthropogenic greenhouse effect and how much is simply a natural 

recovery from previous cooler temperatures. The meteorologic records that could be used to help resolve this issue are 

scarce before the onset of major industrialization ( ~ 1870 

A.D.), and instrumental records remained very sparse well 

into this century for remote polar and desert regions; 

however, the temperature changes that have occurred at the 

Earth's surface during the past few centuries are effectively 

stored in the ground in the form of subsurface temperature 

transients. Paleosurface temperatures can be determined 

from precise measurements of these temperature transients 

by using appropriate mathematical techniques. This method 

is applicable wherever ground-water flow is absent, such as 

in regions of thick permafrost, in "tight" rock formations 

within equatorial and temperate zones, and in ice sheets. 

The determined paleosurface temperatures can be used to 

extend the existing meteorologic records back several centuries and to supplement them in regions where spatial 

coverage is currently poor. 

Thus far, our principal result is that the solid-earth 

surface of Arctic Alaska has warmed 2 to 4 oc during the 

past 50 to 100 yr. This conclusion is based on an analysis of 

numerous subsurface-temperature profiles obtained 

throughout Arctic Alaska. Only two weather stations in the 

region have maintained records longer than 30 years, and 

both stations are on the coast, where they are subject to 

strong maritime influences. Should this warming trend 

continue, it will have a major effect. Models indicate that 

the Arctic Ocean will become ice free during the summer if 

temperatures increase 4 to 5°C above present levels, thus 

affecting the meridional temperature gradient that drives 

weather systems in the Northern Hemisphere. In addition, 

accelerated drainage of water from thaw lakes and lowcenter polygons may occur, owing to degradation of ice 

wedges, allowing the tundra to become drier. The flux of 

the "greenhouse" gas methane from the tundra is highly 

sensitive to water availability within the tundra's active 

layer. 

We continue to improve our equipment and mathematical techniques to determine paleotemperatures with 

greater "temporal" detail. These improved techniques will 

first be applied to Arctic Alaska to improve our understanding of this critical region. Available contemporary climate 

records (weather, tree ring, etc.) are being compiled and 

satellite data (Landsat, A VHRR) are being assessed to aid 

our interpretations. During the next 2 to 5 years, we will 

attempt to acquire and analyze precision boreholetemperature profiles from the Southwestern United States, 

Siberia, Greenland, and Antarctica to determine the magnitude of climatic changes in these regions on a timescale of 

decades to centuries. 

Interrelations Between Gas Hydrates of Northern Alaska and Atmospheric 

Methane 

T.S. Collett and K.A. Kvenvolden 

Geologic Division 

U.S. Geological Survey 

Atmospheric methane, a potential greenhouse gas, is 

increasing at such a rate that the current concentrations 

( = 1. 7 ppm) will probably double in the next 50 years. 

Many researchers have suggested that destabilized gas 

hydrates may be contributing to this build-up in atmospheric 

methane. Little is known about the geologic or geochemical 

nature of gas hydrates, even though they are known to occur 

in numerous arctic sedimentary basins. Because gas 

hydrates occur close to the Earth's surface in arctic regions, 

they are affected by surficial changes in temperature; thus, 

destabilized gas hydrates may be sources of atmospheric 

methane. Under the present climate regime, the gas 

hydrates of the nearshore continental shelf may be the most 

vulnerable to change. Because of the abundance of available geologic data, our research has focused on assessing 

the distribution of gas hydrates within the onshore regions 

of northern Alaska. Our onshore gas hydrate studies are 

being used to develop geologic analogs for potential gas 

Breakout and Poster Sessions 77 
hydrate occurrences within unexplored areas, such as the 

thermally unstable nearshore continental shelf. 

The primary goal of this project is to assess the 

relation between methane hydrate and global climate 

change. To reach this goal, the project has been divided into 

a series of three subprojects: (1) gas hydrate distribution, (2) 

gas hydrate composition, and (3) gas flux characterization. 

These subprojects have been designed so that deliverable 

products will be generated throughout the project. Each 

subproject has a distinct series of tasks and objectives. 

Within subproject 1, all available industry well-log and 

seismic data are being studied in order to determine the 

distribution of gas hydrates in the onshore and nearshore 

areas of northern Alaska. Subproject 2 deals with the 

characterization of the chemistry of the delineated gas 

hydrate occurrences. The primary source of data for this 

subproject has been our ongoing geochemical well sampling 

in the oil fields of the Prudhoe Bay area. Subproject 3 will 

include onshore and offshore geochemical surveys, with the 

first onshore survey scheduled for the summer of 1991. 

Proposed work under subproject 3 will also include the 

establishment of gas-flux monitoring stations, which should 

enable us to directly measure the rate of gas flux from 

decomposing gas hydrates. 

Stratigraphy of Climatic Change in Large Lakes 

S.M. Colman 

Geologic Division 

U.S. Geological Survey 

The sedimentary sections beneath large lakes potentially provide detailed records of past environmental 

changes in their respective basins. Large lakes contain 

varied and complex depositional environments. Paleoenvironmental reconstructions require that these complexities be 

deciphered so that climatic influences can be separated from 

other influences, such as faulting or mass wasting. On the 

other hand, the diversity of environments within large lakes 

is also an advantage for reconstructing past conditions, in 

that some part of the lacustrine system responds to almost 

any kind of environmental change. Finally, some large 

lakes, such as Lake Baikal, offer significant advantages 

over smaller bodies of water because they contain both 

short, high-resolution sedimentary records and long, continuous records. 

The physical stratigraphy of lacustrine deposits commonly reflects climatic and limnologic changes. In addition, the stratigraphy and chronology of lake sediments 

form the framework for the paleontologic, isotopic, and 

geochemical methods that attempt to reconstruct past conditions. High-resolution seismic-reflection profiles provide 

a method for studying the sedimentary framework and 

evolution of lacustrine sequences. Seismic profiles document major events such as glacial advances, water-level 

changes, and fault displacements, as well as outlining 

sedimentary environments and facies distributions. Cores 

located on the basis of the seismic-reflection data provide 

verification of the stratigraphy and the raw materials for 

sedimentological, geochemical, and paleontologic analyses 

78 Proceedings of the U.S. Geological Survey Global Change Forum 

aimed at paleoenvironmental reconstructions. In Lake 

Michigan, for example, sediment texture and magnetic 

properties show a direct relation to Holocene lake-level 

changes, and ostracode assemblages and stable isotopes 

clearly reflect external climatic conditions. 

An essential component of either synoptic or timeseries reconstructions of past conditions is adequate chronologie control of sedimentary records. For the late Quaternary, radiocarbon dating is by far the most common 

chronologie method applied to lake sediments; however, 

traditional radiocarbon methods commonly yield problematic ages, partly because of their sample-size requirements. 

Detrital material older than the lake sediments contaminates 

many organic carbon samples, and disequilibrium between 

the lake waters and the atmosphere is problematic for 

carbonate samples. The small samples required by AMS 

radiocarbon methods permit separation of discrete carbon 

and carbonate fractions, producing more abundant and more 

accurate ages. We have successfully dated sediments in 

Lake Michigan that were previously described as unsuitable 

for radiocarbon dating. 

Large, integrated, multidisciplinary studies of lake 

sediments, including stratigraphy, sedimentology, geochronology, paleontology, and geochemistry, offer an important 

way of reconstructing past climates and environments. This 

is particularly true for lakes such as Lake Baikal, which 

contains a long record of conditions in a region whose 

paleoclimate is virtually unknown. 
Rates of Holocene Climate Change-Evidence From Varved Lake Sediments 

W.E. Dean and J.P. Bradbury 

Geologic Division 

U.S. Geologic Survey 

Varved Holocene sediments in Elk Lake, near the 

present forest-prairie border in northwestern Minnesota, 

provide a high-resolution (annual) record of climate change 

for the last 10,400 years. This region of the northeastern 

Great Plains is situated at a climatic "triple junction" 

between Pacific, arctic, and Atlantic-Gulf air masses and is 

particularly sensitive to climate change. The middle Holocene, between 8,500 and 4,000 years ago is often called the 

"altithermal" or "hypsithermal" implying increased temperature. This period in Minnesota is documented by an 

expansion of prairie vegetation; but this steppe-like environment was probably cold-similar to the prairies of the 

central provinces of Canada today. Climate-sensitive mineral, geochemical, and biological components in the sediments of Elk Lake show that the development of the prairie 

period was asymmetrical with a gradual beginning and an 

abrupt end. This dry period was punctuated with shorterterm, cyclic fluctuations in climatic conditions with periods 

of several hundred years and abrupt ( decadal) transitions. A 

longer, distinctly moister and cooler interval occurred 

between 5,400 and 4,800 years ago. Pollen, diatom, and 

oxygen-isotope data from Elk Lake sediments indicate 

cooler conditions during the last 2,800 years, possibly 

reflecting the neoglacial period of arctic and alpine glacier 

expansion that culminated in the "Little Ice Age" between 

A.D. 1450 and 1850. 

Varve Chronology or 14C Dating-Which Do You Believe? 

W.E. Dean 

Geologic Division 

U.S. Geological Survey 

Paleoclimate records from two very different environments, Elk Lake, Minn., and the Black Sea, have been 

calibrated using annual sediment laminae (varves). Radiocarbon dating of sediments from these two varve sequences 

produces ages that are too old, and this calls into question 

the use of 14C chronologies in nonvarved lacustrine and 

marine sequences. 

Radiocarbon dates of organic carbon from a core 

from Elk Lake are consistently older than the varve-count 

chronology, probably because of systematic incorporation 

of dead carbon (as bicarbonate) in the organic matter of the 

core. For example, the base of the laminated sequence was 

dated by varve enumeration as 10,400 years and by 14C as 

11,380 years. Assuming that varve years are true calendar 

years, the atmospheric 14C age for each sample can be 

determined using a tree-ring calibration curve. The difference (~) between the measured 14C age and the atmospheric 14C age is a measure of the amount of old carbon in 

bicarbonate ions in Elk Lake water that were derived from 

leaching of calcareous glacial drift. In general, values of~ 

decrease exponentially with decreasing age: leaching of 

calcareous drift decreased through time after an initial 

postglacial "pulse" of dissolved-carbonate carbon from 

freshly exposed glacial flour. 

The Black Sea was a large, stratified (meromictic) 

lake during the Pleistocene when sea level was below the 

50-m sill depth connecting the Black Sea with the Mediterranean Sea. As postglacial sea level rose, the Black Sea 

began to fill with Mediterranean Sea water. Increased 

salinity permitted the invasion of the marine coccolithophorid Emiliania huxleyi: Holocene sediments in the Black 

Sea contain distinctive white laminae composed of the 

calcite remains of E. huxleyi. The white, carbonate-rich 

laminae alternate with dark laminae composed of organic 

matter and clay to form varves. The date of the first 

invasion of E. huxleyi into the Black Sea, is 1,633 years ago 

by varve count and 3,200 years ago by AMS 14C. These 

radiocarbon dates are suspect, however, because of the 

problem of reworked and (or) detrital carbonates and 

refractory organic carbon derived from the surrounding land 

masses. A 14C balance for the Black Sea (J.W. Murray, 

University of Washington, written commun., 1991) shows 

that the surface waters of the Black Sea are highly depleted 

and that carbon fixed by plankton and the resulting organic 

carbon flux has an apparent age of 1,400 years. 

Breakout and Poster Sessions 79 
Multiscale Characterization of Land Cover Complexity in Colorado 

Lee De Cola 

National Mapping Division 

U.S. Geological Survey 

Global change research requires a basic understanding of land surface processes and the applied management 

of land information. Research was initiated to develop the 

ability to organize and integrate data not only from different 

scales (meters to megameters) but also from different 

dimensional realms (point, raster, and vector). These multiscale descriptors of complexity can be used to analyze and 

classify land-cover types on a global scale. 

The objective of this research is to determine how 

topography, directly and through climate, influences the 

spatial distribution of vegetation by exploring such questions as: 

• How does the spatial complexity of topography vary with 

location? 

• How does vegetation respond to differences in elevation? 

• Where is terrain aspect an important determinant of 

precipitation? 

• What is an appropriate scale for mapping vegetation 

biomass predicted from temperature change? 

The test area is a 1 ,024- by 1 ,024-km region centered 

on Colorado, containing topographic data from a digital 

elevation model, greenness values from the Advanced Very 

High Resolution Radiometer satellite, point observations 

for temperature and precipitation, and an ecological zone 

polygon coverage. These data are examined at multiple 

scales using a C-language program that links remote sensing 

images with statistical analysis through the use of image 

pyramids. The variables are subjected both to multiscale 

analysis of variance, which characterizes overall spatial 

autocorrelation, and to multifractal analysis, which measures spatial complexity for given values and locations 

within the data. Regression analysis then is used to link the 

variables in a path structure reflecting presumed causal 

order. Results are rendered for a range of scales, but 

geographic information system vector coverages also will 

be produced. 

Preliminary results indicate that the use of lower 

resolution data can save resources such as computer time 

and storage space; however, the research also shows that 

scale is a significant determinant of results, because with 

higher resolution data, location, not elevation, has the 

greater influence on vegetation. An important goal of this 

research is to visualize and map spatial data that will be 

technically reliable as well as useful to the global change 

research and policy community. 

Description of lnterdecadal Trends in Surface Temperatures of the Sierra 

Nevada and Gunnison River Areas Using Singular-Spectrum Analysis 

M.D. Dettinger 

Water Resources Division 

U.S. Geological Survey 

Modification of observed climate variables from 

selected periods within the historical record is one way of 

synthesizing climate-change scenarios. Climatologically 

interesting periods can be identified for this use on the basis 

of climatic trend analyses at regional scales. This strategy is 

being applied as part of Sensitivity of Water Resources 

(SOWR) studies of the Sierra Nevada of California and 

Nevada and Gunnison River of southwestern Colorado. 

Long-term trends in surface-air temperatures have been 

identified for the conterminous United States as a whole and 

in the vicinity of the SOWR studies. The method used was 

singular-spectrum time-series analysis (SSA) of spatial 

empirical-orthogonal functions (EOF) applied to monthly 

averages of daily mean temperatures in the United States for 

80 Proceedings of the U.S. Geological Survey Global Change Forum 

the period 1910-1988 (data from Karl and others, 1988). 

Spatial EOF analysis allows identification of large-scale 

variability, and SSA permits decomposition of selected 

temporal components of that variability (Vautard and Ghil, 

1989). 

Globally the average of observed surface-air temperature has risen by about 0. 5°C this century (Folland and 

others, 1991), but corresponding warming is not evident in 

observations over the conterminous United States. The 

present analyses show that the temperature, on an interdecadal scale, in the United States as a whole warmed about 

0.4°C during 1915-1935 followed by a slow, usually 

oscillatory decline or stasis until the mid-1970's and some 

warming since. Trends since 1935 are more site specific 
than the general warming before. The trend for the United 

States as a whole can be identified in simple area-weighted 

means or in the first spatial EOF (which represents 39 

percent of the variability). The trend suggests oscillations 

with up to 60-year periods, rather than monotonic warming. 

Regional reconstructions suggest that the best example of interdecadal warming in the Sierra Nevada region is 

the period 1915-1935 (the rise was about 0.3 of the 

standard deviation of local temperatures with seasonal 

variations removed). On this time scale, temperatures in the 

Sierra Nevada have been fairly stable since about 1940. In 

southwestern Colorado, the 1915-1935 warming was similar; temperatures after 1935 have been weakly oscillating 

with about a 25-year period. In Colorado, the 1960's show 

a slight decade-long cooling; the period since about 1973 

shows a slight warming. These trends can be contrasted 

with a trend characterized by dramatic warming and cooling 

Pliocene Marine Climate Records 

H.j. Dowsett, LB. Wiggs, and R.Z. Poore 

Geologic Division 

U.S. Geological Survey 

We have documented the character and variability of 

Pliocene marine climate records in the North Atlantic region 

as part of the PRISM (Pliocene Research, Interpretation, 

and Synoptic Mapping) investigation of Earth system 

response to global change. Sea-surface temperature (SST) 

estimates based upon quantitative analysis of planktic 

foraminifer faunas in North Atlantic deep sea cores show 

that high-frequency, low-amplitude variability related to 

orbital forcing was superimposed on long-term changes that 

delineate intervals within the Pliocene that were both 

warmer and cooler than today. One warm interval, centered 

at 3 million years ago, is the basis for a synoptic view of the 

North Atlantic Region. SST estimates from this interval 

Climate, Lakes, and Ostracodes 

R.M. Forester 

Geologic Division 

U.S. Geological Survey 

Lacustrine parameters such as water temperature, 

major dissolved ion (solute) composition, and conductivity 

are coupled to climate parameters on a regional scale. For 

example, lake parameters in a region with a cold-wet 

climate are different from those in a region with a warm-dry 

climate. Climate is a product of regional air masses that 

rates since 1935 in the Delaware River basin (a previous 

SOWR study region). 

REFERENCES 

Folland, C.K., Karl, T.R., and Vinnikov, K.Ya., 1991, Observed 

climate variations and change, in Houghton, J.T., Jenkins, 

G.J., and Ephraums, J.J., eds., Climate Change, The IPCC 

Scientific Assessment: New York, Cambridge University 

Press, p. 195-238. 

Karl, T.R., Diaz, H.F., and Kukla, George, 1988, Urbanization: 

Its detection and effect in the United States climate record: 

Journal of Climate, v. 1, p. 1099-1123. 

Vautard, Robert, and Ghil, Michael, 1989, Singular spectrum 

analysis in nonlinear dynamics, with applications to paleoclimatic time series: Physica D, v. 5, p. 395--424. 

show little to no warming in the tropical regions, whereas 

mid- to high-latitude areas show moderate to strong warming. SST estimates for the last interglacial (isotope stage 5e) 

show a similar pattern but warming during the last interglacial was not as pronounced as the middle Pliocene warming. 

Results indicate that Pliocene warming was amplified at 

higher latitudes, which is generally consistent with the 

regional pattern of global warming predicted by GCM 

equilibrium 2x C02 simulations. The pattern of Pliocene 

SST estimates suggests warm intervals of the Pliocene 

involved increased transport of heat northward by the Gulf 

Stream and North Atlantic Drift. 

interact with surface water in predictable ways, coupling 

climate with limnology. The lake-climate linkage may be 

defined with multivariate techniques and may be portrayed 

with surfaces that plot gridded data from lakes on climate 

axes or vice versa. 

Breakout and Poster Sessions 81 
Lacustrine ostracodes, which are microscopic crustaceans with calcite valves, are sensitive indicators of physical and chemical lake parameters. Ostracode occurrences 

define species-specific regions on surfaces created from 

those lake parameters that are coupled to climate. Modem 

ostracodes often range through the Pliocene, so a modem 

ostracode-to-climate calibration could offer climate reconstructions for the past 5 million years. 

The ostracode-lake-climate relationship will be calibrated along climate gradients to maximize information 

with a minimum number of samples. The lake-climate 

relationship is illustrated using published data from the 

Itasca transect, a well studied climate-evaporation gradient 

in the upper midwest. The ostracode-lake-climate relationship is illustrated using unpublished data collected by 

Alison Smith (Kent State Univ.) from the same area. 

The Effect of Climate Change on the Hydrology of Glacier Regions 

A.G. Fountain 

Water Resources Division 

U.S. Geological Survey 

The general shrinkage of glaciers in the century has 

significantly contributed to the streamflow from glaciercovered regions. In 1977, the amount of water produced by 

glacier wastage in the Columbia River was worth over $18 

million (Tangbom, 1980). The retreat of alpine glaciers 

worldwide accounts for one-fourth to one-half of the 

observed rise in sea level; therefore, understanding how 

variations in the extent of glacier cover affect water resources is an important first step in evaluating the effect of 

climate change on the hydrology of glacier-covered regions. 

The long-term effect of glaciers on streamflow is to 

reduce streamflow variability from that observed in nonglacial basins. Glaciers naturally regulate streamflow by storing water as ice during cold periods and releasing water 

during warm periods. Basins with about 36 percent of the 

area covered by glaciers have the minimum variation in 

runoff. Runoff from glaciers is energy limited rather than 

mass limited like a seasonal snowpack. As the fraction of 

glacier cover increases, peak basin runoff shifts from May 

to late July. 

In order to link the known effect of glaciers on 

streamflow to climate change and the contribution of alpine 

glaciers to sea level changes, we must first be able to predict 

annual mass change with elevation for an individual glacier 

and extrapolate these changes to glaciers in the surrounding 

region. From these results, runoff from the glacier-covered 

• 82 Proceedings of the U.S. Geological Survey Global Change Forum 

region can be estimated. Once these processes are defined, 

runoff models can use results from mesoscale or global 

scale climate models to examine the response of glaciers 

and glacial runoff to different climatic scenarios. 

Currently, the U.S. Geological Survey has designated 

three benchmark glaciers (two in Alaska and one in Washington State) on which intensive measurements of weather, 

runoff, and glacier mass change and extent are being made. 

Low-level monitoring of other glaciers in the region will 

indicate how mass changes in each benchmark glacier relate 

to mass changes in the surrounding glacier-covered region. 

These three benchmark glaciers do not adequately cover the 

range of glacier distribution in the United States and 

Canada. To increase this coverage I propose more benchmark glaciers be added to the U.S. Geological program. 

REFERENCE 

Tangborn, W.V., 1980, Contribution of glacier runoff to hydroelectric power generation on the Columbia River, in Data of 

glaciological studies: Proceedings of the International Symposium on Computation and Forecasts of the Runoff from 

Glaciers and Glacierized Areas, (Thilisi, 1978): Moscow, 

Academy of Sciences of the USSR, Section of Glaciology of 

the Soviet Geophysical Committee and Institute of Geography, Publication 39, p. 62-67, 140-143. 
Report of a Workshop on the Correlation of Marine and Terrestrial Records of 

Climate Changes in the Western United States 

J.V. Gardner, A.M. Sarna-Wojcicki, D.P. Adam, W.E. Dean, J.P. Bradbury, and H.J. Rieck 

Geologic Division 

U.S. Geological Survey 

The eastern Pacific Ocean, dominated by the North 

Pacific High, the Aleutian Low, and the Western United 

States Low, generates the weather and climate of the 

Western United States and has an effect on the entire 

Northern Hemisphere. Changes in the positions and 

strengths of the atmospheric cells through time had a 

profound influence on the climate of the Western United 

States. The California Current is a large heat sink that 

extends along the western U.S. coast from about 50°N south 

to Baja California. This belt of cold surface water modulates the coastal climate of Western North America, but the 

strength and position of the California Current are direct 

responses to the atmospheric pressure cells. The history of 

the California Current is unknown, but it has responded to 

ENSO (El Nino-Southern Oscillation) events, as shown by 

historic records as well as from varves in marine sediments. 

Although there are numerous terrestrial paleoclimate 

records available from the west coast, very few are highresolution records (10 to 1,000 years) that contain the 

uninterrupted history for the late Quaternary, or even for the 

Brunhes. Moreover, there are very few long, highresolution marine records from the Pacific borderland of the 

United States. None have been obtained with modem 

recovery technology (e.g., hydraulic piston cores), and 

none of them are calibrated by an independent, accurate 

chronology (e.g. , magnetostratigraphy, tephrochronology). 

Finally, there are very few convincing physical or temporal 

ties between Quaternary paleoclimate records in the marine 

and terrestrial records of this region. 

A workshop was held at Pajaro Dunes, Watsonville, 

Calif. in January 1991 as part of the USGS Climate Change 

Program to organize and coordinate a project to correlate 

marine and terrestrial paleoclimatic records from the Westem United States and eastern North Pacific Ocean. The 

focus of the project is to develop detailed, high-resolution 

paleoclimatic records of the last 130,000 years, with as 

many climate proxy variables as possible, and a time 

resolution of 1,000 years or less. The workshop convened a 

group of experts from the USGS and the academic community to (1) prioritize potential sites to be immediately cored 

in the Western United States and the eastern North Pacific 

Ocean, (2) review and discuss the best stratigraphic correlation and dating techniques to apply to these cores, (3) 

identify the preferred methods and equipment for obtaining 

the proposed terrestrial and marine sections, and (4) discuss 

the logistics of sampling and developing a data base. 

The priority terrestrial sites include Upper KlamathSouth Cascades, Mono Lake, Calif., Owens Lake, Calif., 

Tulare Lake, Calif., and Ruby Marshes, Nev. The pnority 

marine sites include Gorda Ridge, seamounts off California, the central California continental margin, and laminated sediments in basins off southern California and in the 

Gulf of California. The most promising stratigraphic techniques include paleomagnetic intensity stratigraphy, tephrostratigraphy, and oxygen-isotope stratigraphy. Terrestrial 

coring will be accomplished by conventional drilling, but 

the marine coring requires a new' state-of-the-art, coring 

system, such as the French Stacor. 

Assessing the Human Impact of Global Change in Western United States 

and Alaska 

L.J. Gaydos 

National Mapping Division 

U.S. Geological Survey 

Human populations and their occupation of the land 

are both a cause and an effect of global change. Three 

regions have been selected to study the dynamics of this 

relationship between man and nature: northern California, 

Colorado, and arctic Alaska. The present-day patterns of 

land use and land cover will be used as bases for mapping 

ecological and economic factors such as primary productivity, biomass, biological diversity, economic productivity, 

employment, and population. A model of the present-day 

state of land resources dynamics will be built. Variables in 

this model will be altered to test the impacts in these regions 

of various global change scenarios. Areas that are especially 

sensitive to these changes will be highlighted on resulting 

digital data maps and interactive displays. Policymakers 

will be able to distinguish critical areas and examine 

mitigation strategies before serious damage is done. 

Breakout and Poster Sessions 83 
Role of Volcanic Emissions in Global Change 

T.M. Gerlach 

Geologic Division 

U.S. Geological Survey 

Past work suggests that volcanic emissions play an 

important role in global change. Volcanic emissions have 

been invoked as forcing agents for global change throughout geologic history. Several investigators of modem-day 

climate change have shown statistically significant temperature decreases following large subaerial eruptions of the 

19th and 20th centuries. Little is known, however, of the 

compositions and emission rates of chemically and radiatively active gases and aerosols emitted from volcanoes 

during quiet periods, and even less is known about emission 

rates during eruptions. The lack of information concerning 

the chemistry and volumes of gases emitted by volcanoes 

during both eruptive and quiescent degassing is one of the 

chief impediments to progress in understanding the relationship between volcano emissions and global change. Volcanic emissions are, nevertheless, expected to be a significant 

factor in global change policy issues. Of particular concern 

is the role that volcanic emissions may play in complicating 

and modifying global change that may result from anthropogenic forcing. Thus, research on volcanic emissions is 

needed to provide a scientific basis for developing policy on 

global change. Indeed the U.S. Global Change Research 

Program has identified volcanic emissions as potentially 

important agents of global change, and as early as 1989 it 

recommended the study of volcanic emissions: "The role of 

subaerial and submarine volcanism in contributing radiatively important gases, aerosols, heat, and fluids that 

influence the composition of the atmosphere and ocean will 

be quantified." 

This presentation is intended to provide an overview 

of the research initiated in fiscal year 1991 in the Branch of 

Igneous and Geothermal Processes on the role of volcanic 

emissions in global change. The principal research problems, objectives, approaches, and plans will be outlined. 

The main objectives of the research are to increase data, 

improve monitoring capabilities, and enhance understanding concerning the compositions and emission rates of gases 

released by erupting and quiescently degassing volcanoes. 

The plan is to pursue these objectives over the next several 

years by (1) using currently available techniques to build 

data bases on the emission rates and compositions of 

volcanic gases; (2) applying new technology to improve 

volcanic emission monitoring capabilities; (3) participating 

in experiments to calibrate space-based satellite sensors 

capable of imaging volcanic gas emissions; and ( 4) using 

mass balance models to better constrain the emissions of 

volcanic systems on a global scale, and to better constrain 

their contributions to the biogeochemical cycles of carbon, 

sulfur, and halogens. Various elements of the plan will be 

illustrated with specific examples of projects underway in 

fiscal year 1991 to acquire data on the compositions and 

emission rates of volcanic gases and of secondary aerosols 

derived from volcanic gases at erupting and quiescently 

degassing volcanoes. A brief summary of the preliminary 

results of sulfur-emission studies at Redoubt Volcano, 

Alaska, will be presented, time permitting. 

REFERENCE 

Committee on Earth Sciences, 1989, Our changing planet: The FY 

1990 research plan of the U.S. Global Change Research 

Program, p. 108. 

Climatic and Paleo-Oceanographic History of the Canada Basin, Arctic Ocean 

Arthur Grantz, R.L. Phillips, S.D. May, M.W. Mullen, R.Z. Poore, and H.j. Rieck 

Geologic Division 

U.S. Geological Survey 

The sediments that fill the deep basins and drape the 

isolated ridges of the Canada Basin contain a detailed record 

of the climatic and oceanographic environments that 

reigned in the north polar region from the equable conditions of the Albian to the harsher conditions of the Quaternary. Marine geologic studies on Northwind Ridge and the 

Beaufort Sea continental slope and rise of the Canada Basin 

84 Proceedings of the U.S. Geological Survey Global Change Forum 

from USCGC Polar Star in 1988 and 1989 indicate that a 

large part, and probably most, of this record can be 

recovered with piston cores located on the basis of seismic 

reflection profiles obtained from ice breakers. Using these 

data we hope to document the interrelated history and 

character of middle Cretaceous to Holocene climatic and 

oceanographic conditions in the north polar region, which 
has been especially sensitive to, and strongly affected by, 

climatic change. The detailed marine (and complementary 

terrestrial) sedimentary record that is available in the 

Canada Basin and its environs is also thought to contain 

valuable insights into the physical processes that drove 

global change, and will provide a base line for understanding future changes. 

Preliminary results from Northwind Ridge include the 

recovery of three cores with benthic foraminifera-bearing 

middle Albian dark gray shale from the foot of the ridge, 

which is the oldest sediment so far recovered from the 

Arctic Basin. Nine cores from the ridge crest and eastern 

slope contain as many as 12 cycles of interleaved glacial 

and interglacial deposits that paleomagnetic data suggest 

represent the last 1 million years of glacial history. The 

interglacial sequences are dark brown, foraminifera-rich 

muds with ice-rafted clasts, whereas the glacial events are 

gray mud lacking ice-rafted clasts and marine fossils. 

Faunal and textural analyses suggest the Canada Basin was 

completely ice covered during glacial intervals. Interglacial 

intervals brought an abrupt influx of coarse-grained sediment to the basin from melting icebergs and foraminifera 

were abundant. Sedimentation rates on Northwind Ridge 

ranged up to 9mm per thousand years, and perhaps in places 

as high as 20mm per thousand years. These high rates result 

in expanded sedimentary sections that allow distinct glacial/ 

interglacial events to be defined. Three short intervals of 

reversed polarity in one core, which all fall within glacial 

intervals, may support suggestions by other workers that a 

genetic link between ice ages and geomagnetic field behavior may exist. 

Ten cores from the slope and rise of the eastern 

Beaufort Sea have sampled an as yet undated section 

of Neogene (and Paleogene?) strata, and both condensed 

and ponded Quaternary sections with multiple glacial/ 

interglacial cycles. Detailed lithostratigraphic, paleontologic, paleomagnetic, isotopic, and chemical studies of both 

the Northwind Ridge and Beaufort Sea cores are in progress 

or are planned by a team of USGS and outside investigators. 

The Effect of Changes in Data Resolution on Hydrologic Response 

C.A. Hallam 

National Mapping Division 

U.S. Geological Survey 

The problem of water balance and the timing of the 

flow of water through drainage basins has been studied for 

many years, but it has never been of greater importance than 

it is now. The current studies, which suggest global climate 

change, predict possible changes in both temperature and 

precipitation in the next few decades as a result of man's 

activities. Although there is debate over the exact effect of 

these activities, most agree that there will be warming of the 

globe as a result of changes in the composition of the 

atmosphere. The result may affect the temporal and spatial 

distribution of precipitation, in addition to the amount. If 

this is the case, an understanding of the movement and 

distribution of water on a regional basis will be of even 

more importance than it is now. 

This project will study the changes in the predicted 

flow of water through a drainage basin resulting from 

changes in the resolution of the input data. The runoff 

predictions will be generated by using the PrecipitationRunoff Modeling System and data from a geographic 

information system (GIS). Data describing the physical 

characteristics of the basin will be entered into the GIS, 

integrated arid manipulated to meet the requirements of the 

model, and then output to run the model. 

The manipulation will include the creation of data 

sets for the basin at a series of resolution levels by 

generalizing the raster data base. The model will then be 

used to predict daily flow values for the basin. A comparison of the values at each resolution will be performed by 

using spatial and statistical techniques to determine the 

difference between the flow values for generalized basins 

and the original basin calculations. 

Breakout and Poster Sessions 85 
Coral Fluorescence as an Index of Runoff in South Florida 

R.B. Halley 

Geologic Division 

U.S. Geological Survey 

Some corals contain seasonal growth bands, like tree 

rings, that chemically and physically record aspects of their 

environment (climate) as they grow. Cores from large 

corals, greater than 2 m in diameter, contain records of at 

least monthly resolution that may be several centuries long. 

Corals living adjacent to continental areas record aspects of 

continental runoff and air temperature as part of the environment in which they grow. 

Fluorescent coral skeletons from the Florida Keys 

may serve as a proxy for rainfall or runoff. Excitation by 

short-wave ultraviolet light results in a yellow fluorescence 

that occurs in bands conformable with coral growth bands. 

Fluorescence apparently results from the incorporation of 

organic acids derived from soils of nearby land areas during 

times of high runoff. Intensity of fluorescence is recorded 

through time in the growing coral and shows strong correlation with flow from drainage canals in south Florida after 

1900. 180 of the aragonite skeleton in coral is determined 

by coral growth rate and by temperature and isotopic 

composition of seawater. Growth variability may be minimized by sampling procedures. Through careful comparison between fluorescent and 180 records, it may be possible 

to extract a temperature record from corals in south Florida. 

Although the 180 "paleothermometer" is complicated by 

water of variable isotopic composition originating from the 

Everglades and Florida Bay, corals growing in different 

environments may record signatures either of runoff, precipitation, or Gulf Stream water mass. Hence, coral fluorescence provides a salinity index that, when used in 

conjunction with 180, may allow a refined climate proxy to 

be extracted from coral cores. 

Seawater Temperature and Coral Bleaching in the Florida Keys: No Relation to 

Global Warming . .. Yet 

R.B. Halley, Geologic Division, U.S. Geological Survey 

j.H. Hudson, Florida Keys National Marine Sanctuary 

Coral bleaching is a natural phenomenon during 

which corals lose their color and photosynthetic symbionts 

(zooxanthellae) in response to stress. Bleaching is known to 

occur in response to rapid changes in salinity, light, 

temperature, nutrients, pollutants, exposure to air, and 

disease. Prolonged bleaching can be fatal, but corals often 

recover from bleaching events of several weeks or longer. 

During the 1960's and early 1970's bleaching was rarely 

reported, perhaps because of the small number of divers 

making observations at that time. During the last decade, 

reports of bleaching in the Caribbean, Bahamas, and 

Florida during late summer months have become widespread. Recent bleaching occurrences have been speculatively attributed to summer thermal stress and linked with 

global warming. 

The U.S. Geological Survey maintained thermographs at several sites in the northern Florida Keys between 

1975 and 1988. Temperature records generally show strong 

correlations between sites (correlation coefficients 

[r]>0.95) suggesting that water temperature may be predicted throughout the Florida Keys by using a few longterm thermograph sites. These records also show that 

86 Proceedings of the U.S. Geological Survey Global Change Forum 

temperatures at shelf-edge sites are dominated by the 

Florida Current and inshore sites are dominated by air 

temperature. The temperature records also demonstrate that 

seawater in the Keys was warmer in the 1980's than during 

the late 1970's. Bleaching events reported for the Florida 

Keys in 1979, 1983, and 1987 did not occur during times of 

widespread, high water temperatures. Compared to a tenyear average, 1979 and 1983 were about average years. The 

year 1987 was warm, but not extreme, although September 

was an unusually warm month. The summers of 1981, 

1982, and 1986 were extremely warm, but bleaching was 

not reported for those years. 

Water temperatures at Hen and Chickens Reef show 

some correlation {r=. 7) with Northern Hemisphere air 

temperature (NHAT), although the variation in water temperatures is greater than the variation in air temperatures by 

a factor of about three. This is not a total coincidence 

because Hen and Chickens is situated in an area of the shelf 

where the primary forcing of water temperature is air 

temperature. The reef is at a high latitude (for reefs, at 

25°N), and it is affected by a mixture of climate processes: 

frontal systems characteristic of northern latitudes in the 
winter and westerly trades more characteristic of southern 

latitudes in the summer. It is not surprising that there might 

be some correlation between Northern Hemisphere air 

temperatures and water temperatures at this locality. This 

correlation poses the possibility that if NHA T continues to 

rise, seawater temperatures will follow, perhaps at an 

accelerated rate, with lethal consequences for many species 

of corals common in the Florida Keys; however, it seems 

unlikely that past bleaching events in the Keys can be 

directly linked to global warming. 

The Old Crow Tephra: A Stratigraphic Marker for the Last lnterglaciation 

in Alaska? 

T.D. Hamilton 

Geologic Division 

U.S. Geological Survey 

A recent fission-track age determination of 140,000 

years ago, plus or minus 10,000 years, for the Old Crow 

tephra of Westgate and others (1983) (OCt) seems to 

indicate that it was deposited before the last interglacial 

maximum (oxygen-isotope substage 5e). The OCt has now 

been recognized at 11 sites in Alaska, and its stratigraphic 

placement at nine of these sites is well defined. The 

stratigraphic record at some sites seems to confirm deposition of the OCt before the last interglaciation, but data from 

other sites challenge this widely accepted age relationship. 

At Birch Creek and Halfway House in central Alaska, 

the Old Crow tephra occurs within a paleosol that probably 

formed under forested conditions and that could represent 

substage 5e. At Fairbanks and at the Palisades of the Yukon 

on the other hand, the tephra occurs within silt that clearly 

underlies a conspicuous organic horizon that may have 

formed during substage 5e. Three sites in the Koyukuk 

Valley show comparable variations. At Ky-11, the tephra 

lies between the lower two of three horizons that exhibit 

spruce-pollen peaks; at Ky-12, peat with spruce wood 

occurs in loess 2 m above the tephra; at the Hogatza Mine 

the tephra overlies a peat rich in spruce pollen that indicates 

forest about as extensive as that of the present day. 

The OCt also has been reported at two sites in western 

Alaska. At Imuruk Lake, it coincides with a minor sprucepollen maximum 1.5 m below a major zone of spruce pollen 

that indicates forest limits beyond those at present. In the 

Holitna lowland, the tephra occurs below an extensive 

organic horizon that appears to represent interstadial rather 

than interglacial conditions. 

At four of the sites discussed above (Palisades, 

Fairbanks, Ky-12, and Holitna lowland), the OCt clearly 

occurs below an organic horizon or spruce-pollen peak that 

represents a distinctive warm interval; but at three other 

sites (Birch Creek, Halfway House, and Hogatza Mine) it 

occurs within or just above an equally conspicuous paleosol. Multiple paleosols or spruce-pollen maxima at Birch 

Creek, Halfway House, Ky-11, and Imuruk Lake form 

complex records that make correlations with substage 5e 

uncertain. These multiple organic horizons suggest that no 

single buried forest bed or spruce-pollen peak at any site can 

be assumed to represent a unique "last interglacial maximum." 

The varying stratigraphic positions of the OCt probably were not caused by multiple volcanic eruptions. No 

locality has yet been identified with more than one OCt, and 

geographic distribution and tephra geochemistry also are 

consistent with a single depositional episode. Alternatively, 

the OCt may have been deposited during an early warm 

phase of the last interglaciation when residual glaciers were 

still present, loess deposition was active locally, and soils 

and organic horizons formed elsewhere. High-resolution 

uranium-series ages show that the sea-level maximum 

associated with the last interglaciation lasted from about 

132,000 to 120,000 years ago. An appropriate time for the 

diverse environments indicated by the OCt is just prior to 

this high sea-level event, perhaps about 135,000 years ago, 

plus or minus 5,000 years ago. This age estimate is 

consistent with the younger part of the time interval 

suggested by the recent fission-track age determination 

cited above. 

REFERENCE 

Westgate, J.A., Hamilton, T.D., and Gorton, M.P., 1983, Old 

Crow tephra: A new Pleistocene stratigraphic market across 

north-central Alaska and Western Yukon Territory: Quaternary Research, v. 19, no. 1, p. 38-54. 

Breakout and Poster Sessions 87 
Nutrient and Carbon Dynamics in Soil Systems 

j.W. Harden, R.K. Mark, and D.H. Showalter, Geologic Division 

E.T. Sundquist and R.F. Stallard, Water Resources Division 

U.S. Geological Survey 

Terrestrial soils currently contain about twice as 

much carbon as the atmosphere. Most global models for soil 

carbon rely strictly on the present-day association of soilcarbon budgets and climate/vegetation classes. Our goal is 

to understand the processes that control fixation and oxidation of soil carbon and to develop an approach that 

encompasses the spatial and temporal variations of such 

processes. 

We are developing a simulation of soil as a C02 sink 

during the retreat of the Laurentide Ice Sheet as an illustration of the dynamics of soil carbon. Upon deglaciation, 

fresh deposits act as substrates for vegetation and begin 

accumulating carbon as plant colonization and succession 

proceed. The rate of terrestrial carbon fixation over the past 

18,000 years is dependent on (1) the rate of ice retreat, (2) 

the spatial distribution of soil types, and (3) the rate at 

which carbon accumulates during the development of each 

soil type. Most soil types appear to accumulate carbon 

exponentially, in which rates of C02 fixation typically 

decline by about two orders of magnitude after 1 ,000 to 

10,000 years of deglaciation. Spatial variation of rates 

among soil types also appears to vary by about 2 to 3 orders 

of magnitude within any given age-span. One notable 

exception is peat soils, which have carbon accumulation 

rates at least 10 times higher than any other soil type. 

Based on the dynamics of ice retreat and soil development in the Laurentide region, we hypothesize that (1) 

the rate of carbon fixation by soils was greatest at around 

8,000 years ago, and (2) subsequent declining rates of 

carbon fixation were caused by both the exponential 

decrease in soil carbon accumulation and the deceleration of 

ice retreat. We further suggest that the decline in carbon 

fixation with time in a given soil type is probably determined by the combined influences of decomposition 

dynamics, climatic change, nutrient availability, and soil 

hydrology. These factors play crucial roles in the dynamics 

of the terrestrial carbon budget. 

Estimation of Precipitation Patterns in the Delaware and Gunnison River Basins 

l.E. Hay and W.A. Battaglin 

Water Resources Division 

U.S. Geological Survey 

A method has been developed that uses weather-type 

analysis as a tool for disaggregating general circulation 

model predictions into spatial scales useful for waterresource studies. The method has been applied to the 

Delaware River basin to predict the effects of doubling 

atmospheric carbon dioxide from general circulation model 

output on precipitation patterns in the region. This study 

indicates that changes in regional precipitation patterns 

under double- atmospheric, carbon-dioxide conditions 

result primarily from changes in the weather characteristics 

within a weather type, rather than from changes in the 

weather-type frequencies. 

88 Proceedings of the U.S. Geological Survey Global Change Forum 

In the Gunnison River basin, orographic precipitation 

events dominate the winter season and convective precipitation events dominate the summer season. A convective 

precipitation model will be developed, and it will be used in 

conjunction with an existing orographic precipitation 

model, both being driven by a stochastic weather-type 

generator. Topographic parameters such as elevation, 

aspect, and slope will be quantified at several scales using 

a variety of discritization techniques for use in precipitation 

modeling. Precipitation patterns will be modeled based on 

relations among weather types, topographic parameters, 

and measured precipitation. 
Lake Baikal, Southeastern Siberia: Prospects for Paleoclimate Research 

P.P. Hearn, Jr., and S.M. Colman, Geologic Division, 

U.S. Geological Survey 

E.B. Karabanov 

Limnology Institute 

Russian Academy of Science 

D.F. Williams, Byrnes International Center, 

University of South Carolina 

Located just north of the Mongolian border in southeastern Siberia, Lake Baikal is the deepest ( ~ 1 ,600 m) and 

volumetrically the largest (23,000 km3

) lake in the world. 

The sedimentary section preserved beneath the lake is 

believed to be more than 5 km thick and spans more than 25 

million years. Lake Baikal is an especially promising site 

for paleoclimate research because of its high-latitude location (52° to 56° N) and the extreme continentality of the 

climate in southeastern Siberia. Also, whereas Baikal's 

drainage basin was glaciated during the last ice age, the lake 

itself was not glaciated because of relative dryness. Marked 

variations in sedimentation rates ( < 10 to 100 em per 1, 000 

years), exposure, and thickness allow sampling both very 

long records and shorter high-resolution records. These 

include full glacial cycles (100,000 years), the last glacialinterglacial transition (10,000 years), and short-term events 

like the younger Dryas (1 ,000 years) and the Little Ice Age 

(100 years). 

Geomagnetism and Climate 

D.C. Herzog 

Geologic Division 

U.S. Geological Survey 

The Earth's magnetic field provides a coupling mechanism whereby particle radiation energy from the Sun gets 

directed into the Earth's environment. The Sun emits a 

continuous stream of charged particles or plasma known as 

the "solar wind.' The geomagnetic field shields us from this 

deadly radiation, and the interaction of this plasma with the 

geomagnetic field sets up a magnetohydrodynamic (MHO) 

generator that deposits a million megawatts of power into 

the ionosphere and upper atmosphere causing atmospheric 

heating, altering atmospheric chemistry, and giving rise to 

the familiar auroral lights. During magnetic storms, this rate 

can increase several orders of magnitude. As the number of 

eruptions on the Sun (such as solar flares, which emit huge 

quantities of plasma) increase and decrease over the 11-year 

sunspot cycle, greater and lesser amounts of energy are 

In 1990 the U.S. Geological Survey and the University of South Carolina, in conjunction with other U.S. 

universities, the Soviet Academy of Sciences, and the 

Russian Academy of Science, began a 5-year multidisciplinary paleoclimate study of Lake Baikal. This work is 

applying micropaleontologic, isotopic, geochronologic, 

sedimentological, and geochemical methods to reconstruct 

a Quaternary climate record for southeastern Siberia. 

Reconnaissance coring and high-resolution seismic profiling were begun in summer 1990. Gravity and box cores 

were collected at six sites in the lake and more than 600 km 

of seismic profiles were obtained, the first such data to be 

obtained on Baikal using satellite navigation (GPS). This 

work will be expanded in 1991 and 1992 with the collection 

of 10m piston cores and an additional2,500 km of high and 

mid-resolution seismic profiling. In early 1992 the Soviet 

Ministry of Geology will begin drilling from the ice at water 

depths of up to 800 m with anticipated recovery of cores up 

to 100m in length. 

injected into the Earth's environment, particularly in the 

polar regions where weather systems frequently originate. 

Many correlations are known to exist between climate 

and the sunspot cycle, and between the Earth's magnetic 

field and climate patterns. Droughts in the High Plains 

region of the United States have roughly followed the 

double-sunspot cycle (22 years) since 1820. Temporal 

variations of magnetic field intensity and temperature have 

been found to be inversely correlated over periods of 

500,000 years. Atmospheric vorticity (a measure of stormy 

weather conditions) increases 3 to 4 days after a magnetic 

storm. Relationships have been found between the diurnal 

range of total ozone and geomagnetic activity. Furthermore, 

an electric field potential, averaging about 400,000 volts, 

extends from the Earth's surface up through the troposphere 

Breakout and Poster Sessions 89 
where weather occurs. The weather environment can thus 

be characterized as a highly charged, spherical capacitor 

with a leaky dialectric, embedded in a time-varying magnetic field. Yet a focused effort to understand the dynamics 

and underlying physical mechanisms responsible for the 

correlations between the geomagnetic field and climate has 

never been made. 

The Geomagnetism/Climate Interaction research program is seeking to identify and explain the various processes by which the geomagnetic field influences weather 

and climate. Near-real time regional and global magnetic 

field models are being developed. Simplified theoretical 

simulations will be studied to establish general characteristics of particle movements from the upper atmosphere down 

through the troposphere under the influence of the Earth's 

electromagnetic system. The effects of atmospheric heating 

and alterations in atmospheric chemistry will have to be 

identified, and efforts will be made to incorporate geomagnetic field models into current and future climatological 

models. 

Modeling the Late-Pleistocene Paleohydrology of the Great Basin 

S.W. Hostetler 

Water Resources Division 

U.S. Geological Survey 

Models oflake temperature and evaporation, lake ice, 

lake level, and regional climate have been used to link the 

record of lake level in the Lahontan and Bonneville basins 

to past changes in synoptic-scale atmospheric circulation 

(the position of the polar jet stream) and regional scale 

climatic features (lake-atmosphere feedbacks). Results from 

experiments using the lake thermal and lake-level models 

indicate that repositioning of the polar jet stream during the 

late Pleistocene could have been the primary factor in 

controlling large magnitude changes in the level of Lake 

Lahontan 15,000 to 12,000 years ago. The simulations 

indicate evaporation was reduced (relative to present) by 

~42 percent to 758 mm a - 1 under a jet-stream related 

climatology. Given an evaporation rate of 758 mm a - 1

, 

precipitation rates 76 percent greater than the present-day 

mean ( 170 mm a - 1

) and discharge rates 280 percent greater 

than the present-day mean (2.7 km3 a- 1

) were necessary to 

simulate the highstand of Lake Lahontan 13,000 years ago. 

Results of lake thermal simulations indicate that ice could 

have formed on Lake Lahontan for ~4 months per year, 

leading to a ~55 percent reduction in annual evaporation 

rates (relative to present). With this rate of evaporation, the 

historical maximum 1983 rates of precipitation (300 mm 

a - 1

) and discharge (6.5 km3 a - 1

) would have maintained 

the highstand of Lake Lahontan. The NCAR mesoscale 

model of climate (MM4) was used in modeling experiments 

to investigate the hypothesis that lake-effect precipitation 

was a component of the hydrologic balances of Lakes 

Bonneville and Lahontan during the late Pleistocene. 

Results from the experiments indicate that lake-atmosphere 

feedbacks could have led to lake-effect precipitation that 

helped to maintain the lakes at their pre-highstand levels 

20,000 to 15,000 years ago. Lake-effect precipitation generated by the lakes also could have been delivered to regions 

downwind from the lakes. 

Large-Area Digital Elevation Data and Their Derivatives 

S.K. Jenson 

National Mapping Division 

U.S. Geological Survey 

Digital elevation models (DEM's) are raster representations of land surfaces. Terrain information such as slope, 

watershed boundaries, and drainage networks that can be 

derived from DEM's is integral to models of the hydrologic 

cycle because the characteristics of the terrain surface 

largely determine surface water flow and air flow. Global 

change issues that use models of the hydrologic cycle 

90 Proceedings of the U.S. Geological Survey Global Change Forum 

include seawater infiltration, snow cover, surface and 

ground water supplies, crop yields, extent of wetlands, 

sedimentation, and chemical transport. 

The lack of DEM's is noticeable when inventorying 

large-area data sets. This lack was documented in a 

National Aeronautics and Space Administration Topographic Working Group report published in 1988. Conti-
nental DEM coverage is generally limited to the 5-minute 

resolution coverage provided by the ETOP05 DEM data set 

distributed by the National Oceanic and Atmospheric 

Administration. The Digital Chart of the World (DCW) 

effort by the Defense Mapping Agency to digitize 

1:1,000,000-scale contours by the end of calendar year 

1991 will provide improved digital contour data for much of 

the world; however, the DCW plan will not necessarily 

include the generation of DEM's from those contours. 

Some parts of the Earth have incomplete raster elevation 

data and digital contour and point elevation data at varying 

resolutions. These data could be combined for large areas, 

using surface generation capabilities to interpolate contours 

and points to a gridded format where necessary. The U.S. 

Geological Survey has begun assembling a North American 

data set in this manner, providing a DEM of use to a wide 

community of modelers. North America was selected 

because many promising source data sets were identified 

and because North America is being used as a test continent 

for many global change studies. 

An important characteristic of the new North American data set will be hydrologic integrity. Preliminary 

investigations show that the digital methods developed at 

the Geological Survey to extract hydrologic information 

(depressional storage, slopes, aspects, flow directions, 

drainage networks, and watersheds) from digital elevation 

data can produce meaningful parameters for models of the 

hydrologic cycle even at cell sizes of 1 km. 

Research is in progress to study the effect of DEM 

source and resolution on model parameterization. For 

example, slope calculations are sufficiently sensitive to 

DEM cell size to affect surface water model results 

adversely. Normalization procedures are needed to mitigate 

the effects of DEM characteristics on model results. 

REFERENCE 

Topographic Science Working Group, 1988, Topographic science 

working group report to the land processes branch, earth 

science and applications division: NASA Headquarters, 

Lunar and Planetary Institute, Houston, 64 p. 

Satellite Passive Microwave Observations of Snow Conditions in the Upper 

Colorado River Basin 

E.G. josberger and W.j. Campbell, Water Resources Division 

U.S. Geological Survey 

Per Gloersen and A.T.C. Chang, NASA 

Satellite passive microwave observations from the 

Scanning Multichannel Microwave Radiometer (SMMR) 

provide a unique synoptic record of snowpack properties in 

the Upper Colorado River Basin from 1979 to 1986. These 

all-weather observations provide synoptic snow cover information as well as an index of snowpack water equivalent for 

the entire drainage. For the 8-year period, the SMMR 

observations show that the mean maximum snowpack 

covered 74 percent of the basin. The minimum coverage 

was 35 percent, in 1981, and the greatest coverage was 99 

percent, in 1979. Furthermore, the time series of snow 

cover show that the maximum for each year may be as short 

as 24 days or take place as an extended plateau for as long 

as 3 months. The annual maximum of the spatially integrated satellite observed brightness temperatures provides 

an index of basin water equivalent that correlates with the 

annual discharge (r=0.4), and shows behavior similar to 

that of the snowpack extent. This correlation improves 

when digital elevation data are used to characterize the 

basin (r2 =0.65). Hence, this study combines the smallscale elevation data with the mesoscale SMMR observations to investigate the basinwide snowpack characteristics 

and the hydrology of the basin. 

Breakout and Poster Sessions 91 
Planar Pattern of Delayed Postglacial Uplift in New England: A Datum for 

Measuring Late Glacial Sea-Level Changes 

Carl Koteff and G.R. Robinson 

Geologic Division 

U.S. Geological Survey 

A multiple regression analysis of the elevations of 

ice-marginal glaciomarine deltas no younger than about 

14,000 years ago shows an extremely close fit to a tilted flat 

(equipotential gravitational) surface that rises 0.836 m/km 

to the N27. 5°W. The postglacial uplift pattern of these 

glaciomarine deltas in coastal New England from northeastem Massachusetts into southwestern Maine is very similar 

to that previously recorded for glaciolacustrine deltas of 

similar age from inland areas of New England. These 

patterns indicate that both areas are part of the same 

postglacial crustal uplift block, and that little or no eustatic 

sea level change occurred between approximately 15,000 

and 14,000 years ago, during which time the margin of the 

late Wisconsinan Laurentide ice sheet retreated from Boston, Mass., into southwestern Maine. A different elevation 

trend is shown by several slightly younger glaciomarine 

deltas a short distance north in Maine, where the slope rises 

0.91 mJkm to the N35°W. The difference in trend suggests 

that soon after the ice margin reached Maine, eustatic sea 

level rose rapidly, nearly 7 m during the time the ice margin 

retreated 10 to 15 km, which may have taken only 200 

years. 

Our new data not only confirm the delayed postglacial uplift model previously described for western New 

England, but also indicate that little or no eustatic sea level 

change occurred during a substantial period of early deglaciation. However, shortly after the retreating ice margin 

reached southwestern Maine, sea level began to rise rapidly, while uplift continued to be delayed. Postglacial uplift 

in the region appears to have begun between 14,000 and 

13,300 years ago, before the retreating ice margin reached 

eastern Maine. 

Permafrost and Gas Hydrates as Possible Sources of Atmospheric Methane at 

High Latitudes 

K.A. Kvenvolden and T.S. Collett 

Geologic Division 

U.S. Geological Survey 

The United Nations Intergovernmental Panel on Climate Change has identified permafrost and gas hydrates as 

important high-latitude methane sources on the basis of 

minimal quantitative information. Permafrost and gas 

hydrates are associated in two distinct high-latitude settings: 

(1) on shore, where the permafrost is continuous and the 

zone of gas-hydrate stability ranges in subsurface depth 

from about 200 to 1 ,200 m; and (2) on the nearshore 

Continental Shelf, where relict permafrost has persisted 

since times of lower sea level when the present inundated 

shelf was exposed to very cold subaerial temperatures. 

Three studies that consider methane occurrence in examples 

of these settings are reported here: ( 1) The current release of 

methane from gas hydrates on the Continental Shelf was 

estimated at about 3-5X 1012 g/yr, on the basis of the 

inferred distribution of methane in permafrost-associated 

gas hydrates and the transgression history of the Arctic 

Ocean during the Holocene. (2) Hydrocarbon-gas compo92 Proceedings of the U.S. Geological Survey Global Change Forum 

sttlons were measured in 17 surface-sediment samples 

collected through the ice cover of Harrison Bay. This bay is 

offshore from an area of known gas-hydrate occurrence on 

the North Slope of Alaska. Geophysical surveys indicate the 

presence of offshore permafrost and of gas anomalies in the 

sediment. No major methane anomalies were detected in 

these surface sedimentary deposits, and deeper sampling is 

required to test more completely this nearshore region. (3) 

The gas composition of ground ice in permafrost was 

measured at two sites near Fairbanks, Alaska. In the air of 

a tunnel, where permafrost is subliming, methane concentrations were about 13 ppmv, whereas outside the tunnel, 

methane concentrations were only 1. 7 ppmv. An ice sample 

from the tunnel contained 0.036 mL of methane per liter of 

melted ice. At the second site, near the University of Alaska 

campus, samples from a short core of permafrost contained 

as much as 6 mL of microbially derived methane 

(8 13C=L74 o/oo) per liter of melted ice. These preliminary 
results indicate that (1) gas hydrates may currently contribute methane to the atmosphere and (2) shallow ground ice 

can contain varying amounts of methane at low concentrations and thus be a high-latitude source of methane. 

Paleoclimate Reconstructions From Alaskan Ice Records: Teleconnections 

Between Pacific-North American (PNA), Reverse PNA, and El Nino-Southern 

Oscillation (ENSO) States 

G.P. Landis, j.j. Fitzpatrick, T.K. Hinkley, and R.O. Rye 

Geologic Division 

U.S. Geological Survey 

We propose to reconstruct a detailed, high-resolution 

climate record from glacier ice recovered in southern 

Alaska that will emphasize the annual to most recent 

millennia! time scale. Our results will be compared with 

records covering the same time span from lake varves of 

North-Central United States, coral records from central 

Florida, and the ENSO record both from the Quelccaya Ice 

Cap and sediment records from the Santa Barbara channel 

of southern California. While much is known from the 

continental ice sheets of Greenland and Antarctica, little 

comparable information is available from Alaska, where ice 

contains a climate record that is influenced by the northern 

Pacific Ocean. This same influence dominates all of North 

America. Volcanism in Alaska provides air circulation 

information through tephra layers of known source and age. 

We propose collection of ice core samples at a site(s) 

satisfying the following criteria: ( 1) location above the 

glacial equilibrium line (1 ,000-2,100 m), (2) presence in 

ice of an appropriate signal of annual cycles without 

frequent or major melting events, (3) existence of a polar to 

subpolar glacial regime, ( 4) confinement of ice by broad 

and simple bedrock topography to minimize complications 

from flow deformation, and (5) presence in ice of traceable 

horizons of volcanic products that also are suitable for age 

determinations. The proposed continental records from 

Alaska are critical to any global program of climate change. 

Four complementary disciplines will be applied to the 

study of ice cores obtained. These include (1) study of the 

stratigraphic, structural, and petrofabric properties of the 

ice samples (J. Fitzpatrick), (2) study of occluded, 

adsorbed, and clathrated gas in ice and snow (firn gas) as 

indicators of changing greenhouse and other atmospheric 

gases (G. Landis), (3) study of metals as indicators of 

oceanic, continental, and volcanic exhalation materials in 

ice and snow samples (T. Hinkley), and (4) study of stable 

isotope variations in snow and ice samples as indicators of 

surface temperatures, climatic weather patterns, accumulation rates, and post accumulation modifications to ice (R. 

Rye). Evaluation of our proposed ice core site at Churchill-

-Bona in the Wrangell-St. Elias Range is planned for 

June of fiscal year 1991. Additional ice is available from 

GISP II (Greenland), Byrd core (Antarctica), Dunde 

(China), and Quelccaya (Peru) for correlation with Alaskan 

ice records obtained after fiscal year 1992. 

HCDN (Hydro-Climatic Data Network): A U.S. Geological Survey Streamflow 

Data Set for Climatological Analysis 

j.M. Landwehr and j.R. Slack 

Water Resources Division 

U.S. Geological Survey 

Our research objective is to characterize the temporal 

patterns of streamflow variation over this century, at several 

spatial scales-watershed to meso- to continental-and to 

contrast this variation with that of concurrent meteorological conditions. To do this, it was necessary to assemble a 

suitably large data set of long discharge records that also 

satisfied certain other criteria. Not only must the discharge 

records in this data set be of good quality, with respect to 

minimal measurement errors, but also the watersheds that 

the streams drain need to have been relatively free of 

anthropogenic influences or at least have been consistent in 

the nature and degree of the anthropogenic activity over the 

period of record. The minimal requirement for such analysis 

is that the average monthly flow values should be relatively 

free of regulation by human controls, either overt or 

unintentional. 

Breakout and Poster Sessions 93 
The U.S. Geological Survey has had a program of 

systematically gaging streamflow in the United States and 

its Trust Territories that began in 1888 with the measurement of the flow of the Rio Grande River at Embudo, N. 

Mex. At present, records for over 10,000 sites, many 

currently gaged but also many now discontinued as gaging 

sites, are stored in the USGS WATSTORE data base. We 

worked with USGS district data specialists in each State to 

select those records or portions of records of average daily 

discharge that are consistent with the criteria we delineated 

above. We have identified approximately 1, 700 records of 

essentially unregulated and measured (not estimated) 

streamflow throughout the United States and its territories. 

Because of their utility to a broad range of climate studies, 

there is great interest in this collection of records, not only 

among other Federal agencies, but also among academia 

and private industry. Consequently the discharge data, 

along with auxiliary watershed and statistical characteristics, will be made available from the U.S. Geological 

Survey in both printed and electronic form. 

Stochastic Analysis of 8180 and 813C Time Series Found in a Continuous 

500,000-Year Climatic Record From Great Basin Vein Calcite 

J.M. Landwehr, I.J. Winograd, T.B. Coplen, and A.C. Riggs, Water Resources Division 

K.R. Ludwig and B.j. Szabo, Geologic Division 

U.S. Geological Survey 

DH-11, a 36-cm long core of vein calcite, was 

retrieved from Devils Hole, Nev. It was dated using both 

alpha-counting and mass-spectrometric (MS) techniques for 

both the 230Th-234U and the 234U-238U methods. The 

relationships between age and distance from the free face of 

the core were statistically indistinguishable for the two 

methods, within the respective method's level of precision. 

Given the greater precision afforded by MS, an age-distance 

relationship was established based only on the 21 MS-dated 

samples. The core was found to span the period from 

approximately 60,000 to 570,000 years ago, with an average growth rate of 0. 7 mm per thousand years. The light 

stable isotopes, 8180 and 813C, were analyzed concurrently 

for 285 samples taken at set intervals down the length of the 

core. In the resulting time series, the 813C excursions 

generally precede those of 8180, so that if the series is 

shifted uniformly in time by 7 thousand years, the linear 

correlation between the two can be increased from 

r=-0.58 to -0.75. The range of the normalized 813C time 

series is slightly larger than that for 8180. During full 

glacial times, the normalized 8180 values are more extreme 

than those of 813C, whereas during the transition into an 

interglacial period as well as during the first portion of that 

interglacial, the 813C values are more extreme. 

Spectral analysis of the DH-11 stable isotope time 

series indicates robust peaks (in order of decreasing power) 

at 93, 40, 25, 22.8 and 17 thousand year cycles for the 8180 

series and at 91 , 40, 23, 28 and 18.2 thousand year cycles 

for the 813C series. No evidence is found of the 100 

thousand year cycle widely reported in the marine literature. 

The pattern of temperature variation through the last interglacial period, as inferred from the DH-11 core, is consistent with that found for the Vostok ice core, both in timing 

and duration. Both records are more consistent with the 

earliest high sea level stands indicated by recent redating of 

coral reef terraces from the Huon Peninsula than is the 

SPECMAP series, which was calibrated on the basis of the 

Milankovitch theory of climate change. These results pose 

a challenge to the theory. 

Water, Energy, and Biogeochemical Budgets in the Luquillo Mountains, 

Puerto Rico 

M.C. Larsen, P.D. Collar, and R.F. Stallard 

Water Resources Division 

U.S. Geological Survey 

The Luquillo mountains in eastern Puerto Rico are the 

U.S. Geological Survey research site for the study of 

biogeochemical and geomorphic processes that control the 

94 Proceedings of the U.S. Geological Survey Global Change Forum 

movement and transformation of water, energy, nutrients, 

and bedrock weathering products in the earth-surface environment. Two areas in the mountains are being studied (1) 
the 11,300 hectare U.S. Forest Service-administered 

Luquillo Experimental Forest, and (2) the Rio Grande de 

Loiza basin, an agriculturally developed watershed undergoing urbanization and industrialization. The four principal 

research elements of the Water, Energy, and Biogeochemical Budget program (WEBB) in Puerto Rico are (1) 

Biogeochemical Budgets: Water, energy, ionic, nutrient, 

sediment, and gas budgets will be calculated in two microwatersheds instrumented with meteorologic, soil, hydrologic, and ground-water monitoring equipment. (2) Physical and Chemical Weathering Processes in Undeveloped 

Watersheds of Contrasting Lithology: Chemical-weathering 

and mass-wasting processes in micro-watersheds within two 

dominant geologic terranes (volcaniclastic and quartz diorite) will be compared. In addition, the effects of landslides 

on biogeochemical cycling in each region will be assessed 

by a temporal evaluation of physical, chemical, and mineralogic variation found in landslides of varying dates of 

occurrence. This element will enable the development of 

models to describe the hillslope hydrology and landform 

evolution. (3) Comparison of Developed and Forested 

Watersheds: Paired basins will be selected and gaged in the 

adjacent Rio Grande de Loiza watershed. Budgets of all 

aqueous constituents in flux (Ca, Mg, Na, K, Si, NH4

, 

HC03 , Cl, S04

, N03 , N02 , Br, F, P04 , and dissolved 

organic carbon) will be compared and contrasted in developed and forested basins of similar lithology. Gas-flux 

differences between the two areas will be evaluated using 

chamber techniques and the results related to land-use 

differences. ( 4) Reservoir and Agricultural Pond Gas 

Fluxes: Most soils contain methanotrophic bacteria that 

consume methane faster than methane is produced at 

anaerobic microsites in the soil matrix. Methane is normally 

produced in significant amounts only in the sediments of 

shallow, standing water. In Panama, the bacteria in one 

hectare of shallow pond or lake produce approximately the 

same amount of methane as the soil bacteria in 400 hectares 

of pristine forest consume. To calculate a budget for 

methane in northeastern Puerto Rico, methane production in 

selected reservoirs and agricultural ponds will be determined using bubble collectors. 

Investigation of Climate-Hydrology Interactions Using Coupled Atmospheric 

and Hydrologic Models 

G.H. Leavesley 

Water Resources Division 

U.S. Geological Survey 

Investigations of the interactions of climate and 

hydrology over a range of spatial and temporal scales are 

being conducted using field experiments and selected atmospheric and hydrologic models. These investigations 

address the spatial and temporal distribution of meteorologic variables, including precipitation, temperature, and 

solar radiation, and the interaction of these variables with 

the spatial distribution of basin characteristics such as 

topography, soils, vegetation, and geology. Field data will 

be used to develop and test a system of serially coupled 

atmospheric and hydrologic models for use in investigating 

atmospheric and hydrologic processes and process interactions. A modular modeling system is being developed to 

support the hydrologic modeling components of these 

studies. The system will accept distributed inputs from a 

range of atmospheric models and will be used to simulate 

distributed water- and energy-flux processes over a basin. 

Biogeochemical processes will be added to the system using 

current process understanding and the results of other 

interdisciplinary research studies. 

One investigation is focused on climate-hydrology 

interactions in complex mountainous terrain where snow is 

the major form of precipitation. An orographic atmospheric 

model that simulates the interactions of topography and 

air-mass flux to provide the spatial and temporal distribution of precipitation and air temperature will be coupled to 

a distributed-parameter watershed model. Nodal output of 

the orographic model, at length scales of 2. 5-10 km, will be 

used to provide precipitation and temperature inputs for the 

watershed model. The orographic model will be coupled to 

a mesoscale atmospheric model that can in turn be coupled 

to a general circulation model. Initial test sites include the 

Gunnison River basin in Colorado; the Carson, Truckee, 

and American River basins in Nevada and California; and 

several basins in Oregon and Washington. 

A second investigation is focused on climatehydrology interactions where rainfall is the major form of 

precipitation. Spatial and temporal measures of rainfall 

provided by doppler radar will be used to ( 1) investigate and 

develop techniques to disaggregate atmospheric-model outputs to generate smaller scale convective rainstorms for 

basin-scale applications, and (2) develop improved hydrologic models for runoff and water-balance simulation. 

Initial test sites are selected basins in the Colorado Front 

Range between Fort Collins and Denver. 

Breakout and Poster Sessions 95 
Land Characterization Using Remotely Sensed Data and Artificial Neural 

Networks 

G.P. Lemeshewsky 

National Mapping Division 

U.S. Geological Survey 

General circulation models currently use very simple 

descriptions of the land surface as input. The estimation of 

those land surface characteristics may be improved through 

the generalization of regional data bases. Information 

derived from existing land use and land cover data bases 

will begin to meet these needs, but these data bases are no 

longer current in many areas. The methods that use satellite 

imagery and statistical classification techniques provide 

information more quickly, but the use of neural networkbased techniques for this type of mapping will provide more 

accurate land cover data as well. 

Artificial neural networks, state-of-the-art techniques 

for pattern recognition and image data classification, are 

computer simulations that, to a limited extent, model a 

network of interconnected simple biological neurons. These 

networks can be trained for land characterization. Neuron 

interconnection weights and network configuration interact 

to generate partitions in multispectral feature space. A 

multilayer, feed-forward network configured with two 

internal layers of neurons is recommended for improved 

multispectral classification of remotely sensed image data. 

By using multispectral data as input, artificial neural 

networks can be trained in such a way that the neuron 

weights, and hence the network function, create a desired 

input-to-output classification. Back propagation of an error 

signal can adjust network weights. The performance of 

neural network classifiers can be superior to conventional 

statistical classification techniques when data include spatial or textural information. Incorporating a 3- X 3-pixel 

neighborhood about each multispectral data point suggests 

that the network performs a spatial filtering process. Preliminary research shows that spatial and multispectral data 

integration via neural networks can be used for land 

characterization. 

Biogeochemical Cycling of Carbon and Related Elements in Estuarine Wetlands 

].S. Leventhal, L.L. jackson, K.S. Smith, and L.S. Balistrieri, Geologic Division 

Katherine Walton-Day, Water Resources Division 

U.S. Geological Survey 

The combined effect of increasing greenhouse gases, 

carbon dioxide, methane, and chlorofluorocarbons, is projected to cause a global warming of 1 to 3°C over the next 

century. The effects of this warming on the biosphere and 

geosphere are complex, because of the interdependence of 

many biogeochemical processes. Warming effects may be 

enhanced or decreased, that is positive or negative feedback, as a result of the interdependence of these processes. 

Methane is an important greenhouse gas to consider in these 

feedback loops, because it absorbs radiation more effectively than C02 and with increases of atmospheric CH4 of 1 

percent annually, biogeochemical processes that influence 

CH4 emissions may have a dramatic cyclical feedback on 

global warming. Global warming is projected to cause a sea 

level rise of 0. 5 to 1. 5 m in less than 100 years. Coastal 

fresh and marine wetlands will be influenced spatially 

through creation and loss of wetlands and chemically 

through conversion of fresh water to brackish or saltwater 

marshes. Coastal wetlands are very important contributors 

to the global carbon cycle because of their high biological 

96 Proceedings of the U.S. Geological Survey Global Change Forum 

productivity, storage of organic carbon, and emissions of 

C02 and CH4 . In order to develop predictive models for the 

carbon cycle as regards to global change, it is paramount 

that we understand the processes that control CH4 emissions 

in coastal wetlands where immediate influences of sea level 

rise may be detected. 

We will study the spatial and temporal variability in 

the components of the carbon cycle, including greenhouse 

gas emissions and carbon storage, in fresh, brackish, and 

salt water marshes in Louisiana coastal wetlands. In addition, we will relate carbon cycling in these environments to 

other interrelated processes such as sulfur and trace metal 

cycles. To accomplish this, we will examine physicochemical characteristics of marsh sediments and interstitial 

waters, carbon, nitrogen, and sulfur stable isotope systematics of sediments and biota, and sediment CH4 gas emissions. We will also study core material from offshore 

Louisiana in order to look for fresh to brackish water 

transitions during the Holocene wetland losses and compare 

chemical characteristics of ongoing wetlands processes with 
the chemical signatures displayed in the geologic record. 

Results of these studies will be compared with other studied 

sites described in the literature in order to examine the 

global variability of these processes. The biogeochemical 

process information gained from these studies is important 

to model and forecast effects of global change. 

Monitoring the Dynamics of the Antarctic Coastline With Landsat Images 

B.K. Lucchitta, L.M. Bertolini, j.G. Ferrigno, and R.S. Williams, Jr., Geologic Division 

U.S. Geological Survey 

The extent of advance or retreat of ice shelves and 

glacier tongues along the Antarctic coastline is known only 

for a few well-studied areas; yet to properly assess changes 

induced by global climatic variations, the entire coastline 

should be monitored. This problem is important because 

climate-induced changes in the area and volume of polar ice 

sheets may severely affect the Earth's densely populated 

coastal regions; melting of the West Antarctic ice sheet 

alone would cause a sea-level rise of 3.5 m. 

An extensive set of Landsat images covering Antarctica was acquired in the early to middle 1970's. Recently a 

program to obtain new Landsat images over the Antarctic 

coastal region was initiated by an international consortium 

of the Scientific Committee on Antarctic Research (SCAR). 

These later views of the scenes imaged earlier will permit 

the monitoring of coastal changes. Our pilot study showed 

that the images, after scanning, digitizing, and registration, 

can be manipulated by image-processing techniques, so that 

the extents of shelf ice, glaciers, and open water or seasonal 

ice can be compared, and the changes mapped and quantified. Our study also showed that many crevasse patterns in 

the floating part of outflow glaciers retain their identity over 

as much as 15 years, so that the patterns may be registered 

digitally by using a computer interactive display or optically 

by using a stereoscope. From the registered points, the 

translational movement can be calculated, giving an extensive velocity profile of the glaciers. For example, 70 points 

on the Stancomb-Wills Glacier and Glacier Tongue, eastern 

Weddell Sea, Queen Maud Land, yielded velocities ranging 

from 950 m per year near the grounding line to 1,200 m per 

year at 100-km distance seaward from this line. The 

statistical error of the measurements along individual flowlines was determined to be 3 to 5 percent. This glacier and 

ice tongue have moved exceptionally fast. Similar measurements are possible for most outlet glaciers in Antarctica, 

and we have identified about 20 sets of presently available 

paired Landsat images for further analysis. 

Monitoring coastline changes and obtaining a baseline of current glacier velocities will significantly improve 

our understanding of the present Antarctic environment and 

its sensitivity to future changes in global climate. 

Glacier Growth and Shrinkage Related to Climate Variations and Nonclimatic 

Factors in Alaska 

L.R. Mayo 

Water Resources Division 

U.S. Geological Survey 

At a time when the effects of climate variations are 

the focus of global change research, it is important to 

separate the influences of climate on glaciers from those of 

other processes. Proxy climate signals in glacier behavior 

can be ambiguous because changes in either temperature or 

precipitation can produce growth or shrinkage, and such 

changes can be mixed with signals from geologic, hydrologic, and glaciologic processes. Glacier growth (volume 

increase) can result from either decreased melting or 

increased snowfall, or from non-climatic factors such as 

protection by landslide rock debris, reduction of water 

depth at glaciers ending in water, or recovery after a surge. 

A tidewater glacier, Hubbard Glacier for example, is 

growing and may continue its advance for another 60 km for 

a millennium as it moves a protective terminal moraine 

down Yakutat Bay. At the same time, Columbia Glacier is 

shrinking as it calves into deep water behind a moraine it 

recently abandoned, and retreats rapidly. We do not know if 

the total volume of these glaciers is changing because their 

advances and retreats are asynchronous and the rates are 

unequal. Glaciers on volcanoes and those carrying ash 

deposits from eruptions can also behave somewhat independently from climatic forcing. 

Breakout and Poster Sessions 97 
Wolverine Glacier, 60.4°N latitude in Alaska, 

responds primarily to climate, and it experienced a period of 

growth from 1976 to 1988. Observations of the glacier 

show that variations in winter snowfall exert the primary 

control over its annual ice volume changes. When the 

glacier grows, the mountainous region experiences 

increases of air temperature and precipitation that generally 

take place at temperatures colder than - 5°C at the altitude 

of the glacier in midwinter. Thus, the warming fails to 

convert snowfall at the glacier to rain. Summer temperatures and melting are relatively steady. Cold, dry winters 

have returned since 1989, and the glacier is again shrinking. 

Sea surface temperatures in the Gulf of Alaska and the 

position of the Aleutian Low have influenced these fluctuations. Thus, Wolverine Glacier currently tends to grow 

when its climate varies toward a warmer and wetter state. 

Several global climate models predict warming of winter 

temperatures and increases in precipitation at high latitudes 

with increasing concentrations of greenhouse gases. 

These results support the hypothesis that high-latitude 

glaciers and polar icecaps could grow as climate warms, 

Photogrammetry and Global Change 

R.B. McEwen 

National Mapping Division 

U.S. Geological Survey 

Photogrammetry is the process of using images in a 

quantitative way, both spatially and spectrally, and provides 

engineering integrity for cartography and geographic information systems. This process is concerned with sensor 

geometry and calibration, map projections and geometric 

transformations, data registration and resampling, and, in 

general, all the processes that affect image geometry and 

spectral reliability from the time of acquisition to the 

product. 

Global change studies use images from weather and 

Earth resource satellites with visible, infrared, microwave, 

and radar sensors. Images from aerial photographs and 

other aircraft-borne sensors also are used. Eventually the 

image data are combined and analyzed and entered into 

spatially referenced data bases in geographic information 

systems that are used for modeling. 

The Advanced Very High Resolution Radiometer 

(AVHRR) Antarctic Image Map, scheduled for printing in 

98 Proceedings of the U.S. Geological Survey Global Change Forum 

while low-latitude glaciers shrink~ however, Wolverine 

Glacier is located about 200--600 km west of the primary 

glacierized region in North America (58-62°N), so our 

results may not apply to the behavior of these other glaciers. 

Studies of glaciers in this region are required to investigate 

the transfer of results from present research sites to the main 

mass of glacier ice in North America. 

Oversimplified ideas of global climate change can 

produce ambiguous or incorrect predictions of glacier and 

ice sheet response; therefore, estimates of glacier behavior 

and runoff from climate model scenarios require that 

attention be given to seasonal patterns of both temperature 

and precipitation, as well as the altitude distribution of 

glacier ice in each geographic region. These interactions 

with climate can also be mixed with responses caused by 

variable boundary conditions, ice flow instabilities, and 

oceanic and geologic processes. This combination of processes explains why different glaciers in the same region are 

often observed to be both growing and shrinking. 

August 1991, is an example. This satellite image map, the 

first of the entire continent, was prepared with the cooperation of the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS) in 

the United States and the National Remote Sensing Center 

(NRSC) in Great Britain. The data were supplied from the 

NOAA satellites~ the image mosaic was assembled by the 

NRSC. The map will be printed by the USGS. 

This image map required digital image processing 

and mosaicking and the use of digital cartographic data to 

achieve registration on the Polar Stereo graphic projection. 

Landsat images were used to correct the coastline by 

eliminating seasonal ice, and the result will be the most 

consistent and reliable coastline of the continent at this scale 

(1:5,000,000). The printing process for one visible and two 

infrared bands will require several innovations. The image 

will also be available in digital form. 
Continental Hydrology and Global Climate 

P.C.D. Milly 

Water Resources Division 

U.S. Geological Survey 

The hydrology of the continents helps determine the 

global climate. The hydrosphere and the atmosphere are 

tightly coupled because of the role of water in the radiation 

and heat budgets of the atmosphere. Future progress in 

global hydrology and climate dynamics will require interdisciplinary analyses of the dynamics of this coupled 

system. In recognition of these basic scientific factors, the 

U.S. Geological Survey (USGS) research project, "Continental Hydrology and Global Climate," was established in 

August 1988. The objectives of the project are (1) to 

develop improved models of the global climate system by 

improving their representation of land-surface hydrology, 

and (2) to develop an improved understanding of the global 

hydrologic cycle and its coupling with global climate. Much 

of the research uses the numerical climate model of the 

Climate Dynamics Group at the Geophysical Fluid Dynamics Laboratory (GFDL) of the National Oceanic and Atmospheric Administration, located on the campus of Princeton 

University in Princeton, N.J. This is a transient, threedimensional mathematical model of the global atmosphere, 

including dynamics, radiation, the hydrologic cycle, and 

interactions with the oceans and the continents. It is the 

subject of model development, and one of the tools for 

studying coupled dynamics. Supporting theoretical work is 

also performed using other numerical models and analytical 

techniques. 

As a result of this research, it has been shown that the 

current parameterization of continental hydrology in the 

GFDL climate model permits excessive evaporation, at the 

expense of runoff, for a given atmospheric forcing. The 

causes of these errors have been identified and corrected. 

Furthermore, in preliminary analyses of coupled landatmosphere sensitivity experiments, it has been shown that 

the excessive evaporation leads to increased precipitation 

(hence increased evaporation) and to decreased potential 

evaporation (hence decreased evaporation). The atmosphere 

thus provides positive and negative feedbacks on errors in 

evaporation. We have conducted a study of the effects of an 

erroneous definition of potential evaporation rates in climate models on the computed surface water and energy 

balance of the continents. In this study, we have shown that 

potential evaporation produced by many climate models is 

excessive, and that the calculated values of summer soil 

moisture in the midlatitudes are too low. When the corrected scheme is applied, the estimates of potential evaporation and soil moisture in the GFDL climate model are 

much closer to those based on observational data. Progress 

has also been made on the fundamental hydrologic problem 

of simple analytical descriptions of evaporation. A general 

non-linear solution of the combination problem describing 

evaporation from a wet surface has been derived. It has 

been used to show that the standard linear solution consistently underestimates evaporation. It has also provided the 

basis for a new look at the old problem of equilibrium 

evaporation, or evaporation under conditions of full mutual 

adjustment of land surface and atmosphere. It has been 

concluded that equilibrium evaporation is much more common than suggested by the literature. 

Glacier Monitoring for Global Change-Three Case Studies 

B.F. Molnia 

Geologic Division 

U.S. Geological Survey 

The purpose of glacier monitoring is to document 

changes in glacier systems, focusing on changes in position, 

areal extent, and volume. Equally important is deciphering 

the recent history of the glacier system and documenting the 

chronology of change. Data for glacier monitoring come 

from the following: field observations, surface measurements, radio echo sounding (RES), remote-sensing (aerial 

photography, synthetic aperture radar (SAR) and satellite 

photography) and spectral imagery, published and manuscript maps and charts, and direct and proxy evidence of 

Breakout and Poster Sessions 99 
former glacier positions (trim lines, moraines, radiometric 

dating, lichenometry, and dendrochronology). 

In 1984-1985, Mendenhall Glacier, which has 

retreated for more than two centuries, experienced a minor 

readvance. The advance triggered changes in the glacier's 

drainage, resulting in an order-of-magnitude increase in the 

glacier's rate of retreat. Annual field visits, combined with 

analysis of ground and aerial photography, were used to 

document the sequence of events involved in the accelerated 

retreat and to document that the retreat was not a manifestation of global warming. 

Field observations, measurements of suspendedsediment-load, RES, and analysis of aerial photography, 

satellite imagery, and 80-year-old topographic maps were 

used to determine that Bering Glacier has retreated 8 km 

during this century. Retreat has formed a lake and resulted 

in the sediment starvation and rapid erosion of the beach 

separating the lake from the Gulf of Alaska. Continued 

beach erosion could result in Bering glacier icebergs entering the Gulf, where they could be a threat to shipping, 

including tanker traffic from Prince William Sound. RES 

determined that Bering Glacier occupies a fiord basin 

extending well below sea level and that several hundred 

cubic kilometers of the glacier could ultimately become 

icebergs. 

SAR of the Malaspina Glacier reveal ice-surface 

morphological features that mimic bed morphology and 

provide insights into the glacier's Neoglacial history. Identification of the position of the end moraine of the adjacent 

Hubbard Glacier, under the Malaspina, provides constraints 

on when the Malaspina expanded to its present position. 

Photography, extending back to 1895, and satellite imagery 

document stagnation of the glacier's margin and surges. 

RES determined that Malaspina also occupies a fiord basin 

extending well below sea level. 

Monitoring Land Surface Responses to Social and Economic Pressures 

in Sahelian Africa 

D.G. Moore, National Mapping Division, U.S. Geological Survey 

G.G. Tappan and M.E. Wehde, TGS Technology, Inc. 

The climate of Sahelian Africa is characterized by 

marginal rainfall for crop production and by extreme 

variations in seasonal and annual precipitation; therefore, 

current agricultural production often is not sufficient to feed 

the local population. In addition, social and economic 

pressures result in land degradation, which threatens agricultural and renewable natural resources. Technical assistance programs have been implemented to protect local 

populations from short-term effects that often result in 

famine. Many programs strive to establish conservation 

projects and implement policies of sustainable development. 

Time-series remote-sensed data, which estimate vegetation conditions, are available from the National Oceanic 

and Atmospheric Administration polar-orbiting satellites for 

all of Sahelian Africa. The data are produced for crop 

condition assessments and as an early warning indicator of 

potential famine. They are also used for monitoring grasshopper and locust habitats to prevent plagues that threaten 

crops. The purpose of this research is to develop a procedure for time-series monitoring of short- and long-term land 

surface changes and trends with vegetation index image 

data that can be used in conjunction with other resource and 

monitoring data. 

Definitions of the best resource stratifications and the 

most sensitive parameters from time-series greenness data 

for monitoring change are being investigated. Socioeconomic and natural resources data have been entered into a 

data base that defines and tests stratifications from a variety 

of resource-based land potentials. Because large volumes of 

statistics must be derived from the spatial data base, pattern 

recognition approaches are being developed and tested for 

computer-assisted data extraction. Senegal is being used as 

the test case because considerable socioeconomic, climatic, 

and natural resources data are available from prior projects. 

Current and potential human carrying capacity and total 

monetary value derived from rainfed agricultural crop 

production provide basic information to address the impact 

of change. 

100 Proceedings of the U.S. Geological Survey Global Change Forum 
Quantification of Information Contained in Outputs of General Circulation 

Models 

M.E. Moss 

Water Resources Division 

U.S. Geological Survey 

Mathematical models that generate scenarios containing no temporal correspondence to time series of actual 

occurrences are difficult to evaluate. One such class of 

models consists of atmospheric general circulation models 

(GCM). The lack of paired observations in the time series 

makes standard statistical methods either invalid or ineffective in testing the validity of a GCM. One approach to 

resolving this quandary is the use of a relative information 

measure, which is based on the uncertainties contained in 

the histograms of aggregations of both the model output and 

the data base. Each interval of each histogram is analyzed, 

from a Bayesian perspective, as a binomial probability. For 

the data-based histogram, the reciprocal of the sum of the 

variances of the posterior distributions of probability in each 

interval is denoted as its information content. For the 

model-based histogram, the reciprocal of the sum of the 

expected mean squared errors of the posterior distributions 

in each interval likewise is its information content. The 

expected mean squared error, which accounts for potential 

biases in the GCM, is computed as the expectation of the 

squared differences between the data-based and the modelbased posterior distributions for each interval. The ratio of 

the information content of the model-based histogram to 

that of the data-based histogram is the relative information 

of the model. 

A 5-year monthly precipitation time series for J anuary at a single node of the current version of the Community 

Climate Model, including the Biosphere Atmosphere Transfer Scheme, contains 8. 9 percent of the information in the 

most recent 30 years of data in the Climatological Data Set 

assembled by the National Climate Data Center (NCDC). If 

the 5-year simulation were extended, its relative information content could be expected to approach 14.5 percent. 

For July monthly precipitation, the 5-year simulation contained 11.2 percent of the information of NCDC data base 

and had a limit of 18.1 percent for extremely long simulations. Aggregation of two adjacent cells at the same latitude 

showed some improvements in relative information, but 

longitudinal aggregation with two additional adjacent cells 

degraded relative information to less than either the one- or 

two-cell levels. 

Application of this approach to several GCMs is 

planned for the near term, while longer-term plans are for 

the development of monitoring strategies for climate change 

to be based on the information measure. 

Late Quaternary Sea Level History of the Pacific Coast of North America: 

A Detailed Record of the Last Glacial/Interglacial Cycle 

D.R. Muhs and j.F. Whelan, Geologic Division, 

U.S. Geological Survey 

G.L. Kennedy, Los Angeles County Museum of Natural History 

T.K. Rockwell, Department of Geological Science, San Diego State University 

Marine terraces are common on the Pacific coast of 

North America from Washington state to southern Baja 

California. Such terraces form during stillstands of sea on 

tectonically stable coasts, and during rises of sea level on 

uplifting coasts, when the rate of sea level rise matches the 

rate of tectonic uplift. Thus, marine terraces provide a 

detailed record of sea level high stands if they can be dated 

accurately. Our investigations have shown that solitary 

corals are far more common in west coast marine terrace 

deposits then previously thought and we have generated 

about 80 new 230 ffh/234U ages from terraces along the coast 

from Bandon, Ore., to Cabo Pulmo near the southern tip of 

Baja California. The two most frequent ages are ~125,000 

and ~ 80,000 years ago, which correspond to ages from the 

last interglacial period that have been reported for emergent 

coral reef terraces on tropical island coasts such as Barbados, Haiti, and New Guinea. These ages agree well with 

times of high solar radiation at high latitudes when global 

ice volumes would be minimal, and as such, our data agree 

with the Milankovitch, or orbital- forcing theory of climate 

change; however, our results show that sea level at 80,000 

years ago was much closer to present than data from 

Barbados and New Guinea indicate. 

Breakout and Poster Sessions 1 01 
Stable isotope analyses of marine terrace mollusks 

can be used to infer ocean paleotemperatures. We analyzed 

mollusks from a number of terraces dated 125,000 and 

80,000 years old along the west coast from Oregon to Baja 

California. Results indicate that on open coasts (as opposed 

to protected embayments), ocean temperatures were 

2.0-2.5°C cooler than present at ~ 125,000 years ago and 

were 3.0-5.5°C cooler than present at ~80,000 years ago. 

The cooler-than-present temperatures at 125,000 years ago 

can be explained by warmer land temperatures, which 

would in tum increase the strength of alongshore winds, 

which would enhance upwelling and result in cooler nearshore waters. 

In certain places in southern California and Hawaii, 

calcareous eolianites overlie the 125,000 and 80,000 year 

old marine deposits and are separated from them by a 

paleosol. Contemporary beaches are too small and too low 

in calcareous sand to have provided the source sands for 

these eolianites; however, offshore shelf sediments in these 

areas have abundant calcareous sand and would provide a 

ready source of sediment for calcareous eolianites if 

exposed during a sea level low stand. We hypothesized that 

these eolianites were deposited from wind-transported calcareous sand derived from shelf sediments that were 

exposed during glacially-lowered sea levels. The eolianites 

contain secondary carbonate rhizoliths (root casts) that can 

be dated by uranium-series methods. Results indicate that 

eolianites were deposited during two intervals, between 

~80,000 and ~50,000 years ago, and again between 

~27 ,000 and ~ 14,000 years ago. These intervals agree 

well with solar radiation minima in high latitudes when we 

would expect glacial ice volumes to be at a maximum and 

sea levels to be at a minimum. Thus, eolianites may be 

excellent glacial markers. 

History of Desertification on the Great Plains: A Holocene History of Eolian 

Sand Movement 

D.R. Muhs, H.T. Millard, Jr., R.F. Madole, and C.j. Schenk 

Geologic Division 

U.S. Geological Survey 

Our goal in this project is to develop a detailed 

Holocene climatic history of the Great Plains using the 

geologic record of eolian sands. The Great Plains region is 

an area that is highly sensitive to climatic changes. It is 

characterized at present by a subhumid climate in its eastern 

part and a semiarid climate in its western part. One 

characteristic of the region is extreme year-to-year variability in rainfall, based on climate records of the last 100 years 

or so. This short-term variability is superimposed on trends 

of longer duration and the Great Plains droughts of the 

1910's, 1930's, and 1950's are dramatic examples of such 

variability. On yet a longer timescale, the middle Holocene 

Altithermal interval (8 ,000 to 5,000 years ago) and the late 

Holocene (3 ,500 to 1 ,500 years ago) were periods of 

extreme warmth and dryness on the Great Plains (and 

elsewhere). During the Altithermal, temperatures may have 

been as much as 2°C warmer than present, and precipitation 

was drastically reduced over a period of as much as 3,000 

years. 

The increases of carbon dioxide and other greenhouse 

gases in the atmosphere have led climate model investigators to predict that significant global warming may take 

place within the next century. Midlatitude continental 

interiors, such as the Great Plains, are areas where dramatic 

warming and decreased precipitation are predicted to occur. 

In fact, the middle Holocene Altithermal interval has been 

cited by climate model investigators as one of the best 

analogs to a predicted 21st century warming and drying. 

An understanding of the potential for future climatic 

change on the Great Plains is critical economically. The 

region is one of the most important in the United States for 

crops, cattle, and ground water resources. What is needed 

are data on the areas of the Great Plains that would be most 

susceptible to economic loss due to precipitation reductions 

under a 21st century warming and drying. The best method 

to determine which areas are most susceptible to desertification in the future is to look at which areas were most 

susceptible to such changes in the past. 

Eolian sands are attractive deposits for paleoclimatic 

reconstruction on the Great Plains for a number of reasons. 

Eolian sand is highly sensitive to climatic change because 

stabilizing vegetation on such deposits in semiarid regions 

cannot tolerate significant reductions in precipitation. 

Research conducted to date indicates that there is a history 

of repeated eolian sand movement in the Holocene. Dune 

morphology and stratification, and isotopic and geochemical fingerprinting of sand source areas allow reconstruction 

102 Proceedings of the U.S. Geological Survey Global Change Forum 
of paleowind patterns, which in turn provide the basis for 

atmospheric circulation models and air mass distributions. 

Our ultimate goal is to produce a detailed Holocene history 

The Global Land Information System 

L.R. Oleson 

National Mapping Division 

U.S. Geological Survey 

The Global Land Information System (GLIS) provides scientists with a single, interactive source of information and access to data pertaining to the Earth's land surface 

that can be used in continental- and global-scale Earth 

science and global change studies. 

The GLIS can be characterized as a metadata system 

containing both descriptive information about data sets and 

associated functions that allow scientists to assess the 

potential utility of data sets, determine their availability, 

and place online requests for related data products. The data 

set information in GLIS is maintained in three levels of 

granularity and detail: the directory, guide, and inventory. 

The directory contains high-level, summary descriptions of 

entire data sets. The data set guides contain detailed 

descriptions of entire data sets, including such information 

as sensor specifications, extent of coverage, processing 

history, data quality, and product availability. Data set 

inventories contain detailed information about individual 

data set entities, such as a Landsat scene or an Advanced 

Very High Resolution Radiometer (AVHRR) pass, and 

Methane in Mono Lake, California 

R.S. Oremland 

Water Resources Division 

U.S. Geological Survey 

Mono Lake is a hypersaline, alkaline closed-basin 

lake. The basin was formed 1 x 106 years ago by subsidence 

and was soon followed by regional volcanism. Volcanism 

still persists in the basin. Normally, the lake is monomictic 

and displays a winter turnover. During the El Nifio winters 

of 1982 and 1983, sufficient freshwater was released into 

the lake to induce meromixis, which persisted until November 1988. Our investigations focused on the identification, 

formation, oxidation, and outward flux of methane from the 

lake during and after meromixis. 

of eolian sand movement on the Great Plains that will allow 

reconstruction of drought history, paleowind patterns, and 

probable atmospheric circulation patterns. 

provisions for temporal-, spatial-, and parameter-oriented 

queries of the inventories. The GLIS also offers several 

graphic tools and services such as geographic coverage 

presentations and data set visualizations, including a digital 

image browse capability. A GLIS prototype will be available for user access in May 1991 and will contain references 

to a variety of regional, continental, and global land science 

data sets, including an inventory of AVHRR data held by 

the U.S. Geological Survey's EROS Data Center and an 

inventory of the old Landsat Multispectral Scanner (MSS) 

data recently freed of exclusive-rights restrictions by the 

commercial Landsat operator, EOSA T. A fully operational 

GLIS, planned for 1992, will include an inventory of 

worldwide holdings of A VHRR data, an operational 

A VHRR image browse capability, references to newly 

developed source and derivative global land data sets, and a 

complete inventory of worldwide holdings of Landsat 

Thematic Mapper (TM) and MSS data. A Landsat TM 

image browse capability is planned for 1993. 

The picture of methane in the lake is complicated by 

several factors. The most significant feature was the presence of three discrete sources (Oremland and others, 1987; 

GCA 51:2915). Two sources were associated with constantflow gas seeps emanating from a natural gas deposit beneath 

the lakebed. These widely distributed seeps were characterized by stable isotopes and hydrocarbon abundance indices 

to be of two distinct flavors: bacterial origin and thermogenic origin. Radiocarbon content of the dissolved 

methane in the lake revealed it to be of recent bacterial 

Breakout and Poster Sessions 103 
origin (i.e., a comparable age as the lakewater DIC). The 

seeps, however, were essentially radiocarbon "dead," indicating an age of 720,000 years. Lake sediments have 

methanogenic activity (for example, Kiene and others, 

1986~ AEM 52: 1037; Oremland and G. King, 1989, 

Microbial Mats: 180). This methane originates in the 

sediments, and it is enriched in carbon-12~ however, when 

it diffuses into the bottom water, it becomes depleted in 

carbon-12 because of anaerobic bacterial oxidation. The 

lake's surface waters, however, are supersaturated with 

methane in the atmosphere, and an outward flux of the gas 

has been measured (Miller and Oremland, 1988; GBC 

2:269). Fluxes ranged from 0.4 to 201 J.Lmoles m- 2 h- 1 

during meromixis ( 1985-1987). 

Factors associated with water-column stability influenced the extent and nature of methane release from the lake 

to the atmosphere. Anoxic bottom water increased from 

premeromixis value of 8 J.LM to 60 J.LM by January 1988. 

This value represented the difference between sediment flux 

plus water-column storage minus oxidation and outward 

flux. Complete water-column mixing (November 1988-

September 1989) resulted in the loss of more than 1 X 10 7 

moles of methane from the lake, most of which escaped to 

the atmosphere and bypassed oxidation by bacteria. Methane concentrations in the air on and around the lake were 

significantly above ambient ( 1. 7 ppm) at several locations. 

Highest values (2.4 ppm) were associated with sites at 

Paoha Island, as well as two locations on the lake's northern 

shores. Future efforts will. be directed toward determining 

the seasonal trends of these anomalies as well as their 

source(s). 

REFERENCES 

Kiene, R.P., Oremland, R.S., Catena, A., Miller, L.G., and 

Capone, D.G., 1986, Metabolism of reduced methylated 

sulfur compounds in anaerobic sediments and by a pure 

culture of estaurine methanogen: Applied Environmental 

Microbiology, v. 52, no. 5, p. 1037-1045. 

Miller, L.G., and Oremland, R.S., 1988, Methane efflux from the 

pelagic regions of four lakes: Global Biogeochemical Cycles, 

v. 2, no. 3, p. 269-277. 

Oremland, R.S., Miller, L.G., and Whiticar, M.J., 1987, Source 

and flux of natural gases from Mono Lake, California: 

Geochimica et Cosmochimica Acta, v. 51, no. 11, p. 

2915-2930. 

Oremland, R.S., and King, G.M., 1989, Methanogenesis in 

hypersaline environments, in Cohen, Y., and Rosenberg, E., 

eds., Microbial Mats: Washington, D.C., American Society 

for Microbiology, p. 180-190. 

Assessment of Effects of Potential Climate Change on the Hydrology of the 

Gunnison River Basin 

R.S. Parker and W.A. Battaglin 

Water Resources Division 

U.S. Geological Survey 

A study has been initiated in the Gunnison River 

drainage basin, Colorado, to improve the understanding of 

water-resource sensitivity to the effects of potential climate 

change. The Gunnison River provides a substantial portion 

of water to a complex water-resource system and provides 

an opportunity to develop techniques useful in assessing the 

sensitivity of the water resource to changes in climate. The 

study has been divided into the following categories: (1) 

climate scenarios, (2) streamflow modeling (watershed and 

routing/accounting models), (3) water use and water rights, 

and ( 4) effect on dependent processes. 

The objectives of the climate-scenario category are to 

describe the existing climate regime~ develop alternative 

climate scenarios for use in sensitivity analyses; and define 

reasonable climate scenarios with an hypothesized climate 

change. The streamflow-modeling category will provide 

streamflows for various climate scenarios. This category 

has two major components, watershed or small drainagebasin modeling, and streamflow/reservoir routing through 

the main channel and large tributaries. Watershed modeling 

will be used primarily on small, upland drainage basins 

where snow accumulation and melt processes are important. 

Output from these models will provide the input to downstream accounting and routing models used in waterresource system management. In the third category, existing water use/water rights will be identified so the effect of 

the altered water-resource system can be assessed. Changes 

in climate and resulting changes in streamflow might have 

significant effects on dependent processes such as the 

quality of water or sediment transport. The objective of the 

dependent-processes category is to identify the changes in 

streamflow-dependent processes. There is considerable 

interest in identifying the streamflows needed to maintain 

existing channel morphology in the main channel of the 

Gunnison River. 

104 Proceedings of the U.S. Geological Survey Global Change Forum 
The Panola Mountain Research Watershed: Hydrologic and Biogeochemical 

Process Research, A Watershed Approach 

N.E. Peters, R.P. Hooper, and T.G. Huntington 

Water Resources Division 

U.S. Geological Survey 

The Panola Mountain project was initiated in fall 

1984 to address several scientific issues of the acid rain 

phenomenon. One objective of the project was to investigate terrestrial processes that control streamwater chemistry 

with emphasis on studying those constituents that control 

the acid-base chemistry. Results of this research contributed 

to a major goal of the National Acid Precipitation Assessment Program: the prediction of watershed response to 

acidic atmospheric deposition. Predictive hydrochemical 

models require a mechanistic understanding of the controls 

on water chemistry. Much of this understanding was provided by intensive interdisciplinary watershed studies, 

which were conducted worldwide. Results from these 

studies and from the modeling efforts indicate that the 

processes controlling streamflow generation are not clearly 

understood. Consequently the genesis of water quality 

along hydrologic pathways, particularly those contributing 

to streamflow, also is not clearly understood. In order to 

understand how changes in climatic variables will affect 

water quality genesis, it will be necessary not only to 

research the biogeochemical mechanisms but also to investigate the role of hydrologic pathways in controlling streamflow generation. 

The Panola Mountain Research Watershed (PMRW), 

a 41-hectare drainage, is in the Southern Piedmont physiographic province, 25-km southeast of Atlanta, Ga. PMRW 

lies within the Southern Plains ecoregion, the largest 

ecoregion within the conterminous United States, and it 

contains soils representative of those covering 98 percent of 

the physiographic province. It also contains both dominant 

forest types of the ecoregion, southern hardwood and 

loblolly pine. Rainfall moves rapidly through PMRW (it 

takes 30 minutes from maximum rainfall intensity to peak 

flow at the basin outlet); therefore, it was necessary to 

characterize the water chemistry on short time intervals. 

Field-data collection for the first 3 years focused on event 

sampling, resulting in one of the most extensive databases 

available from small watershed studies in the United States. 

The research objectives for the PMRW under the 

U.S. Geological Survey's Global Change Project of Water, 

Energy, and Biogeochemical Budgets (WEBB) are (1) to 

investigate processes that control the movement and solute 

composition of water along hydrologic pathways in a 

forested Piedmont watershed, and (2) to investigate the 

processes controlling soil solution chemistry. The approach 

for the first objective will focus on catchment ( 41 ha) soil 

solution chemistry and subcatchment (10 ha) scales. The 

second objective will focus on the plot scale. The research 

for the first objective is concerned with which soil solutions 

and how much of each soil solution gets to the stream. The 

research for the second objective seeks to determine the 

chemical evolution of these solutions and predict their 

evolution through time in response to factors such as 

land-use management and vegetation changes. The research 

will expand our knowledge of biogeochemical processes in 

the unsaturated zone. The soils research will be conducted 

primarily at the plot scale with supporting laboratory 

experiments, and it will complement the soil physics done 

at the plot scale needed for the first objective. Methods 

development is a necessary part of this research because so 

many soil chemical properties are operationally defined. 

For example, the validity of using environmental isotopes 

of water for tracing flowpaths is to be addressed, as well as 

the isotopic evolution of precipitation as it travels through 

the watershed. 

Climatic Variability in the San Francisco Bay Estuarine System 

D.H. Peterson, Water Resources Division, U.S. Geological Survey 

D.R. Cayan, Scripps Institution of Oceanography 

Understanding natural and human-caused variability 

in the historic records from our bays and estuaries is 

essential before better predictions of future changes can be 

made. The San Francisco Bay system is one of the most 

important estuaries on the west coast. Records extending 

back to the early 1900's show that the San Francisco Bay 

system has marked variations in both its physical and 

biological elements. While human factors played a role in 

modifying the characteristics in the bay over long periods of 

time, the interannual fluctuations in the bay have been 

Breakout and Poster Sessions 1 05 
dominated by short term climate effects. These climate 

variations include changes in the atmospheric circulation 

patterns, the precipitation levels in central California and 

particularly in the Sierra Nevada, and the discharge into the 

estuary in the spring and early summer from the Sacramento 

and San Joaquin River system. Such variations also must 

have a strong geological and biological signal. 

An interesting refinement on the well-known influence of climate control on the magnitude of fresh water 

supply to the bay is the effect of the exact timing of runoff 

events. This region has a strong annual cycle caused by 

winter precipitation in the cool season, causing rain in the 

bay and snow in the Sierras and dry conditions in the warm 

season. The runoff of the snowmelt in the spring and 

summer may be either accelerated or delayed in response to 

anomalous air temperature patterns during spring. Atmospheric circulation in winter largely determines whether the 

year is wet or dry, and atmospheric circulation in spring 

largely controls the early (warm) or late (cool) timing of the 

fresh w.ater release of the Sierra snow pack. Four scenerios 

(wet warm, wet cool, dry warm, and dry cool) produce 

characteristic modes of variability in the river basin, estuary, and coastal ocean over a broad spectrum of time scales 

including monthly and longer. The response of surface 

salinity (SS, a conservative property, or nearly so, for fresh 

water) shows that both the magnitude and timing of fresh 

water flows (delta flow) affect the bay. For example, in a 

warm spring, snowmelt is early and more rapidly depleted 

so that the summer delta flow is relatively low and late 

summer SS is relatively high. It is crucial to recognize these 

springtime effects of the atmospheric circulation before one 

can discriminate between the natural variability and artificial effects (such as the artificial late spring reductions in 

delta flow caused by agricultural impoundments, diversions, and consumption). The artificial effects can mimic a 

warm spring scenario in the river basin and estuary but not 

in the coastal ocean. 

Phosphate and Trace Metals in Cenozoic Phytoplankton: A Signal of Changing 

Ocean Chemistry 

D.Z. Piper, V.G. Mossotti, and D.j. Bukry 

Geologic Division 

U.S. Geological Survey 

Marine primary productivity is limited by the availability of PO/- and N03

1

- in the current ocean, which is 

virtually fully oxic. Their concentrations simultaneously 

approach zero in surface waters because the PO/-:NO/-

ration (1:15) of their uptake by phytoplankton equals their 

availability in upwelling deep seawater. Under less oxic 

conditions, this balance might not have been maintained 

owing to (1) the fast recycling rates of PO/- and NO/-

between the photic zone and the deep ocean reservoir, (2) 

their short residence times in the ocean of a few lO's of 

thousands of years, and (3) their totally different sources 

and sinks within the ocean. As plankton adjust their 

composition in response to the chemistry of their environment, taking up luxury amounts of nutrients that are in 

excess of a single "limiting" nutrient, a change in the 

PO/-:NO/- ratio of past oceans could be reflected by 

differences in the P04

3 - content of phytoplankton of 

different ages. 

Changes in the seawater concentrations of bioreactive 

trace elements might also be reflected by their concentrations in plankton. The export of many trace elements from 

the fully oxic ocean today is largely via the accumulation of 

organic detritus on the sea floor. Under less oxic conditions 

this might not have been the case. For example, Cr is 

reduced under conditions of denitrification from Cr04 

2

- to 

Cr3

+ and precipitates as Cr(OH)3 . Other factors being the 

same, its concentration in seawater would have been less 

during times when the 0 2 of the deep ocean was lower than 

it is today, caused by its continued removal from surface 

water by organisms and by an accelerated removal rate from 

the deep ocean inorganically. 

We propose to examine the P and metal contents of 

individual tests of planktonic organisms that cover the time 

period middle Tertiary to present. Preliminary work by us 

and others has demonstrated the feasibility of such analyses 

by secondary ion mass spectrometry. 

106 Proceedings of the U.S. Geological Survey Global Change Forum 
Potential Effects of Climate Change on the Surface-Water Resources 

of the Carson, American, and Truckee River Basins 

Alex Pupacko 

Water Resources Division 

U.S. Geological Survey 

The U.S. Geological Survey (USGS), as part of its 

Global Change Research Program, is investigating the 

potential effects of climate change on the water resources of 

the Carson, American, and Truckee River basins. These 

basins, located in western Nevada and central California, 

are adjacent and on opposite slopes of the northern Sierra 

Nevada. The American River drains to the west and to the 

Pacific Ocean. The Carson and Truckee Rivers drain to the 

east into the Great Basin. Hydrologic differences between 

east and west draining basins are a focus of the investigation. Climate scenarios are being developed initially by 

extrapolating historical records of climatic extremes and 

ultimately by using general circulation model predictions. 

These scenarios will be applied to deterministic watershed 

models to evaluate sensitivities and to simulate responses of 

basin-scale hydrologic processes to climate change. Basin 

characteristics are being determined with remote-sensing 

techniques and geographic information systems. The 

project complements a parallel investigation by the U.S. 

Bureau of Reclamation to study the possible effects of 

climate change on water supply and demand, system 

management, and operating criteria. The USGS project will 

involve concurrent research in linking large-scale circulation to local watershed models, and in the use of remotesensing and GIS techniques to define land-surface characteristics and hydrologic processes in mountainous terrain. 

Development of Land Data Sets for Studies of Global Climate Change 

F.G. Sadowski and A.H. Watkins 

National Mapping Division 

U.S. Geological Survey 

The U.S. Geological Survey has begun a major 

initiative to organize, produce, and distribute land data sets 

that will support the land data requirements of the global 

change science community. Satellite image data sets, produced from the National Oceanic and Atmospheric Administration's Advanced Very High Resolution Radiometer 

sensors, will be developed to provide repetitive, synoptic 

coverage of regional, continental, and global land areas. 

These data sets, integrated with related land data and 

supplemented by coregistered Landsat data sets, will enable 

scientists to quantify fundamental land surface attributes 

that are needed to model land surface processes, to detect 

and monitor land surface change, and to map land cover. 

These well-structured, consistent land data sets will form 

the historical record of land observations prior to the era of 

the National Aeronautics and Space Administration's Earth 

Observing System sensors. 

Use of Ash Layers in the Reconstruction of Earth System History: Correlation 

and Age Calibration of High Resolution Stratigraphic-Climate Records in the 

Oceans and on Land 

A.M. Sarna-Wojcicki, C.E. Meyer, and Elmira Wan 

Geologic Division 

U.S. Geologic Survey 

Projections of future variability in the Earth's physical environment, climate, and ecosystems can be made 

from studies of Earth-system history that provide baseline 

data on past natural conditions. Records of past conditions 

need to be precisely dated and correlated among sites on 

various time and space scales to determine whether past 

Breakout and Poster Sessions 1 07 
climate-induced changes are local, regional, or global and 

to determine the timing and rates of these changes. Correlations of past climate records between marine and terrestrial sites are particularly important in such studies. The 

oceans contain a relatively continuous, homogenous, and 

generally correlatable record of climatic changes. The 

variation of past faunal and floral assemblages provides 

information on past physical conditions, and the associated 

oxygen-isotope signal provides a record of volumetric 

changes in the world's oceans through time. By contrast, 

the records obtained on land tend to be much more 

fragmented, and often reflect a much more complex 

response to changes in climate forcing. This response often 

is controlled by local factors as well. In order to understand 

how and why these variations exist, and how past climate 

changes correlate in time and space, we need to identify 

precise reference time-horizons by which marine- and 

land-based records can be correlated. 

For the past 20 years, we have been identifying and 

dating widespread volcanic ash layers that provide correlation and age control for stratigraphic sequences on land and 

in the oceans. Our efforts have focused on Pliocene and 

Quaternary sections along the Pacific borderland of the 

Western United States. For the past 7 years we have also 

studied the Indian Ocean borderland of East Africa. First we 

find and sample macroscopic tephra layers (volcanic ash or 

tuff layers) or disseminated volcanic particles in exposed 

stratigraphic sequences or in cores. We describe the petrography of the tephra and separate and analyze the volcanic 

glass to provide characteristic chemical "fingerprints" by 

which a tephra layer can be identified. Many of the 

widespread tephra layers we have studied are now numerically dated. New layers that we find are dated by the 

appropriate method. Compositions of new tephra samples 

are compared to our data base of about 2,500 previously 

analyzed samples, and the best matches are identified. 

Finally, we establish correlations among sections by a 

combination of chemistry, petrography, other independent 

age data, and characteristic stratigraphic sequences among 

tephra layers. 

Our current focus is correlating and dating highresolution marine-land site transects spanning an age range 

of at least the last 130,000 years within the Pacific borderland of the Western United States, a large region containing 

a variety of ecotones. These tephrostratigraphic correlations 

complement magnetostratigraphy (for example, as at Tulelake, Calif.) and provide a stringent test on other age control 

and correlations, regardless of the precision with which the 

tephra layers are dated. 

Water, Energy, and Biogeochemical Budgets at Sleepers River, 

Danville, Vermont 

j.B. Shanley and E.T. Sundquist 

Water Resources Division 

U.S. Geological Survey 

In cold-temperate regions, the annual cycle of snow 

accumulation and snowmelt may undergo dramatic shifts in 

response to climatic change. Forecasting the effects of such 

shifts requires a more broadly based understanding of 

water, energy, and biogeochemical budgets (WEBB). To 

this end, a joint global change research project by the U.S. 

Geological Survey (USGS) and the U.S. Army Cold 

Regions Research and Engineering Laboratory (CRREL), 

under the USGS WEBB program, was recently initiated at 

Sleepers River Research Watershed, a 112-km2 upland 

basin in rural northeastern Vermont. Sleepers River was 

selected as the research site because of its 30-year hydrologic and energy data base. The project will draw on the 

expertise of the USGS on hydrological and biogeochemical 

processes, cold-regions hydrology, and the engineering 

problems of field instrumentation in a cold-region environment. 

Core data will be collected at a minimum of two 

headwater hillslopes (from ridge to stream channel) representing forested and agricultural (pasture) land usage. 

Vertical and lateral patterns of water movement will be 

studied by a network of time-domain reflectometry (TDR) 

soil-moisture probes installed in soil pits along a downslope 

transect (ridgetop to stream). Water will be collected from 

the unsaturated and saturated zones to study the chemical 

evolution of soil water as it moves toward the stream. 

Spatial and temporal patterns of major solute chemistry and 

carbon- and oxygen-isotope ratios will be coupled with 

water-flux data to identify the dominant hydrologic flow 

paths and biogeochemical reaction pathways. Determinations of trace gas fluxes also will be made in the soil pits. 

The response of the soil thermal regime to incoming surface 

energy and geothermal flux will be investigated by simultaneous measurements of soil-temperature profiles and 

108 Proceedings of the U.S. Geological Survey Global Change Forum 
energy fluxes. The research approach will use new technical 

and theoretical tools to test hypotheses-for example, the 

use of carbon-isotope ratios to assess the contribution of 

carbonate weathering to alkalinity. The core information at 

the hillslope scale will be evaluated from the larger-scale 

perspective to determine the relative importance of hydrochemical processes as basin size increases. 

Baseline Studies for Monitoring Global Climate Change in the Arctic 

Environment: A Remote Sensing-Spatial Data Base Approach 

M.B. Shasby 

National Mapping Division 

U.S. Geological Survey 

In 1989 the U.S. Geological Survey's EROS Data 

Center Alaska Field Office established a 10-year monitoring 

program based on remote-sensed and other digital spatial 

Earth science data bases to support global climate change 

studies in arctic, subarctic, and boreal regions of Alaska. 

The monitoring program is designed to support studies and 

models of Earth system processes at landscape, ecosystem, 

and regional scales. These site and regional models will 

improve parameter estimates for circumpolar and global 

climate change models. A major component of the project 

focuses on research elements associated with the spatial 

integration of widely varying sources of Earth science data 

and multiplatform, multi temporal sources of remote-sensed 

data for land surface characterization. Site-specific information will be correlated through collaborative studies with 

regional and hemispheric level data bases for broad scale 

extrapolations and predictions. 

Establishment of a monitoring program for the arctic 

and subarctic regions will be accomplished by addressing 

the following goals: 

1. Establish eight study sites within Alaska that sample 

unique ecosystems with a high potential for change. 

2. Compile a comprehensive archive of remote-sensed and 

automated Earth science data bases for designated 

sites. 

3. Develop baseline data bases and maps from which to 

document change in the biological and physical components. 

4. Identify and develop data analysis and data integration 

techniques for detecting and monitoring change. 

5. Establish a program for acquisition and integration of 

new data from existing and future satellite systems. 

6. Use geographic information system technology to 

develop parametric and nonparametric models to 

study and predict ecosystem change. 

7. Correlate site and ecoregion level data with statewide 

and circumpolar data for broad scale modeling. 

A key element of the project includes the development of an ecological regionalization map of the entire 

circumpolar arctic and subarctic regions through collaborative efforts with the Environmental Protection Agency and 

Environment Canada. 

Sulfur Isotope Geochemistry of Paleoclimate Change in Lake Baikal, Siberia 

E.C. Spiker and A.L. Bates 

Geologic Division 

U.S. Geological Survey 

Lake Baikal, located in the Baikal Rift of southeastem Siberia, is the deepest and most ancient freshwater lake 

in the world. The lake has accumulated an estimated 5 km 

of sediment over the last 30 million years and potentially 

contains the longest and most complete record of climate 

change in central Asia. Perturbations in climate affect 

vegetative cover, precipitation, and runoff, and they can 

strongly influence the lake's circulation, vertical mixing, 

and nutrient dynamics. These fluctuations have a direct 

effect on lacustrine productivity, redox conditions, and 

sulfur transformations in lake sediment, and they may be 

recorded as down-core variations in sulfur forms and sulfur 

isotopic compositions. For example, warmer average temperatures may inhibit lake overturn and thus lead to lower 

primary productivity, stagnant bottom-water conditions, 

and formation of 34S-enriched pyritic sulfur. 

Breakout and Poster Sessions 1 09 
As part of a large program of joint U.S.-Russian 

research on the paleoclimatology and paleolimnology of 

Lake Baikal, we examined the abundance and isotopic 

composition of the major forms of sulfur in sediment cores 

from the lake. In the initial phase of this study, samples 

were analyzed from cores ( <5 m in length) from two very 

different sedimentary environments within the lake: a site 

near the Selenga delta that has a relatively high deposition 

rate, and a site on the Academician Ridge with a low 

deposition rate. Overall the sulfur content of the sediment 

ranges from 0.02 to 0.55 wt. percent, consisting of 0.01 to 

0.03 wt. percent organic sulfur, zero to 0.03 wt. percent 

monosulfide sulfur, and zero to 0.52 wt. percent disulfide 

(pyritic) sulfur. Sulfur isotopic ratios (d34S) have a 47 per 

mil range, from -3.7 to +43.3 per mil, reflecting large 

variations in the abundance of dissolved sulfate in the lake's 

bottom water and the rate and extent of sulfate reduction in 

the sediment. The patterns of sulfur geochemistry at the two 

sites examined are significantly different, caused by differences in sedimentation and redox conditions. These differences underscore the importance of distinguishing between 

lake wide and local or basin-specific changes in paleolimnology when attempting to interpret how this large and 

diverse lake responded to climate change. 

Examination of Biogeochemical Processes in Tropical Watersheds 

of Puerto Rico and Panama 

R.F. Stallard 

Water Resources Division 

U.S. Geological Survey 

Research is concentrated on investigations of nutrient 

cycles, gas exchange, and weathering and erosion processes 

in small watersheds in northeastern Puerto Rico at the 

Luquillo Experimental Forest (LEF), and in central Panama 

at the Barro Colorado Nature Monument (BCNM). The 

LEF is the site of a recently initiated project funded under 

the Water, Energy, and Biogeochemical Budgets (WEBB) 

Program of the U.S. Geological Survey's Water Resources 

Division (WRD) and run through the Caribbean District 

Office of WRD. The LEF is readily accessible to researchers and is amenable to a complex research program. It is a 

region that climatologically and geologically resembles 

typical tropical environments more than any other area 

within U.S. territory. The BCNM includes Barro Colorado 

Island and surrounding mainland peninsulas in Gatun Lake, 

the largest artificial lake in the Panama Canal basin. The 

BCNM is under the stewardship of the Smithsonian Tropical Research Institute (STRI), which presently shares 

funding for the work. 

Sampling is organized using a quasi-nested-basin 

approach. Micro-watersheds have been selected on contrasting lithologies [Puerto Rico-quartz diorite, basaltic 

volcaniclastics; Panama-andesite and basaltic volcaniclastics]. The micro-watersheds are used to identify and characterize processes in detail. Larger watersheds are used for 

the hydrologic and chemical budgets, because the spatial 

distribution of agricultural development and of many important hill slope processes, such as landslides, is sufficiently 

patchy and uneven that it is impossible to select representative micro-watersheds. In Puerto Rico, the larger watersheds are contrasted with geologically matched nearby 

watersheds that have been agriculturally developed. In 

Panama, the Panama Canal Basin, which has a detailed 

80-year hydrologic record, is used as the reference watershed. Paired sites within the Panama Canal basin are used to 

determine the effects of development. 

The primary objective of the studies of weathering 

and erosion is to use long-term chemical sampling and 

physical monitoring to characterize the processes that control the distribution and transport of major, importantminor, and nutrient elements (AI, C, Ca, Cl, F, Fe, Ge, H, 

K, Mg, Mn, N, Na, 0, P, S, Si, Sr, Ti, Zr) through soils, 

downslope, and out of the watershed. Phenomena of interest to global-change research include the fixation, storage, 

and export of carbon and nutrients as related to biogeochemical and geomorphic processes within the watersheds. The experimental design permits comparison 

between natural and developed environments. The 

exchange of methane and carbon dioxide with the atmosphere is being examined for different types of environments (forests, swamps, lakes) in light of variations in 

hydrologic conditions. The soil-gas work in Panama is now 

completed and is among the first studies to quantify the 

seasonality of methane emission in tropical habitats. 

110 Proceedings of the U.S. Geological Survey Global Change Forum 
Developing Land Surface Characterization Requirements for Water and Energy 

Exchange Models 

LT. Steyaert 

National Mapping Division 

U.S. Geological Survey 

The goal of this research is to enhance our understanding of the types and characteristics of geographic data 

that are required for numerical models of water and energy 

exchange processes at the land surface-vegetationatmosphere interface. The focus is on biospheric modeling 

of the diurnal variations of the land surface energy balance, 

including the partitioning of net radiation into sensible and 

latent heat components. Such models depict the dynamic 

interactions between the free atmosphere and the biosphere 

at the land surface (i.e., radiative energy, momentum, 

moisture, and heat exchanges within the soil-plantatmosphere-system). The Biosphere-Atmosphere-TransferScheme (BATS) and the Simple Biosphere Model (SiB) are 

two examples of this type of land surface parameterization 

under development for global change models. Heterogeneous land surface characteristics, including terrain (elevation, slope, and aspect) and vegetation (type, morphological 

structure, and physiological attributes), are major factors in 

determining the behavior of these interactions. Furthermore, incomplete understanding of processes, temporal 

dynamics, and multiple scales complicate the characterization of surface roughness, albedo, and stomatal resistance. 

Preliminary tasks are to (1) assess, evaluate, and 

document the geographic data requirements for first generation models and more complex biospheric models, in part 

through comprehensive literature review and input from 

expert modelers, and (2) gain further insight into spatial 

data requirements by conducting a demonstration project 

within the complex terrain and heterogeneous landscape 

environments of Colorado and other, less challenging, 

regions to investigate multiscale sensitivity analyses, spatial 

integration methods, and statistical aggregations for biospheric models such as BATS. Other advanced dynamic 

models as tools for land surface characterization will also be 

studied through collaborative projects. 

Simulations based on appropriate zero-dimensional 

modeling as well as coupled modeling for multiscale 

regions within typical global change model cells will be 

based on global data sets and U.S. Geological Survey 

spatial data products, including cartographic data as well as 

derived data sets from Landsat and the NOAA polar 

orbiting satellite's Advanced Very High Resolution Radiometer (AVHRR). Requirements for new thematic products, accuracy, scale/resolution, and role of derivative 

products will be studied. Initial multiscale tests on land 

cover and digital elevation model/solar insolation modeling 

within the Montrose and Limon, Colo., quadrangles are 

underway. 

Consumption of Atmospheric Methane in Unsaturated Soils 

R.G. Striegl 

Water Resources Division 

U.S. Geological Survey 

Recent increases in the atmospheric concentration of 

methane have been attributed to culturally induced increases 

in global sources as well as to diminution of natural 

methane sinks. The overall global methane mass balance is 

not completely defined; extensive field research is required 

to adequately quantify source and sink terms. Consumption 

of atmospheric methane by soil bacteria is the most important terrestrial methane sink, accounting for as much as 10 

percent of the total global sink (tropospheric photooxidation accounts for the majority of the remaining sink); 

however, there is relatively little quantitative information 

about the temporal and spatial distribution of methane 

consumption by soil systems. Likewise, there is a general 

lack of knowledge of the edaphic, hydrologic, and thermal 

controls on the consumptive process. 

We established a network of locations for measurement of soil methane fluxes in the Central and Western 

United States. This network encompasses a wide range of 

conditions of soil temperature, moisture content, and nutrient availability. It includes locations along altitudinal and 

vegetational gradients in the Mojave Desert-Great Basin 

transition zone in Nevada, in the southern Rocky Mountains 

in Colorado, and in tallgrass prairie in Kansas. An objective 

of our study is to characterize the temporal and spatial 

heterogeneity of methane consumption by relating consumption rates to easily measured soil conditions such 

Breakout and Poster Sessions 111 
as surface temperature and soil-moisture content. In addition, field investigations focus on determining the bounds 

on consumption that are defined by environmental 

extremes, and on determining the alteration of methane 

consumption rates caused by cultural disturbance. Measurements at the Nevada site are intended to characterize 

methane consumption for high temperature, low moisture 

content, and low nutrient content conditions; likewise, flux 

measurements through snowpack at the Colorado site characterize the effects of sustained low temperatures. Paired 

measurements at the Konza Prairie Natural Resource 

Research Area in Kansas compare and contrast undisturbed 

prairie grassland with prairie that has been converted to 

agriculture. Effects of biomass burning, agricultural chemical applications, and crop cover have also been investigated at that location. 

A Monthly Water Balance Model to Study Possible Impacts of Climate Change 

in the Delaware River Basin 

G.D. Tasker, M.A. Ayers, D.M. Wolock, and G.J. McCabe, Jr. 

Water Resources Division 

U.S. Geological Survey 

The Delaware River is an important source of water 

for about 20 million people both within and outside the 

basin. When storage in the New York City Reservoir 

System in the upper part of the basin falls below specified 

levels, drought warnings or drought emergency conditions 

are declared, and water use is restricted. The frequency with 

which drought emergency conditions are in effect is termed 

"drought risk." Drought risk, under present climate and 

rules of operation, is estimated by running 50 years of 

monthly temperature and precipitation values through a 

basin model that simulates the operation of reservoirs and 

diversion canals in the basin. The 50 years of synthetic 

temperature and precipitation values are created by generating serially- and cross-correlated random residuals from 

historic monthly means. The basin model uses a modified 

Thornthwaite water-balance model to convert temperature 

and precipitation to natural runoff values. 

Conditions associated with climate change are introduced by modifying historic monthly mean temperature and 

precipitation and rerunning the basin model. The modifications of the historic means are determined by the difference 

in single and double atmospheric carbon dioxide runs for 

three general circulation models (GCMs): the Goddard 

Institute for Space Studies (GISS) model, the Geophysical 

Fluid Dynamics Laboratory (GFDL) model, and the Oregon 

State University (OSU) model. The change in estimated 

drought risk caused by doubling atmospheric carbon dioxide levels varies greatly depending principally on the 

precipitation characteristics of the GCM chosen. Similar 

changes in flow at Trenton and the position of the salt front 

in the Delaware estuary were observed in the model runs. 

Paleobotanical Evidence of Population Dynamics and Paleoclimatic Fluctuations 

R.S. Thompson, Geologic Division 

U.S. Geological Survey 

P.j. Bartlein, Department of Geography 

University of Oregon 

Palynological and plant-macrofossil studies provide 

evidence of changes in population sizes, community structures, and range boundaries that occurred in response to 

long-term climatic changes. Paleobotanical investigations 

illustrate the sensitivities of individual species to climatic 

variations, and they permit assessments of amplitudes of 

change, response rates, and linearity of the responses of 

these taxa. Synoptic-scale maps of vegetation and other 

paleoclimatic proxy data for selected past-time slices provide insights into large-scale changes in climatic circulation. These maps can be compared with mapped output 

from numerical general circulation model (GCM) simulations to validate model depictions of past climates and to 

evaluate the credibility of these models in the prediction 

of future climates. Multivariate analyses of modern 

vegetation-climate relationships provide quantitative estimates of temperature, precipitation, and seasonality from 

fossil records. These quantitative relationships can also be 

112 Proceedings of the U.S. Geological Survey Global Change Forum 
used with numerical climate model simulations to estimate 

the past and future distributions of species and ecosystems. 

Our initial focus has been on the Western United 

States, where several factors have made it difficult to 

establish the modem relationships among plant distributions 

and climatic parameters. These include the complex physiography and climate, the sparse coverage of weather 

stations, and the paucity of species-distributional information. To circumvent these problems, an equal-area grid of 

30-year means of January, July, and annual temperature and 

precipitation values was produced by regionalized regression equations. Distributions of selected modem plant taxa 

were delimited by digitizing outlines from published range 

maps. Probability surfaces generated from these climate and 

vegetation data were used to illustrate the modem relationships among species distributions and climate variables. 

Current research objectives include using this methodology 

to estimate climatic conditions during the Pliocene across 

North America. 

Some Anticipated and Measured Responses of Glaciers to Global Change in 

Alaska 

D.C. Trabant 

Water Resources Division 

U.S. Geological Survey 

The linkage between glaciers and climate and the role 

that glaciers play in the hydrologic cycle are imperfectly 

known. Global temperature increases are expected to cause 

surface melting at higher elevations on glaciers worldwide. 

At first, most of the increased surface melt at high elevations will be refrozen within glaciers as internal accumulation. Runoff modelers need to recognize how the process of 

forming internal accumulation will decrease and delay the 

runoff derived from increased surface melting. 

A small sea-level rise could cause several large 

glaciers in Alaska to begin drastic retreats. A rise that is 

inconsequential to most human activities could increase 

erosion along the narrow beaches that presently separate 

Malaspina, Bering, and other glaciers from attack by the 

waters of the Gulf of Alaska. Recent ice-penetrating radar 

measurements show that the potential retreat of Malaspina 

Glacier is 45 km and of Bering Glacier, 50 km. A small 

sea-level rise also increases the potential for retreat of a few 

actively calving glaciers. The threatened glaciers are seacalving glaciers that are near their extended positions. 

Long-term studies of glacier mass balance and runoff 

from Wolverine and Gulkana Basins, Alaska, show that 

recent increases in glacier ice storage are associated with 

increased basin runoff and increased total precipitation. 

This is contrary to the accepted relation in which ice storage 

increases are assumed to be withheld from unchanged total 

precipitation, which would reduce basin runoff. At Wolverine Glacier, a measured increase in the mean annual 

temperature has been associated with increases in both ice 

storage and basin runoff. The direct relation among mean 

annual temperature, ice storage, and runoff is not expected 

to hold for all glaciers, nor for these glaciers, as temperature 

continues to rise. Because the areal extent and temperature 

range over which the direct relation applies is undefined at 

this time, the sign of its effect on global sea level is 

undetermined. An important implication of this work is that 

in the absence of precipitation and ice storage change 

assessment, the reason for changes in basin runoff are 

ambiguous. 

Our plans are to (1) extend the long-term records of 

glacier mass changes and climate data at existing study sites 

for use in empirical and theoretical assessment of the 

glacier/climate relation; (2) increase the mass balance and 

climate sampling density and coordinate the expanded effort 

with Canadian and other agency colleagues for use in 

improving and ground-truth checking GCM results; (3) 

improve understanding of relation between changing glacier 

mass and the hydrologic cycle; and (4) recognize uniquely 

glacier processes and bring them to the attention of the 

global circulation modeling community. 

Breakout and Poster Sessions 113 
Banded Corals as Indicators of Tropical Pacific Paleoclimate 

G.W. Tribble and C.D. Hunt, Jr. 

Water Resources Division 

U.S. Geological Survey 

The Hawaii District of the U.S. Geological Survey's 

Water Resources Division has recently started a project 

using massive corals of the genus Porites as indicators of 

paleoclimate. The goal of this project is to establish a 

climatic record that augments and predates recorded meteorologic and oceanographic observations at sites in the 

tropical Pacific basin. Specifically, we plan to use growth 

bands of massive corals as environmental recorders of 

rainfall and surface seawater temperature over the past 

several hundred years. 

Geochemical variations in the calcium carbonate 

skeleton of actively growing massive corals can be correlated with environmental conditions in the surrounding 

seawater at the time of skeletal deposition. Furthermore, 

both annual and daily growth bands in such corals can be 

used to establish a chronology analogous to well-known 

studies using tree rings. This chronology can be combined 

with variations in skeletal composition to reconstruct specific environmental conditions at a particular time. For 

example, historic records of surface seawater temperatures 

have been constructed using variations in the ratio of 

oxygen isotopes 160 and 180. 

Several workers have recently demonstrated that 

massive corals may record fluctuations in river discharge by 

incorporating dissolved organic molecules into the skeletal 

matrix. These molecules fluoresce upon exposure to ultraviolet radiation, and the intensity of fluorescence is proportional to the volume of river discharge. We plan to use this 

attribute to reconstruct river discharge records for volcanic 

islands in the tropical Pacific, starting with the Hawaiian 

Islands. We also plan to obtain a record of water temperature using stable isotopes of oxygen. 

Our program is in the early stages of development. To 

date, we have acquired and field tested an underwater drill 

rig capable of coring corals. We currently are engaged in 

choosing sites in the Hawaiian Islands for intensive field 

work, and arranging analytical facilities for the preparation 

and analysis of cores. In collaboration with other workers, 

we plan to establish a record of rainfall and surface seawater 

temperature over the past several hundred years. 

An Investigation of the Water, Energy, and Biogeochemical Budgets of Loch 

Vale and Other Rocky Mountain Watersheds 

j.T. Turk, N.E. Spahr, and D.H. Campbell 

Water Resources Division 

U.S. Geological Survey 

The interaction of climatic change with water, 

energy, and biogeochemical budgets will be most pronounced in watersheds that have biotic communities at the 

limit of their tolerance to climatic conditions. One such 

class of watershed is the alpine/subalpine/montane watersheds typical of the Rocky Mountains. Minor shifts in 

climate can markedly alter boundaries of community structure that define transitions in the watershed processes. 

Because such boundaries are especially well defined in 

these watersheds, and because such watersheds are widespread throughout the Rocky Mountains and other great 

mountain ranges worldwide, they are a critical element in 

understanding the most immediate effects of climatic 

change on watershed processes and the feedback of watershed processes to climate. 

There are three topics in which there is a critical lack 

of understanding of watershed processes in the alpine/subalpine/montane watersheds of the Rocky Mountains: (1) 

processes controlling the flow path and flux and water; (2) 

processes controlling the energy balance and chemistry of 

snowpacks; and (3) processes controlling weathering and 

biogeochemical budgets. The basin and chemical characteristics of the Loch Vale watershed in Colorado are similar to 

alpine and subalpine watersheds throughout the Rocky 

Mountains. Such watersheds are among the most extensive 

of unaltered ecoregions in the Nation. Thus, understanding 

of processes that affect such watersheds is very likely to be 

transferable. 

114 Proceedings of the U.S. Geological Survey Global Change Forum 
Some Recent Advances in Statistical Analysis of Spatial Random Processes 

A.V. Vecchia 

Water Resources Division 

U.S. Geological Survey 

Spatial variability of inputs to basin-scale hydrologic 

models is an important consideration for evaluating uncertainty in the output from such models. Data often consist of 

widely scattered measurements of inputs, such as precipitation, that are subsequently used to generate values over a 

fine grid of locations throughout the basin. Spatial random 

processes provide a convenient framework for generating 

model inputs on a fine spatial scale, conditional on widely 

scattered observations, and possible concomitant information such as digital elevation data. This presentation reviews 

some recent computational advances in fitting rational 

two-dimensional spectra to unequally spaced observations. 

PC-based FORTRAN programs have been written for 

selecting a model, estimating parameters, and using the 

model for interpolation. A data set consisting of snowpack 

measurements from western Colorado is used to demonstrate the methods. 

Hydrologic and Biogeochemical Budgets in Temperate Lakes and 

Their Watersheds, Northern Wisconsin 

j.F. Walker, D.P. Krabbenhoft, and j.F. Elder 

Water Resources Division 

U.S. Geological Survey 

The Wisconsin Water, Energy, and Biogeochemical 

Budgets (WEBB) study area is in the Northern Highlands 

region of northern Wisconsin. The region is a rich mosaic of 

glacier-formed kettle lakes interspersed in a complex, 

low-relief topography. The study area includes seven lakes 

that, for the past 10 years, have been the site of the 

University of Wisconsin-Madison, North Temperate Lakes 

Long-Term Ecological Research (LTER) project. The Wisconsin WEBB project addresses some of the critical gaps in 

the understanding of hydrologic processes that control water 

and biogeochemical budgets in the lakes. 

The overall objective of the Wisconsin WEBB investigation is to understand processes underlying the responses 

of hydrologic, biological, and chemical systems in the study 

area to climate variations and human activities. The initial 

funding supports two research elements, ( 1) rainfall/ 

streamflow/ground-water recharge processes, and (2) surface and ground water interactions. The objectives of the 

first element are to investigate the partitioning of precipitation into quick-response streamflow and ground-water 

recharge, and to develop predictive capabilities for the 

streamflow generation and recharge processes. The objectives of the second element are to identify geochemical 

processes that control the flux of important chemical species 

at the sediment-lake interface, and to investigate the influence of stream and ground-water flow on the solute budgets 

and hydraulic residence time of Trout Lake. 

The approach for the first research element involves a 

combination of isotope sampling and moisture accounting. 

Three sites have been chosen initially: one streamflow/ 

ground-water recharge site and two upland ground-water 

recharge sites (one in an open area and one under the forest 

canopy). Water samples will be collected from the stream, 

piezometers, and lysimeters before, during, and after precipitation events. Several rain gages in the study area will 

provide instantaneous precipitation intensities and water for 

composite isotope samples. A complete climatological station will be installed to provide support data. It complements an existing climatological raft run by the North 

Temperate Lakes L TER project. One emphasis of the 

sampling is investigation of processes controlling the isotopic evolution of precipitation as it moves through the soil. 

The approach for the second research element 

involves fine-scale sampling at the sediment/lake interface 

of Trout Lake and monitoring surface water contributions of 

water and solutes to Trout Lake. The fine-scale sampling 

will use a variety of techniques, including membrane 

equilibrators, core squeezing, microprobes, and seepagemeters. Carbon dioxide and methane production rates for 

sediment extracts will be used to identify critical processes. 

Whole water and filtered samples for nutrients and major 

ions for all tributary streams and the outlet from Trout Lake 

will be used to assess the importance of stream sources to 

solute budgets. Techniques for estimating the hydraulic 

residence time distribution for Trout Lake will be explored. 

Breakout and Poster Sessions 115 
Assessment of the Potential Effects of Climate Change on Salinity Intrusion in 

Delaware Bay 

R.A. Walters 

Water Resources Division 

U.S. Geological Survey 

The purpose of the Delaware River basin study is to 

improve knowledge of the response of the basin's water 

resources to potential climate changes. Details of the 

objectives and an overall study plan are found in Ayers and 

Leavesley (USGS Open-File Report 88-478, 1988). The 

study described here is a subset of the broader study and is 

focused primarily on salinity intrusion in the Delaware 

River. Given changes in freshwater discharge into the 

Delaware River as determined from the larger study, and 

given probable sea-level rise estimates, the purpose here is 

to calculate the distribution of salinity within Delaware Bay 

and River. This salinity distribution will then be used to 

assess saltwater intrusion into aquifers adjacent to the 

estuary. 

The approach adopted for this study is comprised of 

two parts, an analysis of existing physical data in order to 

derive a basic understanding of the salt dynamics and the 

numerical simulation of future conditions based on this 

analysis. The data of interest include stage and salinity data 

from USGS and the Delaware River Basin Commission, 

and tide, salinity, and current meter data from NO ANN OS. 

From these data, rates of the various salt transport processes 

can be calculated, such as those of horizontal residual 

transport, tidally induced dispersion, and transport from the 

estuarine circulation. Knowledge of these rates and their 

changes as a function of changing conditions is an essential 

input to the numerical simulations. 

There are two important constraints in the model: it 

must resolve the spatial scales important to the salt dynamics, and it must be sufficiently efficient to allow extensive 

sensitivity studies. This has led to a three-dimensional 

model that uses harmonic decomposition in time and 

irregular finite elements in space (Walters, CSR, 1992a). 

These equations are coupled to the advection-diffusion 

equation for salt so that density-gradient forcing is included 

in the momentum equations. Although the study described 

here is still in progress, the model has reproduced sea-level 

variations and the three-dimensional structure of tidal 

and residual currents very well. In addition, the study 

has addressed the effects of a 1-m rise in mean sea level 

on hydrodynamics. Remaining work will focus on salt 

dynamics (1992b). 

REFERENCES 

Ayers, M.A., and Leavesly, G.H., 1988, Assessment of the 

potential effects of climate change on water resources of the 

Delaware River Basin-Work Plan for 1988-90: U.S. Geological Survey Open-File Report 88-478, 37 p. 

Walters, R.A., 1992a, A three dimensional, finite element model 

for coastal and estuarine circulation: Continental Shelf 

Research, v. 12, no. 1, p. 83-102. 

Walters, R.A., 1992b, A study of salt transport processes in 

Delaware Bay, in Spaulding, M.L., Bedford, K., Blumberg, 

A., Cheng, R., and Swanson, C., eds., Proceedings of the 

Second International Conference on Estuarine and Coastal 

Modeling: Washington, D.C., American Society of Civil 

Engineers, p. 240-251. 

Synoptic-Scale Climate and Mass Balance Interactions 

in Western North America 

R.A. Walters 

Water Resources Division 

U.S. Geological Survey 

The mass balance of glaciers depends on the seasonal 

variation in precipitation, temperature, and insolation. For 

glaciers in Western North America, these meteorological 

variables are influenced by the large-scale atmospheric 

circulation over the North Pacific Ocean. The purpose of 

this study is to gain a better understanding of the relation 

between mass balance at glaciers in Western North America 

and large-scale atmospheric effects at interannual time 

scales, as well as the behavior of longer-term cumulative 

changes in glacier volume. This study differs from most 

other mass balance studies in that the objective is to 

investigate large-scale similarities between glaciers using 

exploratory data analysis, rather than to examine the relation between mass balance at a single glacier, and local and 

nonlocal forcing. 

116 Proceedings of the U.S. Geological Survey Global Change Forum 
This study is an extension of a previous study 

(Walters and Meier, AGU Monograph 55, 1989) that used 

empirical orthogonal function (EOF) analysis to bring out 

the large-scale similarities and differences in glacier behavior as recorded in the mass balance time-series. Once the 

EOF extraction is finished, the mode amplitude timeseries are correlated with climatological variables such as 

averaged-sea level pressure, 700 mb height anomalies, 

Pacific North America (PNA) index, and Southern Oscillation Index (SOl). Some of these correlations are more 

successful than others. The procedure above emphasizes the 

interannual variability in the data sets. In order to examine 

longer period changes, the filtered interannual variations 

and the cumulative balances are searched for trends and 

patterns. 

The first (largest) mode in the EOF analysis contained 

60 percent of the variance, and it was strongly related to fall 

and winter atmospheric pressure patterns; the second mode 

contained 20 percent of the variance, and it was related to a 

summer pattern where high temperatures caused relatively 

high ablation. Both glacier balances and EOF's show strong 

correlations with large-scale variations in seasonal 700 mb 

height anomalies and sea-level pressure, and weaker correlations with Southern Oscillation Index and Pacific North 

American index. These results support the conclusion that 

the largest modes in the EOF analysis have succeeded in 

capturing the synoptic-scale similarities in the data sets, and 

that the response of the individual glaciers is more highly 

dependent on the large-scale atmospheric conditions than 

local-scale meteorological differences. 

REFERENCE 

Walters, R.A., and Meier, M.F., 1989, Variability of glacier mass 

balances in Western North America, in Peterson, D.H., ed., 

Aspects of Climate Variability in the Pacific and the Western 

Americas: Washington, D.C., American Geophysical Union, 

Geophysical Monograph 55, p. 365-375. 

Modeling the Spatial Distribution of Solar Radiation Incident 

on the Land Surface 

R.D. Watts 

National Mapping Division 

U.S. Geological Survey 

Solar radiation incident at the land surface drives 

several important environmental processes, such as evapotranspiration, photosynthesis, and atmospheric heating. 

Work is underway to quantify the terrain-dependent component of spatial variability, couple it to mesoscale meteorological and other process models, and quantify the effects 

of terrain-induced radiation variability on process aggregation (spatial integration), especially in mountainous 

regions. 

Major terrain geometric factors to consider are 

• orientation of local slope with respect to solar position; 

• shadowing of terrain from direct (refraction-path) solar 

radiation; and 

• horizon obscuration by local and surrounding terrain, 

which diminishes sky view and reduces diffuse radiation. 

The first step in developing spatially accurate models 

of incident solar radiation is to separate terrain geometric 

effects from solar direction and atmospheric transfer 

effects. In 1990, J. Dozier and J. Frew of the University of 

California at Santa Barbara developed an efficient algorithm 

for deducing horizons along terrain profiles; computer 

codes are now being developed to apply their method 

repeatedly across two-dimensional digital elevation models 

(DEM's) at numerous azimuths. For each point on the 

DEM, the software will compute horizon vertical angle as a 

function of azimuth and sky-view solid angle. The former is 

needed for computing shadowing (given solar azimuth and 

elevation), and the latter is used to compute reductions in 

diffuse radiation. The algorithm is structured for coupling to 

either a data- or a model-based specification of atmospheric 

direct and diffuse radiative transfer. 

Breakout and Poster Sessions 117 
Relations Between Upper-Air Flow Patterns, Climate, and Hydrologic Variability 

in the Red River of the North Basin in North Dakota, South Dakota, Minnesota, 

Manitoba, and Saskatchewan 

G.j. Wiehe, Water Resources Division, U.S. Geological Survey 

j.L. Knox, Consulting Meteorologist, Toronto, Ontario 

L.E. Welsh, Hydroclimatology Section 

National Hydrology Research Centre, Saskatoon, Saskatchewan 

The Red River of the North drains about 290,000 km2 

in the United States and Canada. The Red River of the 

North and some of its tributaries are international streams 

that are managed in accordance with provisions of the 1909 

Boundary Waters Treaty between the United States and 

Canada. C02-induced climate change could have an 

adverse effect on streamflow regimen, and changes in 

streamflow regimen could create difficult interstate and 

international legal problems. 

The purpose of this study is to investigate the hydrologic response of the Red River of the North and its 

tributaries to past climatic anomalies. The objectives of the 

study are to (1) analyze 50-kPa atmospheric pressure height 

and 50- to 100-kPa atmospheric thickness patterns for the 

northern hemisphere associated with extreme wet and dry 

periods in the Red River of the North basin during 1947-89; 

(2) assess differences between upper-air patterns that 

accompany wet and dry periods; (3) statistically compare 

surface climate variables to upper-air flow patterns and 

streamflow of the Red River of the North and its tributaries 

during wet and dry periods; and (4) assess circulation 

controls that lead to anomalies in upper-air flow patterns 

associated with wet and dry periods. 

A review of 200 years of flood information on the 

Red River of the North at Winnipeg indicates that several 

major floods during the 1800's were larger than any floods 

that occurred during 1947-89. Streamflow data from the 

main-stem gaging stations on the Red River of the North 

indicate that low-flow conditions during the 1930's were 

more extreme than during 1947-89. Although the upper-air 

data (1947-89) can be used to describe the relations 

indicated in the objectives, the results may not be complete 

because they may not represent the most extreme climatic 

conditions that have occurred during the last 200 years. 

Preliminary analysis of the 50-kPa anomalous pressure patterns for December-January indicates that extreme 

dry periods are associated with the amplification of a high 

pressure ridge over western North America that brings dry, 

adiabatically heated air into the Red River of the North 

basin. In contrast, analysis of anomalous pressure patterns 

indicates that extreme wet periods are associated with 

amplification of a trough over western North America that 

brings moisture-laden air from the southern and central 

United States into the Red River of the North basin. 

Arctic Data Interactive: Demonstration of a Hypermedia System 

D.A. Wiltshire 

Information Systems Division 

U.S. Geological Survey 

In May 1988, the U.S. Geological Survey, in cooperation with the Interagency Working Group on Data 

Management for Global Change, established a program 

with representatives from the Arctic research community to 

facilitate data management. The Arctic was selected as the 

focus for a data management project because (1) climatic 

models suggest that the Arctic will be one of the first areas 

to respond to changing climate, (2) the magnitude of 

environmental change will be greater in the Arctic than on 

other areas of the Earth's surface, and (3) the Arctic 

scientific community is a relatively small and organized 

group willing to enhance access to data and information. A 

key activity that the U.S. Geological Survey has undertaken 

is membership in the Arctic Environmental Data Directory 

Working Group, which is sponsored by the Interagency 

Arctic Research Policy Committee. The working group is 

composed of representatives from Government agencies 

and academia. One of the goals of the working group is to 

facilitate access to Earth science data and information for 

the Arctic and hence improve dissemination. As a first step, 

the working group developed the Arctic Environmental 

Data Directory, which contains more than 350 references to 

118 Proceedings of the U.S. Geological Survey Global Change Forum 
Arctic data sets maintained by U.S. Government agencies 

and other institutions. To meet the data management goals 

of the Arctic research community, the working group has 

undertaken a pilot study known as the Arctic Data Interactive (ADI) to design an integrated information product that 

will be published using compact disc read-only-memory 

(CD ROM) technology. The ADI prototype will include the 

following multimedia elements: 

• Arctic Environmental Data Directory 

• Bibliographic information 

• Full text of research reports and (or) short papers (including illustrations) 

• Selected Arctic data sets 

The project entails developing a prototype computer 

system that includes a mix of textual, numerical, and spatial 

data and possibly related software for data analysis. The 

data will be in standard formats to facilitate use with other 

applications software such as spreadsheets, graphics, and 

image processing. 

The design of the ADI prototype is based on the 

concept of hypermedia technology. Hypermedia is defined 

in the computer and information science literature as a 

software environment for developing nonsequential database-management systems. Hypermedia techniques provide 

the capability to create associative links between structured 

and unstructured information that may include data, text, 

graphics, imagery, and sound. Hypermedia systems are also 

characterized by a user interface that incorporates icons 

(graphic representations) and multiple windows on a computer monitor. 

Carbon Dioxide Contributions of the Terrestrial Biosphere to the 

Global Carbon Cycle 

B.E. Wright 

National Mapping Division 

U.S. Geological Survey 

The terrestrial biosphere plays an important role in 

the global carbon cycle. Since the middle of the 19th 

century, large amounts of carbon dioxide (C02) have been 

released into the atmosphere from the burning of fossil 

fuels, deforestation, and other man-induced effects. Since 

1958, accurate measurements of C02 in the atmosphere 

have been made from several locations around the world. 

The level of C02 in the atmosphere has increased from 

approximately 285 parts per million (ppm) in the preindustrial age to over 345 ppm today. Of the total C02 released 

daily into the atmosphere, about 60 percent remains there 

and about 40 percent is either absorbed by the oceans or by 

the biosphere. A great deal of uncertainty exists regarding 

this latter 40 percent. During the same period in which C02 

has been added to the atmosphere, the total area of the 

world's forests has been reduced. The tropical forests are 

continuing to be destroyed at a rapid rate and this reduction 

in biomass will have long-term implications for the global 

carbon cycle. 

To predict the consequences of continued fossil fuel 

use, deforestation, and other terrestrial changes, complex 

global models of the carbon cycle have been developed. 

Data that are used in these models include rates of fossil fuel 

use, rates of absorption and transmission of carbon, area 

measurements of various vegetation types, estimates of 

future land-use changes, estimates of historical land uses, 

and the effects of increased C02 on plant growth. 

Breakout and Poster Sessions 119 
AUTHOR INDEX 

A 

Acevedo, William 68 

Adam, D.P. 68, 69, 83 

Ager, T.A. 69 

Alexander, R.H. 70 

Ayers, M.A. 56, 112 

B 

Balistrieri, L.S. 96 

Bartlein, P.J. 112 

Bates, A.L. 109 

Battaglin, W.A. 88, 104 

Benjamin, S.P. 71 

Benson, L.V. 71 

Bertolini, L.M. 97 

Betancourt, J.L. 72 

Bliss, N.B. 72 

Bradbury, J.P. 73, 79, 83 

Breed, C.S. 53 

Bromley, Allan 40 

Bukry, D.J. 106 

c 

Campbell, D.H. 114 

Campbell, W.J. 73, 91 

Carneggie, D.M. 74 

Carter, L.D. 75 

Cayan, Dan 76, 105 

Chang, A.T.C. 91 

Christian, Eliot 12, 7 6 

Clow, G.D. 77 

Collar, P.O. 94 

Collett, T. S. 77, 92 

Colman, S.M. 78, 89 

Coplen, T.B. 94 

Corell, Robert 5 

Cronin, Tom 51 

D 

Dean, W .E. 79, 83 

De Cola, Lee 80 

Dettinger, M.D. 80 

Dowsett, H.J. 51, 81 

E 

Eddy, Jack 15 

Elder, J.F. 115 

F 

Ferrigno, J.G. 55, 97 

Fitzpatrick, J .J. 93 

Forester, R.M. 81 

Fountain, A.G. 82 

G 

Gardner, J.V. 83 

Gaydos, L.J. 83 

Gerlach, T .M. 84 

Gloersen, Per 73, 91 

Grantz, Arthur 84 

H/1 

Hallam, C.A. 85 

Halley, R.B. 86 

Hamilton, T.D. 87 

Harden, J. W. 88 

Hay, L.E. 56, 88 

Hearn, P.P., Jr. 89 

Herzog, D.C. 89 

Hinkley, T.K. 93 

Hooper, R.P. 105 

Hostetler, S. W. 90 

Hudson, J.H. 86 

Hunt, C.D., Jr. 114 

Huntington, T.G. 105 

Jackson, L.L. 96 

Jenson, S.K. 90 

Josberger, E.G. 91 

K 

Karabanov, E.B. 89 

Kelmelis, John A. 9 

Kennedy, G.L. 101 

Knox, J.L. 118 

Koteff, Carl 92 

Krabbenhoft, D.P. 115 

Kvenvolden, K.A. 77, 92 

L 

Lachenbruch, A.H. 77 

Landis, G .P. 93 

Landwehr, J.M. 93, 94 

Larsen, M.C. 94 

120 Proceedings of the U.S. Geological Survey Global Change Forum 
Lauer, Donald T. 37 

Leavesley, G.H. 95 

Lemeshewsky, G.P. 96 

Leventhal, J. S. 96 

Lins, Harry F. 27 

Livingston, G.P. 68, 71 

Loveland, Thomas R. 63 

Lucchitta, B.K. 97 

Ludwig, K.R. 94 

M/N 

Madole, R.F. 102 

Mark, R.K. 88 

May, S.D. 84 

Mayo, L.R. 97 

McCabe, Gregory J., Jr. 56, 112 

McEwen, R.B. 98 

Meyer, C.E. 107 

Michaels, Patrick J. 43 

Millard, H.T., Jr. 102 

Milly, P.C.D. 99 

Molnia, B.F. 99 

Moore, D.G. 100 

Morrissey, L.A. 68 

Moss , M.E. 101 

Mossotti, V.G. 106 

Muhs, D.R. 101, 102 

Mullen, M.W. 84 

0 

Oleson, L.R. 103 

Oremland, R.S. 103 

P/Q 

Parker, R.S. 104 

Peck, Dallas 3 

Peters, N.E. 105 

Peterson, D.H. 105 

Phillips, R.L. 84 

Piper, D.Z. 106 

Poore, R.Z. 23, 51, 81, 84 

Pupacko, Alex 107 

R 

Ragone, Stephen 1 

Rieck, H.J. 83, 84 

Riggs, A.C. 94 

Robinson, G .R. 92 

Rockwell, T.K. 101 

Rossi, R.E. 71 

Rye, R.O. 93 

s 

Sadowski, F.G. 107 

Sarna-Wojcicki, A.M. 83, 107 

Schenk, C.J. 102 

Shanley, J.B. 108 

Shasby, M.B. 109 

Showalter, D.H. 88 

Slack, J.R. 93 

Smith, K.S. 96 

Spahr, N.E. 114 

Spiker, E.C. 109 

Stallard, R.F. 88, 94, 110 

Steyaert, L. T. 111 

Striegl, R.G. 111 

Sundquist, Eric T. 33, 88, 108 

Szabo, B.J. 94 

T/U 

Tappan, G.G. 100 

Tasker, G.D. 56, 112 

Thompson, R.S. 51, 112 

Trabant, D.C. 113 

Tribble, G.W. 114 

Turk, J.T. 114 

v 

Vecchia, A.V. 115 

W/XNIZ 

Walker, J.F. 115 

Walters, R.A. 116 

Walton-Day, Katherine 96 

Wan, Elmira 107 

Watkins, A.H. 107 

Watts, R.D. 117 

Wehde, M.E. 100 

Welsh, L.E. 118 

Whelan, J.F. 101 

Wiehe, G.J. 118 

Wiggs, L.B. 81 

Williams, D.F. 89 

Williams, Richie S., Jr. 55, 97 

Wiltshire, D.A. 118 

Winograd, I.J. 94 

Wolock, D.M. 56, 112 

Wright, B.E. 119 

Author Index 121