Summarv Report 1983 

U.S. DEPAllTMEIT 

OF COMMERCE 

IATIOIAL 

OCEANIC AID 

ATMOSPHERIC 

ADMlllSTllATIOI 

EIVIROIMEITAL 

llESEAllCH 

LAIOllATORIES 
Geophysical Monitoring 

for Climatic Change 

No. 12 

Summary Report 1983 

Joyce M. Harris and Everett C. Nickerson, Editors 

Air Resources Laboratory 

Geophysical Monitoring for Climatic Change 

Boulder, Colorado 

December 1984 

U.S. DEPARTMENT OF COMMERCE 

Malcolm Baldrige, Secretary 

National Oceanic and Atmospheric Administration 

Environmental Research Laboratories 

Vernon E. Derr, Director 
To the memory of Jerome Kizza Nimira, a scientist who worked with the 

Geophysical Monitoring for Climatic Change Division from 1978 to 1980. 

Jerome was born in Uganda and studied at the University of Chicago before coming to Boulder. Following his employment with GMCC, he returned 

to Africa, where he was on the staff of the Meteorology Department of 

the University of Nairobi, Kenya, while studying for his doctorate. He 

died on April 13, 1984, after an automobile accident. 

Jerome was a gentleman, compassionate husband and father, and scientist 

whose warmth, sincerity, and generosity touched everyone he worked with. 

He was an example to all of us in GMCC who were fortunate enough to know 

him and work with him. His death saddened us all; his memory will be 

with us. 

ii 
~meticllltJ1llrte nrolnntcal jnctety 

$r~~ia( Aw~x~ 15 c.o~rx~ uporv 

N@ii 'J\auna jijoa@h,S,ervafory 

Janua~ ]983 

iii 
NOTICE 

Mention of a commercial company or product does not constitute 

an endorsement by NOAA Environmental Research Laboratories. 

Use for publicity or advertising purposes of information from 

this publication concerning proprietary products or the tests 

of such products is not authorized. 

iv 
CONTENTS 

DEDICATION 

SPECIAL AWARD FOR MLO 

FOREWORD 

PREFACE 

ACRONYMS 

1. 

2. 

3. 

4. 

SUMMARY 

OBSERVATORY REPORTS 

2 .1 

2.2 

2.3 

2.4 

Mauna Loa 

Barrow .. 

Samoa 

South Pole 

CONTINUING GMCC PROGRAMS 

3.1 

3.2 

3.3 

3.4 

3.5 

3.6 

3.7 

3.8 

3.9 

3.10 

3 .11 

3.12 

3.13 

Carbon Dioxide 

Total Ozone 

Ozone Vertical Distribution 

Surf ace Ozone . . . . . . . 

Stratospheric Water Vapor 

Halocarbons and Nitrous Oxide 

Stratospheric Aerosols--Lidar 

Surface Aerosols . . 

Solar Radiation . . . . 

Station Climatology 

Precipitation Chemistry 

Data Management . . . . 

Atmospheric Trajectories 

SPECIAL PROJECTS . 

4 .1 

4.2 

4.3 

4.4 

4.5 

4.6 

4.7 

4.8 

4.9 

4.10 

4.11 

4 .12 

4.13 

4. 14 

Trajectories During AGASP 

The Flow Climatology From Bermuda, and Its 

Implications on Long-Range Transport . 

Arctic Gas and Aerosol Sampling Program (AGASP) 

C0 2 and Meteorology at SMO . . 

The BRW Surface Aerosol During AGASP . 

Modeling 13c . . . . . . . . . . . . . 

Analysis of SPO C0 2 Data for 1975-1982 

Airborne Latitude Survey of El Chichon Optical Depth 

Concentrations of Trace Gases in the Atmosphere 

The Photovoltaic Power System at SMO .... 

Shipboard Measurements of Atmospheric C0 2 in 1983 

Results of the December 1983 NOAA-SIO C0 2 

Intercomparison. . . . . . . . . . ..... 

The 1982-1983 El Nino-Southern Oscillation Event as 

Recorded in the Global Atmospheric C0 2 Distribution 

Total S02 Observations at MLO Since the Eruption of 

El Chichon Volcano in 1982 . . . . . . . . . . . . . 

v 

Page 

ii 

iii 

vii 

.viii 

ix 

1 

5 

5 

10 

12 

17 

22 

22 

28 

34 

40 

43 

46 

48 

51 

54 

59 

65 

68 

73 

77 

77 

80 

82 

88 

92 

95 

97 

99 

100 

101 

102 

107 

112 

116 
5. 

6 . 

7. 

8. 

9. 

4.15 

4.16 

Development of a Balloonborne S02 -sonde 

C0 2 Measurements in Surface Ocean Waters 

COOPERATIVE PROGRAMS . 

5.1 

5.2 

5.3 

5.4 

5.5 

5.6 

5.7 

5.8 

5.9 

5 .10 

5 .11 

5 .12 

5 .13 

5 .14 

Air Mass Characteristics at BRW During AGASP 

(W. E. Raatz) 

Solar Radiation Measurements at BRW 

(G. Wendler) 

Elemental Carbon Measurements at Whiteface Mountain 

(R. Castillo) 

Aircraft and Surface Observations of Arctic Haze Near 

BRW, April 1983 . . . . . 

(L. F. Radke, J. H. Lyons, D. A. Hegg, P. V. Hobbs, 

and I. H. Bailey) 

The ASRC Aerosol Impactor-Concentrator . . 

(A. W. Hogan) 

Coarse-Particle Soil Dust in Arctic Aerosols, 

Spring 1983 .............. . 

(J. W. Winchester, S. Li, S. Fan, R. C. Schnell, 

B. A. Bodhaine) 

Particulate Sulfur and Chlorine in Arctic Aerosols, 

Spring 1983. . . . . . . . . . . . . . . . . . . · . 

(J. W. Winchester, S. Li, S. Fan, R. C. Schnell, 

B. A. Bodhaine) 

Trace Gases in the Arctic: Indexes of Air Pollution. 

(M. A. K. Khalil and R. A. Rasmussen) 

Atmospheric Particulates at MLO and SPO . . . . . . 

(C. M. Thompson, J. R. Parrington, G. Tuncel, and 

W. H. Zoller) 

and 

and 

The Search for Particles of Cosmic Origin at SPO . . . 

(R. E. Witkowski, W. A. Cassidy, and G. W. Penney) 

C0 2 and Other Air Chemistry Studies at Palmer Station 

(E. Robinson and W. L. Bamesberger) 

Vertical Profiles of Carbon Particles in the Arctic 

(H. Rosen and A. D. A. Hansen) 

S02 , Ozone, and Aerosol Over MLO Since El Chichon. 

(W. F. J. Evans, G. M. Shah, and J. B. Kerr) 

Page 

117 

118 

122 

122 

124 

125 

.. 128 

.. 133 

136 

138 

141 

145 

149 

151 

152 

154 

Optical and Chemical Features of Aerosol Present 

in the Arctic Snowpack . . . . . . . . . . 158 

5 .15 

(A. D. Clark and K. J. Noone) 

Global Atmospheric Measurements of CH4 and C0 2 by 

Gas Chromatography . . . . . . . . 

(L. P. Steele, P. J. Fraser, R. A. Rasmussen, 

M. A. K. Khalil, A. J. Crawford, T. J. Conway, 

and R. H. Gammon) 

INTERNATIONAL ACTIVITIES . . 

PUBLICATIONS AND PRESENTATIONS BY GMCC STAFF, 1983 

REFERENCES . 

GMCC STAFF, 1983 

vi 

. . . . 163 

166 

169 

172 

183 
FOREWORD 

While I stand here on the seawall at the tip of Cape Florida, on Key 

Biscayne, Florida, collecting a sample of tradewind air for the GMCC program, 

a number of thoughts come to mind. 

- It is because of the many thousands of weather and climate observers in 

the past that data are now available to study how and why our climate changes. 

The individuals in the GMCC program continue in that tradition of science in 

an important and unique way. 

- As this air, so recently over the waters of the Gulf Stream, is pumped 

into these small glass flasks, I am painfully aware that the sampling time 

(5 minutes, 2-3 days per week) is extremely short. Although the discrete 

samples collected thus far have provided data for determination of the C0 2 

annual cycle and long-term trend at this tradewind location, increased sampling 

time would allow us to study the synoptic nature of C0 2 variations with 

midlatitude circulations here. Clearly, the past and present economic necessity for discrete sampling should not limit our scientific imagination and 

quest to understand the details of the atmospheric circulation and transport 

of this important constituent. 

- The twice-daily changing water level on this seawall is witness to the 

unseen presence of astronomically induced tidal forcing, which appears to play 

some yet-to-be-determined role in altering our climate. It reminds us that, 

even while we monitor, we must continue to evaluate what should be monitored. 

- The global history of these few captured air molecules reminds us that 

there are other individuals without resources to monitor atmospheric trace 

constituents, but who share concern for the need to monitor them. How can the 

international conununity contribute collectively in a more effective way to 

provide answers to these truly global problems? 

This Summary Report is the 12th in a series that is unique. The GMCC 

program and its documentation are necessary for our times. The series shows 

that since the program began collecting air samples at selected locations 

around the world, it has changed ju ways that are likely to help 11s understand 

how atmospheric trace constituents may influence climate. I commend all the 

individuals involved, from those who collect the samples in widely distributed 

locations to those who define the program, and encourage them to continued 

intelligent vigilance in carrying out the program and in planning and making 

changes for the future. 

vii 

Kirby Hanson 

NOAA 

Miami, Florida 
PREFACE 

This document presents a summary of the research operations and accomplishments by the Geophysical Monitoring for Climatic Change (GMCC) program 

and by outside investigators working cooperatively with GMCC in 1983. It 

includes descriptions of management and operations at GMCC's four baseline 

sites, scientific data from the measurement projects, conclusions from analyses of data, and recent basic research achievements. 

The GMCC program, established in 1971, is one of several research 

programs within the Air Resources Laboratory under the directorship of Lester 

Machta. Its four observatories are located at Barrow, Alaska (in service 

since 1973); Mauna Loa, Hawaii (in service since 1956); American Samoa (in 

service since 1973); and South Pole (in service since 1957). Background 

measurements of aerosols, gases, and solar radiation that are important to the 

climate of the Earth are made at the observatories. The primary groups within 

GMCC are Acquisition and Data Management, Monitoring Trace Gases, Aerosols and 

Radiation Monitoring, and Carbon Dioxide. Specific names of individuals in 

GMCC are not given in the main text of the report; however, the membership of 

each GMCC group is given in sec. 9. Publications and presentations by GMCC 

staff are given in sec. 7. 

viii 
AC 

ACR 

AES 

A GASP 

AL 

ALE 

APC 

ARL 

AS ASP 

ASCS 

ASRC 

BAS 

BDL 

BLM 

BOSS 

BRW 

CAF 

CAMS 

CDC 

CDIC 

CIRES 

CMA 

CN 

CNC 

CPU 

CS I RO 

DAS 

DC 

DEC 

DOE 

DOY 

EC 

ECC 

EML 

ENSO 

EPA 

EPROM 

ERL 

F.R.G. 

FSSP 

GC 

G.E. 

GMCC 

GMT 

GSFC 

HAO 

HASL 

HBW 

HP 

HPIB 

IAEA 

ACRONYMS AND ABBREVIATIONS 

alternating current 

active cavity radiometer 

Atmospheric Environment Service, Canada 

Arctic Gas and Aerosol Sampling Program 

Aeoronomy Laboratory, Boulder, CO (ERL) 

Atmospheric Lifetime Experiment 

Applied Physics Corporation 

Air Resources Laboratory, Rockville, MD (ERL) 

active-scattering aerosol spectrometer probe 

Alaska Soil Conservation Service 

Atmospheric Sciences Research Center, SUNYA, Albany, NY 

British Antarctic Survey 

below detection level 

Bureau of Land Management (USGS) 

Basic Operating System Software 

Barrow Observatory, Barrow, Alaska (GMCC) 

Clean Air Facility 

Control and Monitoring System 

Control Data Corporation 

Carbon Dioxide Information Center, Oak Ridge, TN (DOE) 

Cooperative Institute for Research in Environmental Sciences, 

University of Colorado, Boulder 

Chemical Manufacturers Association 

condensation nuclei 

condensation nucleus counter 

central processing unit 

Commonwealth Scientific and Industrial Research Organization, 

Australia 

data acquisition system 

direct current 

Digital Equipment Corporation 

Department of Energy 

day of year, Julian 

elemental carbon 

electrochemical concentration cell 

Environmental Measurements Laboratory (DOE) 

El Nino-Southern Oscillation 

Environmental Protection Agency 

erasable programmable read-only memory 

Environmental Research Laboratories, Boulder, CO (NOAA) 

Federal Republic of Germany 

forward-scattering spectrometer probe 

gas chromatograph 

General Electric 

Geophysical Monitoring for Climatic Change, Boulder, CO (ARL) 

Greenwich mean time 

Goddard Space Flight Center (NASA) 

High Altitude Observatory, Boulder, CO (NCAR) 

Health and Safety Laboratory (EPA) 

half bandwidth 

Hewlett-Packard 

Hewlett-Packard interface bus 

International Atomic Energy Agency, Vienna, Austria 

ix 
IAMAP 

ICDAS 

IGY 

II CAMS 

I/O 

IOS 

IR 

ISWS 

ITCZ 

IUGG 

JSC 

KUM 

LBL 

LLL 

LST 

MAP/ 

GLOBUS 

MLO 

MSL 

NADP 

NARL 

NASA 

NBS 

NCAR 

NCDC 

NDIR 

NIAR 

NIP 

NMC 

NOAA 

NRL 

NSBF 

NSF 

NWS 

OGC 

ONR 

OPC 

OPEC 

PE 

PI SSA 

PIXE 

PMS 

PMT 

PV 

p3 

RAM 

RH 

RMS 

SAGA 

SAGE 

SEASPAN 

SEAREX 

SEM 

SIO 

SMO 

International Association for Meteorology and Atmospheric Physics 

Instrumentation Control and Data Acquisition System 

International Geophysical Year 

Interactive Instrumentation Control and Monitoring System 

input/output 

Institute for Ocean Sciences, British Columbia, Canada 

infrared 

Illinois State Water Survey 

Intertropical Convergence Zone 

International Union of Geodesy and Geophysics 

Johnson Space Center (NASA) 

Cape Kumukahi, Hawaii 

Lawrence Berkeley Laboratory (DOE) 

Lawrence Livermore Laboratory (DOE) 

local standard time 

Middle Atmospheric Project/Global Budget of Stratospheric Trace 

Constituents 

Mauna Loa Observatory, Hawaii (GMCC) 

mean sea level 

National Atmospheric Deposition Program 

Naval Arctic Research Laboratory, Barrow, AK 

National Aeronautics and Space Administration 

National Bureau of Standards 

National Center for Atmospheric Research, Boulder, CO 

National Climatic Data Center, Asheville, NC 

nondispersive infrared 

Norwegian Institute for Arctic Research 

normal incidence pyrheliometer 

National Meteorological Center, Suitland, MD 

National Oceanic and Atmospheric Administration 

Naval Research Laboratory, Washington, DC 

National Scientific Balloon Facility 

National Science Foundation, Washington, DC 

National Weather Service 

Oregon Graduate Center, Beaverton, OR 

Office of Naval Research 

optical particle counter 

Organization of Petroleum Exporting Countries 

phase-encoded 

particulate integrating sampling sector analyzer 

proton induced X-ray emission 

Particle Measuring Systems 

photomultiplier tube 

photovoltaic 

portable pressurizing pack 

random access memory 

relative humidity 

root mean square 

Soviet-American Gases and Aerosols (Expedition) 

Stratospheric Aerosol and Gas Experiment 

SEAREX South Pacific Aerosol Network 

Sea-Air Exchange Program 

scanning electron microscope 

Scripps Institution of Oceanography, La Jolla, CA 

Samoa Observatory, American Samoa (GMCC) 

x 
SN 

SOI 

SPO 

SRCF 

SRL 

SST 

STD BUS 

STP 

SUNYA 

TECOMAC 

TRACS 

TTO/TAS 

URI 

US ARP 

USCG 

USGS 

UV 

WATOX 

WDC-A 

WMO 

serial number 

Southern Oscillation Index 

South Pole Observatory, Antarctica (GMCC) 

Solar Radiation Calibration Facility (NOAA) 

Smithsonian Radiation Laboratory 

sea surf ace temperature 

standard bus 

standard temperature and pressure 

State University of New York at Albany 

Technical Conference on Observation and Measurement of Atmospheric 

Contaminants 

Trace Atmospheric Constituent Study 

Transient Tracers in the Ocean/Tropical Atlantic Study 

University of Rhode Island, Kingston, RI 

United States Antarctic Research Program 

United States Coast Guard 

United States Geological Survey 

ultraviolet 

Western Atlantic Ocean Experiment 

World Data Center-A, Asheville, NC 

World Meteorological Organization, Geneva, Switzerland 

xi 
Barrow Observatory, Alaska, site of GMCC's surface-based measurements 

for AGASP, March-April 1983. The view is toward the Arctic Ocean. 

xii 
GEOPHYSICAL MONITORING FOR CLIMATIC CHANGE 

NO. 12 

SUMMARY REPORT 1983 

1. SUMMARY 

At MLO, a special series of ozonesonde observations continued through 

1983. The data acquisition system for the lidar was replaced to improve its 

reliability and streamline its operation. The 1983 lidar observations indicate 

that all measured stratospheric aerosol parameters decreased, and that no significant stratospheric aerosol injection was observed against the El Chichon 

background. Solar transmission as well as maximum polarization at sunrise 

generally increased; in addition, turbidity generally declined, reflecting the 

continuing cleansing of the atmosphere following the El Chichon eruption of 

1982. 

At BRW, the power capacity of the air sampling platform and the air sampling room was increased. In early spring, a tracking NIP was installed to 

provide continuous direct irradiance data. A new pressure transducer is giving excellent agreement with the mercurial barometer. In support of AGASP, 

the measurement program at BRW was expanded during the Arctic haze season, 

especially for surface aerosols and solar radiation. 

At SMO, a photovoltaic power system was installed to provide a continuous 

source of power for data acquisition and C0 2 monitoring. After the sudden 

death of Chief Iuli Togi, with whom NOAA negotiated the original SMO land 

lease in 1974, a new lease was arranged. Assurances were received from the 

Iuli family and the Tula village that the continuity of GMCC operations in 

American Samoa would be maintained. 

At SPO, temperature fluctuations, which had plagued CAF in the past, were 

reduced with the installation of larger capacity room heaters and a highvolume, thermostatically controlled blower. A long-term problem with back 

diffusion during periods of high winds was partially corrected by adding a 

second-stage blower to the stack exhaust. One of the most complete CN records 

was obtained this year by the G.E. counter. A solar infrared hygrometer, for 

making discrete observations of the total slant-path water vapor content, and 

a pyrgeometer, for measuring terres' rial IR radiation, were installed for the 

first time. 

The measurement programs continued at the four observatories. These 

programs include C0 2 , total columnar ozone, ozone vertical distribution, surface ozone, stratospheric water vapor, CFC-11 and -12, N2 0, stratospheric 

aerosols, volumetric aerosol scattering coefficient, CN concentration, solar 

radiation, meteorological variables, and precipitation chemistry. In addition, 

a wide variety of cooperative programs were conducted for university, other 

agency, and foreign investigators. 

Continuous measurement of C02 with NDIR analyzers continued at the four 

observatories. Final processing of the data through 1983 was completed except 

for the selection of data for background conditions. Two gas chromatographs, 
designed to measure C02 with precision comparable with the NDIR analyzer, were 

tested in the C0 2 laboratory in Boulder. The GC's require 3-4 times less 

reference gas than the analyzers and are capable of measuring CH 4 as well as 

C02 . 

Flask sampling for C0 2 continued at 22 globally distributed sites. Indications are that the new site near Christchurch, New Zealand, is not ideally 

suited for measurement of background C0 2 , due to its proximity to Christchurch 

and vegetated areas. In 1983, 5600 flasks were analyzed, of which 3500 were 

from the flask network. The remainder were for special projects such as 

cruises and aircraft experiments or were test flasks to monitor analyzer 

performance. 

A return to a higher C0 2 growth rate for 1982-1983 of 1.4 ppm yr- 1 followed the lower rates for 1981-1982 of 1.0 ppm yr- 1 (continuous data) and 

0.6 ppm yr- 1 (flask data). This temporarily reduced growth was probably indicative of a major perturbation of the natural global carbon cycle related to 

the 1982-1983 ENSO event. 

Total ozone observations were continued at the 11 stations in the U.S. 

Dobson ozone spectrophotometer network. On 22 June 1983 an NWS station in 

Fresno, CA, was added to this network. 

Automated Dobson instruments were installed at Poker Flat, AK, and Haute 

Provence, France. Standard lamp calibration checks on Dobson instruments in 

the global total ozone network continued during the year. The unusually low 

total ozone levels at MLO during late 1982 and early 1983 are thought to be 

associated with the stratospheric quasi-biennial oscillation phenomenon, although a small amount of apparent ozone depletion by stratospheric aerosols 

from the eruption of El Chichon cannot be ruled out. The decrease of total 

ozone at MLO since 1970 is about 3% per decade. 

The program of weekly balloon soundings continued to obtain ozone profile 

data at Hilo, HI. The sonde data has aided in the interpretation and processing of Umkehr data, obtained since the eruption of El Chichon, which must be 

corrected for errors due to stratospheric aerosols. These errors in the 1983 

Umkehr ozone profiles probably did not exceed ±10%. A number of tests, conducted to assess the performance of ECC ozonesondes in the troposphere and at 

altitudes between 30 and 40 km, produced generally positive results, although 

one experiment was hampered by balloon failure. 

Surface ozone measurements continued at the four observatories. Concentrations at MLO reached their highest values since measurements began 11 years 

ago. The overall linear trend in the data for the period 1973-1983 is 1.6% 

yr- 1 , which is greatly influenced by high values in 1983. Trends in the data 

at BRW and SMO are less marked. 

The stratospheric water vapor measurement program was continued at 

Boulder. Balloon performance improved, although there were problems with 

measurements taken between 25 and 30 km. 

Flask monitoring of halocarbons and nitrous oxide continued at BRW, NWR, 

MLO, SMO, and SPO. A gas chromatograph was installed at SPO late in 1983 to 

improve measurements of these trace gases. Trends in the data are consistent 

with previous years. 

2 
Lidar measurements acquired at MLO during 1974-1983 have all been processed for vertical profiles of aerosol backscattering ratio, ratio of total 

backscatter to Rayleigh backscatter, and cumulative optical depth. These data 

constitute one of the longest detailed records of lidar observations in existence. 

Continuous measurement of CN concentration and aerosol scattering extinction coefficient provided another year of surface aerosol data at BRW, MLO, 

SMO, and SPO. The least-squares trend lines for the data show no significant 

long-term trends and are essentially unchanged from last year's trend analysis. 

Solar radiation measurements continued at the four GMCC observatories. 

In support of Arctic haze studies, a continuous pyrheliometer was put online 

in March at BRW. In addition, spectral measurements of direct solar intensity 

zenith sky intensity, global diffuse flux, and global total flux were made 

during AGASP. A multilaboratory sunphotometer intercomparison was held in 

Boulder in October. 

Routine and special precipitation chemistry measurements continued at 

GMCC sites of MLO and SMO, and at regional sites. 

Development continued on the hardware and software for CAMS, the microprocessor-based data acquisition system that will eventually replace ICDAS. 

The GMCC trajectory program was enhanced by adding the capability to the 

Northern Hemisphere isobaric model to compute forward trajectories. Backward 

trajectories for 1983 were added to the trajectory inventory for BRW, MLO, and 

SMO. 

GMCC personnel conducted numerous research projects and data analyses, 

many of which are summarized in sec. 4. Several of these studies present 

analysis of data collected during AGASP in March-April 1983. An AGASP study 

of atmospheric trajectories to BRW indicated long-range pollution transport 

from Wesern Asia and Europe during an intense Arctic haze event. Events in 

surface aerosol data collected during AGASP corresponded to changes in origin 

indicated by back trajectories and meterology at BRW. Aerosol scattering 

extinction coefficient was well correlated with daily mean aerosol optical 

depth, indicating that surface measurements reflect Arctic haze above the 

ground. A wealth of data collected during AGASP has been analyzed and published in numerous papers. This experiment has greatly increased our understanding of the nature and origins of Arctic haze. 

Another group of special projects dealt with C0 2 data. One study related 

C0 2 variability at SMO to the latitudinal gradient and changes in atmospheric 

circulation pattern. Another analyzed the record of SPO C0 2 data and found a 

change of the growth rate of C02 from 1 . 7 ppm yr- 1 (1977-1980) to about 1.0 

ppm yr- 1 (1981-1982). Two reports presented C0 2 ocean cruise data that have 

helped to veri fy and fill gaps in the C02 flask data network, giving a more 

complete picture of C0 2 global distribution. A detailed report presents the 

results of the NOAA-SIO C0 2 intercomparison at MLO, which investigated systematic differences between the C0 2 values obtained by the two organizations. A 

preliminary average difference between NOAA and SIO concentration was -0.02 

ppm with standard error of 0.039 ppm. Another report analyzed the possible 

relationships between the latest ENSO event and the global C0 2 record. 

3 
Other special studies include a climatology of 7 years of trajectories to 

Bermuda, which when compared with precipitation chemistry data revealed good 

agreement between high acidity and airflow from North America. An airborne 

survey studied the latitudinal variation in optical depth caused by the El 

Chichon volcanic cloud and found good agreement between MLO measurements and 

those taken during the flight series. Two reports summarize S02 measurements 

made with the Dobson spectrophotometer and a balloonborne ECC sonde. 

In 1983, GMCC supported many cooperative research projects. Fifteen 

summary reports from these projects are presented in sec. 5. They cover such 

topics as air mass characteristics during AGASP at BRW; special solar radiation 

measurements made at BRW; elemental carbon measurements made at Whiteface 

Mountain; aircraft and surface observations of Arctic haze during AGASP; a new 

aerosol impactor-concentrator that allows aircraft sampling in polar regions; 

soil dust, particulate sulfur and chlorine, and trace gases in the Arctic 

during spring 1983; atmospheric particulates at MLO and SPO; meteorites at 

SPO; C0 2 and other air chemistry studies at Palmer Station; vertical profiles 

of carbon particles in the Arctic; S02 , ozone, and aerosol over MLO since El 

Chichon; optical and chemical features of aerosol present in the Arctic snowpack; and measurements of CH4 and C02 by gas chromatography . 

4 
2. OBSERVATORY REPORTS 

2.1 Mauna Loa 

2.1.1 Facilities 

During 1983, ICDAS operated for 98% of the time at MLO. This very good 

ICDAS performance was made possible because of extra efforts by the MLO staff, 

which included voluntary weekend computer watches that virtually eliminated 

any excessively long computer outages over the weekend. 

A failure of the CPU in the NOVA 1220 computer was responsible for 

approximately 105 of the 184 hours of ICDAS downtime. Otherwise AC power 

failures and dropouts accounted for most of the remaining 79 hours. 

Director Kinsell Coulson retired from government service on 30 November 

1983, and a replacement was not named in 1983. 

The MLO meteorological museum moved from the second to third floor to 

make room for the computer. 

2.1.2 Programs 

The principal programs carried out at MLO during 1983 are listed in 

table 1. Brief comments on the programs are given below. 

Table 1.--Summary of sampling programs at MLO in 1983 

Program 

Gases 

c:o; 

Surface ozone 

Total ozone 

Ozone profile 

CFC-11, CFC-12, and N2 0 

Aerosols 

Condensation nuclei 

Optical properties 

Stratospheric aerosols 

Skylight polarization 

Solar Radiation 

Global irradiance 

Direct irradiance 

Diffuse irradiance 

Ins trwnent 

URAS-2 infrared analyzer 

3-L evacuated glass flasks 

0.5-L glass flasks, P3 

0.5-L glass flasks, through analyzer 

5-L evacuated glass flasks 

Dasibi ozone meter 

Dobson spectrophotometers nos. 63, 65 

Dobson spectrophotometer no. 65 

Ba lloonborne ECC 

300-mL stainless steel flasks 

Pollak CNC 

G.E. CNC 

Four-wavelength nephelometer 

Lidar 

Polarizing radiometer 

Eppley pyranometers with Q, GG22, 

OGI, and RGB filters 

Eppley pyrheliometers (2) with 

Q filters 

Eppley pyrheliometer with Q, OGI, 

RG2, and RGB filters 

Eppley pyrheliometer with 13 filters 

Eppley/Kendall active cavity radiometer 

Eppley pyranometer with shading disk 

and Q filter 

5 

Sampling 

frequency 

Continuous 

I pair wk- 1 

1 pair wk- 1 

I pair wk- 1 

I pair wk - 1 

Continuous 

3 day- 1 

5 obs. wk- 1 

I wk- 1 

1 pair wk- 1 

Discrete 

Continuous 

Continuous 

Discrete 

Discrete 

Continuous 

Continuous 

Discrete 

Continuous 

Discrete 

Continuous 

Remarks 

Mountain only 

Mountain and seacoast 

Mountain only 

Mountain and seacoast 

No . 63, Jan-May; no. 65, 

Jun-Dec 

Umkehr, Nov-Dec 

From Hilo Airport 

4 meas., weekdays; O, weekends 

450, 550, 700, 850 run 

694. 3 nm; 2 J 

320, 365, 400, 500, 600, 700, 

BOO, 900 nm; narrowband 
Table 1.--Summary of sampling programs at MLO in 1983--Continued 

Program 

Solar Radiation--Cont . 

Turbidity 

Meteorology 

Air temperature 

Soil tempera tu re 

Dewpoint temperature 

Relative humidity 

Pressure 

Wind (speed and direction) 

Precipitation 

Total precipitable water 

Precipitation Chemistry 

pH 

Conductivity 

Chemical components 

Cooperative Programs 

C02 (SIO) 

C02, 13C, N20 (SIO) 

Surf ace S02 (EPA) 

Total surface particulates 

(DOE) 

Atmospheric electricity 

(Univ. of Minnesota) 

Ultraviolet radiation 

(Temple Univ . ) 

Precipitation collection 

(DOE) 

Precipitation collection 

(EPA) 

Precipitation collection 

(Univ. of Paris) 

Precipitation collection 

(IAEA) 

Wet-dry deposition 

(ISWS) 

Aerosol chemistry 

(Univ. of Maryland) 

Aerosol chemistry 

(Univ. of Arizona) 

13c (USGS, Denver) 

Radiocarbons (USGS, 

Menlo Park) 

Carbon Monoxide 

(Max Planck Inst.) 

Ozone and S02 (AES, Canada) 

Various trace gases (OGC) 

Various trace gases (NCAR) 

Instrument 

J-series 1982 sunphotometers 

WPL seven-wavelength sunphotometer 

P~IOD three-wavelength sunphotometer 

Thermistor 

Max . -min. thermometers 

Hygrothermograph 

Thermistor 

Dewpoint hygrometer 

Hygrothermograph 

Sling psychrometer 

Capacitance transducer 

Microbarograph 

Mercurial barometer 

Bendix Aerovane 

Rain gauge, 8-in 

Rain gauge, 8-in 

Rain gauge, weighing gauge 

Foskett inf rared hygrometer 

HAO infrared hygrometer 

pH meter 

Conductivity bridge 

Ion chromatograph 

Infrared analyzer (Applied Physics) 

5-L evacuated glass flasks 

Chemical bubbler system 

High-volume sampler 

Field mill, air conductivity meter, 

surface antenna 

Ultraviolet radiometer 

HASL wet-dry collector 

Misco model 93 

Likens funnel collector 

Likens funnel collector 

Exposed collection pails 

Nuclepore filters 

Quartz filters 

10-L stainless steel flasks 

NaOH collector 

Chemical reaction with l!gO 

Brewer MK I spectrophotomete r 

Stainless steel flasks 

3-L stainless steel flasks 

6 

Sampling 

frequency 

Discrete 

Continuous 

Continuous 

Continuous 

l day- 1 

Continuous 

Continuous 

Continuous 

Continuous 

Discrete 

Continuous 

Continuous 

Discrete 

Continuous 

1 day- 1 

I wk 1 

(;ontinuous 

Continuous 

Continuous 

Discrete 

Discrete 

Discrete 

Continuous 

1 pair wk- 1 

Every 12 days 

Continuous 

Continuous 

Continuous 

Continuous 

Continuous 

Twice wk- 1 

Continuous 

Continuous 

Continuous 

2 wk- 1 

Discrete 

Continuous 

I pair wk - , 

Discrete 

I set wk- 1 

(3 flasks set- 1 ) 

pair wk- 1 

Remarks 

380, 500, 778, 

narrowband 

380, 422, 500, 

778, 862 nm; 

380, 500, 778 

narrowband 

862 nm; 

596, 680, 

narrowband 

nm; 

MLO and Kulani Mauka 

HLO and Kulani Mauka 

Kulani Mauka 

Rainwater collections, 6 sites 

Mountain and seacoast 

Dependent on wind direction; 

1 filter wk- 1 

Radiation responsible for sunburning of skin 

NADP 

Day-night discrimination 

Day-night discrimination 

Halocarbon flasks 
Carbon Dioxide 

The concentration of C02 in the atmosphere was monitored continuously by 

the URAS-2 infrared analyzer during 1983. The instrument performed satisfactorily without major problems. Preliminary results indicate that the rate of 

increase of C02 concentration was approximately 0.7-1.0 ppm yr- 1 for 1983. 

The weekly C0 2 flask sampling programs at MLO and Cape Kumukahi were 

continued during the year. Flasks were lost or broken during shipment on only 

four occasions. 

Outgassing from the volcanic caldera at the summit of Mauna Loa caused 

disruptions of some of the C0 2 records in every month of the year. It occurred 

mainly between 0000 and 0800 LST during the downslope wind flow regime. The 

monthly occurrences are listed in table 2. 

Table 2.--Monthly occurrences of outgassing from the 

volcanic caldera on Mauna Loa during 1983 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

No . of days 7 7 6 5 10 6 7 12 16 7 2 4 

Percent of days 23 25 19 17 32 20 23 39 53 23 7 13 

Ozone 

Total ozone in the atmospheric column was measured on 208 days during 

1983. In addition, the Dobson spectrophotometer was used for weasuring the 

ozone profile by the Umkehr technique on 5 days per week during the year, and 

134 published Umkehr measurements were obtained. A special series of ozonesonde observations was continued through the year; 34 flights were made. 

Problems developed with the ozone generator, and it was returned to 

Boulder on 16 May 1983. A zero filter was used for the remainder of the year. 

A new chart recorder was installed and calibra ted on 13 June 1983 . 

Surface Aerosols 

The nephelometer operated well for most of 1983. During the last 

2 months, however, it encountered an intermittent problem in channels 3 and 4 . 

The problem was finally isolated and determined to be dirty contacts on the 

circuit boards and some bad operational amplifiers. The Boulder Laboratory 

nephelometer was installed, and it was operated in October alongside the MLO 

unit for comparison . No problems were encountered . 

7 
Stratospheric Aerosols--Lidar 

Forty-three successful lidar stratospheric backscatter observations were 

performed during 1983 . 

The Data General NOVA 2 lidar computer system that was installed in 1974 

was replaced with a Digital Equipment LSI-11/23. The new computer has improved 

the lidar system's reliability, simplified its operation, and significantly 

decreased the time required to perform an observation. The new system provides 

the base for many future lidar system upgrades. 

The 1983 lidar observations indicated, as expected, a definite but erratic 

decrease in all measured stratospheric aerosol parameters. Total stratospheric 

non-Rayl~igh ~ackscatter decreased from a January average of apEroxi~ately 

1.2 x 10 3 sr 1 to a December average of approximately 0.6 x 10 3 sr 1 . Likewise, the average monthly peak backscatter ratio decreased from approximately 

8.2 to 3.3, and the center elevation of the main backscatter ratio peak value 

decreased from approximately 22 to 19 km from January to December. 

During 1983 no significant stratospheric aerosol injection was observed 

against the El Chichon background at MLO . 

Solar Radiation 

A normal incidence pyrheliometer, four global pyranometers with Q, GG22, 

OGl, and RG8 cutoff filters, and a diffuse Q pyranometer with shading disk 

were operated the whole year to obtain continuous radiation measurements. A 

filter-wheel pyrheliometer with Q, OGl, RG2, and RG8 cutoff filters was operated to obtain discrete broadband radiation measurements. Transmission generally increased as the year progressed. 

The active solar tracker operated the whole year with only minor problems. 

The 16-channel DAS was replaced by a 32-channel DAS in July, and both operated 

well after correction of an initial hardware problem with the 32-channel DAS 

that resulted in a 1-mo loss of observations. The dome and shutter controllers 

operated reasonably well. Instruments mounted on the spar included a normal 

incidence pyrheliometer, an infrared water vapor meter, a seven-wavelength 

sunphotometer, and a three-wavelength sunphotometer first installed in August. 

Overall operation was fairly good during the year. 

Turbidity measurements were obtained with hand-held sunphotometers J202 

(380 and 500 nm) and J314 (778 and 862 nm) during most of the year before 

being temporarily replaced in October by instrument J321 (380 and 500 nm) for 

the rest of the year. Atmospheric turbidity generally declined during 1983. 

Skylight polarization was measured using an eight-wavelength polarizing 

radiometer. Maximum polarization at sunrise increased during the year, reflecting the continuing cleansing of the atmosphere following the El Chichon 

eruption of 1982. 

Meteorology 

Meteorological measurements were continued without major problems throughout 1983. 

8 
Precipitation Chemistry 

The precipitation chemistry program continued without difficulties at 

about the same level of activity as in prior years. Snow samples from SPO and 

rainwater samples from SMO were added to the existing program schedule for 

analyses at MLO. Weekly samples are being collected at both sites. 

Cooperative Programs 

The large number of cooperative programs continued normally through 1983. 

A brief sununary of some cooperative efforts follows. 

Aerosol particulates were collected on Nuclepore filters for the 

University of Maryland and on quartz filters for the University of Arizona on 

a weekly basis. The filter pumps were operaterl discriminately by a master 

controller on the basis of time of day, wind speed, wind direction, and CN 

concentration. An a~rosol absorption study by the University of Washington 

required daily changes of special filters until the project was discontinued 

in June. 

Erythema radiation was integrated on an hourly basis for Temple University 

throughout the year. 

Total ozone and S02 in the atmosphere were measured during the whole year 

with a Brewer MK I spectrophotometer supplied by AES, Canada. Samples of C0 2 , 

collected by relatively long-term exposure of vats of sodium hydroxide solution 

at MLO were analyzed by USGS, Menlo Park, CA, for radiocarbon content. A new 

instrument for CO from the Max Planck Institute in Mainz, Germany, was 

installed and online at the end of February. Many mechanical and logistical 

problems followed. 

The SIO Applied Physics infrared analyzer continued to measure atmospheric 

C0 2 without major problems during 1983. Flask samples of air from MLO and 

Cape Kumukahi continued to be supplied to SIO on a weekly basis. 

MLO continued to participate in NADP under the direction of ISWS, by 

sending wet and dry samples of atmospheric deposition collected at the observatory. Bulk collections of atmospheric deposition were supplied all year to 

DOE. Other precipitation chemistry projects added in 1983 included (1) a 

short-term project with J. Halbig of University of Hawaii in which samples 

were collected on an event basis starting mid-1983 and continuing until 

mid-1984 at Hilo and Kana sites; (2) W. Keene's (University of Virginia) 

organic acid analysis program on rainwater samples from MLO; and (3) negotiations for a berylium 10 project on MLO rainwater samples, to be coordinated by 

G. Stensland at ISWS. 

Two sets of equipment were operated at MLO in 1983 for measuring various 

parameters related to atmospheric electricity. The equipment installed many 

years ago by W. Cobb (ARL) measures electrostatic potential, air-earth current, and positive/negative conductivity of the air. It operated well throughout the year. The second set of instruments from D. Olson of the University 

of Minnesota, which measured electrostatic potential and air-earth current, 

was shut down in May for the year due to lack of chart paper. Otherwise it 

operated normally. 

9 
2.2 Barrow 

2.2.1 Facilities 

During 1983, the safety and power capacity of the air sampling platform 

at BRW were upgraded. In addition, the amount of power available in the air 

sampling room was increased, as was the number of receptacles. 

The lidar hut was moved from NARL to the observatory and placed adjacent 

to the garage. 

A Honda ATC 200E three-wheel cycle was 

to allow tundra crossing during summertime. 

required some major engine maintenance, but 

added to the observatory's fleet 

The Bombi all-terrain vehicle 

is still running. 

The BRW LST zone was increased by 1 hour and is now 9 hours behind GMT as 

of 30 October. 

2.2.2 Programs 

Programs carried out at BRW during 1983 are listed in table 3. Comments 

on selected programs follow. 

Carbon Dioxide 

The URAS-2T infrared analyzer performed quite well during the year. 

However, problems occurred with the aged strip chart recorder. 

Flask sampling went well. Midway through 1983, P3 samples were taken on 

the roof near the sampling stack to provide air sample conditions in closer 

agreement with the through-the-analyzer method. 

Surface Ozone 

The surface ozone detector, ozone generator, and strip chart recorder 

operated well all year. 

Halocarbons and Nitrous Oxide 

The weekly flask sampling occurred without problem in 1983. 

Surface Aerosols 

The G.E. CNC was problematic throughout the year. The main sources of 

downtime were flooding of the optical chamber during shipment and solenoid 

problems. 

The Pollak counter and four-wavelength nephelometer performed well. 

Solar Radiation 

In early spring, a tracking NIP was installed to provide continuous direct 

irradiance data. An all-sky camera was set up during the Arctic haze study 

and continued to document sky conditions through summer. 

10 
Table 3.--Summary of sampling programs at BRW in 1983 

Program 

Gases 

--co; 

Surface ozone 

CFC-11, CFC-12, and N2 0 

Aerosols 

Condensation nuclei 

Optical properties 

Aerosol chemistry 

Aerosol chemistry 

Solar Radiation 

Global irradiance 

Direct irradiance 

Direct irradiance 

Turbidity 

Sky documentation 

Meteorology 

Air temperature 

Dewpoint temperature 

Relative humidity 

Pressure 

Wind (speed and direction) 

Precipitation Chemistry 

pH 

Conductivity 

Coope rative Programs 

Total surface particulates (DOE) 

Aerosol chemistry (URI) 

Global radiation (SRL) 

Ultraviolet radiation (Temple Univ.) 

C02 , 13C, N20 (SIO) 

Precipitation gauge (ASCS) 

Carbonaceous particles (LBL) 

Various trace gases (OGC) 

Incident and reflected radiation 

(Univ. of Alaska) 

Magnetic fields (USGS) 

13C (USGS) 

Various trace gases (NCAR) 13C/ 12C (CSIRO) 

Instrument 

URAS-2T infrared analyzer 

0.5-L glass flasks, P3 

0.5-L glass flasks, through analyzer 

5-L evacuated glass flasks 

Dasibi ozone meter 

300-mL stainless steel flasks 

Pollak CNC 

G.E. CNC 

Four-wavelength nephelometer 

Streaker, Cascade impactor 

PMS aerosol spectrometer 

Eppley pyranometers with Q and RG8 

filters 

Tracking NIP 

Eppley pyrheliometer with Q, OGl, 

RG2, and RG8 filters 

Sunphotometers with 380-, 500-, 778-, 

and 862-run narrowband filt e rs 

All-sky camera (Fisheye) 

Thermistor 

Max.-min. thermometers 

Hygrothermograph 

Dewpoint hygrometer 

Hygrothermograph 

Capacitance transducer 

Microbarograph 

Mercurial barometer 

Bendix Aerovane 

pH meter (samples analyzed at MLO) 

Conductivity bridge (samples analyzed 

at MLO) 

High-volume sampler 

High-volume sampler 

6 Eppley pyranometers 

Ultraviolet radiometer 

5-L evacuated glass flasks 

Wyoming shielded precipitation gauge 

Dichotomous sampler 

(quartz and Millipore filters) 

High-volume filter 

Daily Millipore sampler 

Stainless steel flasks 

Up-down pyranometers 

Magnetometer 

10-L stainless steel flasks 

3-L stainless steel flasks 

5-L glass fl a sks 

11 

Sampling 

frequency 

Continuous 

1 pair wk- 1 

1 pair wk- 1 

1 pair wk- 1 

Continuous 

1 pair wk- 1 

Discrete 

Continuous 

Continuous 

Discrete (Mar-May) 

Continuous (Mar-May) 

Continuous 

Continuous 

Discrete 

Dis crete 

Continuous (Mar-Aug) 

Continuous 

1 day- 1 

Continuous 

Continuous 

Continuous 

Continuous 

Continuous 

Discrete 

Continuous 

Discrete 

2 mo- 1 

Continuous 

(1 filter wk- 1 ) 

Continuous 

(2 filters wk- 1 ) 

Continuous 

Continuous 

1 pair wk- 1 

2 mo- 1 

Continuous (1 set 

of fillers wk- 1 ) 

Continuous 

(1 filter wk- 1 ) 

Continuous 

(1 filter day- 1 ) 

1 set wk- 1 (3 flasks 

set- 1 ) 

Continuous (program 

ended in Dec 1983) 

station check wk- 1 

pair mo- 1 

pair wk- 1 

pair mo- 1 
Table 4.--Summary of sampling programs at SMO in 1983 

Gases 

co; 

Surf ace ozone 

Total ozone 

Program 

CFC-11, CFC-12, and N20 

Aerosols 

Condensation nuclei 

Optical properties 

Solar Radiation 

Global irradiance 

Direct irradiance 

Turbidity 

Meteorology 

Air temperature 

Soil temperature 

Dewpoint temperature 

Relative humidity 

Pressure 

Wind (speed and direction) 

Precipitation 

Precipitation Chemistry 

pH 

Conductivity 

Cooperative Programs 

C02, ~C, N20 (SIO) 

ALE project: CFC-11, CFC-12, 

NzO, CH3CC1 3 , CC1 4 (OGC) 

ALE project: CH4 , CO, C02 (OGC) 

Various trace gases (OGC) 

13c cusas) 

Wet-dry deposition (NADP) 

Bulk deposition (EML) 

Hi-Vol sampler (EML) 

Hi-Vol sampler (SEASPAN Project) 

Instrument 

URAS-2T infrared analyzer 

0.5-L glass flasks, P3 

0.5-L glass flasks, through analyzer 

5-L evacuated glass flasks 

Dasibi ozone meter 

Dobson spectrophotometer no. 42 

300-mL stainless steel flasks 

Pollak CNC 

G.E. CNC 

Four-wavelength nephelometer 

Eppley pyranometers with Q and RG8 

filters 

Eppley pyranometers (2) with Q 

filters on tilted mounts 

Eppley pyrheliometer with Q filter 

Eppley pyrheliometer with Q, OGl, 

RG2, and RG8 filters 

Sunphotometers with 380-, 500-, 778-, 

and 862-nrn narrowband filters 

Thermistor 

Max.-min. thermometers 

Hygrothermograph 

Thermistor 

Dewpoint hygrometer 

Hygrothermograph 

Sling psychrometer 

Capacitance transducer 

Microbarograph 

Mercurial barometer 

Bendix Aerovane 

Polyethylene funnel, bottle 

Corning model 125 meter with 

semimicro combination electrode 

Beckman model RC-16C meter 

5-L evacuated glass flasks 

HP5840A gas chromatograph 

Carle gas chromatograph 

Stainless steel flasks 

10-L stainless steel flasks 

HASL wet-dry collector (new 

Chemetrics, Dec 81) 

Plastic bucket 

Hi-Vol pump and filter 

Hi-Vol pump and filter with clean 

sector controls 

14 

Sampling 

frequency 

Continuous 

1 pair wk- 1 

1 pair wk- 1 

1 pair wk- 1 

Continuous 

3 day- 1 

1 pair wk- 1 

Discrete 

Continuous 

Continuous 

Continuous 

Continuous 

Continuous 

Discrete 

Discrete 

Continuous 

1 day- 1 

Continuous 

Continuous 

Continuous 

Continuous 

Discrete 

Continuous 

Continuous 

Discrete 

Continuous 

1 day- 1 

1 day- 1 (GMCC); 

1 wk- 1 (NADP) 

day- 1 (GMCC); 

1 wk - 1 (NADP) 

3 h- 1 

1 set wk- 1 

(3 flasks set- 1 ) 

2 pair mo- 1 

1 wk- 1 i wet; 

2 mo 1 , dry mo- 1 

wk- 1 

wk- 1 
co2 -in-air standards were in Boulder for a recalibration procedure, and a set 

of traveling standards was sent to SMO for use in the weekly calibrations. 

The original standards were returned to SMO and went back online in July. 

No serious air line problems were experienced during the year; however, 

the section of aluminum line from the remote building at the Point to the top 

of the stairs, a distance of approximately 200 m, was replaced with Dekabon 

tubing. Also, because of erratic operation, the CryoCool freezeout trap 

located at the Point was taken offline in November, and the original condensation trap system was reinstalled. This reduced trap-tending chores at the 

Point to a once-per-week draining of the condensate collector bottles. These 

bottles retain approximately 75% of the ambient air moisture, or about 700 mL 

wk- 1 . The remaining 25% is removed by a freezeout trap cooled by a Cincinnati 

Sub-Zero freezer located in the main observatory building next to the analyzer. 

To minimize servicing of this system's relatively low-volume trap, a modification was made in November. A large, ~z-L glass thimble trap was added to the 

Cincinnati freezer system to remove all remaining water from the ambient air 

arriving from the Point. This freed the low-volume trap from the task of 

removing the ambient air moisture, and hence lengthened its use before freezeup from about 1 to 2 days to an essentially unlimited time. The thimble trap 

is changed once per week during the weekly calibration check, when ambient 

airflow through the analyzer is not required. This combination of condensation trap at the Point and large-volume thimble trap ahead of the low-volume 

trap permits uninterrupted ambient airflow thr·)ugh the analyzer between weekly 

calibrations, and results in a higher quality data set. 

Ozone 

Both the surface ozone instrument, a Dasibi ozone meter, and the Dobson 

ozone spectrophotometer operated routinely all year. 

Surface Aerosols 

The SMO complement of aerosol equipment remained unchanged during 1983, 

and operated routinely with only a few minor problems. 

Solar Radiation 

All sensors operated normally during 1983. 

Meteorology 

A new pressure transducer was received and put online during June. It is 

a replacement unit for the one destroyed by the lightning strike in March 1982. 

The EG&G dewpoint hygrometer failed twice during the year and on both 

occasions had to be sent back to Boulder for repairs. The unit is extremely 

sensitive to power fluctuations and cannot tolerate the SMO powerline variations. 

All other SMO meteorological sensors operated routinely. 

Precipitation Chemistry 

Three collection programs were maintained all year: NADP wet/dry collecting, DOE/EML monthly bulk precipitation sampling, and GMCC daily bulk sampling. 

15 
Flask Sampling Programs 

During 1983 flask sampling methods were used to investigate three main 

types of trace gases: C0 2 , chlorofluorocarbons, and light hydrocarbons. In 

addition to GMCC sampling for C0 2 and chlorofluorocarbons, cooperative program 

flasks were collected for the NCAR TRACS program, OGC, USGS, and SIO. A new 

cooperative flask program for C0 2 with G. Pearman, CSIRO, will be initiated 

early in 1984, and will involve filling a pair of flasks each month and sending 

them to Aspendale, Australia, for analysis of the 13c/ 12c ratio. 

Cooperative Programs 

One cooperative program was added during March 1983. A SEASPAN Hi-Vol 

sampler was installed on the GMCC tower at Matatula Point by the principal 

investigator, J. Prospero, University of Miami, and his assistant, T. Snowden. 

The SEASPAN network is a Southern Hemisphere complement to the Northern Hemisphere SEAREX Asian dust network. 

2.3.3 A Special Tribute 

Individuals within GMCC as well as cooperative scientists familiar with 

SMO operations were surprised and saddened in 1983 by the sudden death of 

Chief Iuli Togi, the Samoan Matai, with whom NOAA negotiated the original SMO 

land lease in 1974. Chief Iuli passed away suddenly on 15 September 1983 at 

his home in Tula village, just hours after returning to Samoa after a lengthy 

stay in San Francisco. The GMCC presence in Samoa is by definition an alien 

one, set in a different culture with different customs. The late Chief Iuli 

Togi was aware of this and took part in helping to bridge the gap between the 

daily life of Tula village and the high technology of the GMCC operation. The 

marriage of the village and the GMCC Observatory operation under his guidance 

was orderly, lasting, and trouble-free. We owe him a debt of gratitude for 

his understanding, commitment to purpose, and benevolent guidance. A large 

portion of the success of GMCC at Cape Matatula has been possible because of 

him. 

GMCC is also grateful for the advice and assistance obtained from two 

Samoans in making the transition to the lease arrangement in effect now. One 

whose advice and assistance proved invaluable was the American Samoa delegate 

to the U.S. Congress, Fofo I. F. Sunia. Mr. Sunia was contacted in Washington 

by the NOAA Congressional Affairs Officer, Joan Barrows, and he provided advice 

concerning an appropriate NOAA response. Additionally, Mr. Sunia aided NOAA 

by contacting a second Samoan, High Chief Salanoa S. P. Aumoeualogo, the senior 

Matai (chief) of Tula village, and received Chief Salanoa's assistance in 

communicating with the surviving Iuli family members on behalf of GMCC concerning the death. 

As a result of efforts by the above individuals, the NOAA response to 

Chief Iuli's death and funeral was appropriate, assurances were received from 

the Iuli family and Tula village concerning continuity of the GMCC lease operations in American Samoa, and interim arrangements agreed upon concerning disposition of lease funds during the transition period between Chief Iuli's 

death and selection of a new chief to hold the Matai title of Iuli. 

16 
2.4 South Pole 

2.4.1 Facilities 

SPO continued excellent operation in 1983. Figures 3 and 4 show the 

current facility layout. The few changes made in the CAF from the previous 

year include the addition of the frost-point hygrometer and the NCAR gas 

chromatograph, and some minor modifications and relocations of equipment and 

storage areas. A high-volume thermostatically controlled blower was installed 

on the wall near the ICDAS rack, and several room heaters were replaced by 

larger capacity units. This greatly reduced the interior temperature fluctuations that had plagued the CAF in the past. The ceiling water leakage reported 

in 1982 was not present this season. Several outlets were added to the roof 

to facilitate flask sampling. In August, the vestibule was repainted, and new 

linoleum was laid to correct ice and frost damage. 

The sampling stack required removal of internal frost buildup twice. In 

June, several leaks found on the stack manifold valve stems were repaired with 

steel-filled epoxy. A long-running problem with back diffusion during periods 

of high winds was partially corrected by adding a second-stage blower to the 

stack exhaust. Because the stack air is exhausted into the room, strong winds 

blowing over the sampling stack create a venturi effect that tends to set up a 

relative pressure difference between room and outside air, causing contaminated 

air to diffuse backward up through the stack exhaust. This could be corrected 

by venting the exhaust to the outside. 

Increasingly heavy demand on the station powerplant resulted in 36 

brownout-power interruptions. Although no instrument damage resulted, the 

fluctuations caused ICDAS to crash. Despite these problems, an ICDAS online 

efficiency of 99.3% was maintained. 

Halocarbon 

Frost Pt 

Hygrometer 

GECNC 

C02 Tanks 

Cryocool Hum1d1fier Oco2 D 

NOAA/GMCC Mel. 

Bookcase 

File Desk 

...--- Grid North 

Sacramento Peak Obs. Computer 

Table 

Shelves 

Dobson Parts 

Shelves 

Dob 

~~ Dobson Room 

(NOAA/GMCC) 

t::=::=~;;;;:;;:;:==:'..J -------- C14 sphere SUNY 

Storage 

C14 Sphere 

Storage 

_ _,,---,Friedman 

Cylinder Desk 

Deck 

Q) 

"' "' 0 

iii 

Storage 

Solar 

Keeling 

Flask 

Storage 

Desk D R~~~~on r----- _ 

(NOAA/ I 

GMCC) 1 

C14 Sphere : 

Keeling Flask ' FW ~ 

Storage Table 

Figure 3.--CAF floor plan at SPO, 1983. 

17 
]

_,,. --17 1m ---~1 GMCC 

Sampling Stacks Floodlights 

c@ 

!:!:!) 

Electrical 

Outlets 

@]Frost Pt. Hygrometer 

E Wood crate co 

,..: 

0 

I /R Hygrometer 

([:ti Floodlight 

Room Air Exhaust 

---Grid North 

LBL Pump Enclosure 

High Volume 

Sampling Stacks 

Pyrgeometer RGB 

p<·H·H•) 

Air Temp O 

Pyranometers 

Floodlight 

Ladders 

IT!] [i!) 

Electrical 

Outlets 

Figure 4.--CAF roof plan at SPO, 1983. 

D 

Dobson Hatch 

NWS NIPQ 

B ~GB 

2.4.2 Programs 

Table 5 lists the 1983 programs, some of which are described below. 

Carbon Dioxide 

The URAS analyzer operated well all season. In December, a new version 

of BOSS was implemented to allow ICDAS control of the Q gas. Some data in May 

and June were affected by the sampling-stack leaks. Replacement of two regulators, the CryoCool unit, numerous dynapumps, and diaphragms was necessary. 

Flask samples were alternately taken through the analyzer and on the windward 

edge of the roof. The P3 sampler was modified from parallel to series flow, 

and operated well after changing the operating procedure so that the entire 

unit was preheated indoors prior to going on the roof. 

Ozone 

Surface ozone and Dobson measurements continued with no major difficulties. 

Halocarbons 

Halocarbon sampling proceeded with no problems. 

18 
Table 5.--Sununary of sampling programs at SPO in 1983 

Program 

Gases 

co; 

Surface ozone 

Total ozone 

CFC-II, CFC-12, and N2 0 

Aerosols 

Condensation nuclei 

Optical properties 

Aerosol chemistry 

Solar Radiation 

Global spectral irradiance 

Direct spectral irradiance 

Turbidity 

Albedo 

Terrestrial (IR) radiation 

Total water vapor 

Meteorology 

Air temperature 

Snow temperature at 1 m 

Snow temperature surface 

Room temperature 

Dewpoint temperature 

Pressure 

Wind (speed and direction) 

Cooperative Programs 

C02 , 13c, N20 (SIO) 

Total surface particulates 

(DOE) 

Total surface particulates 

(EPA) 

Aerosol chemistry (Univ. 

of Maryland) 

Aerosol chemistry (Univ. 

of Arizona) 

Aerosol physical properties 

(SUNYA) 

Carbon aerosol (LBL) 

Various trace gases (OGC) 

14C (NOAA/ARL) 

Snow acidity (NOAA/ARL) 

CH 4 , CO (NCAR) 

Instrument 

URAS-2T infrared analyzer 

0.5-L glass flasks, P3 

0.5-L glass flasks, through analyzer 

Dasibi ozone meter 

Dobson spectrophotometer no . 80 

300-mL stainless steel flasks 

Pollak CNC 

G. E. CNC 

Four-wavelength nephelometer 

Streaker, Cascade impactor 

Eppley pyranometers with Q, OGI, and 

RG8 filters 

Eppley pyrheliometers with Q and RG8 

filters 

Eppley pyrheliometer with Q, OGl, RG2, 

and RG8 filters 

Sunphotometers with 380-, 500-, 77B-, 

and 862-nm narrowband filters 

Eppley pyranometers with Q, OGI, and 

RGB filters 

Eppley pyrgeometer 

Infrared solar hygrometer 

Platinum resistor 

Platinum resistor 

Platinum resistor 

Platinum resistor 

General Eastern hygrometer 

Capacitance transducer 

Microbarograph 

Mercurial barometer 

Bendix Aerovane and recorder 

5-L evacuated glass flasks 

High-volume sampler 

High-volume sampler 

High-volume samplers 

High-volume samplers 

Pollak CNC with diffusion battery 

Nuclepore filters 

High-volume sampler 

Stainless steel flasks 

10-L stainless steel cylinde r 

3,000 psi spheres 

125-mL Nalgene flasks 

Baseline gas chromatograph 

Aluminum flasks 

19 

Sampling 

frequency 

Continuous 

pair (2 wk)- 1 

pair (2 wk)- 1 

Continuous 

3 day-I 

1 pair wk- 1 

pair wk- 1 , summer; 1 pair 

mo - i, winter 

Discrete 

Continuous 

Continuous 

Discrete 

Continuous 

Continuous 

Discrete 

Discrete 

Continuous 

Continuous 

Discrete 

Continuous 

Continuous 

Continuous 

Continuous 

Continuous 

Continuous 

Continuous 

Discrete 

Continuous 

2 mo- 1 (3 flasks 

sample- 1 ) 

Continuous 

(1 filter wk- 1 ) 

Continuous 

(1 filter wk- 1 ) 

Continuous 

Continuous 

Discrete 

Discrete 

Continuous 

Twice mo- 1 

(3 flasks 

set- 1 ) 

mo- 1 

(2 cylinders 

sample- 1 2 

500 psi day 1 

Weekly 

Daily 

Weekly 

Length of Record 

Jan 74-present 

(excl. Nov 7BNov 79) 

Jun Bl-present 

Nov 79-present 

Jan 76-present 

Dec 63-present 

Jan 77-Dec 79 

Jan 80-present 

Jan 74-present 

Jan 74-present 

Jan 79-Dec 79; 

Jan 81-present 

Jan-Dec 82 

Feb 74-present; 

OGI disc. Mar 

Oct 75-present 

Jan 77-present 

Jan 74-present 

Jan 82-present; 

83 

OGI disc. Mar B3 

Har 83-present 

Dec 81-Jan 82; 

Jan 83-Dec 83 

Har 77-present 

Mar 77-Apr B3 

Apr B3-present 

Jul 78-present 

Jan B3-present 

Dec 75-present 

Feb BO-present 

Jan BO-present 

Dec 75-present 

1957-present 

Hay 70-present 

Hay 70-present 

Jan 79-present 

Jan 82-present 

Jan 74-present 

Nov B3-present 

Jan B2-present 

1980-present 

Jan Bl-present 

1972-present 

1982-present 

Apr B3-present 

Apr 83-present 
Surface Aerosols 

The Pollak CNC again operated with no major troubles. For the first time 

at SPO, two complete G.E. CNC's were at the station during the winter period, 

one online and another as backup. The G.E. CNC experienced all of its traditional problems during the year: air leaks, a flooded casting, valve seizure, 

sporadic drift in the daily set zero adjustment, PMT replacement, and two 

instances of circuit failure. Despite this, the instrument was kept running 

all year and yielded one of the most complete records to date. 

The nephelometer operated with no major problems all season. Occasionally, a power brownout caused all four channels to drop to zero. A procedure 

was developed that allowed these to be reestablished at their previous levels, 

saving hours or days of lost data that formerly occurred when the instrument 

recovered on its own. 

Solar Radiation 

Two instruments were installed for the first time at SPO. In late summer, 

a solar infrared hygrometer was used to make discrete observations of the 

total slant-path water vapor content. Three months of data were returned 

before sunset. Beginning in March, a pyrgeometer and two temperature sensors 

were added to measure terrestrial IR radiation. The OGl upward-facing and 

albedo pyranometers were discontinued at this time. A second Q pyrheliometer 

was installed to begin comparisons with the existing Q pyrheliometer. In 

December 1982, solar radiation intercalibrations were made by D. Nelson. 

Because of equipment failure, the discrete albedo program was discontinued. 

The old Voltz turbidity meter was replaced by the newer J-series dualwavelength model. 

Meteorology 

A General Eastern dew-frost-point hygrometer was installed. During the 

winter months, it frequently became clogged with ice crystals and had to be 

brought indoors for cleaning. This problem was solved by enclosing the instrument in a wooden crate. All meteorological instruments operated normally 

with the exception of the wind direction component, in which a loose servo 

shaft coupling in the Aerovane was responsible for a 4-mo interval of questionable data before the problem was isolated and solved. Systematic differences 

between GMCC and station meteorology office parameters, which have been present 

for several years, were documented. 

ICDAS 

ICDAS operated exceptionally well all year, with an online efficiency of 

99.3%. All failures were caused by station brownouts, and the NOVA computer 

was brought up quickly in most cases with no trouble. 

Cooperative Programs 

All programs operated without incident with the following exceptions: 

The PISSA, which shuts off sampling pumps when the wind comes from outside the 

clean air sector or is calm, failed in February, and was operated in a manual 

mode until July. It was then repaired by a modification that allowed it to 

20 
work without the faulty relay for which there was no replacement . The 14C 

sphere shipments arrived with damaged containers due to cold weather and rough 

handling. The 3000-psi-charged spheres were packed in vermiculite to avoid 

danger of an accidental breakage in shipment. Cascade and streaker filter 

programs were discontinued. 

A major new program this season was the NCAR gas chromatograph, used to 

measure CH4 and CO. Numerous problems were encountered in initiating the 

program. A valve damaged in shipment was overhauled. The hydrogen generator 

performed sporadically for the entire year, and problems maintaining instrument 

temperatures resulted in poor CO data. Nevertheless, usable CH4 data were 

obtained, and the program is continuing for the 1983-1984 season. 

21 
3. CONTINUING GMCC PROGRAMS 

3.1 Carbon Dioxide 

3.1.1 Continuous C02 Measurements 

In the GMCC program, 1983 was a milestone year for continuous measurement 

of atmospheric C0 2 by in situ NDIR analyzers. BRW has now produced a 10-yr 

continuous record and began a second decade of measurements in July 1983. The 

somewhat younger C0 2 programs at MLO, SMO, and SPO also continued in 1983, and 

within 3 years, each of these will attain 10 years of continuous C02 records. 

The methods of analysis, data acquisition, and preliminary processing have 

been described in preceding GMCC Summary Reports (Peterson, 1978, pp. 20-25; 

Mendonca, 1979, pp. 16-23). Provisional daily C02 concentrations from the 

four observatories through 1982 are archived with WMO. 

The record from each observatory has now been processed to final values; 

however, the difficult procedure of selecting the data for background conditions has not been completed. When the selection is final, separate reports 

examining the continuous C02 record at each station will be made available. 

The monthly means in fig. 5 and table 6 reflect the current state of selection 

of the data and are therefore provisional. 

This year a two-part, in-depth comparison was begun of the GMCC continuous 

C02 program at MLO with that of C.D. Keeling of SIO. The first part consisted 

of a comparison of monthly means, calculated using hourly data determined by 

SIO to be background, for the period May 1974-December 1983. This data comparison was followed by a field experiment in which the effects of analyzers, air 

lines, pumps, freezeout traps, etc., in each system were examined. A more 

detailed discussion of the methods and results of this comparison is given in 

sec. 4.12. 

3 45 

SPO 

34 0 

& t,~, ....... 335 ,• . 

"' 0 I ' u 

330 

325 

1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 

YEAR 

Figure 5.--Provisional selected monthly mean C02 concentrations from 

continuous measurements at BRW, MLO, SMO, and SPO. Values are in ppm 

with respect to dry air (X81 mole fraction scale). 

22 
Table 6.--Provisional selected monthly and annual mean C0 2 

concentrations (ppm relative to dry air--X81 mole fraction scale) 

for continuous measurements at BRW, MLO, SMO, and SPO 

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 

mean 

BRW 

-1973 322.0 323.4 327.8 332.7 333.5 

1974 336.5 336.0 336.7 337.1 336 . 9 335.9 328.7 323.5 324.2 328.8 332.0 335.2 332.6 

1975 336.8 336.6 337.1 337.7 337.9 335.4 330.1 324 . 4 324.6 329.3 334 . 3 336.5 333.4 

1976 337.0 336.7 337.7 338.0 337.8 336 . 8 331.0 323 . 5 325.1 329.8 334. 1 336.6 333.7 

1977 336.8 336.9 338.2 339.2 339.4 337.4 330.1 325.4 326.8 332.0 334.7 338.8 334.6 

1978 339.1 340.2 341.5 341.0 340.8 339 . 4 332.6 327.7 327.4 332.1 338 .8 339.4 336.7 

1979 340.1 341.3 342.5 342.4 342 . 9 342 . 0 333.6 327 . 7 329.3 333.1 338.1 341.5 337.9 

1980 341. 9 342.4 343.4 343.3 343 . 3 342 . 6 337.3 331. 8 331. 4 337.9 340.5 342.6 339.9 

1981 344.3 345.5 344.6 345.8 346.8 344 . 4 338.2 331. 8 333.3 338.8 342.2 344.9 341.7 

1982 345.8 347.2 348.3 348.4 348.0 345 . 7 339.2 333.2 333.2 337.9 342 . 1 344.5 342.8 

1983 347.4 347.0 348.2 348.2 348.3 346 . 8 339.8 333 . 6 333.8 339.4 346 . 1 346.9 343.8 

MLO 

- 1974 333.1 332.1 331.1 329 . 1 327 . 4 327 . 3 328 . 2 329.6 

1975 330.6 331.4 331. 9 333.2 333.9 333.4 331.9 330.0 328.5 328.4 329.3 331 . 0 331.1 

1976 331. 6 332.6 333.6 334.7 334.7 334.2 333.0 330.8 329.0 328.6 330.2 331 . 6 332.0 

1977 332.7 333.2 334.9 336. 1 336.8 336.1 334.8 332.6 331. 3 331.2 332.4 333.5 333.8 

1978 334.7 335.2 336.5 337.8 338 . 0 338.0 336.4 334.5 332.5 332.3 333.8 334.8 335.4 

1979 336.0 336.6 337.9 339.0 339 . 1 339.3 337.6 335.7 333.8 334.1 335.3 336.8 336.8 

1980 337.8 338.3 340.1 340.9 341.5 341. 3 339.4 337.7 336.1 336. 1 337.2 338.4 338.7 

1981 339.3 340.4 341. 7 342.5 343.0 342.5 340.9 338.8 337.1 337.1 338.5 339.9 340.l 

1982 340.9 341. 7 342.7 343.7 344.3 343.4 342.0 340.0 337.8 338.0 339.2 340.6 341.2 

1983 341.4 342.7 343.1 345.4 346.1 345.6 344.2 342.4 340.1 340.1 341. 4 343 . l 343.0 

SMO 

-1976 330.7* 330.6* 330.8 331.2 330.7 331.2 331.1 331.1 331.3 331.5 331. 9 331. 8 331. 2 

1977 331.7 332.0 332.0 332.4 332.3 332.6 332.6 333.1 332.9 332. 9'" 333. l;, 333. 7;; 332.6 

1978 

1979 334.6* 335.4* 335.9* 335.7 335.9 336.0 336.3 336.3 336.3 336.6 336 . 7 336.8 336.1 

1980 337.5 337.6 337.9 337.3 337.8 338.0 338.4 338.3 338.2 338.1 338 .5 338.9 338.0 

1981 339.0 339.3 338.8 339.6 338.8 339.3 339 . 0 339.1 339.2 339.0 339 .5 339.8 339.2 

1992 340.4 340.5 340.4 339.8 339.9 340.1 340.5 340.4 340.1 340.0 340.2 340.2 340.2 

1983 340.0 340.5 340.8 340.6 341. 1 341.6 341. 9 341. 9 341.9 342.1 342.4 342.6 341.4 

SPO 

- 1975 329.1 328.8 328.5 328.3 328.6 328.6 329 . 4 329.8 330.1 330.3 330.2 330.3 329.3 

1976 330.1 329.8 329.6 329.6 329.7 329.9 330 . 3 330.7 331.0 331.1 331.1 331.1 330.3 

1977 330.9 330.3 330.3 330.6 331 . 0 331.4 331. 8 332.2 332.7 333.0 333.0 332.7 331. 7 

1978 332.6 332.4 332.3 332.5 333.0 333.3 333 . 8 334.4 334.9 335.0 334.9 334.7'" 333.7 

1979 

1980 336.1 336.0 336.0 336.2 336.6 336.9 337.4 337.7 337.9 338.1 338.0 338.0 337.1 

1981 337.8 337.8 337.9 337.9 338.1 338.3 338 . 7 339.0 339.2 339.1 338.9 338.5 338.4 

1982 338.5 338.6* 338.4 338.6 338.9 338.9 339.2 339.6 339.9 339.8 339.5 339.2 339.1 

1983 339.7 339.5 339.5 340.0 340 . 41. 340. 5 341.0 341.6 341. 7 341.8 341. 8 341. 7 340.8 

*Substituted flask data. 

The in-house calibration of working gases for the observatories and the 

flask sample analysis program continued in 1983. One hundred sixty-eight tank 

calibrations were performed. All calibrations are traceable to GMCC secondary 

standards calibrated manometrically by C.D. Keeling at SIO. These standards 

were calibrated in 1982 and are due for calibration again in late 1984. 

An experiment with new technology began in 1983 with the acquisition of 

two gas chromatographs custom built by R. Weiss of SIO (Weiss, 1981). These 

instruments are designed for measuring C0 2 with a precision comparable with 

23 
the NDIR analyzers (~0.1%). After initial testing in Boulder, a GC will be 

installed at MLO in 1984 to begin a program of C0 2 monitoring for comparison 

with the NDIR system. A primary advantage of the gas chromatographs is the 

decrease in the rate of reference gas usage; a single tank will last a year or 

more compared with 3-4 months with an NDIR. In addition, the gas chromatograph 

is capable of measuring CH4 , a trace gas with possible climatic significance. 

3.1.2 Flask Sample C0 2 Measurements 

The C0 2 flask sampling network (see fig. 6) consists of 22 globally distributed sites, at which whole air samples are collected in 500 cm3 glass 

flasks once or twice per week for subsequent analysis in Boulder. The first 

year of sampling for three new stations (HBA, NZL, and KPA; see table 7) was 

completed in 1983. Although sampling at HBA began in December 1982, the flasks 

will not arrive in Boulder for analysis until the summer of 1984 because of 

the inaccessibility and complicated logistics associated with Antarctic research programs. Indications are that the NZL site, intended as a replacement 

for the Falkland Islands site, which has been inoperative since the war of 

February 1982, is not ideally suited for measurement of background C0 2 . This 

is due to its location downwind of Christchurch and its proximity to vegetated 

and agricultural areas. Current plans are to begin flask sampling at Cape 

Grim, Tasmania, in 1984 to sample background air at midlatitudes of the Southern Hemisphere. This cooperative project with CSIRO will also provide a basis 

for intercomparisons between GMCC and another of the major C0 2 monitoring 

laboratories. The stations collecting samples in 1983 are listed in table 7. 

A WMO report giving detailed descriptions of the sampling sites is currently 

in preparation. 

In 1983 some 5600 flasks were analyzed, of which ~3500 were from the 

flask network. The remainder were special project samples (e.g., cruises, 

aircraft experiments) and test flasks run to monitor analyzer performance. 

All flasks were analyzed on the semiautomatic flask analysis system in Boulder 

(Komhyr et al., 1983b). The only modification to the system was a new gas 

transfer pump that was installed in August 1983. This modification may reduce 

or eliminate a flask analyzer bias correction that has been applied to the 

60' s 

tl(J· }. ~~~~ --t~~ __, ~~~.__-+--..____. 

~ w •1 \tll'• O>•* w'• »'• -n•c v:,•l .... , 

Figure 6.--Map showing the locations 

of the sampling sites in the GMCC 

C02 flask sampling network during 

1983. 

24 
Table 7.--GMCC C0 2 flask network sampling sites during 1983 

Code Station Latitude Longitude Elevation 

(deg) (deg) (m) 

AMS Amsterdam I. 37.95S 77. 53E 150 

ACS Ascension I. 7. 92S 14.42W 54 

AVI St. Croix, VI 17. 75N 64. 75W 3 

AZR Terceira I. , Azores 38.75N 27.08W 30 

BRW Barrow, AK 71. 32N 156.60W 11 

CBA Cold Bay, AK 55.20N 162.72W 25 

CMO Cape Meares, OR 45.00N 124.00W 30 

cos Cosmos, Peru 12. 12S 75.33W 4600 

GMI Guam, Mariana Is. 13. 43N 144. 78E 2 

HBA Halley Bay, Ant. 75.00S 27.00W 0 

KEY Key Biscayne, FL 25. 67N 80.17W 3 

KPA Kitt Peak, AZ 32.00N 112. oow 2095 

KUM Cape Kumukahi, HI 19.52N 154.82W 3 

MBC Mould Bay, Canada 76.23N 119. 33W 15 

MLO Mauna Loa, HI 19.53N 155.58W 3397 

NWR Niwot Ridge, co 40.05N 105. 63W 3749 

NZL New Zealand 43.83S 172. 63E 3 

PSA Palmer Station, Ant. 64.92S 64.00W 10 

SEY Mahe I., Seychelles 4.67S 55.17E 3 

SMO Cape Matatula, Am. Samoa 14.25S 170.57W 30 

SPO South Pole, Ant. 89.98S 24.80W 2810 

STM Station M 66.00N 2.00E 0 

1980-1982 flask data. The bias was believed to be caused by a slight 

(~0.25 ppm) absorption of C0 2 in the original transfer pump (Komhyr et al., 

1984a). Another change in methodology was an improved testing procedure 

whereby each flask was checked for leaks between analysis and return to the 

field. This procedure appears to be effective in reducing the number of 

samples contaminated by stopcock failure. Also in 1983 tests were begun on 

3-L 0-ring stopcock flasks as a possible replacement for the greased, groundglass-type stopcock. 

The flask analysis procedure was further modified in April 1983 with the 

inception of a GMCC-CSIRO-OGC cooperative program to measure by gas chromatography the CH4 in flasks from the GMCC C0 2 network. Initial tests demonstrated 

the feasibility of using the overpressure in P3 -collected samples to inject 

two sample aliquots into the GC without contaminating the remaining sample 

prior to NDIR analysis. The standard procedure now is to analyze one member 

of each flask pair for CH4 , then recombine the pair for NDIR C0 2 analysis. A 

global atmospheric CH4 distribution analogous to that now available for C0 2 

should prove quite valuable in understanding the global carbon cycle. The CH4 

program is discussed in sec. 5.15. 

The complete flask C0 2 data set for 1968-1982 has been processed into 

final concentrations this year, and the data have been archived with WMO, 

25 
WDC-A, and DOE/CDIC. Processing to final concentrations included (1) analyzing for systematic errors and, when the errors could be quantified (e.g., 

pressure broadening effect, nonlinearity), making appropriate corrections; 

(2) determining drift-corrected, X81 mole fraction scale C0 2 concentrations 

for all tanks used for flask analysis and recalculating each sample concentration using the final tank values; (3) deleting samples that were defective 

because of sampling error or instrument malfunction during analysis. The 

final data set was then examined and a subset of the data considered representative of background air was selected. Details of the data processing and 

selection, and an analysis of the final 1968-1982 C0 2 flask data set are given 

by Komhyr et al. (1984a). 

In table 8 the annual mean C0 2 concentrations for the flask sites are 

given, including preliminary values for 1983. A convenient way to display the 

global distribution of atmospheric C02 concentration as determined by the GMCC 

flask network is the zonally averaged C0 2 -latitude-DOY surface shown in 

fig. 7. The smoothness of the surface is obtained by first selecting a background subset that includes ~85% of the total data set. Cubic spline functions 

are then fit to the data, and the spline functions become the input for generating the surface. Since the intent is to create a smooth surface, continental 

and high-altitude sites (except SPO) and sites indicating strong longitudinal 

gradients have not been included. Despite all the smoothing, the surface and 

companion two-dimensional contour plot (fig. 8) are a powerful way to convey 

the main features of the seasonality and latitude dependence of atmospheric 

C0 2 on a global scale. Flask sampling programs carried out on ships in remote 

regions have generally supported both the accuracy of the surface and the 

representativeness of the flask network sites (Harris and Bodhaine, 1983, 

pp. 99-102; this report, sec. 4.11). 

One objective of the C0 2 monitoring program is to document the increase 

in atmospheric C0 2 due primarily to the burning of fossil fuels. A detailed 

discussion of the variation of the rate of increase over space and time based 

on the 1968-1982 flask network data is given by Komhyr et al. (1984a). With 

Table 8.--Annual mean atmospheric C0 2 concentrations (ppm relative to 

dry air--X81 mole fraction scale) for the flask network sites 

Station 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 

AMS 0 0 0 0 0 0 0 0 0 0 0 (335.9) 337 . 8 339 . 3 339 , i. [340 .9 ] 

ASC 0 0 0 0 0 0 0 0 0 0 0 [337.3] 338 . 8 339 . 7 340 . 7 342 .6 

AVI 0 0 0 0 0 0 0 0 0 0 0 337.1 339 . 6 340. 4 340 . 9 342 . 0 

AZR 0 0 0 0 0 0 0 0 0 0 0 0 338.4 339. 6 341. 2 343 . 0 

BRW 0 0 0 327 . 4 330 . 2 332.0 333 . 4 333 . 0 333.9 335 . 0 336 . 6 337.7 340 . 2 341. 5 342 .7 344 . 0 

CBA 0 0 0 0 0 0 0 0 0 0 0 337.8 339 . 8 341. 3 341. 9 343 .4 

CHO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 341 .2 342 . 9 

FLK 0 0 0 0 0 0 0 0 0 0 0 0 0 339 .7 0 0 

GMI 0 0 0 0 0 0 0 0 0 0 0 337.7 340 . 0 341. 2 341 .0 342 . 7 

KEY 0 0 0 0 0 330.7 [333 . 4] 0 332.7 335 . 2 336 . 7 338.8 (340 . 2) 342 .0 341. 6 343 . 4 

KUM 0 0 0 0 0 0 0 0 332.3 334 . 4 335 . 7 337.4 339 . 3 340 .4 341. z 342 . 5 

~!BC 0 0 0 0 0 0 0 0 0 0 0 0 340 . 3 341. 9 342 .5 343 . 7 

HKO 0 0 0 0 0 0 0 0 0 0 0 337.3 0 0 0 0 

HLO 0 [322.8] 325.2 0 0 0 0 0 332.1 333 .6 335 . 2 336.7 338 . 9 340 .4 341. 0 342.5 

NWR 323 . l 324.1 325.6 325 .2 326.3 330.2 [334 . o I 0 332.1 334 . 8 335 . 7 337.0 338 . 1 339 .9 340 .9 342 . 4 

PSA 0 0 0 0 0 0 0 0 0 0 333 . 9 335.2 (337 . 5) 340 .0 339 . 8 341 .0 

SEY 0 0 0 0 0 0 0 0 0 0 0 0 339 . 3 340 . I 340. 5 340 . 8 

SHO 0 0 0 0 0 [330.2] 330 .8 330 .) 331.5 332 .8 334 . 3 336.0 338 . 1 339. 3 340.4 341.4 

SPO 0 0 0 0 0 0 0 329 .4 330.2 331. 5 333 . 7 335.5 336 . 7 338. 5 339 .3 340 . 8 

STC 0 324.0 326.4 326. 9 327.6 0 0 0 0 0 0 0 0 0 0 0 

STH 0 0 0 0 0 0 0 0 0 0 0 0 0 341. 9 341. 7 342 . 7 

Note: () = number of interpolated points ~one-half of total number of points; [ ] = incomplete year. 

26 
o .. no 

LJ 

Figure 7.--A three-dimensional representation of the variation in space 

and time of atmospheric C0 2 at the surface, synthesized from the flask 

network measurements for 1980-1983. The resolution of the zonally averaged surface is 20 days and 10° latitude. The Northern Hemisphere is 

dominated by the seasonal biospheric cycle. 

the addition of the 1983 flask and continuous analyzer data to the record, an 

interesting anomaly in the growth rate trend has emerged. From 1976 to 1981 

both the flask and continuous analyzer records show a mean growth rate of 

1.6 ppm yr- 1 . From 1981 to 1982 the growth rate drops to 1.0 ppm yr- 1 for the 

continuous analyzer data and 0.6 ppm yr- 1 for the flask data. This drop is 

followed by a return to a higher value for 1982-1983 of 1.4 ppm yr- 1 for both 

the flask and continuous data. Since this sharp decrease in the C0 2 growth 

rate is not paralleled by a similar decrease in fossil fuel production (Rotty 

and Marland, 1984), it is probably indicative of a major perturbation of the 

natural global carbon cycle. For a discussion of the possible connection of 

this growth rate anomaly with the intense ENSO event of 1982-1983, see 

sec. 4.13. 

From tables 6 and 8 it is possible to compare the continuous analyzer and 

flask annual means at the four GMCC baseline observatories. For 1976-1983 the 

mean differences are 0.1 ± 0.2, -0.1 ± 0.2, 0.1 ± 0.2, and 0.0 ± 0.2 ppm for 

BRW, MLO, SMO, and SPO respectively. This agreement is quite good considering 

the differences in sampling methodology and analysis and the differences in 

selection procedures applied to each data set. 

Y(AR 

Figure 8.--The surface of fig. 7, 

shown as contours in the latitudetime plane. Note the slight increase from 1981 to 1982 compared 

with that from 1980 to 1981. 

27 
The quality of the C02 flask data is further monitored through an ongoing 

exchange of data for flasks collected quasi-similtaneously by GMCC and SID at 

BRW, KUM, MLO, and SMO (Bodhaine and Harris, 1982, p. 27; Harris and Bodhaine, 

1983, p. 31). Figure 9 presents the comparison data through the end of 1983. 

In general, the agreement is good; the mean difference for 506 samples is 

0.0 ± 0.5 ppm. SMO shows the most scatter, which may be related to the high 

moisture content of the samples collected there. It can be concluded that if 

any systematic difference exists between the GMCC and SID flask programs, it 

is not larger than 0.2-0.3 ppm. 

2 

0 ~o.,-e_....,,, r""" v e -l BR'1 

:i: -2 

t' ...... :U~i·t, -~~ 

.. .. 

0 

-1 

-2 

0 

1----:;J .. Ul!I' 4.~~d--'>Jh.~ e Q:>"ll'.n'::.'· . · .r -~'lo . e 'ftj~ ~W · o o"' e - % o SMO 

JF'HAHJ'JASONDJrHAHJJASOHlllF'HAHJJA&OND 

198 I 1982 1983 

Figure 9.--Differences between the 

atmospheric C0 2 concentrations in 

quasi- simultaneously collected 

flask samples as measured by NOAA/ 

GMCC (0.5-L flasks) and SIO (5.0-L 

flasks). 

3.2 Total Ozone 

3.2.1 Routine Observing Program 

Routine total ozone observations were continued in 1983 at three GMCC 

stations, one foreign cooperative station, two domestic cooperative stations, 

three NWS stations, and GMCC headquarters, Boulder. On 22 June 1983 a fourth 

NWS station was put into operation at Fresno, CA. 

Table 9 lists the 11 stations of the U.S. Dobson ozone spectrophotometer 

network, the periods of record when observations were made, the instrument 

numbers, and the agencies responsible for taking the observations. 

In November 1983 an automated Dobson instrument was installed at Poker 

Flat, AK. Because of the low elevation angle of the Sun, no observations were 

made during the rest of the year. Plans are to begin the automatic Umkehr 

observations and total ozone observations at this station in early February 

1984. 

The standard lamp technique of checking Dobson spectrophotometers for 

gross calibration errors is based on experimental observations that instruments 

accurately calibrated on relative and absolute scales yield standard lamp 

readings: 

N =log (I/I')+ K 

28 
Table 9.--u.s. Dobson ozone spectrophotometer station network, 1983 

Station Period of record Inst. no. Agency 

Bismarck, ND 01 Jan 1963-present 33 NOAA 

Caribou, ME 01 Jan 1963-present 34 NOAA 

Wallops I., VA 01 Jul 1967-present 38 NOAA; NASA 

SMO 19 Dec 1975-present 42 NOAA 

Tallahassee, FL 02 Jun 1973-present 58 NOAA; Fla. State Univ. 

Boulder, co 01 Sep 1966-present 61 NOAA 

MLO 02 Jan 1964-present 65 NOAA 

Nashville, TN 01 Jan 1963-present 79 NOAA 

SPO 17 Nov 1961-present 80 NOAA 

Huancayo, Peru 14 Feb 1964-present 91 NOAA; Huancayo Obs. 

Fresno, CA 22 Jun 1983-present 94 NOAA 

at the A, B, C, and D Dobson instrument wavelength pairs that are essentially 

constant provided, also, that the internal light-scattering characteristics of 

the instruments are similar. (In the above equation, I/I' is the lamp light 

intensity ratio for, say, the A wavelength pair, and K is an associated instrumental constant.) Mean absolute calibration error for such instruments, calibrated with standard lamps, is estimated to be ±1.5% at the 95% confidence 

interval. This error is about twice as large as that which occurs when spectrophotometers are calibrated by direct comparison of instruments. Thus, use 

of standard lamps for calibrating spectrophotometers on an absolute scale is 

not generally recommended. 

Accurate relative calibration of Dobson spectrophotometers implies accurate optical wedge and wavelength-setting calibrations for the instruments. 

An instrument with an improperly calibrated optical wedge will, for example, 

yield wrong N values in most instances for a standard lamp whose N values have 

been correctly determined. Because only a limited portion of the optical 

wedge is used when a standard lamp test is performed, the calibration error 

determined from correct and observed N-value differences is not, in general, 

representative of the instrument as a whole. Thus, it is important that spectrophotometer calibration errors determined from tests with standard lamps not 

be used for correcting ozone data obtained in the past with the improperly 

calibrated instruments. At most, the lamp tests indicate that an instrument 

calibration problem exists, and that remedial action is required. 

3.2.2 Calibration Checks on Dobson Instruments in the Global Network 

Calibrated standard. lamps were sent to 87 Dobson spectrophotometer observatories during 1981-1983 to check on the calibration level of Dobson instruments in the global total ozone station network (Grass and Komhyr, 1984). 

Data received from 77 stations (table 10) indicated that 21 instruments 

required recalibration. As a result of this effort, arrangements are under 

way to conduct international comparisons of Dobson instruments in Melbourne, 

Australia, in 1984. Participating countries will be Australia, India, and 

Japan. 

29 
Table 10.--Results of calibration checks on Dobson spectrophotometers 

using traveling standard lamps 

Station 

Region 1--North America 

Toronto, Canada 

Resolute, Canada 

Churchill, Canada 

Goose Bay, Canada 

Edmonton, Canada 

Reykjav{k, Iceland 

SPO 

Bismark, ND 

Caribou, ME 

Wallops I., VA 

Tallahassee, FL 

Nashville, TN 

MLO 

SMO 

BRW 

Boulder, CO 

Boulder, CO 

Region 2--South America 

Mexico City, Mexico 

Huancayo, Peru 

Cachoeira Paulista, Brazil 

Natal, Brazil 

Buenos Aires, Argentina 

Buenos Aires, Argentina 

Region 3--Western Europe (1) 

Bracknell, U.K. 

Bracknell, U.K. 

Halley Bay, U.K. 

Argentine Is., U.K. 

Seychelles, Seychelles 

St. Helena I., U.K. 

King Edward VII Point, U.K. 

Lerwick, U.K. 

Arosa, Switzerland 

Arosa, Switzerland 

Hohenpeissenberg, F.R.G. 

Cologne, F.R.G. 

Oslo, Norway 

Oslo, Norway 

Trams¢, Norway 

Region 4--Western Europe (2) 

Aarhus, Denmark 

Uccle, Belgium 

Biscarrosse, France 

Magny-Les-Hameaux, France 

Lisbon, Portugal 

El Arenosillo, Spain 

Vigna Di Valle, Italy 

Inst. 

no. 

77 

59 

60 

62 

102 

50 

80 

33 

34 

38 

58 

79 

63 

42 

76 

61 

82 

98 

87 

114 

93 

97 

99 

41 

2 

31 

73 

57 

35 

103 

32 

15 

101 

104 

44 

8 

56 

14 

92 

40 

11 

85 

13 

120 

47 

30 

Date of 

ca lib. check 

811015 

811211 

820101 

810511 

811130 

820323 

820125 

820715 

820602 

820617 

821001 

820927 

820602 

820828 

820429 

820602 

820709 

811030 

820418 

821021 

820909 

830120 

830314 

820622 

820622 

820707 

821108 

821108 

821130 

830408 

830411 

830408 

810610 

811027 

82----

820502 

820422 

82----

821213 

Instr. calib. 

error (%)•'• 

-0.15 

-0.74 

+l. 62 

+0.00 

+0.08 

+0.44 

+I. 32 

+0.88 

-1.25 

-0.96 

+0.88 

+l. 18 

-1. 25 

+0.81 

+l. 62 

-0.37 

+0.30 

+I. 32 

-4.84 

-3.67 

+O. 73 

-0.15 

-0.07 

-0.15 

+0.59 

+2. 13 

-0.88 

-0.08 

-6. 10 

-0. 96 

-0.29 

-1.17 

+O. 74 

+I. 25 

-2.42 

+ l. 98 

-0.07 

+0.66 

+0.44 
Table 10.--Results of calibration checks on Dobson spectrophotometers 

using traveling standard lamps--Continued 

Sta ti on 

Inst. 

no. 

Region 4--Western Europe (2)--Cont. 

Brindisi, Italy 

Sestola, Italy 

Cagliari/Elmas, Italy 

Casablanca, Morocco 

Cairo, Egypt 

Cairo, Egypt 

46 

48 

113 

106 

69 

96 

Region 5--Eastern Europe, U.S.S.R. 

Leningrad, U.S.S.R 

Belsk, Poland 

Hradec Kralove, Czechoslovakia 

Budapest-Lorine, Hungary 

Bucharest, Romania 

Potsdam, G.D.R. 

Potsdam, G.D.R. 

Region 6--India 

New Delhi, India 

New Delhi, India 

Srinagar, India 

Varanasi, India 

Mt. Abu, India 

Poona, India 

Kodaikanal, India 

Quetta, Pakistan 

Quetta, Pakistan 

Bangkok, Thailand 

Singapore (U.K.) 

Manila, Philippines 

Region 7--Australia, Japan 

Sapporo, Japan 

Sapporo, Japan 

Kagoshima, Japan 

Tateno, Japan 

Tateno, Japan 

Tateno, Japan 

Naha/Kagamizu, Japan 

Shiangher, China 

K'un-ming, China 

Aspendale, Australia 

Aspendale, Australia 

Perth, Australia 

Cairns, Australia 

Brisbane, Australia 

Hobart, Australia 

McQuarie Island, Australia 

InvercargiJl, New Zealand 

108 

84 

74 

no 

121 

71 

64 

36 

112 

10 

55 

54 

39 

45 

43 

100 

90 

7 

52 

5702 

5703 

5704 

116 

122 

5706 

5705 

75 

3 

105 

115 

111 

81 

6 

12 

78 

17 

Date of 

calib. check 

821227 

830110 

821221 

830602 

840309 

840310 

811022 

820107 

820204 

820103 

820420 

8205--

8205--

82----

82----

82----

82----

82----

82----

82----

830408 

830610 

831101 

820105 

820106 

811210 

811120 

811120 

811124 

81]221 

820330 

820413 

820906 

820618 

820817 

820713 

820715 

820705 

821028 

830303 

Instr. calib. 

error (%);'; 

+3.30 

-0.08 

-1. 25 

-1. 47 

+0.52 

+0.29 

+1. 32 

-3.30 

-3.52 

+3.30 

+0.59 

-0.44 

-0.44 

-1. 47 

+1. 76 

-1. 62 

+2.27 

+0.44 

+2.57 

+1. 91 

+10.79 

-1. 25 

-0.44 

-0.44 

+4.55 

+3.08 

+3.37 

+1.32 

-3.52 

+O. 15 

-2.05 

+0.59 

+0.15 

-8.95 

+6.60 

-4. 11 

-8 .80 

-0.29 

+O. 15 

*See text for significance of calibration errors. Positive error means 

that instrument yields ozone values that are too large. 

31 
3.2.3 Modernization and Calibration of Dobson Spectrophotometers 

During 1983, GMCC personnel continued to participate in the WMO Global 

Ozone Research and Monitoring Project to upgrade the quality of Dobson ozone 

spectrophotometers throughout the world. Table 11 lists the instruments that 

were reconditioned and calibrated. 

All instruments in table 11, except the one in Bangkok, Thailand, have 

been automated for Umkehr observations and semiautomated for total ozone 

observations. A Dobson instrument is now in operation at Haute Provence Observatory in France. Instrument 63 has been installed at Poker Flat, AK. 

Instruments 76, 87, 81, and 72 will be installed in 1984 at MLO, HI; Huancayo, Peru; Perth, Australia; and Pretoria, South Africa; respectively. 

Table 11.--Dobson instruments modernized and calibrated during 1983 

Station Instrument number 

Bangkok, Thailand 90 

Haute Provence, France 85 

MLO 63 

Hauncayo, Peru 87 

Boulder, co 76 

Boulder, co 72 

3.2.4 Data 

Daily 1983 total ozone amounts (applicable to local apparent noon at each 

station) for all stations in the U.S. network have been submitted for publication by the World Ozone Data Centre, Atmospheric Environment Service, 

4905 Dufferin Street, Downsview, Ontario M3HST4, Canada, in Ozone Data for the 

World. Table 12 lists provisional monthly mean 1983 total ozone amounts for 

the NOAA observatories and cooperative stations. 

3.2.5 Data Analysis 

Total ozone values at MLO during late 1982 and early 1983 were unusually 

low compared with most previous years, and the possibility was considered that 

partial destruction of ozone may have occurred by stratospheric aerosols from 

the eruption of El Chichon volcano in late March-early April 1982 (Komhyr et 

al., 1984c). Although a small amount of ozone depletion by the aerosols 

cannot be ruled out, the major effect appears to be a temporary natural ozone 

decrease associated with the stratospheric quasi-biennial oscillation 

phenomenon. Figure 10 is a plot of the 12-mo running means of total ozone 

32 
Table 12.--Provisional 1983 monthly mean total ozone amounts (milli-atm-cm) 

Station Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

Bismarck, ND 328 352 381 395 380 338 305 295 301 291 296 348 

Caribou, ME 341 367 384 385 380 355 346 332 304 302 310 341 

Wallops I., VA 325 327 353 370 349 340 326 314 303 300 284 292 

SMO 264 256 257 263 260 265 264 265 266 272 274 261 

Tallahassee, FL 284 291 306 318 323 328 303 294 279 282 

Boulder, CO 305 317 356 372 357 321 314 291 292 277 282 338 

MLO 225 236 249 276 277 283 271 268 266 261 255 257 

Nashville, TN 316 334 349 384 361 352 338 337 315 305 292 320 

Huancayo, Peru 256 258 254 253 251 251 259 261 265 265 260 260 

Fresno, CA 326 316 311 299 282 276 296 

SPO 309 312 311 

data for MLO since 1958. The 12-mo filter removes the annual cycle from the 

data and reveals the prominent quasi-biennial oscillation as well as longer 

period variations in ozone shown in the figure. Note that a minimum occurred 

in the quasi-biennial ozone oscillation in early 1983. Ozonesonde 

observations at Hilo, HI (sec. 3.3) in December 1982 and December 1983 showed 

the atmospheric region of reduced ozone to be above the ozone maximum. The 

lower ozone amounts probably resulted from stratospheric circulation changes 

and associated changes in ozone transport, of which the quasi-biennial 

oscillation in ozone is a manifestation. 

A longer period variation in ozone is clearly evident in fig. 10, and the 

decrease in ozone at MLO since 1970 is about 3% per decade. Whether this 

decrease in ozone is due to ozone depletion by chlorofluorocarbons, or the 

result of a long-term variation in the strength of the stratospheric circulation between equatorial and polar regions (associated, for example, with solar 

intensity variation) is unknown. 

se 60 62 61 66 68 10 12 H 76 78 ao 02 e1. Y~AR 

Figure 10.--The 12-mo running means 

of total ozone data for MLO. 

33 
3.3 Ozone Vertical Distribution 

3.3.1 Umkehr and Ozonesonde Observations at MLO Following the Eruption 

of El Chichon Volcano 

A classic set of Umkehr data obtained at MLO since 17 May 1982, following 

the eruption of El Chichon volcano in late March-early April 1982, has illustrated dramatically the adverse effects of stratospheric aerosols on Umkehr 

observations. To aid in interpretation and processing of the Umkehr data, and 

to obtain ozone profile data for comparison with satellite ozone measurements, 

a program of weekly balloon ozone soundings was begun in Hilo, HI, in September 

1982 and continued throughout 1983. 

The Umkehr observations were made with specially calibrated Dobson instrument 65. On the average, 10 observations were made per month during MayDecember 1982; 11 per month during 1983; and 7 per month during January-March 

1984. Measured apparent changes in ozone per year, in standard and short 

Umkehr layers 1-9, are plotted month by month in fig. 11. The ozone changes 

are expressed in percent relative to the ozone amounts present during the 

months indicated on the plots. (For example, the May 1982 ozone value minus 

the May 1983 value, expressed in percent, is plotted for May 1983.) This 

method of data presentation not only eliminates annual cycle ozone variations, 

but it focuses on errors in the ozone measurements due to aerosols, assuming 

that the aerosol error effect became markedly diminished 1 year after the 

eruption of El Chichon. Evidence for substantial clearing of the stratosphere 

from May 1982 to early 1983 is available from optical photometry at MLO, 

indicating that the stratospheric aerosol optical depth decreased during this 

time period from about 0.27 to 0.05 (DeLuisi et al., 1984). 

The plots of fig. 11 show that the stratospheric aerosols caused ozone 

amounts initially to be overestimated by the standard and short Umkehr methods 

in layers 1-3. Maximum overestimates in layer 2, for example, were 230% and 

166% for the standard and short Umkehr methods, respectively. Both methods 

~ 

~ -50 

·= "' 50 Cl 

r: 

Jg .. ·---.... (.) 

c 

!'! -50 

"' a. 

~ -100~~~~-+---'~ 

c 100 ,_,....,..............,.~~~ 

"' 

~ 50 or 

o~ 

-50 

JSNJM MJSNJM MJSNJM 

1983 1984 1983 1984 1983 1984 

34 

Figure 11--0zone changes per year at 

MLO in standard (~-) and short 

(---) Umkehr layers 1-9, plotted 

month by month, and expressed in 

percent relative to the ozone amount 

present during the month indicated. 

(For example, the May 1982 ozone 

value minus the May 1983 value, 

expressed in percent, is plotted in 

May 1983.) The dotted curves ( ... ) 

are similar data for total ozone. 
underestimate ozone amounts by up to 30%-40% in Umkehr layers S-8. In layer 

9, the standard method underestimates ozone amounts by 11S% in May 1982, 

causing fictitious negative ozone values to be recorded. By December 1982, 

however, the ozone underestimates in layers S-9 are reduced to between S% and 

1S%, and remain essentially unchanged through March 1983, suggesting that the 

results are not wholly fictitious, but reflect real differences in ozone, with 

the early 1983 values being lower than the early 1984 values. 

That a real change in ozone occurred at MLO is indicated by the total 

ozone difference plot of fig. 11. The plot shows that August 1982-March 1983 

total ozone values at MLO were lower than values during August 1983-March 1984. 

The February 1983 value, in particular, was lower than the February 1984 value 

by 1S%. 

Balloon ozone observations were made at Hilo with ECC sondes (Komhyr, 

1969). Monthly mean ozone partial pressures measured during September 1982-

December 1983 are listed in table 13. Because the sondes yield ozone amounts 

too low above 10 mb (Komhyr et al., 1984b), the measured values were increased 

by 2.S% at 10 mb, S.0% at 7 mb, and 8.0% at S mb, and are believed to be in 

error by not more than 10% at S mb. 

Mean ECC sonde and Umkehr ozone profiles are plotted in fig. 12. The 

plots for September 1982, when the stratospheric aerosol optical thickness was 

still relatively high (O.lS), clearly demonstrate the adverse effect of aerosols on the Umkehr measurements. Relative to the sonde data, Umkehr ozone 

amounts are particularly low in layers S and 6, but much too high in layers 2 

and 3. The ozone maximum is erroneously indicated by the short Umkehr method 

to be in layer 4 instead of layer S. By December 1982, however, when the 

Table 13.--Monthly mean ozone partial pressures at select atmospheric 

pressure levels derived from ECC ozonesonde soundings at Hilo, HI 

Mo- No. 1013 700 soo 300 200 lSO 100 70 so 30 20 10 7 s 

Year fl ts. mb mb mb mb mb mb mb mb mb mb mb mb mb mb 

09-82 3 11 26 16 12 s 6 18 46 7S 116 137 94 SS 29 

10-82 1 19 29 29 13 13 14 30 74 90 137 147 72 30 

11-82 

12-82 3 6 29 27 12 6 6 13 42 80 123 134 77 48 30 

01-83 3 20 30 20 11 8 6 6 23 74 113 12S 7S S6 3S 

02-83 4 5 3S 28 13 8 4 9 26 53 132 122 84 S5 3S 

03-83 4 28 36 27 18 10 9 12 28 68 97 124 94 63 38 

04-83 2 36 33 34 lS 13 10 14 29 83 129 138 lOS 63 33 

OS-83 1 16 40 34 24 22 17 S2 39 60 112 142 94 S4 30 

06-83 2 29 46 31 lS 18 27 28 47 81 131 142 88 57 36 

07-83 2 8 33 14 7 5 11 18 46 88 122 144 96 63 36 

08-83 2 11 27 20 12 7 8 29 Sl 8S 118 141 91 62 41 

09-83 3 7 23 15 9 10 13 21 45 78 131 142 92 60 40 

10-83 1 17 28 21 8 7 4 20 48 80 127 141 86 S8 32 

11-83 3 10 23 17 11 9 7 9 3S 72 118 134 95 S9 36 

12-83 2 13 24 33 13 10 10 9 3S 86 112 134 9S S8 38 

3S 
.0 

E 

c 

~ 

::> 

(/) 

(/) 

~ 

a. 

.0 

E 

c 

~ ::> 

(/) 

"' ~ 

a. 

10 :_ 

100 

HILO/MLO 

DEC 1982 

ECC SONDE &-------0 (3) 

STD. UMKEHR--(14) 

SHORT UMKEHR-----(14) 

40 

- 30 

20 

HILOIMLO - 11 10 JAN·FEB·MAR 1983 

ECC SON DE o---o (11) 

STD. UMKEHR--(46) 

SHORT UMKEHR-----(46) 

1000 0 

0 50 100 150 200 250 0 50 100 150 200 25d 0 50 100 150 200 250 

10 -

HILOIMLO 

APR·MAY·JUN 1983 

HILOIMLO 

JUL·AUG·SEP 1983 OCT·NOV·DEC 1983 

ECG SONDE <>----<> (6) 

STD. UMKEHR--(30) 

40 

30 

20 

ECG SON DE o-----<> (5) 

STD. UMKEHR--(29) 

SHORT UMKEHR ·--_:l29J 

ECG SONOE _______... (7) 

STD UMKEHR--(27) 

SHORT UMKEHR---(27) 

HILO/MLO - ~- 10 

: I SHORT UMKEHR-----(30) 

50 100 150 200 250 0 50 100 150 200 250 0 

Ozone Partial Pressure in μmb 

t

1 1 I 1 

50 

'" 11 11 0 

100 150 200 250 

E 

.""-

c 

Q) 

"'Cl 

. .E 

<( 

E 

.""-

c 

Q) 

"'Cl 

.3 

:;:; 

<( 

Figure 12.--Monthly mean ozone profiles for September and December 1982, 

and seasonal profiles for 1983, all derived from Umkehr and ozonesonde 

observations in Hawaii. Monthly mean values for September and December 

1983 are shown by crosses (+). Numbers in parentheses denote the number 

of observations per month. 

stratosphere had substantially cleared (aerosol optical thickness -0.06), 

representation of the correct mean ozone profile by the Umkehr observations is 

considerably improved, the main discrepancy being ozone values still too high 

in Umkehr layers 2 and 3. In 1983, the mean seasonal Umkehr data agree well 

with corresponding ECC sonde data, except for short Umkehr ozone values in 

layer 4 that are too high. This and other differences among the 1983 Umkehr 

and sonde ozone profiles are not necessarily due to aerosols, but may stem 

from deficiencies in the algorithms used in processing the Umkehr data. From 

36 
comparison of the Umkehr and sonde data, it is estimated that the aerosoleffect errors in the 1983 Umkehr ozone profiles probably do not exceed ±10% . 

3.3.2 Umkehr Observations with Automated Dobson Spectrophotometers 

Considerable concern has been expressed in recent years about possible 

partial destruction of atmospheric ozone by anthropogenic pollutants. The 

region near 40-km altitude has been shown to be particularly vulnerable to 

ozone depletion by chlorofluorocarbons (NRC, 1984). A potentially favorable 

method of monitoring long-term changes in ozone near 40 km is by means of 

Dobson ozone spectrophotometer Umkehr observations (Reinsel et al., 1984). 

Manual Umkehr observations are difficult and tedious to make. With automation of Dobson spectrophotometer no. 61 in 1981 at GMCC, Boulder, CO, new 

impetus was given to the possibility of using Umkehr observations for monitoring long-term changes in ozone. The automated observations are not subject to 

operator bias; an increased frequency of observations is likely; and a potential exists for obtaining high-quality data over extended time periods if all 

instruments in a network are subjected to uniform calibration procedures. 

Funding was obtained in 1982 from EPA, CMA, WMO (Voluntary Cooperation 

Program), and NOAA for automating six additional Dobson instruments and establishing them in a global station network for long-term stratospheric ozone 

observations, and for providing comparison data for satellite ozone measurements. The seven automated Dobson instrument .Umkehr observatory sites are 

Boulder, CO (40°N, 105°W); Haute Provence Observatory, France (44°N, 6°E); 

Huancayo Observatory, Peru (12°S, 76°W); MLO (20°N, 156°E); Perth, Australia 

(32°S, 116°E); Poker Flat, AK (65°N, 148°W); and Pretoria, South Africa (26°S, 

28°E). The sites were selected for wide latitudinal coverage, favorable observing conditions, logistics ease, and station proximity to an existing or 

future lidar aerosol observing facility. Stations implemented in 1983 were 

Haute Provence and Poker Flat. Observations at Haute Provence began in 

September. The installation at Poker Flat was made in October when the Sun 

was too low in the sky for observations to be made, but observations will 

begin in February 1984. Establishment of the remaining stations is expected 

to be completed in 1984. 

In automating the Dobson instruments the principle and method of measurement are left unchanged, except that a computer rather than a human observer 

controls instrument functions. Modification of the Dobson instrument entails 

several alterations. To attain long-term optical wedge stability, the glue 

normally used to bind the wedge sections together is removed. Metal tracks of 

the optical wedge are replaced with tracks made of Rulon plastic bearing material to prevent possible binding of the wedges during operation. A stepper 

motor is added to the wedge mechanism for control. For smooth operation, 

Rulon bearings are also built into the instrument Q (wavelength-setting) lever 

mechanisms, to which stepper motors are also added. Temperature is monitored 

with transducers built into the instrument. The normally used photomultiplier 

high-voltage power supply is replaced with a programmable high-voltage supply. 

Finally, a signal-processing card is added to the output of the Dobson instrument for interfacing with the computer instrumentation. 

A block diagram of the automated instrument system is shown in fig. 13. 

A Hewlett-Packard 9915A computer controls the Dobson instr1ITTent functions via 

37 
SHELTER HATCH 

AND OUTDOOR 

PRECIPITATION 

DETECTOR 

I PEDESTAL I 

KEYBOARD 

CLOCK/ 

CALENDAR 

DOBSON 

INSTRUMENT 

Q1 Q2 cs ow 

HP2240A 

MEASUREMENT 

AND CONTROL 

PROCESSOR 

HPIB 

HP9915A 

COMPUTER 

MONITOR 

INDOOR BACKUP 

PRECIPITATION 

DETECTOR 

PRINTER 

I AC POWER AND UNINTERRUPTABLE POWER SUPPLY I Figure 13.--Schematic diagram of the 

automated Dobson instrument system. 

an HP2240A measurement and control processor and an electronics drawer. Each 

day at midnight, the computer calculates the times of Umkehr observations for 

that day and readies itself for the observations. At the appropriate time in 

the morning, the instrument shelter hatch opens, provided that precipitation 

is not occurring, and Umkehr observations commence. As observations progress, 

the instrument slowly rotates on its pedestal mount so that the axis of the 

instrument points at all times in the direction of the Sun to minimize variations in zenith skylight polarization effects. Observational data are recorded 

on cassette tape, plotted on a video monitor, and output by a printer. A 

calendar-clock times all operations. Commands and data are input into the 

computer with an external keyboard or a keyboard built into the 9915A computer. 

At prescribed times during the day, the Umkehr observations may be interrupted for total ozone observations. Total ozone measurements are made semiautomatically. The observer inputs data to the computer, specifying what type 

of observation to make and, for observations on direct sunlight, places a Sun 

director with ground-quartz plate over the instrument's light inlet window. 

After aligning the instrument and Sun director correctly with respect to the 

Sun, the observer presses a button switch. The observation is then made automatically. Observational data and computed total ozone values (for direct Sun 

observations) are recorded on the cassette tape and output by the printer. 

During total ozone or Umkehr observations the instrument continually monitors 

its own temperature and makes appropriate adjustments to its wavelength selector lever positions so that observations are always made on correct wavelengths. 

Up to 17 days of observations can be recorded on one cassette tape. Selected observational Umkehr data with applicable total ozone values are mailed 

to the World Ozone Data Center in Canada for reduction to Umkehr ozone profiles 

38 
by the standard (Mateer and Diitsch, 1964) and short (Mateer and DeLuisi, 1981) 

Umkehr data-processing techniques. 

3.3.3 High-Altitude Ozonesonde Tests 

Tests on ECC ozonesondes were continued during 1983 to assess their performance relative to other types of ozone-measuring instrumentation, in the 

troposphere and at altitudes between 30 and 40 km. In July 1983, NASAsponsored balloon flights were conducted at NSBF in Palestine, TX, with the 

following instruments and missions: (1) Multiple-instrument gondola--This 

gondola carried six in situ UV photometers from Harvard University, NOAA/AL, 

NASA/JSC, and NASA/GSFC. There were 2 UV remote sensors from NASA/GSFC, and 

12 ECC sondes from NOAA/GMCC, NASA/GSFC, the Canadian AES, and the F.R.G. 

Hohenpeissenberg Observatory. (2) The Universit y of Minnesota Gondola--This 

gondola carried the University of Minnesota ma~s spectrometer, a second 

NASA/JSC in situ photometer, a second remote sensor from NASA/GSFC, and a 

NOAA/GMCC ozonesonde. (3) Triplets--This series of 16 balloons each carried 

3 electrochemical sondes from F.R.G., Canada, NASA/GSFC, and NOAA/GMCC. 

During the balloon flights, total and Umkehr ozone profiles were taken by 

Dobson and Brewer spectrometers located at Palestine, TX. 

The multiple-instrument gondola experiment ~as only partially successful 

because of balloon failure at an altitude of 2) km. (The experiment was repeated in October 1983, but balloon failure occurred again at about the same 

altitude.) Results from the University of Minnesota gondola experiment are 

shown in fig. 14. The triplet soundings with ECC ozonesondes were highly successful, and a report comparing the performance of the various instruments is 

in preparation at NASA/GSFC. 

1 

..0 10 

E 

c 

(1) 

.... 

:::J 

C/) 

C/) 

(1) 

.... 

a.. 100 

1000 

PRESS. ECC-UV 

(mb) 03 

% DIFF. 

283.6 43.9 40 

205.9 19.6 

95.1 -0.7 

51 .7 0.6 

29.9 4.0 30 

21.9 5.5 

10.4 4.5 

7.3 2.7 

5.1 -2.5 

3.0 -12.4 20 

2.6 -5.9 

JULY 18, 1983 

PALESTINE, TEXAS 

ROBBINS 10 UV PHOTOMETER .......... 

KOMHYR 

ECG SONDE 

0 50 100 150 200 250 300 350 

Ozone Partial Pressure in μmb 

E 

.:::t:. 

c 

(1) 

-0 

:::J 

..... 

..... 

<t:: 

Figure 14.--Comparison of Komhyr's 

(GMCC) ECC ozonesonde and Robbins' 

(NASA/GSFC) UV photometer ozone 

vertical distribution data. 

39 
3.4 Surface Ozone 

3.4.1 Operations 

Measurement of ozone near the surface at the GMCC observatories continued 

throughout 1983. The Dasibi ozone monitors used at MLO and BRW were recalibrated early in 1984, and the data for these two stations reflect the application of this calibration information. In addition, our network standard 

Dasibi monitor was recalibrated against the NBS standard photometer in October 

1983. This was the first time our standard had been compared with the new NBS 

photometer; previous comparisons were made with a different NBS standard instrument. It appears that the two standards give very similar results, and no 

major change was noted in the relationship between our standard and the two 

NBS instruments. Results of the October 1983 comparison have been incorporated in the MLO and BRW data. Small adjustments for 1981 and 1982 also are 

incorporated in the data presented here. 

A comparison between the SMO instrument and our network standard was 

delayed until 1984 to correspond to planned facilities improvements. Data for 

1983 should, therefore, be considered preliminary. At SPO an apparent calibration shift at the end of 1982 has not been resolved, and further tests on the 

instrument are required before the 1983 data are made available. 

3.4.2 Data Analysis 

Surface ozone concentrations at MLO reached their highest values in 11 

years that measurements have been made there. This can be seen in fig. 15 

where the monthly mean values corresponding 1100-1800 GMT (2100-0400 LST) are 

plotted for 1973-1983. The hours 1100-1800 GMT correspond to the downslope 

flow at the observatory, which is most representative of free tropospheric 

air. It appears that the largest increases have taken place in the seasonal 

maximum, which occurs in the spring. Two of the last 3 years have shown maxima about 20% higher than the typical value. Adding the data from 1983 to the 

previous 10 years of data gives an overall linear trend of 1.6% yr- 1 for 1973-

1983. 

Figure 15.--Monthly mean surface 

ozone amounts at MLO, with a linear 

least-squares fit to the data. 

40 
The location of MLO above the tradewind inversion at an average pressure 

of 680 mb suggests that of all the GMCC observatories MLO should give surface 

ozone values that are the most representative of the free troposphere. During 

1983, ozone profile measurements using the ECC ozonesonde were made on approximately a weekly schedule from Hilo, HI. These soundings provide an opportunity 

to compare the surface ozone measurements at MLO with the complete tropospheric 

profile from the ozonesondes. Figure 16 shows profiles on 4 days in February 

and 4 in March with the surface value at MLO plotted at 680 mb on the profile. 

These flights were all made at about 1800 GMT, which is still during the downslope regime at the observatory. The dashes indicate a line of constant mixing 

ratio. The surface ozone measurements appear to represent well the ozone 

amount at the 680-mb level as given by the ozonesonde profile. Even on 

30 March 1983, where there appears to be a region of enhanced ozone at the 

observatory level compared with levels above and below, the surface ozone corresponds well to the profile. 

Several interesting features of these ozonesonde profiles relate to the 

source of ozone that is observed at MLO. On 2 and 16 February there are broad 

layers higher in the troposphere where the mixing ratio is much less than that 

at the observatory, indicating that on these days ozone is being advected horizontally at the observatory level. On 23 and 30 March, on the other hand, 

there are relatively narrow layers of enhanced ozone at the observatory level. 

Below that level, the ozone decreases sometimes quite markedly, so that near 

sea level the values are considerably reduced. This is in keeping with destruction of ozone in the layer below the tradewind inversion near the ground, 

and is the reason generally lower values are observed at MLO during the upslope 

regime. For 36 days in 1982 and 1983 when ozonesonde soundings were available, 

·;; PARTIAL PR[SSUR[ Ill NMIOBARS 

; sq_~-,--.-~r-~--..::" r-~-p ---,1 ~.,.-=::;==1 

a 

~ 100~'+--~~~--h~r-- -tr ~~ ~-t+-f ~--j 

50 PARTIAL PRESSURE IN NANOBARS 

OZONESONOE OATA FROM HILO, HAWAII 

I HAUNA LOA SURFACE OZONE 

41 

Figure 16.--0zone profiles from 

Hilo, HI, during February and March 

1983 compared with the surface ozone 

amount at the same time at MLO. A 

line of constant mixing ratio 

(dashed) is also shown. 
the average concentration at the observatory level from the soundings was 

31.3 nb, while the surface ozone concentration at the observatory was 29.8 nb 

with a standard deviation of the differences of 3.8 nb. Since the sounding 

location in Hilo is separated by approximately 55 km from the observatory, it 

is clear by looking at some of the smaller scale features of the profiles at 

the observatory that part of the variance is explained by the location 

differences. It can be concluded that indeed the surface measurements at the 

observatory are representative of free troposphere ozone values in this 

region. It also confirms that the ECC soundings give values in the troposphere that are on the same scale as the surface measurements that are trace-

;ihle to UV photometry . 

.! t 1s of some i_nt e r e st lo dete rmine the f r equency of ozone sound i ngs 

reql1ired to de t e rmine long-term ozone changes in the troposphere. The surface 

ozoue data for hours 1100-1800 GMT at MLO can be used to compute the trends 

bas ed on the full data s et and for monthly means based on a decreasing number 

of days. Table 14 gives the linear trend and standard errors of the monthly 

Table 14.--Linear least-squares trends of surface ozone monthly anomalies* 

Station Trend Std. error 

(% yr-1) (% yr-1) 

MLO (1973-1983) 

All days 1. 62 1.11 

15 days J.54 1. 09 

10 days 1. 59 ]. 15 

7 days 1. 55 1. 17 

6 days 1. 15 1. 29 

5 days 1. 74 1. 23 

4 days 2. 16 1. 22 

3 days 1. 46 1. 24 

BRW ( 1973-1983) 1.23 1. 04 

SMO (1976-1983) -1. 07 1. 59 

*At MLO the trends are computed using varying numbers of days to compute 

the monthly mean. Daily averages at MLO are based on hours 1100-1800 GMT . 

anomolies (long-term monthly mean s1ilitracted from each month) for decreasing 

numbers of daily values. On the basis of the magnitude of the trend and the 

variability in the trend estimate, it appears that with about 2 days a week of 

data the trends remain quite comparable with those when data is available every 

day. Thus an ozonesonde program with two soundings a week should be able to 

monitor long-term trends in tropospheric ozone behavior if variability at 680 

mb is representative of variability in the rest of the troposphere. 

Trends in the data at BRW and SMO are less marked than at MLO (figs. 17 

and 18, and table 14). The significance of the trends at all of the stations 

is still questionable and at MLO the magnitude is greatly influenced by the 

high values in 1983. 

42 
•l--~~~~-.--~.--__..,.~-.--~~~.--__..,.~--.------1 

n .. ,, OAT!: " 

Figure 17.--Monthly mean surface 

ozone amounts at BRW, with a linear 

least-squares fit to the data. 

" 

~ 

¥ 

1: 

!i u( 

~ 

~P. 

'!L 

~-

" " " " " ., .. DATE 

Figure 18.--Monthly mean surface 

ozone amounts at SMO, with a linear 

least-squares fit to the data. 

3.5 Stratospheric Water Vapor 

3.5.1 Operations 

Routine stratospheric water vapor soundings were made in Boulder in 1983. 

In addition, four soundings were made at Palestine, TX, and two at Laramie, 

W'i, as part of intercomparison programs designed to assess the reliability of 

stratospheric water vapor measurement systems. 

The frost-point hygrometer used in the soundings has undergone only minor 

changes since inception of the program in 1980. Balloon performance, although 

greatly improved over 1982, is still not optimum. The use of the two balloon 

systems described last year (Harris and Bodhaine, 1983) led to greater reliability but limited the altitude from which good data could be obtained. 

Because initial descent rates at altitudes above 25 km are not fast enough to 

give good ventilation through the air intake of the system, the measurements 

at altitudes between 25 and 30 km often show evidence of contamination. It is 

hoped that modifications under way will extend the height of accurate measurements to about 30 km, as obtained in the past. 

During 1983 it was discovered that an error was being made in correcting 

for hysteresis effects on the pressure sensor for descent pressure measurements. Since this involves a fixed offset in the mechani sm of the baroswitch, 

the percentage errors in pressure determination are largest at low pressures 

(highest altitudes). These errors amount to about 9% in mixing ratio at 10 mb 

and decrease to less than 1% below 80 mb. Data prior to 1983 presented in 

previous Summary Reports are shown corrected in this report. 

Prior to June 1982, the thermistors used to measure frost-point temperature in the hygrometers were calibrated at NRL, Washington, DC, by J. Mastenbrook. These calibrations were performed using platinum resistance probes 

with a Mueller bridge. The thermistors in Boulder are calibrated using two 

quartz thermometers manufactured by HP. With the termination of the program 

in Washington, DC, the platinum thermometers of NRL were transferred to NOAA/ 

GMCC. Simultaneous calibrations of thermistors using both the platinum and 

43 
quartz probes show differences that lead to frost-point temperature discrepancies of less than O.OS°C at -90.0°C. This leads to water vapor mixing ratio 

differences of less than O.S% at stratospheric levels near lS mb. 

3.S.2 Data Analysis 

During 1983 nine stratospheric water vapor balloon soundings were made at 

Boulder from which valid data were obtained. In addition, two soundings were 

made from Laramie, WY, and four from Palestine, TX. Figures 19a and 19b are 

profiles of soundings made in 1981 and 1982. These profiles were presented in 

previous Summary Reports but are shown here corrected for the pressure error 

discussed earlier. The data from Boulder and Laramie are shown in fig. 19c. 

Because one of the Laramie flights yielded data from about 40 mb down and the 

other down to SS mb, the two flights were combined into a single profile. 

Figure 19d shows the profiles obtained at Palestine. 

The two flights at Palestine in October 1983 and the one in May 1981 were 

conducted as part of an international intercomparison of stratospheric water 

vapor measuring systems. Preliminary results of these comparisons, as well as 

a comparison carried out in Laramie (data shown in fig. 19c) with the NOAA/AL 

Lyman-alpha water vapor instrument, indicate that the NOAA/AL instrument gives 

results about O.S ppmm higher than the GMCC frost-point hygrometer. Comparisons with other types of equipment were not as conclusive. The NCAR cryogenic 

a 

c 

.. 

• • N<t.!lt• I jfi.. •• ti.• I' 

1/'Qllt 

""'" 

"'""' 

-r ' -r-- -

----'---+Ib l 

{ 

J 

" 

u 

-

d 

i 

1 

u~.~1--+-+-::=i,___-+----!,__-:----!,,__~---!~--+-

"'usM11•1'>QR.o"Q'ppm<r.1 

Figure 19.--Profiles of stratospheric 

in ppmm at Boulder, CO, for (a) 1981, 

Palestine, TX, for (d) 1981 and 1983. 

12 February 1983 is also shown in (c). 

first profile give volume mixing ratio 

44 

:\•o11U1Mw.oU , 

~~ ] l .. "']tl2 

·~· ' ) I- - ·-- I I I ! 

I \._ \ I\ 

\. ?j- \ ( 

['--._ <..., 

'- I '---

' .. 

111i,.e4 • .1.•u tr ~ •. u 

water vapor mass mixing ratio 

(b) 1982, and (c) 1983, and at 

A profile at Laramie, WY, for 

Numbers along the top for the 

in ppmv. 

-
sampler appears to give values at about the same level as the frost-point 

hygrometer. Complete results of this intercomparison series will be available 

in 1984. 

Sufficient soundings have been made i n Boulder to obtain average seasonal 

patterns in the stratosphere between 200 and 20 mb. Figure 20 shows the seasonal values averaged for 1981-1983. For each season there are from 6 to 8 

"' 

., 

j 

"' 

\ 

' ' I 

' ' 1/ ' ·211 

_ .-

' ' ' ' ' \ \ \ I I\ J 

--

' ' ........ .... ............... _ 

.... .-.- ............ 

-- ,--.... -- ~ - - -·'22--

1 

J. .....-.... I ,,,' I 

I ' -

\, 

I 

I 

I 

/ 

" 

I ', "-

Figure 20.--Seasonal variation of 

stratospheric water vapor at Boulder, 

CO, based on data for 1981-1983. 

Isopleths are of mass mixing ratio 

in ppmm. Note that the spacing of 

the isopleths changes so that from 2 

to 3 ppmm, it is 0.2 ppmm; from 3 to 

5 ppmm, it is 1 ppmm; and from 5 to 

13 pp mm . it is 2 pp mm . 

soundings. The seasonal groupings were chosen to emphasize the m1n1mum that 

appears in the spring. Be l ow 60 mb the seasonal cycle dominates with the 

driest values appearing between 150 and 100 mb in the spring. This minimum 

moves upward and fills as the year progresses. If there is any annual cycle 

above 60 mb, it is very weak. Also above this level the mixing ratio increases 

gradually during all seasons so that the average increase between 19 and 26 km 

is about 0.042 ppmm km- 1 The increase is usually attributed to a source from 

the oxidation of methane in the middle and upper stratosphere. In this case, 

the increase is somewhat larger than that shown by Mastenbrook and Oltmans 

(1983), which was based on data from Washington, DC, and included many more 

soundings. The minimum near 70 mb is considerably drier at Boulder than at 

Washington, DC, and at all levels the mixing ratio at Boulder is less than the 

long-term average at Washington. The average annual profile over Boulder of 

the stratospheric mass mixing ratio is given in table 15. This can be compared 

with a similar table in Mastenbrook and Oltmans (1983). 

Table 15.--Annual average mass mixing ratio at Boulder, CO, 

for selected pressure levels for 1981-1983 

Pressure Mean mixing Pressure Mean mixing 

level ratio level ratio 

(mb) (ppmm) (mb) (ppmm) 

20 2 .59 90 2.32 

30 2.57 100 2.40 

40 2 . 47 120 2 .58 

so 2 . 37 140 3. 11 

60 2 . 30 160 4 . 46 

70 2.25 180 7 . 98 

80 2.25 200 16 . 28 

45 
3.6 Halocarbons and Nitrous Oxide 

3.6.1 Operations 

Air samples in paired stainless steel flasks were collected weekly during 

1983 at BRW, NWR, MLO, and SMO for CFC-11 (CC1 3 F), CFC-12 (CCl2F2), and nitrous 

oxide (N20) analyses. At SPO, samples in paired flasks were collected weekly 

only during January and December; at other times, they were collected once per 

month. 

The samples were analyzed on a gas chromatograph at GMCC, Boulder. A 

Hewlett-Packard 87XM computer was procured in September and interfaced with 

the laboratory integrating recorders so that chromatographic peak-height data 

could be processed and stored on disk at the end of each analysis. 

In September, a Shimadzu mini-2E gas chromatograph was procured for use 

at SPO. The chromatograph was modified by removing the injection port and 

installing a gas sampling valve, and by removing carrier gas inlet controls 

and installing a metal diaphragm flow controller. Operating and servicing 

instructions for the chromatograph were prepared for use by SPO personnel. 

After testing, the chromatograph, an HP 3390A integrating recorder, 

calibration gas (tank 3081), and accessories were shipped to SPO in early 

November. The apparatus was installed and became operational at SPO in late 

December. 

3.6.2 Calibration 

In early September, three 48.7-1 steel gas cylinders (tanks 3077, 3081, 

and 3093) were filled with clean mountain air to serve as CFC-11, CFC-12, and 

N20 gas standards. The tanks were filled at Climax, CO, at an elevation of 

3.8 km. Pumping equipment consisted of a 15-μm inlet air filter, a -70°C water 

vapor cold trap, a metal bellows forepump, and a RIX high-pressure three-stage 

air compressor. The pumps were powered by a gas-powered generator. Tanks 

3077, 3081, and 3093 were pressurized to 1800, 2050, and 2050 psi, respectively. 

The NOAA/GMCC halocarbons and N20 calibration gas standard (tank 3072), 

as well as tanks 3081 and 3093, were transported for calibration to OGC 

(Beaverton, OR) in late September. Calibrations of the standard indicated 

that CFC-11 and N20 concentrations have remained stable since 1977. The CFC-12 

concentration has been increasing in the past, but appears to have stabilized 

during the last 2 years. 

3.6.3 Data Analysis 

CFC-11, CFC-12, and N20 selected data are shown in figs. 21-23, respectively, for 1977-1983. The BRW halocarbon data exhibit an annual cycle with 

highest concentrations during November-December and lowest values during JuneJuly. Similar periodicity in the data is not evident at the other stations. 

SPO data continue to exhibit the most variability due to sampling problems. 

The N20 data have not been corrected for C0 2 interference during chromatographic gas analyses. 

46 
NWR • . 

. . ·.;c ,·p·-...... .... -.,.-· ~: .. •i-~"'fi-i.\~ f•.:=•• I 

.... 0 

:; 

0 

" N 

g 

> ~ f- 0 

0.. " ~ M 

g N M u.. 0 N 

-' :c u 

u g 

'~ .. , I 

.. ' 

···~ .: 4 . ,l ,-.,. ...... .,. · . 

77 78 79 80 81 82 83 78 79 80 Bl 82 83 

Figure 21.--CFC-ll da ta record . Figure 22.--CFC-12 data record. 

0 

"' M 

~ ,., 

0 

0 

,., 

0 

"' " 0 

Q) 

" 0 

., 

0 "' 

;;; 

" 0 

"' 0 

"' <J 

~ 

0 

<J 

> " a:J 0 

0.. " ~ 0 

0 

0 0 "' N 

z .. "' 

:i: 

(ol 

l'l 

0 

;;; 

0 

0 

" 0 

~ 

:i: 

., 

0 

gj 

~ 

0 " 

0 

"' 0 

" "' 0 

Q) 

., 

MLO 

., .. ; •• ;.,...,J,',. ~J,~:.~.,,,.,.~:..L. i:".~l~t:'.Y":'~:"".'.4."fl"'f<o~ . ·~ . . . ~ . 

SMO. , • , . . tj.~~'•.'t~~ 

- . __ ·'-~~~-. ··~·~·· .'7>-r,.-,.· · : .; ·r .. ~·. ·. ··:"'r-•~<"',,_ .,.. "'" • ·: ~'. 1• • • •• 

SPO 

77 78 79 80 81 B2 83 

Figure 23.--N2 0 data record. 

47 
Table 16.--Mean mixing ratios for 1983, and results of secondorder regression analyses of CFC-11, CFC-12, and N20 data for 1977-1983•'• 

No. of Mean mixing Mixing ratio Growth rate 

Station obs. ratio for 1983 on 1 Jan 1977 Growth rate change 

CFC-11 (pptv) (pptv) (pptv yr - 1 ) (pptv yr- 2 ) 

BRW 524 227.3 154.2 ± 0.58 11.09 ± 0.36 0.01 ± 0.05 

NWR 555 223.2 154.0 ± 0 . 71 8.93 ± 0.42 0.26 ± 0.05 

MLO 517 218.7 148.2 ± 0 . 62 10. 02 ± 0.39 0. 13 ± 0.05 

SMO 541 213.7 135. 4 ± 0.51 11. 81 ± 0.32 0.03 ± 0.04 

SPO 66 208.6 135.5 ± 1.97 12. 10 ± 1. 33 -0.03 ± 0.20 

CFC-12 (pptv) (pptv) (pptv yr- 1 ) (pptv yr- 2 ) 

BRW 436 378.3 269.7 ± 1. 77 16. 11 ± 0.92 0.10 ± 0 .11 

NWR 347 374.6 279.6 ± 2.25 9.72 ± 1. 10 0. 77 ± 0. 13 

MLO 414 368.9 268.3 ± 1. 66 15.00 ± 0.95 0 .10 ± 0. 12 

SMO 473 362.9 241.0 ± 0.92 18.02 ± 0.55 0 .10 ± 0.07 

SPO 80 353.3 238.2 ± 2.38 17.02 ± 1. 38 0.10 ± 0. 19 

N20 (ppbv) (ppbv) (ppbv yr- 1 ) (ppbv yr- 2 ) 

BRW 539 304.1 300.2 ± 0.34 0.48 ± 0. 19 0.01 ± 0.02 

NWR 544 305.6 299.1 ± 0.42 1. 07 ± 0 . 23 -0.01 ± 0.03 

MLO 538 304.1 298.4 ± 0.41 1.10 ± 0 . 23 -0.03 ± 0.03 

SMO 470 310. 1 300.2 ± 0 .54 0.84 ± 0 . 31 0 .11 ± 0.04 

SPO 190 302.0 300.3 ± 0.61 0.69 ± 0.36 -0.07 ± 0.05 

•'•Coefficients are followed by their standard deviations. 

Mean concentrations for 1983 and results of second-order least-squares 

regression analyses of the 7-yr halocarbon and N20 data sets are summarized in 

table 16. Indicated growth rates are all highly significant. Significance 

(95% confidence interval) of the growth rate changes appears to be highly dependent from year to year on the last year's data. For the full 7-yr record, 

only the MLO and NWR CFC-11 and the NWR CFC-12 second-order terms are statistically significant. 

Table 17 contains CFC-11 monthly average data for each station during the 

period 1977-1983. SPO data should be used cautiously since they are quite 

scattered and sparse (see fig. 21). This SPO variability problem is caused, 

we believe, by air samples having to be stored many months before analysis. 

CFC-12 and N2 0 data are not tabulated because calibration gas instability 

and C0 2 interference corrections have not been ascertained completely. 

3.7 Stratospheric Aerosols--Lidar 

Lidar measurements acquired since 1974 by GMCC at MLO have been uniformly 

processed for vertical profiles of aerosol backscattering ratio, ratio of total 

backscatter to Rayleigh backscatter, and cumulative optical depth. For 1974-

1981, 173 profiles were analyzed. A NOAA Data Report, soon to be printed, 

will provide details of the processing procedure and results. Lidar measurements from 1982 to the present were also processed in the same fashion as the 

48 
Table 17.--Monthly average CFC-11 concentrations (pptv) 

using pressurized flask pairs 

Month BRW NWR MLO SMO SPO Month BRW NWR MLO SMO SPO 

1977 1980 (cont.) 

Jan 141.4 Jul 191.7 187.2 189.3 177 .9 

Feb 130.1 Aug 193.0 187.0 176.6 

Mar Sep 193.6 184.6 186.6 181.1 

Apr Oct 193.8 190.0 194.5 179.3 185.9 

May Nov 193.0 195.1 192.4 178.7 

Jun Dec 199.0 190.9 190.9 179.3 176.9 

Jul 1981 

Aug 156.8 144.1 Jan 198 . 6 194.l 188.4 181. 2 178.4 

Sep 156.9 144.2 Feb 203.5 194.0 192.2 187.8 

Oct 165.7 152.4 144.3 Mar 200 . 0 198.7 193.5 182.8 

Nov 164.7 154.3 144.7 Apr 202.2 193.7 195.1 186.0 

Dec 169.6 156.3 141. 3 May 200.6 198.3 194 . 3 186.8 

1978 Jun 202.5 199.0 197.8 186.3 

Jan 168.1 160.2 148.5 Jul 202.2 199.0 198.6 188.1 

Feb 164.9 154. 3 146.7 Aug 203.7 201. 2 197.8 189.4 

Mar 166.3 158.4 153.2 Sep 203.4 202.3 200.2 191. 1 

Apr 168.9 158.8 152.8 Oct 208.1 203.9 202.3 192.1 

May 167.6 160.1 151.8 Nov 210.4 201. 7 200.7 194.1 183.7 

Jun 168.4 160.5 152. 0 Dec 213.0 202.8 203.1 194.7 194.1 

Jul 169.6 159.6 152.0 162.4 1982 

Aug 169.7 164.1 154.7 Jan 211. 1 204.3 200.8 198.5 

Sep 179.3 166.5 154.4 Feb 214.3 202.4 205.5 200.7 

Oct 175.5 164.0 156.6 Mar 214.9 208.4 202.8 197.5 

Nov 180.8 166.6 159.8 171. 9 Apr 213.4 208.6 203.6 201. 3 

Dec 179.6 166.1 158.7 160.8 May 211.5 208.9 206.1 199.9 

1979 Jun 210.5 209.4 204.4 202.8 

Jan 175.1 169.3 161. 6 157.1 Jul 213.8 213.0 205.7 201.6 

Feb 178.2 170.9 165.4 165.4 Aug 214.0 210.6 207.7 203.5 

Mar 181. 2 171. 0 162.7 Sep 216.2 212 . 9 209.6 204.0 

Apr 180.8 170.6 163.5 Oct 217 . 5 212.0 210.3 204.9 

May 179.8 169.6 163.8 Nov 221 . 0 217.0 210.4 204.7 233.4 

Jun 179.3 170.0 162.5 Dec 221.2 217.5 209.6 204.5 214.5 

Jul 180.7 172.8 164.8 1983 

Aug 180.0 167.7 Jan 223.1 215.1 211. 6 210. 2 207.4 

Sep 186.5 177 .0 163.9 Feb 222.4 218.8 212.9 206.9 

Oct 186.6 183.2 170.6 Mar 223.5 219.7 214.6 211. 7 

Nov 188.l 180.5 168.8 Apr 224.8 223.2 215.5 211. 1 

Dec 188.6 182.8 179.4 169.4 May 220.8 217.6 210. 7 

1980 Jun 226.3 222.2 222.9 212.0 

Jan 191. 4 183.3 181. 7 172.6 169.5 Jul 229.1 223.3 222.2 213.8 

Feb 190.1 183.3 181. 3 173.0 168.8 Aug 225.0 223.5 221. 4 211. 7 

Mar 192.5 184.3 174.8 Sep 226.6 224.6 219.7 213.6 

Apr 190.9 187.6 183.9 174.3 Oct 230.1 226.3 223.4 217.4 

May 191. 0 181. 3 177 .4 187 . 1 Nov 233 . 9 227.6 223 . 3 215.8 

Jun 192.2 185.6 178.5 Dec 231. 9 231. 0 217.8 221. 2 '?09.8 

49 
1974-1981 measurements, and some results were published in Harris and Bodhaine 

(1983). A NOAA Data Report is also being prepared for presentation of lidar 

observations for 1982-1983, covering the El Chichon event. 

Presented here is a brief summary of the 1974-1981 lidar observations. 

Figure 24 is a plot of number of lidar data sets per month vs. time spanning 

1974-1981. A data set consists of an average of a few to about 20 lidar shots, 

and more than one data set is usually obtained during an evening or morning 

(darkness) measurement episode. The data acquisition system only permitted 

storage of averages of single shots, so measurement noise statistics could not 

be calculated by conventional mathematical procedures. Results of processed 

measurement sets were compared to gain some quantative understanding of measurement variability. 

Figure 25 shows stratospheric aerosol optical depth data determined from 

the 1974-1981 lidar observations. Optical depth was determined by integrating 

a lidar profile starting at 15 km and ending at the highest altitude at which 

a signal is detectable. For periods of stratospheric quiescence, the highest 

altitude was about 25-28 km. During the El Chichon event, the highest altitude 

was about 10 km higher than the quiescent period. 

A closer look at fig. 25 shows a rather high optical depth in the winter 

of 1974-1975. The higher values are attributed to the well-known eruption of 

DeFuego in the fall of 1974. From 1976-1977 stratospheric optical depth was 

very low and probably representative of stratospheric quiescence or background 

conditions. In 1978 there appears to be some activity that might be attributable to the eruptions of Westdahl in the fall of 1977, and Bezymianny in the 

spring of 1978. The number of observations made in 1979 are too few for clear 

o...,...,-.,..,~_;;;..;;.,.w.,~m"""'....,..~,....;\jpw..i,;1,~~.....,.,.,........., 

1971 19lS 1976 1977 1979 1979 1990 1991 1992 

TIHE 

Figure 24.--Distribution of MLO sets 

of lidar data per month vs. time. A 

set consists of up to 20 shots, and 

usually 3 sets are taken per observation episode. Previous to 1980, 

many sets consisted of only a few 

observations. 

50 

Figure 25.--Stratospheric aerosol 

optical depth over MLO, determined 

by lidar. The optical depth is 

representative of a layer of atmosphere with base at 15 km and top at 

the highest point of a lidar sounding. The time axis starts in 

November 1974 and ends in December 

1981 . 
interpretation; however, Mount Soufriere erupted in April 1979 and was known 

to have increased the stratospheric aerosol concentration. In 1980 Mount St. 

Helens erupted, and a stratospheric aerosol cloud was observed over the Northern Hemisphere. 

The data presented in fig. 25 constitute one of the longest detailed 

records of lidar observations in existence. It clearly complements the 

historical solar transmission measurement and will be a valuable additional 

source of data for studies of climatic effects of stratospheric aerosols and 

of Umkehr error effects of stratospheric aerosols. 

3.8 Surface Aerosols 

3.8.l Introduction 

The GMCC aerosol monitoring program during 1983 included the continuous 

measurement of CN concentration and aerosol scattering extinction coefficient 

(a ) at BRW, MLO, SMO, and SPO. A Pollak CNC is located at each station to 

ac~Pas an onsite standard for CN measurements. A G.E. automatic CNC operates 

continuously at each station, and daily calibration points are provided by the 

Pollak counter. 

A four-wavelength nephelometer at each station continuously measures a 

at 450-, 550-, 700-, and 850-nm wavelengths. Calibrations of the nephelom-sp 

eters are performed at 2-mo intervals by filling them with C0 2 gas and adjusting the instrument outputs to the known Rayleigh scattering coefficients of 

C0 2 . The use of C0 2 as the calibration medium provides an additional check on 

the internal consistency of the instrument with respect to wavelength, because 

the Angstrom exponent of a Rayleigh scatterer is known to be nearly equal to 4. 

(The Angstrom exponent varies slightly with wavelength because of dispersion 

effects.) 

All data were recorded as I-min and 1-h means by ICDAS at all four sites. 

A Leeds and Northrup Speedomax 250 chart recorder running at a speed of 

1 in h- 1 provides a backup recording to fill in missing ICDAS data for each 

station. All data are available as 10-min or 1-h means in graphics, printout, 

or magnetic tape form. 

3.8.2 Operations 

All Pollak CNC's operated properly throughout 1983. Locations and serial 

numbers of GMCC instruments are given in table 18. Pollak observations for 

all stations have been keypunched and are available as data files on the 

Table 18.--Serial numbers and locations of GMCC instruments during 1983 

Instrument BRW MLO SMO SPO Boulder 

Pollak CNC 16 13 22 15 19, 20, 21 

Nephelometer 105 103 106 107 104 

51 
Boulder computer. For the SPO Pollak counter data, coincident meteorological 

observations were also keypunched and are available i n the same file. 

The G.E. CNC's and nephelometers operated propeLly most of the year at 

all f our stations. Approximate data recoveries for the GE CNC's and nephelometers respectively were 75% and 81% at BRW, 96% and 85% at MLO, 98% and 96% at 

SMO, and 93% and 97% at SPO. Data gaps were caused both by instrument downtime and ICDAS downtime. Data lost during ICDAS downtime will be recovered 

from backup chart recorder data . 

3.8 . 3 Data 

Daily means of a and CN concentra tion at the GMCC stations are presented sp 

in fig. 26, and monthly means for the entire data record at each station are 

AEROSOL DATA F'OR BARROW 

JAN fEB MAR APR MAY JUN JUL AUG SEP OCT NQV DEC 

W.IJN-Tlt or TlH: ·FA R 1'518.1 

AEROSOL DATA F'OR SOUTH POLE 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH Of' THE YEAR 1983 

52 

JAN FEB MAR APR MAY JUN HlL AUG SEP OCT NOV DEC 

MONTH OF THE YEAR 1983 

Figure 26.--Daily geometric means of 

light-scattering and CN data at BRW, 

SMO, and SPO. For each station, CN 

concentration (bottom) is shown as a 

solid line. Light-scattering data 

(middle) are shown for 450 run 

(dotted), 550 nm (solid), 700 nm 

(dashed), and 850 nm (long-dashed). 

Angstrom exponents (top) were calculated from 450- and 550-nm (dotted), 

550- and 700-run (solid), and 700-

and 850-nm (dashed) light-scattering 

data. 
MONTHLY MEAN AEROSOL DATA FOR BAP.ROW 

.. 

MO~THLY MEAN AEROSOL DATA ron SAMOA 

.. YEAR 

MONTHLY MEAN AEROSOL DATA FOR SOUTH POLE 

presented in fig. 27. 

data have been omitted 

that have delayed data 

Figure 27.--Monthly geometric means 

of light-scattering and CN data for 

the entire data record, as in 

fig. 26. The straight dashed lines 

are least-squares linear trend lines. 

Monthly means f or 1983 are given in table 19 . The MLO 

from this year's report because of instrument problems 

editing. 

The BRW data in fig. 26 clearly show the annual cycle in CT , with a maximum in March and a minimum in June. The well-known Arctic haze~Pcaused by the 

transport of anthropogenic and natural pollutants from the midlatitudes, is 

evident each spring in the CT data shown in fig. 27. The CN data in figs. 26 

and 27 show a more variable ~gmiannual cycle, with maxima usually occurring in 

March and August, and minima occurring in June and November. 

The SMO CT and CN data continue as in previous years with no significant 

annual cycles g~ long-term trends. The Angstrom exponent dat a continue to 

show negative values, suggesting that the SMO seasalt aerosol size distribution 

has a strong peak near l~μm diameter. 

The 1983 SPO a data in figs. 26 and 27 show annual variations similar 

to those observed igpl979, 1981, and 1982: a minimum in May and large events 

dominating the record in late austral winter. These events, such as the one 

in late July in fig. 26, are caused by the transport of seasalt in the upper 

53 
Table 19.--Monthly geometric means of CN concentration (cm- 3 ) and 

a 1,- (m-1) at 450, 550, 700, and 850 nm for BRW, SMO, and SPO during 1983 sp 

Jan Feb Mar Apr Hay Jun Jul Aug Sep Oct Nov Dec 

BRW 

CN 258 126 283 229 156 181 213 259 231 145 99 138 

a (450) I. 40-5 1.57-5 2.39-5 I. 94-5 7.35-6 2.58-6 2.27-6 1.76-6 2.89-6 2 . 31-6 6.93-6 9.20-6 

asp(550) I. 28-5 I. 42-5 2. ll-5 I.69-5 6.04-6 I. 99-6 1.88-6 1.53-6 2.56-6 I. 97-6 6.40-6 8.50-6 

asp(700) 8.79-6 9. 72-6 I. 36-5 1. 09-5 3. 72-6 1. 15-6 I. 22-6 1.09-6 1.78-6 1.36-6 4.55-6 6. 19-6 

Usp(850) 6.57-6 7. 17-6 9.51-6 7.62-6 2.64-6 8 . 41-7 9.21-7 8.73-7 1.43-6 1.01-6 3.48-6 4.78-6 

sp 

SMO 

CN 193 225 233 180 214 195 236 194 263 240 238 271 a (450) 1.34-5 1.36-5 I. 29-5 1.42-5 I. 39-5 1.53-5 1.51-5 J . 42-5 2.28-5 I. 84-5 I. 05-5 I. 60-5 

Usp(550) 1. 32-5 1.34-5 1.27-5 1.43-5 I. 39-5 1. 51-5 1.48-5 1. 41-5 2.23-5 I. 76-5 9.95-6 1.52-5 

asp(700) 1 . 39-5 1. 42-5 1.32-5 1. 51-5 1. 42-5 1.60-5 I. 5 7-5 l.50-5 2.36-5 I. 82-5 1.01-5 1.55-5 

asp(850) J. 55-5 1.58-5 I. 45-5 1.67-5 1. 53-5 I. 82-5 1.79-5 1. 70-5 2.68-5 2.04-5 1.14-5 I. 69-5 sp 

SPO 

CN 110 122 97 41 25 15 10 12 32 85 152 ll 1 a (450) 3.00-7 4. 75-7 3.60-7 3.46-7 2.27-7 2.70-7 3.36-7 4.65-7 4.35-7 9 . 28-7 7.25-7 

asp(550) 1. 84-7 3. 16-7 2.63-7 2. 60-7 1.55-7 I. 95-7 2.69-7 4.00-7 3.38-7 7. 91-7 6.26-7 

asp (700) 2 . 40-7 1.85-7 1. 69-7 1.82-7 9.47-8 I. 24- 7 I. 89-7 2.97-7 2.36-7 5 . 99-7 4.99-7 

Usp(850) 7.00-8 1. 39-7 I. 23-7 I. 35-7 7.82-8 9.62-8 1.59-7 2.49-7 1. 94-7 4. 89-7 4.33-7 sp 

*A compact exponential format is used for o such that 1.40-5 = 1.40 x 10- 5 . sp 

troposphere from stormy regions near the coast to the interior of the Antarctic 

continent. The familiar annual cycle in CN concentration in figs. 26 and 27 

show austral summer concentrations in excess of 100 cm- 3 and winter concentration below 10 cm- 3 . 

The least-squares trend lines given in fig. 27 are essentially unchanged 

from last year's analysis (Harris and Bodhaine, 1983, p. 50). In no case is 

the trend from the beginning to the end of a data record significant compared 

with the standard error about the regression line. 

3.9 Solar Radiation 

3.9.1 Introduction 

The basic solar radiation monitoring program at the four GMCC baseline 

observatories consists of two global pyranometers, two normal incidence 

pyhrheliometers, and two dual-wavelength sunphotometers. The two pyranometers, 

quartz (Q, 0.30-2.80 μm) and RG8 (0.695-2.80 μm), and one quartz pyrheliometer 

operate continuously with the output voltages recorded on ICDAS. The second 

pyrheliometer has a filter wheel and, along with the two sunphotometers, is 

hand-operated several times a day when the Sun is unobstructed by clouds. The 

same pyranometers and pyrheliometers have been in operation since at least 

1976 with only the following instrument changes. The RG8 at SMO has been 

chartged three times because of filter deterioration. The quartz pyranorneter 

at SMO was changed on 1 January 1983 because of detector deterioration. The 

continuous pyrheliometer at BRW was put online in March 1983. Several instruments, not considered part of the basic program, have been added or deleted 

from observatory programs between 1976 and 1984 (see previous GMCC Summary 

Reports). 

54 
3.9.2 Instrument Intercomparison 

On an annual basis a traveling-st andard pyranometer and pyrheliome ter are 

sent to each station for a quality control i nter comparisou. The trave ling 

standards are then rout i nely checked against absolute standards mai11t a ined by 

SRCF. 

The present sunphotometer program was begun in early 1982, and calibratio11 

and quality control procedures are being instituted. The self-calibrating 

instruments are calibrated, when possible, at the observatories by the La11gley 

technique, or are calibrated relative to standards maintained in Boulder. 

Principal responsibility for the sunphotometer calibration during 1983 has 

been with SRCF. 

The following summarizes 1983 activities at the GMCC sites relative to 

the basic solar radiation monitori ng program and to special ac t ivi t y . 

3.9.3 Barrow 

Prior to 1983, a continuous tracking pyrheliomet e r was 11ot overaLe J ~L 

BRW because of the large amount of cloud cover. As a result of r e ce11t interesl 

in the c lear-sky periods with respect to Arctic haze, and in au a tte111p t to 

document the extent of clear periods better, a continuous pyrheliomel e r h'd S 

put online in March 1983. The clock dri ve tracke r has prove d very ac c urat1: , 

and the solar decl i nator can be set from cha rts when conditi olls a re t oo cluudy 

to align it directly. The clock drive mechanism was ad a pted for cold weathe r 

operation by removing the existing lubricants and r eplacing them with extreme 

cold-dry lubricants. 

An all-sky, 190° field-of-view, time-lapse camera was operated at BRW for 

most of the sunlight portion of 1983. The speed was nominally one frame pe r 

5 minutes. The 16-mm color movie film documented sky conditions al the 

station. 

During March an intensive effort was made to measure spectral optical 

properties of Arctic haze using remote-sensing techniques at the observatory. 

This effort was in conjunction with the broader AGASP flight program. The 

remote-sensing techniques used involved relative measurements of various 

spectral components of short-wave solar radiation . Spectral measurements we re 

made of direct solar intensity, zenith sky i11tensity, global diffuse flux, and 

global total flux. Aerosol optical depth was derived from the direct Sunintensity measurements, and the results are reported by Dutton et al. (1984). 

The results from the diffuse and global measurements are being prepared for a 

NOAA Data Report. 

The traveling-stcrndard pyranometer and pyrheliometer were ;1L BHW from 

8 June to 6 July 1983 . No significant char1ge from previous years W3S detected 

in the station instruments' sensitivity relaL.ive to the traveling standard. 

3.9 . 4 Mauna Loa 

Mauna Loa is unique among the GMCC observatories because its location and 

climate offer reliably frequent opportunities for solar observation th.rough a 

clean, dry atmosphere. As a result, more long-term and short-term GMCC solar 

55 
radiation programs have been carried out at MLO. Previous GMCC Summary 

Reports discuss several ongoing or terminated solar measurement projects at 

MLO. The following summary provides an update for 1983. 

A computer-automated solar observatory now operates at MLO. The observatory consists of a moderate-sized, active solar-tracking spar housed in a 

16-ft-diameter astronomical observatory dome. The dome aperture automatically 

opens, follows the Sun, and closes each day. Certain environmental conditions 

such as high wind, rain, or excessive clouds will automatically close the dome 

or prevent it from opening. A microcomputer-based data acquisition system 

records up to 32 channels of analog voltage data on magnetic tape. The active 

solar-tracking spar is accurate, in the absence of clouds, to about ±0.05°, 

and resets to the sunrise position at or near sundown. Instruments mounted on 

the spar include a pyrheliometer, a seven-wavelength sunphotometer, a threewavelength sunphotometer, and a two-wavelength solar hygrometer. 

An Eppley/Kendall ACR is occasionally operated at 

calibration for the two basic-program pyrheliometers. 

2.5 years, the sensitivity of this continuous tracking 

changed by more than ±0.3% relative to the ACR. 

MLO as a reference 

Over a period of nearly 

pyrheliometer has not 

Two pyranometers, GG22 (0.400-2.80 μm) and OGl (0.530-2.80 μm), were put 

back online in late 1982 and operated throughout 1983. The instruments were 

put back online, after being removed in early 1981, to gather as much information as possible on the decay of the El Chichon debris cloud. The instruments 

operate continuously, but the data are no longer archived as was the case 

prior to 1981. 

A shaded quartz pyranometer operates continuously at MLO measuring global 

diffuse solar flux. The shade mechanism is a small disk on a narrow rotating 

arm driven by a clock drive, which keeps the pyranometer detector from being 

exposed to the direct Sun. The instrument has operated on an experimental 

basis since 1979, but tracking problems until late 1981 reduced the amount of 

useful data. 

A continuous-output three-wavelength sunphotometer (PMOD), designed after 

specifications provided by the WMO, began operating on the automated spar in 

September. Extraterrestrial calibration constants are derived several times 

per week and remained within ±1.0% throughout 1983. The GMCC PMOD sunphotometer was sent to Boulder for 3 weeks in October, where its calibration was 

compared with several other instruments. 

A leveling error in the monitoring quartz pyranometer was detected in 

1983 during detailed analysis of earlier MLO flux data. The leveling error 

(~1.0°) had no significant effect on daily averages or total energy integrals 

as archived at Asheville, but did affect instantaneous readings such as those 

used when evaluating the radiation field at specific times. The error was 

detected by examining ratios between different instruments and was verified in 

a continuous postcalibration of the pyranometer. The continuous calibration 

was accomplished by the shading-disk technique using the tracking pyrheliometer 

and diffuse pyranometer. The leveling error first occurred in February-March 

1980 and was unknowingly corrected in August 1981. The actual error was a 

function of time of year and was less than 5% at a zenith angle of 60°. 

Several calibrations of the hand-operated J series sunphotometers were 

carried out at MLO during 1983. Recalibration of two instruments, J202 and 

56 
J314, (380/500 and 778/862 nm) over a 2.5-yr period have shown them to be very 

stable; their calibration constants all remained within ±2%. These calibrations require extraordinary effort on the part of the station personnel, and 

were crucial to the evaluation of the El Chichon stratospheric cloud. 

The traveling-standard pyranometer and pyrheliometer were at MLO from 

19 July to 20 August. No changes in the sensitivity of the station instruments relative to the standards were detected. 

3.9.5 Samoa 

The location of SMO is of particular importance because of its sea level 

elevation in the Southern Hemispheric tropics. Here the solar flux is measured 

at the ocean-atmosphere boundary where the maj o r global heating occurs. SMO 

is the only GMCC station where this measurement is made. 

In the past, serious instrument degradation has occurred at SMO. This 

degradation is assumed to occur because of the warm, moist, and salty environment at the observatory. Deterioration of the RG8 pyranometer filter dome was 

prevented by fitting an additional clear glass dome over the RG8 dome. The 

area between the two domes is vented by pressurized dry air to prevent moisture, and to some extent, heat buildup. The modified instrument was tested 

and calibrated in Boulder prior to deployment in late 1983. 

The traveling-standard pyranometer and pyrheliometer were at SMO from 

26 September to 7 October. No change in the station instrument calibration 

was detected. 

3.9.6 South Pole 

Several changes to the program at SPO occurred during 1983. An upwardfacing pyrgeometer was installed on the roof of CAF in April to measure 

downward terrestrial infrared flux. Ancillary air and snow surface temperature 

measurements were made to support the pyrgeometer measurements. Discrete 

albedo measurements with a portable instrument were discontinued. The discrete 

albedo instrument suffered from several shortcomings and rarely produced 

useful data. The continuous albedo measurements are still being made, however, 

and improvements are planned for the structure that supports the downwardfacing detector. The current structure holds two shortwave pyranometers (Q 

and RG8) and will hold a pyrgeometer in early 1984. The structure is occasionally turned to an upward position for intercomparison with the normally 

upward-facing detectors. 

A new Eppley pyrheliometer SN 21948 was sent to SPO to replace 

tracking NIP SN 2968 that had shown some alignment irregularities. 

instruments operated during most of 1983. 

the quartz 

Both 

Observations with the OGl pyranometers, global flux and continuous 

albedo, were discontinued in March 1983. The OGl albedo measurements began in 

1981, and the global flux in 1976. The instruments were removed to permit 

data acquisition space for the pyrgeometer and to conform with the basic solar 

program at the other GMCC sites. 

57 
A solar hygrometer for measuring precipitable H2 0 was operated at various 

times at SPO, but experienced some mechanical and electrical problems. The 

instrument was returned to Boulder for maintenance and calibration. 

The traveling-standard pyranometer and pyrheliometer were online at SPO 

in late December 1982 and in 1983. 

3.9. 7 Boulder 

A semiautomated solar observatory, similar to the MLO facility, is now 

maintained in Boulder. The Boulder facility is used only as required for 

calibration and instrument testing. The dome uses analog logic for solar 

tracking and an HP85 for data acquisition. 

A multilaboratory sunphotometer intercomparison was held in Boulder from 

3 to 7 October 1983. Representatives from nine organizations made side-by-side 

measurements of atmospheric optical depth with 19 sunphotometers. Measurements 

at similar wavelengths were compared directly. The many varied wavelengths at 

which measurements were taken has complicated final complete analysis of the 

intercomparison. The most common wavelength used was 500 run, and preliminary 

comparison showed good agreement (within ±0.01 optical depth units) between 7 

of 11 instruments when the optical depths were tabulated using calibrations 

supplied by the instrument owners. Much larger discrepancies were occasionally seen at shorter wavelengths, particularly using owner-supplied calibration 

constants. The optical depths generally compared well at wavelengths longer 

than 500 nm and at all wavelengths when derived from Langley plot slopes. Of 

the 19 instruments, 4 gave consistently unacceptable results at one or more 

wavelengths. Good filters, careful maintenance, and recent calibration are 

all apparently necessary for maximum-quality results from modern sunphotometers. 

Traveling-standard pyranometer SN 12617 and pyrheliometer SN 13909 have 

been frequently calibrated in the past few years. The most recent calibrations 

have been performed by SRCF. The results of these calibrations are given in 

table 20. Although the calibration values have changed somewhat, particularly 

Year 

1973 

1974 

1978 

1981/1982 

1983 (Jan) 

1983 (Oct) 

Table 20.--Calibration history of the GMCC travelingstandard radiometers (mV mW- 1 cm- 2 absolute) 

Pyranometer 

SN12617 

0.0790 

0.0788 

0.0763 

0.0764 

0.0751 

0.0741 

58 

Year 

1975 

1981 

1981 (Apr) 

1983 (Oct) 

1984 

Pyrheliometer 

SN13909 

0.0758 

0.0759 

0.0756 

0.0757 

0.0758 
for the pyranometer, the annual field station intercomparisons have been 

conducted using the original calibration value of both the station and standard 

instruments. Only at SMO has any station instrument shown a significant 

change relative to th~ traveling standards since 1976. At SMO the pyranometer 

drifted about 1.2% yr 1 for about 4 years. The SMO data were corrected to 

agree with the standard before being archived. 

3.10 Station Climatology 

3.10.1 Instrumentation and Data Reporting 

The interpretation of local measurements of trace gases, aerosols, and 

atmospheric turbidity requires accurate measurements of station pressure, air 

temperature, and moisture content. Surface winds must also be known to evaluate the potential influence of local pollution sources. Standard off-theshelf instrumentation was chosen for most of these measurements. Wherever 

possible, WMO-recommended standards for exposure were used. 

A propeller-type anemometer is used (Aerovane, no. 141, Bendix, Inc., 

Environmental Science Division, Baltimore, MD) to measure the wind speed and 

direction. A synchro-to-DC converter is used to translate the phase representation of direction to a DC voltage. Orthogonal components are used to 

average the wind. Station pressure is measured with a capacitance-type transducer (no. 1201C, Rosemount, Inc., Minneapolis, MN). The voltage output of 

the transducer is recorded without further processing. At BRW, MLO, and SMO 

the air temperature is measured with linearized thermistors (no. 44212, Yellow 

Springs Instrument Co., Yellow Springs, OH). The thermistors are encapsulated 

in stainless steel shells that are exposed in aspirated Sun shields (no. 43404, 

R. M. Young Co., Traverse City, MI). A resistance-type thermometer, with a 

minimum acceptable temperature of -85°C (no. 954PL, Stow Labs., Hudson, ME) is 

mounted in a naturally ventilated radiation shield (no. 43103-A, R. M. Young 

Co., Traverse City, MI) at SPO. Dewpoint hygrometers are used at all four 

stations (no. 911, EG&G Inc., Newton, MA, at BRW and SMO; no. 1200ASP, General 

Eastern Instrument Co., Watertown, MA, at MLO and SPO). 

Hourly average values, scaled in metric units, are processed and reported 

for each measurement listed above. The data are stored on microfiche and 

magnetic tape. 

and variable. 

year. 

3.10.2 Barrow 

The microfiche listings are organized by station, date, time, 

The files are usually available 6 months after the end of the 

A description of the BRW site, its surroundings, and climatology can be 

found in previous GMCC Summary Reports. Wind roses of the hourly average 

resultant wind speed, in three speed classes, as a function of direction for 

1977-1983 and for 1983, are in general agreement (fig. 28). The predominant 

wind direction is northeasterly for 1983 as opposed to north-northeasterly for 

1977-1983. At the same time, easterly winds (NE-SE) occurred 54% of the time 

in 1983 compared with 61% for the 7 years of observations. Southwesterlies 

were slightly more prevalent than in previous years. In December 1983 a maximum wind speed of 25.0 m s- 1 was reported. This is the maximum for the 7-yr 

period as well. Wind speeds of 10 m s- 1 and greater were observed 14% of the 

59 
BARROW 

1983 

w 

WI ND SPEED(ll/S) 

-..61'WS<5 

~5iWS<IO 

D •s•10 

N 

s WIND FR!JI. 

" 

E 

BARROW 

77-83 

w 

WI ND SPEED(ll/S) 

- 15'WS<6 

mmo,ws<10 

D ••••o 

N 

s WIND FR~ 

" 

Figure 28.--Wind rose of surface winds for BRW for (left) 1983 and 

(right) 1977-1983. The distributions of the resultant wind direction 

and speed are in units of percent occurrence for the year and 7-yr 

period, respectively. Wind speed is displayed as a function of 

direction in three speed classes. 

E 

time in 1983 compared with a 7-yr average of slightly less than 10%. The 

average pressure for 1983 was 1014.0 mb (see table 21). This value is 0.7 mb 

greater than the 7-yr average. The average temperature is -14.7°C, which is 

2°C colder than the 7-yr average. The -45°C minimum for the year was within 

2°C of the minimum for the previous 6 years. The coldest temperature reported 

by NWS in Barrow was -49°C in 1924. 

3.10.3 Mauna Loa 

A description of the MLO site and its climatology can be found in previous GMCC Summary Reports. The combined wind distribution for 1977-1983 in 

fig. 29 shows a much higher occurrence of southerly winds than would be expected from synoptic-scale flow analysis. The effect of Mauna Loa Mountain is 

to redirect stronger, predominantly easterly or westerly winds aloft down the 

slope with a more southerly component. The distribution for 1983 is in excellent agreement with the 7-yr average that is presented. The pronounced peak 

in the southeast direction in 1983 is not as significant when combined with 

the neighboring sectors. Thus 32% of the time the wind is southeasterly (ESESSE) compared with 28% for the 7-yr average. Wind speeds equal to 10 m s- 1 

and greater occurred 4.7% of the time in 1983 compared with 7.1% for the 7-yr 

average. The significant change in the winds at MLO occurred in the first 

half of the year, dur ing which time a peak wind of only 13 m s- 1 was observed 

(see t~ble 22). Typically peak winds associated with Pacific storms exceed 

20 m s 1 . Associated with abnormally strong zonal flow across the subtropic 

Pacific, almost no storms were encountered in Hawaii. April was most anomalous, with 92% of the winds less than or equal to 5 m s- 1 . For the 7-yr 

60 
Table 21. --BRW 1983 monthly climate summary•'• 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1983 

Preva i 1 ing wind ENE ENE ENE ENE ENE E ENE E SSW ENE NE NE NE 

direction 

Average wind 5.6 7. 2 5.9 7.3 6.0 5.5 4.5 5.6 6 . 3 6.8 7.2 8.6 6.4 

speed (m s- 1 ) 

tlaximum wind 14 15 12 17 13 12 8 15 19 18 21 25 25 

speedt (m s- 1 ) 

Direction of ma x. 90 70 270 50 20 230 120 230 80 80 50 200 200 

windt (deg.) 

Average station 1017.1 1011 . 6 1022.6 1019.5 1020.2 1010.1 1012.3 JOOS. I 1008. 4 1010.9 1006. 7 1024.0 1014.0 

pressure (mb) 

Maximum pressuret 1026 1028 1030 1038 1034 1024 1021 1019 1025 1029 1020 1045 1045 

(mb) 

Minimum pressuret 1008 997 1007 1000 995 998 1001 987 983 984 991 1002 983 

(mb) 

Average air -29.8 -27.2 -27.3 -19.0 -10.9 -1.3 0.4 -0.3 -6 . 2 -16 . 0 -19.7 -19.9 -14 . 7 

temperature (°C) 

Haximum temperaturet -18 -18 -18 -2 0 8 II 8 0 -I -8 -3 JI 

(°C) 

tlinimum tempera turet -45 -38 -37 -31 -17 -5 -3 -6 -17 -32 -31 -38 -45 

(°C) 

*Instrument heights : ~ind, 16 m; pressure, 9.5 m (tlSL); air and dewpoint temperature, 3 m. Wind and temperature 

instruments are on a tower located 25 m northeast of the main building . 

tHaximum and minimum values are hourly averages . 

average, 69% of the winds are in this range. No rain fell at the observatory 

in January through March. MLO received only 156 mm of precipitation in 1983 

compared with 1242 mm in 1982. The average station pressure for the year was 

681.8 mb compared with a 7-yr average of 681 mb. The average temperature was 

7.9°C compared with a long-term average of 7.0°C. The winter and spring 

months were also warmer than usual. 

MAUNA LOA 

1983 

w 

WIND IJl.1)( ) 

-.5'SIWS < 6 

l' IO 

D •• • •• 

N 

s WIND FREQ 

" 

E 

MAUNA LOA 

77- 83 

w 

WIND SPl:Ell(ll/S) 

-.5,WS < 5 

VJl'Dl'IJ5,WS < LO 

D ••••• 

N 

s WIND FREQ. 

" 

Figure 29.--Wind rose of surface winds for MLO for (left) 1983 and 

(right) 1977-1983. See legend for fig. 28. 

61 

E 
Table 22.--MLO 1983 monthly climate summary-{~ 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1983 

Prevailing wind WSW SW SW SE SE SE SE SE SE SE SE SSW SE 

direction 

Average wind 6.2 4.S 4.2 3.1 4. I 4.7 S. I 4.9 4.6 4 . 4 s.s 6.2 4 . 8 

speed (m s-1) 

Maximum wind 13 II II 11 9 13 14 13 12 13 14 IS IS 

speedt (m s- 1 ) 

Direction of max. 2SS 270 240 131 161 129 142 137 123 133 124 184 !84 

windt (deg.) 

Average station 681.3 681. 3 682 . 3 680.8 681. 7 682.S 682.4 682.9 681.6 681.S 682 .9 680 . 4 68! .8 

pressure (mb) 

Maximum pressuret 684 68S 68S 684 68S 68S 68S 685 68S 686 686 68S 686 

(mb) 

Minimum pressuret 677 678 680 678 679 679 679 681 679 678 679 674 674 

(mb) 

Average air 8.1 6.9 8.S 6.1 8.0 8.8 10. 2 9.5 8. 0 7. I 8. 0 S.3 7.9 

temperature (°C) 

Maximum temperaturet 18 16 16 14 16 18 19 18 17 16 18 15 19 

(OC) 

Minimum temperaturet -2 -I -2 o o 2 o o -1 -2 

(OC) 

Precipitation (mm) o 0 o 8 3 64 20 21 3 3 34 1S6 

1'Instrument heights: wind, IO m; pressure, 3399 m (MSL); air and dewpoint temperature, 2 m. Wind and temperature 

sensors are located approximately 15 m southwest of the main building on a tower. Pressure seosors are located in 

the observatory building . 

tMaximum and minimum values are hourly averages . 

3. 10. 4 Samoa 

Southeasterly winds, including the directions east-southeast through 

south-southeast occurred 72% of the time in 1983 at SMO compared with an 

average of 63% for 1977-1983 (fig. 30). The shift in the occurrence frequency 

to more southerly direction is probably a result of the anomalous flow pattern 

caused by the ENSO event. A large high-pressure area over French Polynesia 

during January through March would explain more southerly winds and drier 

SAMOA 

1963 

w 

WI NO SPEEO(ll/ S) 

- .A:iii; WS < $ 

~5iWS IO 

D WS•IO 

N 

s WINO FREQ. 

"' 

E 

SAMOA 

77-63 

w 

WI ND SPEEO(ll/S) 

-.51iiWS<5 

lzmJ 5' W'S <10 

D WS• IO 

N 

s WIND f'RP4 

ll 

Figure 30.--Wind rose of surface winds for SMO for (left) 198j and 

(right) 1977-1983. See legend for fig. 28. 

62 

E 
Table 23.--SMO 1983 monthly climate summary;'• 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1983 

Prevailing wind SSE SSE SSE SSE SE SSE SE SE SE SSE SE NW SE 

direction 

Average wind 4. 1 3.8 3.1 '4.6 4.5 5.0 5.4 6.5 6 . 0 5.3 3.7 3.5 4.7 

speed (m s- 1 ) 

Maximwn wind IO 9 8 10 10 14 II II II 8 11 14 

speedt (m s- 1 ) 

Direction of max. 143 148 97 149 145 147 149 147 141 147 137 313 149 

windt (deg.) 

Average station 1003 . 7 1004.6 1002 . 9 100 I. 9 1001 .2 1000 1002 . 4 

pressure (mb) 

Maximum pressuret 1008 1010 1006 1005 1005 1003 1010 

(mb) 

Minimum pressuret 999 1001 1000 999 999 996 996 

(mb) 

Average air 26.9 27.8 27.3 26.4 26.5 25.9 24.9 24.4 25 . 3 25.3 26 . 5 26.9 26 . 2 

temperature (°C) 

Maximum temperaturet 31 31 30 30 30 29 29 27 29 31 31 31 31 

(°C) 

Minimum temperaturet 24 24 24 24 24 24 21 22 23 21 21 23 21 

(°C) 

Precipitation (mm) 187 223 163 170 78 78 15 20 124 135 247 347 1787 

*Instrwnent heights: wind, 14 m; pressure, 30 m (NSL); air and dewpoint temperature, 7 m. Wind and temperature 

sensors are located atop Lauagae Ridge, a distance 110 m northeast of the station . Pressure sensors are located 

in the station. 

tNaximum and minimum values are hourly averages. 

conditions at SMO. The wind shift was most noticeable in April when the wind 

was southeasterly 89% of the month. At no time during the first 5 months did 

the speed exceed 10 m s- 1 . The precipitation amount of 1.79 m for the year 

was only slightly less than 1.81 m recorded the previous year. The months 

May-August had less precipitation than they did in 1982 (table 23). The 

average temperature for the year was 26.2°C; the maximum, 31°C. 

The exposure of the instrumentation at SMO is considerably different from 

that at the other GMCC stations. Since February 1977, the anemometer has been 

located at a height of 14 m on a sampling tower atop Lauagae Ridge. In this 

location there are no major obstacles to the wind flow from the westerly direction, but the shape of the bluff displaces the wind from easterly directions. 

Temperature is measured at a height of 7 m on the same tower. Dewpoint temperature is measured from air samples drawn from the sampling stack. Station 

pressure is measured in the main building located about 100 m west of the 

sampling tower. On 28 March 1982 lightning hit the sampling tower causing 

damage to most instruments located on top of the ridge as well as to some in 

the station building. Some sensors could be repaired, but the wind and pessure 

sensors required replacement. A significant part of the pressure and humidity 

record is missing as a result of this lightning strike. 

3.10.5 South Pole 

The wind rose for 1983 is significantly different from the 7-yr average, 

(fig.31) in that 1983 is almost void of winds in excess of 10 m s- 1 Hourly 

average wind speeds of 10 m s- 1 or greater usually occur about 3.5% of the 

time. In 1982 they were observed 7% of the time. In 1983 only 9 hours were 

reported. This is reflected in the peak wind statistics and in an annual 

average wind speed of only 3.9 m s- 1 compared with the 7-yr average of 5.3 ms 1 

(see table 24). The most prevalent wind direction is north-northeast, as 

in previous years. At SPO north is defined as being along the prime meridian. 

63 
SOUTH POLE 

1963 

w 

WI ND SPEED(M/S) 

- 51iil'S<5 

~5i11'S<IO 

D ••••• 

N 

s WIND FREQ. 

x 

E 

SOUTH POLE 

77-83 

w 

WIND 9PIBll(N/5) 

- "''ft<& 

_l,ft<IO 

Dn•to 

J • 

N_ 

s WIND '!llll 

" 

E 

Figure 31.--Wind rose of surface winds for SPO for (left) 1983 and 

(right) 1977-1983. See legend for fig. 28. 

The full extent of the austral winter on the Antarctic plateau is displayed by the fact that for 8 months the monthly average temperature is below 

the annual average. The average for 1983 is -53.2°C, 3.6°C below the 7-yr 

average. The hourly-average maximum temperature was -21.2°C; the minimum, 

-78.4°C. 

Table 24.--SPO 1983 monthly climate summary-1• 

Jan Feb Har Apr Hay Jun Jul Aug Sep Oct Nov Dec 1983 

Prevailing wind N E ENE E E E ENE NNE NNE NNE ENE NNE NNE 

direction 

Average wind 

speed (m s- 1 ) 

3. 4 3. 8 4.3 4.0 3. 8 4. 5 3. 8 4. 3 4 . I 4. 0 2.5 3.6 3. 9 

Maximum wind 6 9 10 IO 10 9 10 II 8 6 8 II 

speedt (m s- 1 ) 

Direction of max. 28 20 12 40 31 26 22 15 39 3 307 25 39 

windt (deg.) 

Average station 687 . 3 682 . 5 678.6 678 .9 682 . 8 673 . 3 667.7 671. 4 669.7 668.0 671.8 682.3 6 76 . I 

pressure (mb) 

Maximum pressuret 694 695 694 688 706 699 68! 689 690 693 680 695 706 

(mb) ~linimum pressuret 678 672 667 670 666 657 653 654 643 643 663 676 643 

(mb) 

Average air -31.3 -44.7 -57.6 -58.7 -59 .0 -64 . 7 -65.7 -61.4 -60.4 -57. 3 -44.6 -32.1 -53.2 

temperature (°C) 

Maximum temperaturet -21 -33 -37 -42 -39 -44 -SI -47 -32 -48 -33 -23 -21 

(oC) 

Minimum temperaturet -37 -SS -73 -71 -76 -7S -76 -74 -78 -70 -S6 -41 -78 

(OC) 

* Instrument heights: wind, 10 m; pressure, 2850 m (MSL); air tempera tu re, 2 m. The anemometer and thermometer a re located on a mast 30 m grid north of CAF . Pressure measurements are ma<Je inside CAF . tMaximum and minimum values are hourly averages . 

64 
3.11 Precipitation Chemistry 

Routine and special precipitation chemistry measurements continued at the 

GMCC sites of MLO and SMO, and at the regional sites. Special studies continued at MLO using the ion chromatograph for anion analyses for the six-site 

network. The Washington, DC, network continued to operate with two observers. 

3.11.1 Baseline Measurements 

The five-site special network on the island of Hawaii and a sixth site on 

Kauai operated on approximately a weekly schedule. Site locations were dis-

'°' 

,,, 

rn 

lS) 

;'lj 

' CT 

~ 

.: Ql 

lJl 

5D 

1. 8J 

MLO 

J.5 "' .., 

:i: 

l.7 '4 

' O' 

~ 

3 

•.a ;!; 

•.l 

J.7 ID) 

J.a !I) 

.., !il :i: 

t:.0 ' CT 

~ 

3 !j) 

.l 

'·' l'J 

, ,7 

OJ 

J.9 

!il 

II.~ 

•.1 

.., OJ :i: .... .t CT 

~ 

3 

.. l'J 

"' 

Figure 32.--Monthly precipitation weighted mea~s for si~ sites on the 

islands of Hawaii and Kauai during 1983 (+ H ; 0 S04). The sites in 

order of increasing elevation are Kumukahi, Kauai, Halai Hill, 

22 Mile, Kulani Mauka, and MLO. 

65 

' 

.., 

:i: 

~ • .t.I 

•.7 
cussed in previous GMCC Summary Reports. As seen in fig. 32, the acidity at 

MLO and Kulani Mauka, the most elevated sites, remains at much higher levels 

than the acidity at the three sites at lower elevation on Hawaii. An opposite 

trend, a decrease in sulfate with increasing elevation, i~ also evident. However, the removal of the seawater component results in SQ4 values quite similar to those measured at MLO (fig. 33). Agreement of so4 at Halai Hill and 

Kauai, sites with similar elevation and orientation to the trade winds, was 

excellent (fig. 32) after the beginning of April. 

15' 5J 

'" :is 

+MLO 

IT 6. Kulani Mauka l.J': 

c 22 Mile ::: 

O" 

::: " ~ 

.: r, 

O" 

~ 

.: 

" " 

25 E 

Figure 33.--Monthly precipitation weighted (left) sulfate means and 

(right) excess sulfate means for five sites on the island of Hawaii. 

At MLO three independent pH measurements have been made for the past 

several years. The GMCC laboratory values (designated as event field pH in 

fig. 34) are measurements completed immediately after precipitation events at 

MLO. NADP field values were measured weekly at MLO, and NADP laboratory values were measured by ISWS at least 1 week after the field values from the same 

7.0 

!.> 

l( 

~-~ 

5.~ 

:i: 

0. 

•.S 

II.~ + Weekly Lab pH 

6 Weekly field pH 

:.~ O Event Field pH 

J..O 

Figure 34.--Monthly precipitation 

weighted pH at MLO. Values vary as 

a function of time between sample 

collection and measurement. (No 

rain fell prior to 4 April.) 

66 

e ~ MLO 

u 11 Ku Jani Mauk a 

c "' D 22 Mile 

~ 0 Halal Hill ~ 

• Kumukahl 0. IC u 

~ 

"' l':· 

Figure 35.--Monthly precipitation at 

five Hawaiian sites for 1983. 
Table 25.--Annual precipitation data for the six-site Hawaiian network 

Site 

MLO 

Kulani Mauka 

22 Mile 

Halai Hill 

Cape Kumukahi 

Kauai 

Elevation 

(m) 

3399 

2530 

1829 

122 

0 

152 

Precipitation 

(cm) 

1982 1983 

100.10 15.37 

166.60 39.29 

251.63 116. 62 

498. 14 217.14 

254.05 100 .54 

382.98 161. 30 

precipitation sample bucket. It is evident that the pH of precipitation increases for several weeks following sample collection, probably due to the 

consumption of organic acids (Keene et al., 1983). Note that data from the 

first 3 months of 1983 in MLO are not missing. No rain fell prior to 4 April, 

and total annual rainfall was well below normal for the entire island of Hawaii 

See fig. 35 and table 25. 

Snow samplf data fQr BRW and SPO are shown in fig. 36. Monthly precipitation weighted H and SO~ means for SMO are shown in fig. 37. 

laJ 

~ Tj 

... 

• 3 so 

25 

BARROW + 504-

0 H~ 

J,9 

"·' 

.., 

:I: 

"l 

.. ~ 

' 

. " 3 

SOUTH POLE 

Figure 36.--Snow sample ion concentrations for BRW and SPO during 1983 . 

3.11.2 Regional Measurements 

In a continui ng effort to upgrade the NOAA regional precipitation sites, 

two stations have been closed and three new stations opened in 1983. The 

Research Triangle Park, NC, site was closed because of its proximity to several other NADP stations; the Huron, SD, site was closed because of a problem 

67 
SA MOA 

:i.5 

.. 1 

Figure 37.--Monthly precipitation 

weight~d means ~or SMO during 1983 

(+ = H ; 0 = S04). 

.. ,. " 22G 

2GJ 

1: 

,, )l~''.l I ,, 

'·' 

• J,I 

l.1 

,L. , ,, ....... O.Ji.......i,.......i.,.....~~..,._.;.,-.4-'--t/,-"fl--'"<'i-"-+r--'or-"""T", -.:,o-, ""'_,\-'i'· i;. 

1S7S 1976 1977 1178 19tl 1S!2 1913 

Figure 38.--Monthly precipitation 

weighted hydrogen ion concentration 

for the Washington, DC, area. The 

center bars highlight the summer data. 

Each annual mean is noted at the top 

of the corresponding column. 

with local pollution sources. 

SD, Lilley Cornett Woods, KY, 

College, PA. 

The three new sites are located in Cottonwood, 

and near Pennsylvania State University, State 

3.11.3 Washington, DC, Network 

The data for the Washington, DC, network are shown in fig. 38. 

3.12 Data Management 

3.12.1 Acquisition 

The passing of 1983 marks 10 years of operation for the minicomputercontrolled signal-recording system known as ICDAS. The first installation of 

ICDAS was in January 1974 at SPO. Similar systems were installed at BRW in 

May 1974 and at MLO in September 1974. The SMO installation was completed in 

January 1976. At MLO and SPO there were major interruptions to the data during the first 2 years of operation. At MLO, the main causes of the interruptions were inadequate control of the environmental temperature and the need to 

collect lidar data with the same minicomputer. At SPO, problems in 1975 were 

caused by incorrect changeover of the software. 

ICDAS has performed well. The performance statistics by station and year 

beginning in 1978 are shown in fig. 39. The ICDAS unit at MLO has been operational 93.3% of the time since it was moved to a stable thermal environment in 

the main building in 1977. For the period 1978 to present, ICDAS has operated 

for 96.2% of the time at SMO, 98.8% at SPO, and 90.1% at BRW. During 1983, in 

particular, BRW had considerable problems with the magnetic tape drive, accounting for most of the failure time of 18%. Breakdowns at the other stations for 1983 were minimal: MLO, 2%; SMO, 1%; and SPO, 1%. All continuously 

measured variables are recorded on ICDAS including C0 2 , ozone, solar irradiance, aerosols, winds, pressure, and temperature. 

68 
SPO SllO Ml.O 

3.12.2 Data Processing 

BRW 

Figure 39.--ICDAS performance 

statistics by station and year for 

1978-1983. 

All data editing and processing is performed at the Boulder facility, 

employing a CDC 750 computer. A minicomputer system within GMCC, called the 

Reduction Facility, is intermediary to the CDC 750. In the Reduction Facility 

data are transferred from the station tapes to a tape format more acceptable 

to the larger facility. All the data are transferred in 1-mo segments to the 

CDC 750. No significant hardware or software changes were made in 1983. A 

DECtape II (TU-58) is used to read data from CAMS into the reduction system. 

In the future, all incoming CAMS tapes will be duplicated to 1600 bpi PE tapes 

for permanent storage before the data are transferred to a computer file. 

Work continued through the year on the software to transfer the data. 

3.12.3 CAMS Development and Testing 

The most significant advances in the development of a control and monitoring system to replace ICDAS were in the completion of hardware component 

testing and the preparation of software. For the most part, the electronic 

boards and peripherals were selected and tested early in the year. A deployment plan was prepared that suggested the implementation of four CAMS per 

station with a spare on the shelf. In the final analysis, the CAMS to support 

the aerosol measurement was combined with the unit for solar radiation, and 

the monitoring of ozone data was combined with meteorological sensor signals. 

A third CAMS operates the C02 analyzer. Once the configuration was determined, 

software specifications were revised for the specific units. By the end of 

the year the software for two of the units was written, but not completely 

tested. Twenty units were built: three active CAMS and one spare per station. 

About half were tested by the end of the year. Five additional CAMS are required in other applications and as spares to remain in Boulder. 

CAMS uses the STD BUS as a means of interfacing with the Z80 microcomputer. 

The STD BUS uses a mother-board interconnecting system concept and is designed 

to handle any of a variety of STD-compatible modules. The compact modules for 

the STD BUS are 4 . 5 x 6 . 5 in, allowing for system partitioning by function 

(RAM, EPROM, I/O). With the completion of hardware testing, the following 

modules were found to be necessary. The first six modules are common to all 

units. 

69 
(1) Z80 Central Processor Module, MDX-CPUl (Mostek MK77850). 

(2) Universal Memory Expansion Board, MDX-UMC (Mostek MK77759). 

(3) Battery Backup RAM Module, MDX-BRAM (Mostek MK77760). 

(4) Battery Clock Module, MDX-BCLK (Mostek, MK77979). 

(5) Serial I/O Module, MDX-S102 (Mostek, MK77670). 

(6) Monitor board (developed and constructed in-house). 

(7) Analog Input Board (Data Translation, DT2742). 

(8) Analog Input Board (Data Translation, DT2744). 

(9) Analog Input Power Converter Board (Data Translation, DT2715). 

(10) Digital I/O Panel Controller, DIOP (Mostek, MK77672). 

(11) Digital I/O Panel (Mostek, MK77673). 

(12) Digital I/O Card (ProLog, 7601). 

(13) Remote I/O Controller, RlOC (Mostek, MK78208). 

The analog input boards are used in two modes: programmable gain mode DT2742 

and fixed gain mode DT2744. Each analog input board requires a power converter board. The digital I/O panel and interface are used to control C02 calibration solenoids. The digital I/O card is used to acquire wind data in the 

meteorology CAMS. The remote I/O controller acquires asynchronous serial I/O 

from a companion unit (RS-422) at the Dasibi ozone monitor. 

Using the serial I/O modules that provide an RS-232 port, CAMS interfaces 

with three devices. Data are recorded on preformatted cartridge tapes (DEC, 

TU-58). Each tape holds about 130,000 observations allowing, in most cases, 

14 days or more operation between changes, Each CAMS contains two tape drives 

to facilitate automatic tape drive reassignment in case of a failure. A control panel is also supplied (Burr-Brown, TM-76; fig. 40). Designed as a durable, compact remote-entry terminal for computer access, this modular panel 

serves as a real-time data display as well as a means by which the operator 

controls processing and enters data. Hard copies are obtained on a dot-matrix 

printer (Epson MX-80). One printer is shared by the three CAMS in operation 

at the station. A switch is used to control access. Routine printouts give 

the results of instrument calibrations and summaries of daily observations. 

CAMS also maintains the time and date with a battery-powered clock. The 

random-access memory is also battery powered so that CAMS can recover to a 

normal state after a power outage. A thermometer on the monitor board measures the internal temperature. If the temperature exceeds the value specified for the electronics, a message is displayed to the observer. Figure 41 

70 

Figure 40--An exposed view of CAMS . 

In addition to the control panel, 

the tape drives, card cage, and 

power supplies are visible. 
Figure 41--Station configuration of 

the aerosol-solar radiation and the 

meteorology-ozone CAMS. 

shows the aerosol-solar radiation and the meteorology-ozone CAMS in station 

configuration. 

Previously, all software for the microcomputer data logging and control 

requirements had been written in FORTRAN. These applications had limited I/O 

requirements that could be met by simply suspending acquisition tasks so that 

data could be output. The requirements for CAMS contained a significant increase in input and output such that a multitasking scheduler using interrupt 

priorities was necessary. Such a system was not feasible under FORTRAN. The 

problem was solved by changing to the language FORTH, which is more suitable 

to the microprocessor. A multitasking version of FORTH was purchased and 

device drivers were written. FORTH software development and testing began in 

June, and continued through the remainder of the year. 

Along with reliability, one of the primary design considerations of CAMS 

is the ready access to data to allow the station staff to have active quality 

control of the measurements. This is accomplished in part by maintaining a 

file of the past 24 hourly average values, which can be printed at any time. 

At a specific time each day the file is recorded on tape. The observer can 

read and print the contents of any data file on tape when desired. The printout of the file of hourly average values is formatted just as the computer 

resident file is. A single dot-matrix printer is provided for the three active CAMS. An RS-232 switch is used to select the active CAMS. 

71 
3.12.4 CAMS for C0 2 

The design of the C0 2 CAMS incorporates two distinct modes of processing: 

(1) regular processing, during which ambient air is sampled for minutes 0-49, 

calibration gas W2 for minutes 50-54, and calibration gas Wl for minutes 55-59 

of each hour; and (2) weekly calibration processing, during which six 

calibration gases are sampled repetitively for 5 minutes each. The CAMS automatically controls the flow of the various gases by switching solenoids. 

The default mode of processing is regular processing. A weekly calibration may be started by pushing the F7 button on the front panel (fig. 40) 

and requesting the weekly calibration option. The F7 button has another option that allows manual setting of relays for a specified number of seconds to 

test the flow of gases from different tanks. When the relays are set in this 

manner no data are stored, since this function is for testing and is not part 

of normal data acquisition. 

The weekly calibration consists of 5-7 hours or cycles of data. For each 

cycle, Wl and W2 concentrations are derived by finding the quadratic equation 

that best fits the four calibration points (low, mid, high, and Q gases), then 

solving for Wl and W2 along this parabola. The quadratic equation is fit by 

Gaussian elimination with row pivoting. 

The operator may obtain printed reports that show minute voltages and the 

computed hourly concentration, hourly concentrations for the past 24 hours, or 

weekly calibration results. These data are also recorded on cassette. 

3.12.5 CAMS for Meterology and Ozone 

The specifications for the operation of the meterology-ozone CAMS called 

for detailed data display to facilitate quality control on the part of the 

observers at the station. Display takes the form of 1-min average values of 

all the active parameters being measured and a printout of a file of the previous 24 hourly values. The 1-min averages are displayed on the front panel 

of CAMS along with the date and time. Although these values are scaled, they 

are not recorded. Ten-minute and hourly averages are recorded along with a 

set of flags that indicate the proper operation of peripheral systems that can 

affect data quality. The printout of the hourly average values for the previous 24 hours will constitute part of a routine daily weather report. 

The accurate reporting of weather conditions is important to the interpretation of all measurements at the observatories. The daily weather report, 

performed at a specific time (0000 GMT) daily, will serve as a definitive 

check on the continuous measurements. Included in these measurements is an 

estimate at the wind speed and direction, a direct comparison between the 

pressure transducer monitored by CAMS and the mercurial barometer, and a comparison between the air temperature at 2 m and the shelter temperature. Where 

conditions permit a meaningful comparison, a set of dewpoint temperatures will 

be measured as well. The precipitation amount will be recorded at the three 

northernmost stations. The comparison between independently observed values 

and those displayed on CAMS will serve as a daily check on data quality. The 

daily observations include determinations of the sky cover, cloud type, visibility, and weather conditions. These observations are reported on the printout of the hourly data, and are part of the official record. 

72 
3.13 Atmospheric Trajectories 

Since 1981 GMCC has had a computer program that produces atmospheric 

trajectories. The development and use of this model is documented in the two 

previous Summary Reports (Bodhaine and Harris, 1982, pp. 71-74; Harris and 

Bodhaine, 1983, pp. 67-75) and by Harris (1982). Those publications detail 

the computational methods employed in the isobaric and the isentropic versions 

of the trajectory program. 

This report updates the status of the program and gives examples of 

results obtained during 1983 . A number of special projects in sec. 4 use 

trajectories in combination with other data to investigate airflow to various 

locations under study. See specifically secs. 4.1, 4.2, and 4.4. In 

addition, trajectories produced by this model were used to study origins of 

air arriving along a research cruise track and are presented in Parungo et al. 

(1984). 

Table 26 gives a description of the input data obtained from NMC through 

NCAR for the trajectory program. Table 27 shows periods of missing data 

within this data set for which no trajectories can be computed. During 1983, 

the inventory of trajectories for BRW, MLO, and SMO (table 28) was expanded. 

To date, no trajectories have been computed for SPO. 

Figure 42 shows a new feature of the trajectory plotting program, which 

allows four levels to be displayed on one map for comparison. Trajectories in 

this form are marked with letters A for 1000, B for 850, C for 700, and D for 

500 mb and are plotted for one arrival time (0000 GMT or 1200 GMT). 

The capability of computing forward trajectories was added to GAMBIT!, 

the Northern Hemisphere isobaric model. Forward trajectories departing 

Norilsk, U.S.S.R., on 16 February 1982 are shown in fig. 43. Five days later 

(the approximate travel time to Alaska) on 22 February, Shaw (1982) noted haze 

at Ester Dome, about 650 km southeast of BRW. He suggested Norilsk (69.4°N, 

88.5°E), the largest copper-nickel smelting complex in the world, as a 

possible source for the haze. Backward trajectories arriving at BRW on 

this day (fig. 44) show transport from the area of Norilsk, which would be 

expected judging from the forward trajectories in fig. 43. 

Dates 

Parameters 

Levels 

Program 

Table 26.--Descri ption of NMC data purchased from NCAR 

Northern Hemisphere 

65 x 65 grids 

1975-1983 

u, v, z, T 

1000-100 mb (mandatory 

levels) 

GAMBITl, GAMBIT3 

73 

2.5° global grids 

1977, 1979-1983 

u, v, z, T 

1000-100 mb (mandatory 

levels) 

GAMBIT2 
Table 27.--Breaks in NMC data for 1000, 850, 700, 500 mb 

Northern Hemisphere 

Year 65 x 65 grids 2.5° global grids 

1975 14-15 Jan N.A. 

16-31 Jan (1000 mb only) 

16-18 May 

1976 None N.A. 

1977 None None 

1978 None N.A. 

1979 None None 

1980 07-08 Aug 26-28 Nov 

30-31 Dec 25-31 Dec 

1981 01-07 Feb 01-07 Feb 

04-10 Oct 29 Aug-06 Sep 

03-11 Oct 

16-20 Dec 

1982 12-19 Jan 22-25 Feb 

22-26 Feb 29 Jun-18 Jul 

03-11 Jul 28-30 Jul 

27-31 Jul 10-17 Aug 

09-16 Aug 

1983 09 Apr-01 May 08 Apr-01 May 

18-21 Jun 14-16 Oct 

03-05 Sep (N.H. only) 

23-26 Nov 

(S .H. only) 

In another example, forward trajectories (fig. 45) depart from Bennett 

Island on 18 February 1983, the date of a venting episode on this Russian 

island. At least 53 cases of venting have been documented by satellite photos 

during the past 11 years. At first this venting was thought to be volcanic, 

but scientists now believe it is a periodic methane hydrate release. Note 

that air arrived at BRW from Bennett Island after only 1-1.5 days. 

Numerous questions were asked concerning the usefulness of trajectories 

in the Arctic, so the real data coverage north of 80°N was investigated by 

Station 

BRW 

MLO 

SMO 

Table 28.--Inventory of trajectories for GMCC observatories 

Dates 

Feb, Mar, Apr 1979-1983 

Miscellaneous short periods 

1975-1983 

1977, 1979-1983 

74 

Levels 

(mb) 

850, 700, 500 

1000, 850, 700, 500 

850, 700, 500 

1000, 850 
BRW TRAJECTORIES ARRIVING 83073 - 3/ 14 / 83 AT C1l 

A: 1000 MB 

B: B50 MB 

' 1110•11 

C: 700 MB 

D: 500 NB 

<:" 

120~. 

Figure 42.--BRW trajectories 

arriving 14 March 1983 at 0000 GMT 

on the (A) 1000-, (B) 850-, (C) 

700-, and (D) 500-mb pressure surfaces. Numerals on the trajectories 

indicate number of days to travel 

from that point to the destination. 

TRAJECTOR I ES TO BRW (71 JZN. 15662W) 82053 - 2 22 62 

A: C1l 700 MB 

B: OZ 500 MB 

C: 12Z 700 MB 

D 12Z 500 MB 

t201 w 

/, 

90' w 

Figure 44.--BRW backward trajectories arriving 22 February 1982 on 

the 700- and 500-mb pressure surfaces. 

75 

TRAJECTORIES FROM NOR (6940N, 8850E) 62047 - 2/ 16/ 62 

A: OZ 700 MB C: 12Z 700 MB 

B: OZ 500 MB D: 122 500 NB 

120 ... W 

1.; •• 

Figure 43.--Forward trajectories 

departing from Norilsk on 16 February 1982 on the 700- and 500-mb 

pressure surfaces. 

BEN TRAJECTORIES DEPARTING 63049 - 2/18183 AT C1l 

I.: B50 MB M: 700 MB U: 500 MB 

1aci•w .~·. 

Figure 45.--Forward trajectories 

departing from Bennett Island on 

18 February 1983 at 0000 GMT on the 

(L) 850-, (M) 700-, and (U) 500-mb 

pressure surfaces. 
obtaining from NMC lists of actual weather observations in that region. The 

weather observations for 9 February 1984 1200 GMT were deemed representative, 

though the numbers may vary somewhat from day to day: 

TIROS (temperature soundings)--175 

Upper-air reports (temperature, pressure, wind, moisture)--4 

Drifting buoys (temperature, pressure)--13 

Land stations (surface observations)--8 

Aircraft reports (wind, pressure, altitude)--8. 

For areas where no real data are available, the NMC global circulation 

model obtains information using continuity and extrapolation from areas where 

data are available; for example, continuity northward from lower latitudes, 

continuity upward from the surface (when only a surface observation is 

available), and continuity from the previous analysis. On the basis of the 

numbers of real observatations and experience, it is felt that in most cases 

valuable information can be gained from Arctic trajectories . 

In contrast to trajectories that show possible transport paths for 

industrial pollution into the Arctic (figs. 42 and 43), fig. 46 shows a fairly 

common track that often results in cleaner conditions at BRW. Note the 

trajectories show no travel over land. The cyclonic curvature is an 

indication of possible cleansing by precipitation during transport to BRW. 

BRW TRAJECTORIES ARRI\ IC'G 82039 2 8 82 AT OZ 

L:: 500 ~18 

1e0'w 100'-w 

76 

Figure 46.--BRW trajectories 

arriving 8 February 1982 at 0000 GMT 

on the (1) 850-, (M) 700-, and (U) 

500-mb pressure surfaces. 
4. SPECIAL PROJECTS 

4. 1 Trajectories During AGASP 

Atmospheric trajectories were calculated for various Arctic locations 

for March and April 1983 during AGASP. The results of the trajectory study 

appear in Harris (1984); highlights are presented here. For information 

concerning the trajectory model, see sec. 3.13. The focus of this study was 

on trajectories arriving at BRW and along AGASP flight tracks 1-4 north of 

BRW. Trajectories along AGASP flight track 8 north of Bod¢, Norway, were also 

analyzed. (See sec. 4.3 for flight tracks and background information on 

AGASP.) 

Figure 47 shows trajectories arr1v1ng at BRW that are typical of those 

calculated for several days before the AGASP flights north of BRW. During 

this period (6-10 March 1983) trajectories circled the pole with cyclonic 

curvature, showing no contact with industrial areas. Also there is no 

evidence of direct steady flow from midlatitude oceans, as shown in fig. 46 

(sec. 3.13), which could have the effect of bringing clean air into the Arctic 

Basin. At this time Bodhaine et al. (1984) found surface aerosols at BRW 

representative of background Arctic haze. During the week of the AGASP 

flights, which occurred close to 0000 GMT on 12, 14, 16, and 18 March, 

trajectories changed to over-the-pole flow from Eurasia at the 850-, 700-, and 

500-mb levels. These levels were examined for long-range transport because 

Schnell and Raatz (1984) found the highest aerosol concentrations between 

800-600 mb during the AGASP flights. The idea that long-range transport to 

BRW does not occur at the surface is consistent with the fact that air flowing 

adiabatically northward from midlatitude pollution sources must rise as it 

approaches the pole along an isentropic surface. A three-dimensional picture 

and discussion of airflow along these domed surfaces can be found in Harris 

and Bodhaine (1983, pp. 70-75). 

BRW TRAJECTORIES ARRl\'ING 83069 3 JO 81 AT OZ 

Lo B50 MB M· 700 MB ~ 500 MB 

.r;c; ... 

! 

77 

Figure 47.--BRW trajectories 

arriving 10 March 1983 at 0000 GMT 

on the (L) 850-, (M) 700-, and (U) 

500-mb pressure surfaces. Numerals 

on the trajectories indicate number 

of days to travel from that point to 

the destination . 
Figure 42 (sec 3.13) shows trajectories arriving at BRW on 14 March at 

0000 GMT, the date when the strongest winds (about 15 m s- 1 ) and least 

vertical wind shear were seen in the 850-, 700-, and 500-mb trajectories 

(marked B, C, and D). Near this time the maximum optical depth measured 

during 10-20 March at BRW was recorded (Dutton et al., 1984), and surface 

aerosoJ concentrations at BRW were about 50% higher than the background haze 

levels found earlier (Bodhaine et al., 1984). The 1000-mb trajectory marked A 

in fig. 42 shows light meandering winds that, unlike at the higher levels, 

show no transport from known industrial sources to explain the haze events 

seen at the observatory and on the aircraft. This trajectory is typical of 

the 1000-mb trajectories studied for the AGASP period. 

Trajectories arriving along AGASP flight tracks 1-4 north of BRW were 

computed and compared with the BRW trajectories. Trajectories arriving only 

several hundred kilometers north of the observatory showed significant differences from those arriving at BRW at the same time. The pattern that persisted 

in most of the trajectories from flight tracks 1-4 is demonstrated in fig. 48, 

which shows the relationship between the flight-track trajectories and the BRW 

trajectories for 0000 GMT on 12 March. In general, the influence of an Arctic 

anticyclone residing in the East Siberian Sea early in the period (Raatz, 1984) 

was stronger on the flight-track trajectories, whose destinations, being north 

of BRW, were closer to the center of the anticyclone. Hence more of these 

trajectories originated in northeastern Siberia compared with the BRW trajectories, which more often originated in western Asia or Europe. The fact that 

the origins of the air changed gradually as the aircraft flew north out of the 

transport zone and not uniformly throughout the three levels (Harris, 1984) 

might explain some of the haze-layering effects seen by Schnell and Raatz 

(1984) from the aircraft. 

Forward trajectories from BRW were computed for the period of AGASP to 

track the air after it passed the observatory. Figure 49 shows air arriving 

at BRW (solid) and departing from BRW (dashed) on 12 March 1983 at 0000 GMT. 

These trajectories indicate that air reaching BRW on this date soon escaped 

the Arctic Basin and flowed into the North Pacific region. In contrast, 

_.;. r .r 

78 

Figure 48.--Trajectories arriving 

at 73.07°N, 159.82°W (solid) along 

AGASP flight track 1, and trajectories arriving at BRW (dashed) for 

12 March 1983 at 0000 GMT. 
Figure 49.--Trajectories arriving 

(solid) and departing (dashed) from 

BRW on 12 March 1983 at 0000 GMT on 

the (L) 850-, (M) 700-, and (U) 

500-mb pressure surfaces. 

150~. 

<' 

120~. 

f 

'illi'f 

Figure 50.--Trajectories arriving 

(solid) and departing (dashed) from 

BRW on 14 March 1983 at 1200 GMT on 

the (L) 850-, (M) 700-, and (U) 

500-mb pressure surfaces. 

fig. 50 shows that the air arriving at BRW 2 days later on the 850- and 700-mb 

pressure surfaces remained in the Arctic, probably because of the influence of 

the anticyclone previously mentioned. 

During AGASP flight 8 (31 March) from Bod¢, Norway, north to Svalbard and 

beyond, haze was present during the southern portion of the flight. In the 

vicinity of 79.00°N, the aircraft flew through an aerosol front into clean 

air. This event was noted visually and shows up dramatically in measurements 

taken aboard the aircraft (Raatz and Schnell, 1984). Figure 51 shows trajec79 

Figure 51.--Trajectories arriving 

at 73.76°N, 24.86°E (solid) and at 

81.00°N, 17.00°E (dashed) along 

AGASP flight track 8 on 31 March 

1983 at 1200 GMT. 
tories arriving along flight track 8 at two locations about 800 km apart, for 

the time closest to the flight (1200 GMT). Those arriving at 73.76°N, 24.86°E 

during hazy conditions are south of the aerosol front. The source areas 

suggested by these trajectories are Europe at the lower levels and central 

Asia at 500 mb. The trajectories arriving at 81.00°N, 17.00°E, close to the 

northernmost point of AGASP flight 8, are north of the aerosol front. Source 

areas indicated by these trajectories are Greenland and northern Canada. At 

this point in the flight, the aircraft was in nonhazy air. 

4.2 The Flow Climatology From Bermuda, and Its 

Implications on Long-Range Transport 

The transport of pollutants off the North American Continent is one part 

of the overall chemical budget that is being studied under WATOX. As a 

contribution to the understanding of this transport, back trajectories were 

calculated from Bermuda and a flow climatology was developed for a 7-yr 

period. Highlights of this study are presented here; a more complete report 

can be found in Miller and Harris (1984). On a daily basis, 10-day back 

trajectories were produced for the 850- and 700-mb levels from January 1975 to 

December 1981. Details of the computer model that produced the trajectories 

are presented in Harris (1982). The 850-mb trajectories constitute the data 

base for determining the climatology; the 700-mb trajectories were used for 

comparison. 

A classification system was adopted based on the hypothesis that the 

North American Continent is a source of pollutants and the fact that the 

precipitation that falls in Bermuda is strongly governed by the position and 

strength of the Bermuda high. The movement of this anticyclone north and 

south determines if the flow is strongly westerly (winter) or if it has a more 

southerly component (summer). Figure 52 shows the sectors used to categorize 

the trajectories: northwest (NW), west-southwest (WSW), south-southwest (SSW), 

southeast (SE), northeast (NE), and no direction (H). The NW and WSW categories were created because of the dual nature of North American pollution 

source configurations, and can be combined to cover all of North America. 

Category H in most cases was observed during periods when the Bermuda anticyclone was far north and flow was mainly of a weak circular nature. The 

distance back for the 10-day period was also measured, and was generally 

greater than 1000 km except during weak flow conditions (category H). 

A OZ 850MB C: 12Z 850 MB 

Figure 52.--The classification 

system used for the period of study 

(1975-1981). 

80 
"' Q) 

"' ra 

u 

0 

~ .0 

E 

:J 

z 

2000 

1000 

SE SSW WSW NW NE H Missing 

Sector 

Figure 53.--A histogram of all 

850-mb trajectories to Bermuda from 

1975 to 1981. 

c 

0 

. .,, 

~ 

·a. 

"(3 

Q) 

ct 

0 

.... 

Q) 

Q) 

E 

:2: 

2000 

1000 

SE SSW WSW NW NE H M 

Sector 

Figure 54.--A histogram of the 

gmount of rainfall for the associated trajectories to Bermuda. 

Figure 53 presents the number of trajectories that fell in each category 

for the entire 7-yr period. The obvious conclusion is the predominance of the 

northwestern trajectory in the flow pattern to Bermuda. If WSW and NW are 

combined, 58% of the trajectories are accounted for. 

Because one of the objectives of the WATOX project is the determination 

of the precipitation chemistry in Bermuda, a back trajectory was prepared for 

each daily rain event in the 7-yr period. In fig. 54, the category of trajectory is plotted vs. the total amount of rainfall for the associated trajectory 

over the 7-yr period. It is important to note that precipitation is higher 

for southerly flow than would be expected if the rainfall were distributed 

evenly for all trajectories (compare figs. 53 and 54). As an initial comparison between the trajectories and the chemical data, the pH values published by 

Jickells et al. (1982) are plotted against the number of trajectories from the 

81 
5. 

5 2 

44 

42 

·--.... ' 

M A 

1980 

, ,' 

., 

, ' 

, ,' ' 

, 

, 

, 

, 

0 

Months 

N 

pH 

No of Tra1ec1aries 

D M 

1981 

A 

100 z 

0 

~ 

n 

"' ~ 

<> 

~ 

~ 

z 

:ii 

"" :ii 

50 ~ 

Figure 55.--A comparison of pH values at Bermuda for the first year of 

WATOX vs. trajectories for that period from the WSW and NW categories 

(rain only). 

NW and WSW sectors (fig. 55). There is good agreement between high acidity 

and flow from the North American sectors. This gives further credence to the 

hypothesis of Jickells et al. that there is long-range transport of acidic 

material to the Atlantic from the United States and Canada . 

4.3 Arctic Gas and Aerosol Sampling Program (AGASP) 

4.3.1 Introduction 

Haze over the Arctic icecap was first extensively documented in contemporary scientific literature by Mitchell (1957). He noted that the haze was 

generally observed during periods of otherwise clean air, extended over 

altitudes from near the ground to 500 mb, and extended over air routes up to 

1000 km. On the basis of a range of optical and physical evidence, Mitchell 

suggested that the haze was composed of non-ice particles less than 2 μm in 

diameter. Beginning in the mid-1970's, research results of scientists such as 

Holmgren et al. (1974), Radke et al. (1976), Bodhaine et al. (198la), and Rahn 

(198la, 1981b) confirmed the presence of much higher concentrations of aerosols 

in the Arctic atmosphere than one would expect in a remote and supposedly 

pristine environment. The data further suggested that the haze had an anthropogenic component. 

Radiative-transfer modeling studies of Arctic haze have indicated that 

average local atmospheric heating by solar absorption from a thick layer of 

carbon aerosol in the Arctic haze may be comparable with that from doubling 

atmospheric C0 2 concentrations (Porch and MacCracken, 1982; Vallero et al., 

82 
1984). These effects are most pronounced in the high Arctic latitudes, partly 

because of the high surface albedo of large and persistent areas of snow and 

ice. 

In the spring of 1983, Arctic haze was studied with six aircraft (three 

from the United States, two from the Federal Republic of Germany, and one from 

Norway) and from three surface-based networks operated by Norway and Sweden, 

Canada, and the United States. Each aircraft measurement program was coordinated with at least one surface station. In many cases the same make and 

model of instruments were used in the aircraft as on the ground. The most 

extensive aircraft program in the haze study was built around flights of the 

NOAA WP-3D Orion, the aircraft used for the airborne portion of NOAA AGASP. 

NOAA AGASP was designed to extend into three dimensions the Arctic haze 

measurements conducted at surface stations such as those at BRW; Alert, 

Canada; and Ny Alesund, Spitzbergen. In so doing, a much broader picture of 

haze over the Arctic icecap would be obtained and the representativeness of 

the ground-based measurements ascertained. 

The WP-3D flew 144 flight hours on 12 separate research missions during 

AGASP; approximate flight tracks and mission numbers are shown in fig. 56. 

In support of aircraft operations, aerosol and radiation measurements were 

conducted at BRW (Bodhaine et al., 1984; Dutton et al., 1984) and the Alert 

background station (Hoff and Trivett, 1984), before, during, and after the 

flights. 

Thirty-five scientists from 17 different institutions joined the WP-3D 

research program to conduct their specialty measurements and analyses. See 

Harris and Bodhaine (1983, p. 88) for a list of participants and programs. 

AGASP provided funds for mounting instruments on the aircraft and for 

field expenses for the cooperating scientists. Support for data analyses was 

the responsibility of the respective scientists. CIRES and GMCC provided 

AGASP-I 

March-April 1983 USSR 

83 

Figure 56.--Approximate flight 

tracks of the NOAA WP-3D during the 

AGASP project. Flight 6 went into 

the stratosphere during a tropopause 

fold event, and flight 12 was over 

the center of the Icelandic low, 

into which 11 dropwindsondes were 

released in a planned pattern. 
personnel and support services for 

for data archiving and publishing. 

ONR, and NASA. 

4.3.2 Haze in the Alaskan Arctic 

organizing and directing the program, and 

Support for AGASP was provided by NOAA, 

Four NOAA WP-3D flights were conducted in the vicinity of BRW during 

11-18 March 1983. These flights occurred during a period when there was 

strong organized transport of aerosol from midlatitudes across the pole into 

the Alaskan Arctic (Raatz, 1984; Harris, 1984). Aircraft instrumentation is 

discussed by Schnell (1984a). 

In this report, CN concentrations reflect, for the most part, particles 

in the Aitken (<0.2-μm-diameter) size range. Particles of 0.370- to 0.495-μm 

diameter lie within the large-particle range (0.2- to 2.0-μm diameter). Giant 

particles (>2.0-μm diameter) are presented in spectral format. For a discussion of these terms see Junge (1963). 

Large-particle data are an independent in situ measure of the aerosol 

involved in light scattering (a ). The nephelometer, used to measure light sp 

scattering of aerosols, is most sensitive to particles in the size range 0.1-

to 1.0-μm diameter, with maximum sensitivity for particles near 0.5-μm diameter. The range of 0.370- to 0.495-μm diameter (as measured by one channel 

of the 15-channel laser aerosol spectrometer) falls just below the maximum 

sensitivity of the nephelometer. Thus, light scattering would be expected to 

respond in the same manner as the large-particle concentrations. Also presented are aerosol spectra for 0.195- to 10-μm-diameter aerosols obtained from 

composites of the in situ PMS ASASP-lOOX and FSSP aerosol probe data. 

A summary of data on the vertical structure of the Arctic haze observed 

in the vicinity of BRW is shown in fig. 57. On 11 March (fig. 57a), the haze 

was distributed in at least six well-defined layers. Two days later, on 

13 March (fig. 57b) the haze was stronger but confined to a band from 600 to 

800 mb. The haze became weaker on 15 March (fig. 57c) and 17 March (fig. 57d) 

as the Arctic anticyclone moved closer to BRW (Raatz, 1984). 

Aerosol spectra for haze layer 4 (centered at 750 mb in fig. 57a) and for 

the clear air directly below this layer (centered at 820 mb) are shown in 

fig. 58. The haze band contains 4-8 times more aerosol particles (and mass) 

than the cleaner air. The aerosols in the haze layer and in the clear air 

both exhibit volume peaks in the 1- to 3-μm diameter range. 

The positioning of the anticyclone after 17 March produced a change from 

a direct transport pathway for the aerosols (into the Alaskan Arctic from 

Eurasia) to a more complicated and less direct flow pattern (Harris, 1984). 

Except for 17 March, all profiles were taken within this aerosol transport 

zone, defined as a zone of strong pressure gradients (and therefore strong 

winds) between two synoptic pressure systems. Such relatively rapid transport 

of air pollutants into the Arctic was hypothesized by Carlson (1981), and 

transport zones were documented by Raatz (1984). The aerosol profiles 

(fig. 57) further suggest that the main level of transport of Arctic haze to 

BRW during this period was centered around 700 mb. 

84 
a 

b 

(I? 

::> 

II) 

II) 

Q) 

11: 

c 

d 

400r-~,-.....,..,....,..,...,_..--~~..--~~~-,...~~-,-~~~-,..~~--..--~~..--~ 

400 

500 

600 -

700 

800 

900 

1000 

1100 

400 

500 

600 

700 

March 11, 1983 

25 so 1, 

,.,,_--,t,.----,,;.,,-..--,,bo-~b- .,,.;,..,.------,--,! 

( ~~~~~-;, 1983 ,..-.'~,.--!.;.--.1....,_~....,.i~"'=--~~......,., 

(03 

I I 

1

Exlinclion _.,.J (X 10·6 m· 1) 

-10 

3 40 50 6 J 80 I - 60 - 50 - 40 - 30 - 20 - 10 

5'1J 100 2bo I 500 1000 ' I I I Temperalure 

Condensation Nuclei 0.0 I 0.05 0.1 0.5 1.0 5,0 10.0 (•C) 

CN (cm3) Parlicle Concentration (cm-3) 

Figure 57.--0zone, u , CN, large-particle concentrations (0.370- to 

sp 

0.495-μm diameter) and temperature-dewpoint profiles upwind of BRW. 

(a) Descending, 2134-2226 GMT, 11 March. (b) Lower portion, descending 

(dashed line), 2204-2240 GMT, 13 March; upper portion, ascending (solid 

line), 0232-0258 GMT, 14 March. (c) Descending, 2224-2318 GMT, 

15 March. (d) Descending, 2234-2325 GMT, 17 March. 

85 
t0 

'E 

(.) 

-

0 

O'l 

.Q 

""O 

z ' 

""O 

103 

102 

101 

100 

101 

162 

163 

104 

~~~ ~~-~~~~101 ti;"> 

E 

(.) 

I----------+-~-----< 100 t0 

E 

::l. "----- ----= ------".._____:_.::~ 10-l -

0 

O'l 

,___~_,___________,_ ___ ____.______, 10-2 0 

""O 

' t--- ---------+=--------------< 1 o-3 ~ 

AGASP-1 

March 11, 1983 

• ASASP-100-X 

-5 o FSSP 

10 -1 10 100 

Diameter (μm) 

Figure 58.--Aerosol concentration 

and mass spectra for haze in layer 4 

of fig. 57a (AGASP-1) centered at 

750 mb, and for clear air below this 

layer, centered at 820 mb for 10-min 

sampling periods. The particle 

diameter range over which the FSSP 

data are measured is indicated by 

the range bars; the particle concentration (mass) is plotted at the 

center of the log interval. 

4.3.3 Haze in the Norwegian Arctic 

During the third period of the AGASP experiment, research flights were 

conducted out of Bod~, Norway, north into the Norwegian Arctic. Air masses 

entering this region have recently passed over various European and Asian 

industrial areas and are thus assumed to retain air mass and aerosol properties representative of their source regions. 

The overall synoptic weather situation during this time period was 

characterized by a persistent return-flow pattern whereby a stationary, 

quasi-persistent cyclonic system transports aerosols from central Europe 

northeastward, and then returns the aerosols southwestward to Svalbard and 

Iceland on the back side of the cyclonic flow (Raatz, 1984). 

Vertical profiles of Arctic haze from near Svalbard are shown in fig. 59. 

The haze pollution was of similar concentration to that observed in Alaska, 

but was persistent throughout the troposphere both on 31 March (fig. 59a) and 

on 4 April (fig. 59b). This haze was associated with both dry and moist 

layers in the atmosphere. 

Figure 60 presents a time series of aerosol and meteorological parameters 

measured by the aircraft from 1200 to 1520 GMT immediately following the 

profiles shown in fig. 59a. During the major portion of the time series the 

aircraft was flying at the 622-mb level. 

From 1220 to 1315 GMT, while the aircraft was northbound, CN concentrations averaged around 450 cm- 3 . They abruptly decreased to a mean value of 

80 cm- 3 after 1320 GMT and remained at this low level until 1342 GMT. This 

86 
z 

0 

ti 

~7 zE 

w 0 

u 

z 

AGASP-6 

400 March 31 . 1963 

500 

700 

800 

a 900 

I 1000 -

Ii 

.s 1100 25 so10 30 40 50 60 70 80 ~ 

" 10 20 50 100 200 

"' 0.01 "' 400 " AGASP-9 a: April 4, 1963 

500 

600 

700 -

800 

~I Exlincuon -usp (X 10·6 m·1) 

1o do 40 so so 10 I 0'o 

b 900 

1000 

1100 

20 s'o 100 200 sco 1poo 1 20 oo Condensalion Nuclei ."°I -'--~'"'.:..,,....,,_ 6~1-~o'°''.s~1'-;:,........ -:":_..,.,. 

CN (cm-3) Particle Concenlral•on (cm·3) 

Figure 59.--0zone, a , CN, sp large particle concentration, and 

temperature-dewpoint profiles near Svalbard: (a) descending, 1032-

1145 GMT, 31 March 1983; (b) descending, 0806-0915 GMT, 4 April. 

12:00 1000 12:40 

AGASP-6, March 31, 1983 

13:20 14:00 14:40 15' 20 (Z) 

1000 

500 

- 200 

I 8 E 50 

100 

- 50 t----+--+---t--'-l--+--+--l-+--1---+-+-----l "' I 

~ 20 - 20 

x 10 -

be; - 10 

~ -20 

w 

w -30 a: 

fil -40 0 

-20 

-30 

- -40 

VJ 

w 

w 

a: 

350 ~-+--+---;~-t,+--+--+--H--+-+---+--t 350 

Cl 

w 

0 

300 I •moo OIRfOT IDlf 

250 

20 

"' 10 

e o l---+--+---;- -H--+----1--1-+--+--'--+---t 

.0 516 

E 622 ----.....~---~P_R_Es_s_u_R_E-;-----+---. 

conlinenlal polar 

air mass 

arctic 

air mass 

conlinenlal polar 

air mass 

TIME (Z) 12:00 12:40 3:20 14:00 14:40 15:20 (Z) 

73.84N 76.59 79.04 80.39 78.68 7610 74.85N POSITION I I ' I I I I I I I 24.47E 25.72 23.30 15.51 18.49 21.96 22.44E 

TURNING POINT 

250 

20 

87 

Figure 60.--Time series of meteorological and aerosol parameters for 

31 March 1983 (immediately following 

the profiles in fig. 59a) as the 

aircraft passed through an Arctic 

aerosol front located in the region 

of 79°N, then turned and reentered 

it. 
decrease in CN concentrations was accompanied by the disappearance of visual 

haze and extremely improved horizontal and vertical visibilities. At 80.39°N, 

15.51°E (1350 GMT) Lhe aircraft turned south and 20 minutes later reentered 

the haze-laden air mass at 1410 GMT, whereupon the CN concentrations rose 

again to 400-500 cm- 3 . A similar but less dramatic variation is seen in the 

light-scattering data. 

This aerosol front marks the boundary between polluted air from the 

Soviet Arctic being transported in a return-flow pattern and cleaner Arctic 

air originating over Greenland. 

4.3.4 Summary and Conclusions 

On the basis of these and a wide range of other measurements, the following conclusions may be drawn: (1) Arctic haze, associated light scattering, 

and increased aerosol concentrations occur in both dry and moist air layers 

throughout the Arctic winter troposphere. (2) Moist air depletes CN. (3) The 

haze may be in higher concentrations aloft than at the surface. (4) Aerosol 

concentrations (mass) can differ by an order of magnitude between haze and 

clean-air layers. (5) The boundaries of the haze in both the horizontal and 

vertical can be sharp and well defined (i.e., aerosol fronts). 

4.3.5 Further Results from the AGASP Program 

A special issue of Geophysical Research Letters, May 1984, contains 29 

papers on the results of the 1983 Arctic haze studies. The AGASP data set is 

being maintained within the GMCC offices in Boulder. This includes all NOAA 

WP-3D sensor data tapes; relevant North American and European weather maps; 

Canadian, European, and U.S. radiosonde data for the Arctic; copies of all 

mission notes and reports; continuous 16-mm nose-camera movie film of all 

flights; and reports of the type, amount, and quality of data collected by 

cooperating scientists. Requests for access to these data should be forwarded 

to Director, GMCC, NOAA/ERL, U.S. Department of Commerce, 325 Broadway, 

Boulder, CO 80303. 

4.4 C02 and Meteorology at SMO 

Regimes of C02 concentration can be related to the different air masses 

being sampled at baseline stations to obtain a more accurate assessment of 

background levels from the complete record of C0 2 data. For example, during 

February 1979-January 1982, variations of up to 3 ppm in daily average C0 2 

concentration at SMO (14.3°S, 170.6°W) over periods of a few days were related 

to the latitudinal gradient and changes in atmospheric circulation pattern. 

The amount of this variability had a seasonality that was related to seasonality in C0 2 latitudinal gradient and circulation regimes. 

The atmospheric circulation patterns affecting SMO have been summarized 

by Bortniak (1981). The surface analysis of fig. 61 will allow a quick review 

of these patterns. This map presents the surface synoptic pattern for one 

particular day and was chosen only to show examples of the three main circulation features controlling the low-level atmospheric circulation at SMO. The 

88 
positions and strengths of these features varied, within limits, from day to 

day over the course of the year. The most persistent feature, bringing the 

easterly trade winds to SMO, consisted of one or two anticyclonic centers over 

the central and eastern South Pacific Ocean. Next in importance is a southerly 

current, produced by an anticyclonic center over the region from Australia to 

New Zealand, at times in conjunction with travelling cyclones in the midlatitude westerlies. The third circulation feature was a cyclonic center or 

trough to the northwest of SMO, producing a northwesterly air flow. This 

feature, less frequent than the southerly current, but significant during 

several months of the year, moved into or developed in a position whereby air 

from north of the intertropical convergence zone was brought to SMO. This 

conclusion is reinforced by the coincidence of peaks in C0 2 and methyl chloroform (CH3 CC1 3 ) associated with this circulation regime. Methyl chloroform is 

released into the atmosphere by certain industries primarily in the Northern 

Hemisphere and was measured at SMO as a part of ALE (Prinn et al., 1983). The 

South Pacific easterly trade flow in fig. 61 was perturbed from the usual 

situation in which there was a more continuous east-to-west flow across SMO. 

The breakdown of the easterly trade flow into a weak trough or into one or 

more weak closed circulations near the longitude of SMO was a second pattern 

that sometimes resulted in the mixing of Northern Hemisphere air southward to 

SMO. At SMO's latitude, the easterly trade-wind marine layer during all 

seasons extends an average of about 2 km above the surface at 160°W, which is 

about 10° east of SMO (Van Loon et al., 1971). 

Shifts in position and changes in strength of the three main circulation 

features resulted in a 3-yr-average seasonal variation in the lower tropospheric circulation at SMO, which is consistent with long-term average patterns 

discussed by Bortniak (1981). This seasonal variation is demonstrated in 

fig. 62. It shows the average percentage frequency of occurrence by month of 

the 10-day 1000-mb trajectory origins in four direction sectors from SMO 

during the 3-yr study period. Throughout most of the year, airflow from the 

ENE and ESE sectors around anticyclones in the central and eastern South 

Pacific Ocean predominated. However, there were significant changes in the 

frequency of occurrence of airflow from other sectors. During December-April 

(austral summer and early austral autumn), the southerly current around 

Australia-New Zealand anticyclones, and the northwest flow in cyclonic circulations to the west and northwest of SMO also affected the circulation at SMO a 

significant amount of time. By autumn, the frequency of periods of northwest 

flow had decreased markedly, while the southerly current had begun to reach 

89 

Figure 61.--NMC surface streamline 

analysis for 29 April 1980 at 

0600 GMT. A= anticyclone; C = 

cyclone. 
ENE ESE SSE-WSW WNW-NNE 

DEC i!i~~- il!t,\l[l:-~:::::·: :iil!!ii 

JAN 1,\i!!~~!!~~ll l 

FEB ~'!!·!:: 

MAR i:;i:~:!!!!i!il 

APR mrnm 

:t ~@~] 

MAY '[!l: 

JUN 

JUL .:I 

AUG !i!t:! 

SEP :1 

OCT :m: 

:::::::: 

I I 

20 40 60 I I I I I I 

20 40 60 20 40 60 I I I 20 40 60 

PERCENTAGE FREQUENCY 

Figure 62.--Percentage frequency by 

month of 10-day, 1000-mb trajectory 

origins in four different direction 

sectors from SMO for 1979-1981. 

SMO considerably more often. Thus, the austral winter circulation at SMO was 

characterized by an alternation between only two regimes--easterly flow around 

central and eastern South Pacific anticyclones and southerly flow around 

Australia-New Zealand anticyclones. The circulation during austral spring 

(September-November) was the steadiest of the year. Easterlies predominated; 

there was a reduced occurrence of southerlies; and northwest flow was still 

considerably less frequent than during the December-April period. 

Komhyr et al. (1984a) have shown for the years 1979-1982 that the C0 2 

gradient to the north and south of SNO was greatest from about February to 

May. The gradient to the north was increased by a bulge in C0 2 around 5°-15°N, 

while C0 2 concentration decreased to the south with a weaker gradient. The 

latitudinal gradient was weakest between August and November. During this 

time, the C0 2 bulge was less pronounced, and the Southern Hemisphere gradient 

was nearly flat. 

The seasonal changes in atmospheric circulation combined with this 

seasonally varying latitudinal gradient to produce the pattern of C0 2 variation observed at SMO averaged over the 3-yr. study period. The period of 

maximum latitudinal gradient overlapped the period during which all three main 

circulation features contributed significantly to the low-level atmospheric 

circulation at SMO. Figure 63, showing C0 2 daily averages for 1980, demonstrates the tendency for the greatest day-to-day variation in C0 2 to occur 

90 
345 

'E 

a. 

~ 340 

~ u 

JJS 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

1980 

Figure 63.--C02 daily average concentrations at SMO for 1980. Values 

are in the X81 mole fraction scale. 

during this February-May (day of year 32-152) period. Highest C02 concentrations were measured when cyclonic circulations to the west and northwest 

brought air to SMO from the C0 2 maximum at 5°-15°N, while lowest 

concentrations were observed when the Australia-New Zealand anticyclone 

controlled the circulation at SMO. Figure 64, a plot of average departure of 

C02 from spline value as a function of surface wind direction, demonstrates 

the effect of the maximum in latitudinal gradient at this time. Although 

during May there were no cyclonic circulations to the west or northwest of SMO 

strong and persistent enough to produce 10-day trajectory origins in the 

WNW-NNE sector, there were periods with northwest surface winds and 1- to 

3-day trajectory origins to the northwest. These periods were associated with 

the type of perturbation in the easterlies mentioned earlier as sometimes 

being associated with the mixing of Northern Hemisphere air southward to SMO. 

During the overlapping periods of least C0 2 latitudinal gradient and 

steadiest circulation pattern (day of year 214-335 and 245-335, respectively), 

fig. 63 demonstrates the tendency for the least day-to-day variation in C0 2 

concentration. The plot of average C0 2 departure as a function of surface 

wind direction (fig. 65) for November shows the lack of dependence of C0 2 on 

wind direction at this time of year. 

During the 3 years considered in this study, southern oscillation indices 

near the long-term average suggest that the atmospheric circulation over the 

tropical and South Pacific Ocean during this period was also about normal. 

Thus, the results of the study presented here probably apply to long-term 

average conditions. Although not completed yet, this study does suggest the 

following conclusions with regard to C0 2 at SMO: (1) Concentrations in 

unperturbed easterly trade flow are representative of the Southern Hemisphere 

tropics. (2) Concentrations associated with southerly flow around AustraliaNew Zealand anticyclones are influenced by Southern Hemisphere midlatitude 

levels, and thus are not representative of the tropics, except from about 

August through November when the Southern Hemisphere gradient is very small. 

(3) Concentrations in northwest flow are not representative of the Southern 

Hemisphere tropics, except during about September through November when the 

COz bulge at 5°-15°N is slight. 

91 
w 

C02 '!> 

DEP 

PPM 

20 

N 

Sl 1,8 

358 

Figure 64.--Average departure of 

daily average C0 2 concentration as a 

function of surface wind direction 

for the month of May in 1979-1981. 

Data for south through west directions were eliminated because of 

local contamination. Numbers next 

to data points give the number of 

C0 2 hourly averages used in the 

average for the 3 months. 

E w 

C02 '?I 

DEP 

PPM 

15 

N 

30 

E 

493 

I 

~ 

Figure 65.--Average departure of 

daily average C0 2 concentration as a 

function of surface wind direction, 

as in fig. 64, but for November. 

4.5 The BRW Surface Aerosol During AGASP 

4.5.1 Introduction 

AGASP, an airborne and surface experiment, was conducted during March and 

April 1983 (Schnell, 1984a). During the first four flights, on 11, 13, 15, 

and 17 March, vertical aerosol profiles were made near BRW. Quantities 

measured aboard the aircraft included CN concentration, aerosol scattering 

extinction coefficient (a ), and particle size distribution. Quantities sp 

measured routinely at BRW at the surface, and therefore during AGASP, included 

CN concentration and a (Bodhaine, 1983). For the duration of the AGASP 

sp 

experiment, an aerosol spectrometer and a special sunphotometer were operated 

at BRW (Bodhaine et al., 1984; Dutton et al., 1984). 

4.5.2 Instrumentation 

CN concentration was measured both on the aircraft and on the ground 

using G.E. automatic CN counters. Operation of these instruments was described 

92 
in GMCC Summary Report No. 5 (Hanson, 1977). On the aircraft, a singlewavelength (525 nm) nephelometer (model 1590, Meteorology Research, Inc.) 

measured a . A four-wavelength nephelometer at BRW operates continuously at 

450-, 550-~P700-, and 850-nm wavelengths. A PMS ASASP-lOOX, which covers the 

aerosol size range of 0.09-3.0 .μm (diameter) in 15 intervals, was operated on 

the aircraft, and an ASASP-X, which covers the same size range in 60 intervals, was operated at BRW. Surface-based measurement results are presented 

here. 

4.5.3 Results 

Ten days of surface-based hourly mean CN, a , and Angstrom exponent data 

sp 

from BRW are presented in fig. 66. Surface meteorological data are presented 

in fig. 67. The CN data in fig. 66 (bottom) vary between about 150 and 

700 cm- 3 , except for t~e large event on 14 March that is most likely of local 

origin. The a data in fig. 66 (middle) show a fairly constant background sp 

Arctic haze near 2 x 10- 5 m- 1 during 9-11 March, a series of events reaching 

4 x 10- 5 m- 1 during 12-16 March, and a return to background Arctic haze for 

the remainder of the period. The Angstrom exponent data in fig. 66 (top) show 

three well-defined regimes: (1) relatively low values during 9-11 March; (2) 

higher values during 12-14 March; and (3) highest values during the remainder 

of the period. These Angstrom exponent data suggest a change in aerosol size 

distribution toward relatively more small particles on 12 March and again on 

14 March. 

The meteorological data in fig. 67 show that the surface winds were 

generally from north to north-northeast at about 4 m s- 1 throughout the time 

period, suggesting that the known local sources identified by Bodhaine et al. 

(198la) did not influence the 10-day period of surface measurements. The 

relatively constant RH data in fig. 67 suggest that the large events in a 

sp 

during 11-16 March were not caused by aerosol growth in response to increases 

Figure 66.--Hourly means of (bottom) 

10 II 12 13 " 10 18 " 18 CN concentration, (middle) a ' and .. .. sp "n ,_ (top) Angstrom exponent at BRW. The ]. ~ small calibration points .: 0 0 squares are 

i i ., for CN concentration provided by the "' 

'? - lrtmth '"''"'" ,,,,,,,r, "' //tr!M HtlU..-: Pollak CN counter. The a data are 0 sp .... 

><• .. given at 450 (dotted), 550 (solid), ~ 

I -.~ 700 (dashed), and 850 (long- e .. nm 

"' dashed). Wind direction and speed b" 

are shown in the upper portion of 0 0 

" " the middle graph. Angstrom exp onM en ts were calculated from a data I sp E• 

" at 450 and 550 nm (dotted), 550 and z 700 nm (solid), and 700 and 850 nm 

(dashed) using the formula 

CJ. = - /J. log a /!J. log A.. All times 10 11 "' 13 1• 10 18 17 18 GMT. sp MARCH 1983 are 

93 
~:t=ttJ I ± tt¥¥3 9 1u 11 ra 13 14 1~ 1ti n ie 

MARCH 1983 

Figure 67.--Hourly means of wind 

direction (Dir), wind speed (Sp), 

relative humidity (RH), temperature 

(T), and pressure (P) at BRW. All 

times are GMT. 

in relative humidity. The surface pressure data in fig. 67 are in agreement 

with the description by Raatz (1984) of a high-pressure system moving past the 

BRW site. The events in the a data were apparently caused by a change in 

sp 

trajectory origin as the high-pressure system moved. Harris (1984) shows that 

during 9-11 March, 5-day back trajectories from BRW originated over the Arctic 

Basin, whereas on 12 March a change occurred such that trajectories originated 

over Asia. 

Figure 68 presents a time series of total particle numbers counted in 

each of three size ranges of the aerosol spectrometer. Ranges 1, 2, and 3 

detect 0.24- to 0.84-μm, 0.15- to 0.30-μm, and 0.09- to 0.195-μm diameter 

particles respectively. Clearly, the data in fig. 68 qualitatively follow the 

a data in fig. 66. Furthermore, the events beginning on 12 March showed 

sp 

much larger increases in the small-particle ranges than in the large-particle 

ranges, in agreement with the Angstrom exponent data. Three events that 

occurred primarily in the small-particle range 3 are evident on 9, 13, and 

18 March. 

10 12 13 14 15 IB 

March 1983 !GMT) 

94 

Figure 68.--Total number concentration for particle diameters in 

size ranges 1 (0.24-0.84 μm), 2 

(0.15-0.30 μm), and 3 (0.09-

0.195 μm) for aerosol spectrometer 

data at BRW. All times are GMT. 
0.>I I I I I I I ~ 

1f ::f T· ~\ ··~ : ·~ i "'[ ~\i>-- '\ 1' :- 01 ~ T O.O 9 I 10 11 12 T 14 15 16 17 18 19 ° 

March 1983 (LST) 

Figure 69.--BRW aerosol optical 

depth (1) data (base e) at 550 nm, 

and a averages for the times 

durin~pwhich optical depth data were 

taken. Data are plotted at 1200 LST. 

The dashed lines provide continuity 

for missing optical depth data on 

15 March. 

Figure 69 shows a comparison of daily mean aerosol optical depth data at 

550 nm, and the a data averaged over the time intervals when the optical sp 

depth data were taken (about 0900-1600 LST). The two data sets show similar 

variations and a calculated correlation coefficient of 0.69. Therefore, 

surface aerosol measurements are qualitatively representative of the Arctic 

haze above the ground and account for approximately 48% of the variability. 

4.6 Modeling 13c 

Some preliminary results of a model for 13C/ 12C variations are available 

for examination. The model differs from previous models in that biosphericatmospheric carbon fluxes were specified by E. Box (University of Georgia, 

Athens; personal communication, November 1983). Box developed the fluxes as 

functions of climatic variables based on plant growth experiments. These 

carbon fluxes were used in a two-dimensional global diffusion model that 

simulated gas exchange with a two-layer noncirculating ocean. Fossil fuel 

burning as a function of latitude provided a major perturbation in the model. 

This model was more fully described in Harris and Bodhaine (1983, pp. 76-78). 

The units used for 13C in the model were not the same as for C0 2 , because 

concentration units do not clearly show the variability between the ratio of 

13C to 12C. Whereas extremes of 13C0 2 would differ by only a few tenths of a 

part per million, the normalized ratio, o13C, yields a convenient scale 

emphasizing differences in 13 c/ 12 c: 

o13c = - 1 1000 [ 

( 13c,1zc) J 

where R = 0.0112372. 

The basis of the 13C model is that the ratio 13C/ 12C changes slightly 

when carbon goes from one reservoir to another. For example, when C0 2 from 

burning of fossil fuel is added to the atmosphere, the lower 13C/ 12C of the 

new C0 2 dilutes the ratio of the total C0 2 , and a new lower value of 13C/ 12C 

results. When C0 2 goes into the biosphere from the atmosphere (carbon goes 

from atmospheric C0 2 to organic plant material) 13C is discriminated against, 

and only 98.2% of it enters the biosphere as compared with the amount of 12C 

taken in by the biosphere. Consequently, the remaining 13C/ 12C is increased. 

95 
In vegetative rotting, the 12C and 13C are returned to the atmosphere, restoring the former 13C/ 12C ratio in the absence of any other influences. 

In ocean-atmosphere exchange of C0 2 there is a preference (fractionation) 

for both the ocean-to-atmosphere flux and for the atmosphere-to-ocean flux. 

The amount of fractionation for those fluxes is smaller than for the atmosphere-biosphere flux, however, and a smaller effect is expected. Details of 

the ocean-atmosphere fractionation are given by Siegenthaler and Miinnich 

(1981). 

"' I 

"' ai 

I 

u <D 

'.: I 

<O 

..: "' 

I 

. . 

I 27 53 79 105 131 157 183 209 235 261 287 313 339 

DAY OF THE YEAR 

Figure 70.--Results from the 613c 

model (solid line) and from 1983 

(unpublished) data from Friedman 

(dots) for BRW. 

"' I 

"' ai 

I 

/;! <D 

~ I 

"' ..: 

I 

.. 

. : 

.. 

I 27 53 79 105 131 157 183 209 235 261 287 313 339 

DAY OF THE YEAR 

Figure 71.--Results from the o13C 

model (solid line) and from 1983 

(unpublished) data from Friedman 

(dots) for MLO. 

The carbon fluxes specified are given by Gillette and Box (NOAA/GMCC; 

unpublished manuscript, 1984). Model results for o13C are presented in 

figs. 70-73 along with experimental data for 1983 from I. Friedman (USGS, 

Denver, CO; personal communication, March 1984). Friedman's data are provisional and unselected. For the latitude and altitude of BRW, there is fairly 

good agreement between model results and Friedman's data. For the latitude of 

MLO, model results for sea level agree better with the observational data than 

do the model results for 3-5 km (the altitude interval in which MLO is situated). This fact has led to discussions on sampling times to avoid upslope 

air and how best to obtain air samples for 6 13C analysis. At SMO there is a 

much greater annual fluctuation of the model results for that altitude and 

latitude than is observed in the data. A preliminary explanation of this has 

to do with a large equatorial and tropical biosphere-atmosphere carbon 

exchange. We are presently looking into this problem. At SPO there is again 

a larger seasonal fluctuation in the model results than what has been observed 

by Friedman. We feel that this too is a reflection of the equatorial biosphere-atmosphere exchange rates that are used in the model. 

96 
"' cD 

I 

,.\lai 

- I 'O 

"' ...: 

I 

... 

. . 

I 27 53 79 105 131 157 1B3 209 235 261 2B7 313 339 

DAY OF THE YEAR 

Figure 72.--Results from the o13C 

model (solid line) and from 1983 

(unpublished) data from Friedman 

(dots) for SMO. 

"' cD 

I 

,.\l ai - I 'O 

...: "' 

I 

I 27 53 79 105 131 157 1B3 209 235 261 287 313 339 

DAY OF THE YEAR 

Figure 73.--Results from the o13c 

model (solid line) and from 1983 

(unpublished) data from Friedman 

(dots) for SPO. 

4.7 Analysis of SPO C0 2 Data for 1975-1982 

GMCC C0 2 data for SPO were calibrated with SIO standard C0 2 gases, corrected for nonlinearities and pressure broadening, and corrected for discontinuities caused by instrument alterations. After removal of data representing 

known contamination episodes, spectral analysis showed negligible power in 

periods shorter than 5 days. 

Comparison in fig. 74 of the GMCC C0 2 record with Australian C0 2 concentrations obtained in the midtroposphere by CSIRO (Pearman et al., 1983a) shows 

a similar growth rate of C0 2 . There are differences in the annual cycles at 

the two locations, however. The Australian values are higher by 0.46 ppm on 

the average and the RMS difference is 2.35 ppm. 

Comparison in fig. 75 of the GMCC continuous vs. SIO flask C0 2 record for 

SPO (Bacastow and Keeling, 1981) shows fairly good agreement except for 1975 

where there appear to be systematic errors in the GMCC values. There are also 

noticeable differences at the end of 1978 after which the GMCC continuous C0 2 

analysis was terminated for 1 year. The mean di fference between GMCC and SIO 

C0 2 values is 0.15 ppm, and the RMS difference is 0.41 ppm. 

In fig. 76 spectral analysis of the linearly detrended (1.51 ppm yr- 1 ) 

time series shows only one significant peak at 1 yr- 1 . Little power is 

contained for periods shorter than 2 months. There is some unresolved power 

for periods of about 3.6 years, possibly associated with change of C0 2 input 

or with El Nino events. 

Annual growth rates were comp11ted by differentiating the spline-fitted 

function, which had knots at the beginning and end of each year. The spline 

was fit to monthly means with 2 years of ficticious data on either end of the 

record. If we disregard the suspect 1975 to mid-1976 data, fig. 77 shows a 

97 
/'~ 

. : .(.'<t./ 

:::;; 

::> 

·.·.::/. -.. ·.-:,-....._../ 

·/ 

!"~ .;~\/ .-; ·"'7 

\ : 

~-,,,.,,, 

( 

.. ·..;.,;~ .· .. ·· 

1"75 1"111 IVT7 lint! 111?8 11180 111111 

YEAR 

Figure 74.--Atmospheric C0 2 concentrations for the midtroposphere over 

Australia determined by CSIRO (Pearman et al., 1983a) compared with C0 2 

concentrations derived from the GMCC 

continuous analyzer at SPO. 

+ ~o 

t.J 

0.. 

Cll 

t:.. 

0 

""i' s 

N 

I 

.. I 

0 

Figure 76.--Smoothed sample spectrum 

for 5-day means of atmospheric C0 2 

concentrations from 1975 to 1982 at 

SPO. The C0 2 values were selected 

by a statistical method. Bandwidth 

of the Parzen lag window and 95% 

confidence intervals are shown on 

the figure. A linear trend was 

removed from the time series before 

the spectrum was computed. 

98 

g 

.. 

. .... j.-• • 

~I' I / , ,:::.:. .,' 

:~ ,,/ "7 

'°" -!y..: -" -.: . . =SPO 

• = SIO FLASKS 

11175 111111 IVT7 1"78 111?8 

YEAR 

A ./''\ I ' -,,/ / ·-r· 

... / 

11180 111111 19112 

Figure 75.--Atmospheric C0 2 concentrations at SPO determined for flask 

samples analyzed by SIO (Bacastow 

and Keeling, 1981) compared with C0 2 

concentrations derived from the GMCC 

continuous analyzer at SPO. 

11175 1"111 IVT7 1"78 111?8 lllllO 111111 11162 

YEAR 

Figure 77.--Annual growth rate as a 

function of time for selected data. 
:;i 

~ 

s 

"' 0 

E' 

p. 

~q ..,o 

0 

u 

<I., 

9 

q_ 

i 

., 

i 

0 

N 

I 

1m 11119 11177 111'1'8 111'1'11 1-

YEAR 

1961 1982 

Figure 78.--Spline fit to 5-day 

means, reduced by the long-term 

function for selected data. 

general lowering of the growth rate of C0 2 from about 1.7 ppm yr- 1 (1977-1980) 

to about 1.0 ppm yr- 1 (1981-1982). 

Seasonal variation~ of the detrended data were obtained by fitting 

splines to the 5-day means after subtracting tlHc long-term growth rate that 

was differentiated above. The knots were monthly and were movable. The 

results (fig. 78) show an apparent trend to smaller annual cycles. 

4.8 Airborne Latitude Survey of El Chichon Optical Depth 

The fourth, and apparently final, NASA-sponsored airborne survey of El 

Chichon volcanic optical properties was flown in May 1983. The flight series 

came about primarily as a result of the mechanical failure of the NASA SAGE 

satellite, which would have provided much of the needed information. The 

flights showed substantial latitudinal variation of the volcanic material more 

than a year after the eruption, and the distribution had changed differently 

with time than had been expected. GMCC participated in the four flight series 

by providing instruments and/or personnel for measuring aerosol optical depth 

in the 0.38- to 0.862-μm wavelength region. On two of the flight series, 

December 1982 and May 1982, GMCC also provided and operated additional instrumentation for measuring relative global diffuse, total, and reflected solar 

flux. 

The latitudinal variation of El Chichon 500-nm optical depth at the times 

of the flights is shown in fig. 79. Flight series 1 and 3 display a broken 

trace because of lower flight altitudes and frequent night flights to facilitate lidar operations. The appearance of the relative minimum near 30°N was 

unexpected, but was recorded on several instruments on the last three of the 

four flight series and probably did not exist at the time of the first series. 

The sunphotometers used on the flights were identical to the ones used at 

the GMCC baseline stations, but were independently calibrated. Additional details of the observational procedures, probable errors, and results are given 

by Dutton and DeLuisi (1983b) and DeLuisi et al. (1983). 

99 
FIL If Dales 

19 <kl 82 - 4 Nov 82 70 - IOO"W P - l 

40.c 82-4Jan 83 110-UO"W CV-990 

O >B 28Jan 8J- S Fib Bl 55- 7S"W P-3 

20 Apt 8J - 20 May BJ 80 - 18() 0 W CV - 990 

,_; 

· 0 02 

M)• 41D" JO• 20" 

South Latitude 

_ , 

• A 

Nor1h 

Figure 79.--Aerosol optical depth 

(500 nm) as a function of latitude 

from four NASA stratospheric survey 

flight missions as measured by GMCC. 

Numbers on curves correspond to 

flight numbers. Lettered points 

(A-D) indicate optical depth values 

obtained at MLO during times correspond i ng to the airborne latitude 

surveys (A~ flight 1, B ~ 2, etc.) . 

The only GMCC site at wh i ch optical depth readings can be directly compared with the aircraft data is MLO, because of similar observing conditions 

and elevation. The 500-nm aerosol opti cal depths measured at MLO during the 

times of each flight series are indicated as lettered points A-D on fig. 79 

(A corresponds to flight 1, B to 2, etc.). The MLO values were averaged over 

several days corresponding to when the aircraft crossed the MLO latitude, 

19°N, even though the aircraft was at a much different longitude. The 

excellent agreement between aircraft and MLO data substantiates the areal 

representativeness of the MLO observations and the temporal representati veness 

of the aircraft results. Further discussion of these and other GMCC opti cal 

depth measurements of El Chichon spectral aerosol optical depth is given in 

Dutton and DeLuisi (1983a). 

Climate sensitivity studies of Chou et al. (1984) have shown that the 

global climate response to stratospheric aerosols of volcanic origin is highly 

dependent on the latitude distribution of the optical depth. Inclusion of 

observed latitudinal distribution of aerosol i n this and similar models should 

improve attempts to simulate El Chichon's actual climatic effects. 

4.9 Concentrations of Trace Gases in the Atmosphere 

A new program was begun to assemble and archive measurements of atmospheric trace gases for development of a worldwide data base that supplements 

the routine and special observing programs at the GMCC baseline stations. The 

intention is to identify deficiencies in the collection of data for specific 

constituents and to provide a focal point for data that have not been widely 

disseminated. Although the work has only just begun and the list of entries 

is relatively short, all available information is being put into the data 

base, which will be continually updated. A data base of this sort will be 

pertinent and useful to any individual presently working or considering 

starting to work on a specific trace constituent. The data base contains 

information on the measurement itself, the location, the time, and the source 

reference, thereby providing a basis for the determination of data-rich and/or 

data-void regions. Such a data base, which contains concentrations and 

fluctuations of a specific trace gas, may also aid in the location and identification of specific sources and sinks. In addition, as the data base becomes 

more complete, it will be capable of providing information to atmospheric air 

quality models of varying degrees of complexity. 

Data have been collected for the following species: CH4 , CO, 0 3 , C0 2 , 

H2 , and N2 0. These data were collected from many separate studies, and each 

100 
study may include one or more measurements. When the data from the separate 

studies are combined, one begins to obtain some measure of global coverage. 

Most of the readings were taken in the troposphere between 6 and 8 km. Current efforts also involve the collection of data for NO and for N0 2 . However, 

it has been very difficult to find atmospheric concentration data involving 

SO , because of the short atmospheric lifetime of SO constituents; most of 

th~ work being done in this area involves the measurgment of fluxes. The data 

base also includes names of individuals or organizations considered especially 

knowledgeable about a specific trace constituent, the work they are doing, and 

how long they have been doing it. 

Although this project is still in its early stages, the data base will be 

expanded to include as many trace constituents as possible using concentration 

data throughout the troposphere and stratosphere. 

4.10 The Photovoltaic Power System at SMO 

In 1983, the solar power system at SMO was installed and tested. The 

system was purchased and installed with funds provided by the DOE Federal 

Photovoltaic Utilization Program, under interagency agreement DOE-Al01-

79CS-300-87. A request for proposal was released in September 1981 (NOAA 54-

81). The source evaluation board selected the Solarex Corp. of Rockville, MD, 

as the system supplier (NOAA contract NA82RAC00041). To decrease costs, NOAA 

used the suppliers' specifications to purchase directly the batteries and the 

material for the photovoltaic array stand. Detailed specifications of the 

system were reported in Harris and Bodhaine (1983). 

As stipulated in the contract, Solarex submitted a system acceptance test 

plan in March 1983. The plan called for testing the power from the PV panels 

when the Sun is unobstructed and within 10° of normal to the panels. The test 

involves isolating the individual strings, which consist of 10 modules each, 

and measuring the voltage and current output as the load is varied. The 

output is plotted as a function of voltage and current on an x-y plotter. 

Then the open circuit voltage, closed circuit current, and peak power output 

are determined from this plot. Each string contains one module with an 

imbedded thermometer that is intended to measure the cell temperature. The 

cell temperature determines the efficiency of the modules. Results of these 

tests are listed in table 29. The observed variation in cell temperature 

between strings is a function of systematic variations in the ventilation 

across the array and is not due to insolation differences. Smoke tests confirmed the observed lack of ventilation across the southern end of the array, 

and in particular string no. 9. The average output of the array is 5.5 kW at 

insolation levels of 1 kW m- 2 and cell temperatures of 59°C. When adjusted 

to standard conditions (1000 W m- 2 , 25°C) the calculated output is 6.2 kW. 

This is only slightly in excess of the specified power level of 6.0 kW. 

The main problem discovered in 

peak power voltage V of 145 V for 

pp 

these test results is the relatively low 

string no. 9. At this voltage the array 

will supply power, but it is too low to charge the batteries efficiently in 

the afternoon. The cause of this relatively low voltage is the excessive 

temperature of the modules in the absence of normal ventilation. The most 

logical first step, trimming the vegetation along this portion of the ridge to 

101 
Table 29.--Results of tests of the SMO photovoltaic system 

String Time 

no. (LST) 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

1220 

1310 

1225 

1306 

1230 

1258 

1235 

1255 

1240 

1250 

Measured values 

Insolationt Cell 

(mW cm- 2 ) temp.§ 

(°C) 

104 

102 

103 

106 

104 

104 

104 

62 

63 

58 

57 

55 

55 

52 

54 

65 

65 

Values derived from IV curves* 

V I V I P 

oc SC pp PP p 

(V) (A) (V) (A) (W) 

196 

195 

201 

199 

202 

202 

204 

202 

193 

198 

3.98 

3.99 

3.96 

4.00 

4.11 

4.24 

4.03 

4.34 

4.00 

4.31 

149 

150 

155 

151 

154 

156 

158 

154 

145 

154 

3.48 

3.52 

3.44 

3.48 

3.66 

3.65 

3.50 

3.86 

3.53 

3.72 

520 

528 

532 

523 

563 

569 

553 

593 

510 

576 

*IV is current voltage; V , open-circuit voltage; I , short-circuit 

OC SC 

current; V , peak-power PP voltage; I , peak-power current; P , peak power. pp p 

tinsolation is measured with the pyranometer at the same tilt as the panels. 

Scattered clouds were present. 

§Throughout the test, the air temperature was approximately 29°C and the wind 

speed was less than 1 m s- 1 . 

allow better airflow, will be tried soon. A decrease in the cell temperature 

of 10°C is expected to result in an increase in the output of 10 V. 

The Solarex engineers also recommended a means of varying the output of 

the array so that energy can be pumped into the batteries in conditions of 

slowly varying insolation. In the normal charging cycle, once the battery 

voltage reaches a level near its upper limit, its charging efficiency decreases 

in the presence of steady input. To increase the efficiency of charging, it 

is necessary to vary the input voltage. This was done by shorting two or 

three modules from each string, depending on conditions, and waiting for the 

voltage to recover. This method did not work as planned partly because of the 

reduced array voltage. Once the modules were ''cutout,'' the system came into 

equilibrium at this new, reduced power level, charging at an even slower rate 

than before. Readjustment of the limit voltages only seems to help at specific charge levels. Further testing of the charging cycles will continue. 

Eventually it may be necessary to add a circuit to limit the time the arrays 

are in the clipped mode. 

4.11 Shipboard Measurements of Atmospheric C0 2 in 1983 

4.11.1 Introduction 

The increase of atmospheric C0 2 concentration has been well documented 

through in situ measurements at the baseline observatories at MLO, BRW, SMO, 

and SPO (Harris and Bodhaine, 1983, pp. 24-26; Keeling et al., 1976a, 1976b). 

102 
Although high-quality data from a few stations may be sufficient to establish 

this global trend, higher spatial resolution is needed to locate regional 

sources and sinks of C0 2 and to provide boundary conditions and verification 

for carbon cycle models (Pearman et al., 1983b; Pearman and Beardsmore, 1984). 

For this reason the GMCC C0 2 flask sampling network was expanded in 1979 and 

now consists of 22 globally distributed stations collecting flask samples once 

or twice weekly (see sec. 3.1). This network is now producing data unique in 

coverage and quality, detailing the spatial and temporal variability of atmospheric C0 2 (Komhyr et al., 1984a, pp. 26-33). 

To assess the suitability of the network sites for measuring regional or 

baseline atmospheric C0 2 concentration unperturbed by local sources or sinks, 

GMCC undertook a flask sampling program aboard the NOAA research vessel 

DISCOVERER during May and June of 1982. The results from this cruise demonstrated the feasibility of obtaining good samples collected by minimally 

trained but conscientious personnel, and the generally good agreement between 

the cruise data and the atmospheric C0 2 concentration determined from the 

flask network (Harris and Bodhaine, 1983, pp. 99-102). The shipboard data 

were also useful in pinpointing the locations of steep gradients in C0 2 

concentration, which could only be inferred from the sparser network data. 

The success of this limited project encouraged the C02 group to participate in several cruises in 1983 and 1984. The cruises and dates are listed in 

table 30, and the cruise tracks are shown in fig. 80. To date, the emphasis 

has been on the Pacific Ocean and the Southern Hemisphere. This is due to 

both specific interest in these regions and the availability of ships and 

cooperative investigators. 

In general, the samples have been collected in pairs of 0.5-L glass 

flasks using a portable sampling unit (Komhyr et al., 1984a). On the AKADEMIC 

KOROLEV and the DISCOVERER 1984 cruises, samples were collected in 3-L evacuated flasks equipped with greaseless stopcocks. In all cases the samples were 

Table 30.--GMCC shipboard flask sampling programs 

Cruise Dates Type of sampling Species measured 

DISCOVERER May-Jun 1982 0.5-L flasks C0 2 

POLAR STAR Dec 1982- 0.5-L flasks C0 2 , CH4 

Mar 1983 

KNORR Jan-Feb 1983 0.5-L flasks C0 2 

(TTO/TAS) 

FUJI Feb-Mar 1983 0.5-L flasks C0 2 

DISCOVERER Mar-May 1983 0.5-L flasks C0 2 , CH4 

A. KOROLEV Oct-Dec 1983 3-L flasks, gas C0 2 , CH4 

chromatograph C0 2 , CH4 , pC02 

KNORR (Long Oct 1983, 0.5-L flasks C02 , CH4 

Lines) Jan 1984 

POLAR SEA Dec 1983- 0.5-L flasks C0 2 , CH4 

Mar 1984 

DISCOVERER Feb-May 1984 3-L flasks, gas C0 2 , CH4 

chromatograph C0 2 , CH4 , pC0 2 , pCH4 

103 
ao•.,i .. --

J. ,,~~ 

" .-.J, 

' 60"••t-

' 

>I~ 

-, j~ 

'I 

{. 

!'" ' zo"•i ·- • ~ 

) 

... ""'" ·, 

,, 

' 

'j/~ 

J 

.: 

. -'i.-... ... . 

--. -, _(. .. . 

~ .... -·__ -_=:) 

\., it:t -.1.~ ,1 -c. r,i.s) {! ; 

:_,:r~ .. .... ' .... -.. ..,; 

' ' :o'• .. ,•t l!.,,'1 

.... 

.ao"s 

,,,., 

μ 

,._ 

.a.:i'L 

·-0 

...___.-·-~+---~~ 

. do ~• ~. ~I 

Figure 80.--Cruise tracks for the shipboard flask sampling programs 

carried out from 1982 to 1984. The closed circles indicate the locations of the GMCC C0 2 flask network sites (see sec. 3.1 for details of 

the network). 

analyzed for C02 concentration on the semiautomatic NDIR C02 flask analysis 

apparatus at the GMCC laboratories in Boulder. As indicated in table 30, 

flasks from the more recent cruises have also been analyzed for CH4 . These 

data are discussed in sec. 5.15. 

4.11.2 Results and Discussion 

Selected C02 data for three of the 1983 cruises are presented in 

figs. 81, 82, and 83. The quality of the samples (as defined by the percentage of sample pairs agreeing to ~0.5 ppm) varied among the three cruises: the 

POLAR STAR, 60%; the FUJI, 89%; and the DISCOVERER 1983, 75%. These values 

w 345 

_J 

5344 

en 

z 3 43 

0 

H 

1-- 342 

u 

a: 

a: 341 

u.. 

w 340 _J 

0 

:!: 339 

~ 338 

:!: 337 

Cl. 

Cl. 336 

N 8 335 

1982 

"' "' "' "' 

0 POLAR STAR 

x PALHER srnnoN 

----- C02-LAT-DO'I' SURFACE 

"' ...... "' "' 

DAY OF YEAR 

1983 

104 

Figure 81.--C02 vs. DOY for the 

1982-1983 POLAR STAR cruise flask 

samples. Palmer Station flask data 

are shown for comparison. The 

dashed line consists of data extracted from the C02-latitude-DOY 

surface of fig. 7, sec. 3.1. 
- 3~5 

w 

__J 

a: 344 u 

Ul 

z 343 

0 

;::: 342 

u 

& 341 

L... 

w 340 __J 

0 

!: 3 39 

-

~ 338 

!: 33 7 

a.. 

a.. 336 N 

0 

U335 

o ruJI + AHSTE~DAH ISLAND 

X PALMER STATION 

C02-LAT-DOY SURrACE 

+ 

~- ~~~~o x 

m m m - N ~ v ~ w ~ m m m - N ~ • n w ~ m m m - N ~ ~ n n ~ n ~ n ~ ~ ~ n w w w w w w w m m w ~ ~ ~ 

DAY OF YEAR 1983 

Figure 82.--C02 vs. DOY for the FUJI 

cruise flask samples. Amsterdam Island and Palmer Station flask data 

are shown for comparison. The dashed 

line is from fig. 7, sec. 3.1. 

;::i 355 

__J 

a: 

u 

Ul 

z 

0 350 H 

tu 

a: 

Cl:'. 

L... 

w 345 __J 

0 

:i: 

CD 

x 

- 341l 

:i: 

a.. 

a.. 

N 8 335 

0 DISCOVERER 

X CAPE KUHUKAHI 

+ GUAM 

* SAMOA 

C02-LAT-DOY SURFACE 

• • • 

~ w m n m ~ m n m ~ m ~ m ~ m n m ~ m n ~ 

~ ~ w w ~ ~ m m m m ~ ! = = ~ N M ~ • • ~ 

DAY OF YEAR 1983 

Figure 83.--C02 vs. DOY for the 1983 

DISCOVERER cruise flask samples. 

Flask data from Cape Kumukahi, Guam, 

and Samoa are included for comparison. The dashed line is from 

fig. 7, sec. 3.1. The latitudelongi Lude scale indicates the five 

sections of the cruise as discussed 

in the text. 

are comparable with the average (85%) for the flask network as a whole. The 

factors affecting sample quality include storage time (1-3 months for DISCOVERER 

1983; 2 months for the FUJI; 3-6 months for the POLAR STAR), storage temperature, sample water vapor content, and technique of the sample taker. It is 

likely that storage time and temperature are responsible for the deterioration 

of some of the cruise samples. The data were selected by rejecting high 

members of bad pairs followed by a more subjective rejection of values lying 

far from the bulk of the data. 

The cruise of the USCG vessel POLAR STAR sponsored by NSF's USARP during 

a us tral summer 1982-1983 was of particular interest in that it afforded an 

opportunity to assess directly the representativeness of Palmer Station for 

the latitude band centered at 65°S. In fig. 81 the weekly flask data from 

Palme r Station are plotted for comparison with the POLAR STAR data. From 

DOY 362, 1982, to DOY 63, 1983, the ship circumnavigated the Antarctic continent, remaining south of 60°S and going as far as 77°S. The mean C0 2 concentrati on for POLAR STAR flasks for this period is 339.9 ppm (N = 40, a= 0.6), 

wh ile for Palmer Station the mean is 339.4 ppm (N = 15, a= 0.4). 

Although the POLAR STAR data show a higher degree of variability, the 

agreement between the two data sets is quite good, indicating that atmospheric 

C0 2 i n this part of the Southern Hemisphere is well mixed zonally, and that 

Palmer Station is indeed a regionally representative site. The variability in 

the POLAR STAR data is probably real and may be related to variation in sea 

i ce cover, upwelling, and/or marine productivity causing short-term fluxes of 

105 
C0 2 between the ocean and the atmosphere. The dashed line in fig. 81 represents data extracted from a C0 2 -latitude-DOY surface constructed from zonally 

averaged C0 2 data from the GMCC network (see sec. 3.1). The agreement between 

the surface and the circum-Antarctic cruise data supports the validity of 

zonally averaging C0 2 data, especially in the Southern Hemisphere. The slight 

downward trend until DOY 72 is due to the Southern Hemisphere seasonal cycle 

of -1 ppm, while the increase from DOY 72 through 76 indicates a latitudinal 

gradient of -l-2 ppm between 39°S and 26°S off the eastern coast of South 

America at this time of year. The latter feature is seen clearly in both the 

POLAR STAR data and the zonally averaged surface, while the scatter of the 

cruise data tends to obscure the small seasonal trend. 

The GMCC flask sampling program aboard the Japanese research vessel FUJI 

was a cooperative venture with J. Kelley of the University of Alaska Geophysical Institute. The ship made a south-to-north transect across the Southern 

Indian Ocean from the Japanese station at Syowa, Antarctica, to the island of 

Mauritius. In fig. 82 the C0 2 data are plotted vs. DOY together with data 

from Amsterdam Island and Palmer Station for comparison. 

The flask samples collected aboard the FUJI were quite good, with only 2 

bad pairs out of 18, and 1 good pair rejected as being contaminated. The 

period from DOY 51 through 68 covers from 69°S to 23°S and shows little or no 

gradient, with a mean C0 2 concentration for the shipboard flask samples of 

339.4 ppm (N = 17, a= 0.3). For comparison, the mean concentration for this 

period is 340.2 ppm (N = 6, a= 0.7) at Amsterdam Island and 339.0 ppm (N = 5, 

a= 0.2) at Palmer Station. The agreement of the cruise data with station 

data is quite good, lending further support to the representativeness of the 

Southern Hemisphere flask sites. There is, however, a tendency for the 

Amsterdam Island flask data to be higher, as expected from the Southern 

Hemisphere latitude gradient, and more variable than the FUJI or Palmer 

Station data. The agreement of the cruise data with the C02 -latitude-DOY 

surface is also quite good. The divergence occurring north of 30°S (DOY 66) 

is probably a result of the zonal averaging of the surface, and suggests the 

existence of a small longitudinal gradient in midlatitudes of the Southern 

Hemisphere. 

The GMCC flask sampling program aboard the NOAA research vessel DISCOVERER 

during March through May of 1983 was a continuation of the GMCC C02 Group's 

collaboration with the NOAA PMEL's C02 Dynamics Study begun in 1982. The C0 2 

data from the DISCOVERER are plotted vs. DOY in fig. 83 with station data and 

a projection from the C0 2 -latitude-DOY surface for comparison. Since this 

cruise covered a large portion of the North and equatorial Pacific over a 

period of several months when latitudinal gradients are known to change 

(Komhyr et al., 1984a; Pearman et al., 1983b), it is useful to break it down 

into five sections. (1) From DOY 63 to 79 the ship steamed south along 170°W 

from 50°N to 20°N. A north-south gradient of ~I ppm was observed, which is in 

good agreement with the zonally averaged surface. Near 20°N the agreement 

with Cape Kumukahi is good. The observed gradient is typical for the North 

Pacific at this time of year. (2) From DOY 92 to 102 the track is south along 

158°W from 20°N to the Equator. Initially the C0 2 concentration gradient 

closely follows the C02 -latitude-DOY surface, but after decreasing by ~1 ppm 

the concentration increases by -1 ppm, between 2°N and the Equator. This 

feature is probably real and is an example of the type of variability that can 

be located by shipboard sampling but not by land-based sampling sites. 

(3) From DOY 102 to 117 the track is east along the Equator from 154°W to 

105°W. The C0 2 concentrations measured here are variable and 1-2 ppm higher 

106 
than the projection from the surface, while agreeing well with Guam and Cape 

Kumukahi data. Although the variability is somewhat higher than expected, the 

difference between the cruise data and the surface can be explained by the 

fact that the surface is zonally averaged and the equatorial portion includes 

data from Ascension Island (8°S) in the Atlantic and the Seychelles (5°S) in 

the Indian Ocean, as well as Guam and Samoa. In this case it is clear that a 

large longitudinal gradient does exist, with the eastern equatorial Pacific 

some 2 ppm above the zonal mean. The magnitude of this difference probably 

varies from year to year and is large in 1983 following the strong ENSO event. 

The addition in 1984 of Christmas Island (2°N, 158°W) to the flask sampling 

network will greatly improve our equatorial coverage in the Pacific. (4) From 

DOY 117 to 125 the ship traveled from the Equator to 22°N along 105°W. On 

this segment a strong gradient of 4 ppm was observed in close agreement with 

the C02 surface, although the gradient from the cruise data occurs earlier 

than from the zonally averaged C0 2 surface, suggesting the influence of 

continental air as the ship approached the Mexican coast. (5) From DOY 125 

to 142 the ship traveled along the west coast of the United States, stopping 

at San Diego, and terminating in Seattle. The C0 2 concentrations on this 

segment are in general agreement with the C0 2 surface while exhibiting significant variability probably caused by rapid exchange between the atmosphere and 

shallow coastal waters, and the proximity to the vegetated continent. 

Overall, the DISCOVERER 1983 cruise supports the representative nature of 

the Pacific Ocean flask sampling sites and underscores the need for an equatorial Pacific site. Taken together, the results from the shipboard flask 

sampling programs have consistently shown that the GMCC C0 2 flask sampling 

network consists of regionally representative background sites from which a 

fairly detailed assessment of the global distribution of atmospheric C0 2 at 

the surface may be obtained. Further, it is shown that a zonally averaged 

C0 2-latitude-DOY surface represents this distribution quite well (typically 

within 0.5-1.0 ppm) although differences of 1-2 ppm between measurements and 

the surface may be found where longitudinal gradients become significant. 

Note that the 1983-1984 Long Lines cruise should provide some information on 

longitudinal gradients when compared with the KOROLEV and POLAR SEA cruises. 

The acquisition of two custom built gas chromotographs from R. Weiss of 

SIO (Weiss, 1981) allows in situ, continuous measurements of C0 2 and CH 4 in 

the air and pC02 and pCH4 in surface seawater. Such measurements were made on 

the SAGA expedition aboard the Soviet research vessel AKADEMIC KOROLEV and on 

the DISCOVERER 1984 cruise. These measurements will provide more detailed 

information on the air-sea exchange of C0 2 and CH4 and on the distribution and 

variability of marine sources and sinks of these climatically important 

species, as well as allowing greater precision and higher resolution in determining gradients than can be obtained by flask sampling. 

4.12 Results of the December 1983 NOAA-SIO C0 2 Intercomparison 

4.12.1 Introduction 

As part of a comparison of the 10-yr joint record of atmospheric C0 2 

measurements at MLO by NOAA and SIO, a special set of field tests was cooperatively developed in 1983 to assess possible instrumental sources of disagreement in the present measurement programs. Seven tests were conducted, each 

lasting 8-33 hours. These tests, designated A to G, were carried out during 

the week of 5-12 December 1983. A summary is given in table 31. 

107 
Table 31. --Summary of NOAA-SIO C0 2 intercomparison at MLO, December 1983•'• 

Working air standard Ambient air (high-tower line(s]) 

Single-line air intake test; i.e., tests A, B, C, & F 

A 35 (37) 336.95 336.95 0.00 341.95 341.86 0.09 

(±0.025) (±0.024) (±0.029) 34(37) (±0.060) (±0.050) (±0.039) 

B 31(32) 343.39 343.41 -0.02 

(±0.029) (±0.036) (±0.038) 

c 14(15) 343.41 343.36 0.05 13(15) 342.07 341. 95 0.12 

(±0.059) (±0.051) (±0.080) (±0.103) (±0.092) (±0.058) 

F 16(18) 343.49 343.42 0.07 17(18) 342.24 342.09 0.16 

(±0.035) (±0.025) (±0.045) (±0.056) (±0.044) (±0.046) 

Dual-line air intake tests; i.e., tests D & E 

D 45(48) 343.41 343.41 0.00 39(48) 341.99 341. 84 0.15 

(±0.021) (±0.018) (±0.028) (±0.056) (±0.061) (±0.024) 

E 46(50) 343.41 343.40 0.01 48(50) 341.86 341. 85 0.01 

(±0.022) (±0.019) (±0.022) (±0.072) (±0.071) (±0.025) 

Eavesdrop test; i.e.' both systems under normal operation 

G 24(27) 342.25 342.27 -0.02 

(±0.121) (±0.099) (±0.039) 

*Concentrations are in parts per million. Entries in parentheses are standard deviations from the 

mean (am). 

tN refers to NOAA selected data, S refers to SIO selected data. Data omitted are individual 

10-~in averages that are greater thaft 2a from the mean. 

4.12.2 Experimental Procedures 

During each test cycle, except in tests B and G, a control gas mixture of 

dried pressurized natural air, WA (for working air), was sampled for a 10-min 

period with another 10 minutes used to sample ambient air obtained 80 ft above 

the ground on a high tower, TW (for tower air). These were compared with two 

standard reference gases, designated Wl and W2. The gases WI, W2, and WA were 

specially prepared dried C0 2 -in-air gas mixtures in pressurized steel cylinders 

with C0 2 concentrations determined in advance by GMCC. The analyzers used 

were an APC at SIO and a Hartmann and Braun URAS-2 at GMCC. 

The timing and sequence of the gases used was 5 minutes of low reference 

gas Wl, 5 minutes of high reference gas W2, 10 minutes of WA, and 10 minutes 

of TW. An array of four solenoid valves alternately selected one of the four 

gases. The WA and TW gases were treated as unknown, so that their C0 2 concentrations were calculated by interpolation of data from Wl and W2, assuming 

linear instrument response. For WA and TW, 10-min averages were computed each 

half-hour for each analyzer, taking into account short-term changes in sensitivity and drifts of the analyzer output. 

The guiding principle in designing these tests was to take both systems 

offline arid to begin by eliminating all differences between the systems except 

those from the two analyzers. Then the two systems were allowed to be brought 

to their respective normal configuration of sampling lines, plumbing, and 

water freeze traps. 

In tests A, B, and C, beginning on 5 December, as many hardware differences as possible were eliminated between the analysis systems. Ambient air 

108 
was taken through a common line (SIO high tower) and through a common pumping 

system (SIO). The selected gas mixture passed through a common water vapor 

freeze trap, after which it flowed separately to each analyzer. In tests B 

and C, the times for reference gases Wl and W2 were increased to 10 minutes. 

Ambient air was not measured in test B. 

Test D, begun on 8 December, was designed to determine whether certain 

identified hardware differences between the two systems would cause differences in the results. Specifically, each analyzer received ambient air from 

separate lines on the high tower through separate plumbing systems. Each 

system also included its separate water freeze-out trap. The timing sequence 

was the same as in test A. Test gases Wl, W2, and WA were still common to 

both systems. Results from this test showed a consistent difference of about 

0.15 ppm (URAS minus APC) between the NOAA and SIO tower air. Because the 

mean of the WA differences was ~0.05 ppm, the bias in the TW data appears to 

have occurred in the tower air lines or the pumping systems, and not in the 

analyzers. In hopes of pinpointing the source of the difference, test E was 

run. 

Test E, begun on 9 December, was designed to decide between the pumping 

system or the air lines as the source of the difference found in test D. The 

tower air lines were reversed so that one pump used the other's air line. The 

lines were also switched after the pumping system. The end result was that 

each analyzer sampled its own tower air, but the air was pumped by the other's 

pumping system. It was thought that if the difference found in test D changed 

sign, then the source was in one of the pumping systems. If there was no 

change in the offset from test D, the source might be a contaminated air 

intake 1 ine. 

Test F, begun on 10 December, was similar to test E, following it continuously in time, except that a common air line (SIO high tower) was directed 

through the GMCC plumbing to both analyzers. 

Test G, begun on 11 December, was an "eavesdropping" test on the normal 

operation of each analyzer, except that the SIO analyzer had previously been 

calibrated with C0 2 -in-N2 gas mixtures, and in this test it used C0 2 -in-air 

mixtures. (Beginning on 18 December 1983, SIO changed its normal operation of 

the APC to C0 2 -in-air reference gases.) Test G was based on averages every 

hour, rather than every half-hour, since this is the normal operation for the 

GMCC system. 

4.12.3 Results 

When the same C0 2 -in-air test gas mixture (WA), sampling sequence, and 

plumbing (tests A, B, C, and F) were used, the analyzers were found to give 

nearly identical results. In test A, a gas mixture predetermined by GMCC to 

contain 336.95 ppm was assigned as WA. The difference in C0 2 concentration 

calculated for WA between the analyzers was 0.00 ppm with a standard deviation 

from the mean (o ) of 0.029 ppm. In tests B, C, and F, a gas mixture predetermined to containm343.48 ppm was assigned as WA. The analyzers showed a 

difference (URAS minus APC) of -0.02 ppm with o = 0.038 ppm in test B, a 

m 

difference of 0.05 ppm with o = 0.080 ppm for test C, and a difference of 

m 

0.07 ppm with o = 0.045 ppm in test F. The average weighted difference for 

m 

109 
all four tests (A, B, C, and F) was 0.011 ppm. With the possible exception of 

test F, WA gave no significant difference in recorded concentration for the 

two systems. 

The agreement suggests that any difference in the nonlinearity of the two 

analyzers over the range 335-345 ppm was less than 0.1 ppm. The linear 

interpolation used to estimate WA was later determined to introduce a maximum 

error of 0.04-0.05 ppm from the true value of the nonlinear response of the 

URAS analyzer determined on 7 December 1983. To have achieved the best 

observed agreement, the nonlinearity of the APC must have been of similar 

magnitude and sign. Similar nonlinearities have been found in previous comparisons of APC and URAS analyzers undertaken at SIO. 

A second significant result of tests A, B, C, and F was the similar RMS 

noise level (o ) for each instrument and test when measuring WA through common 

plumbing and w~ter freeze-out trap. While the weighted a for the APC over 

all four tests (0.16 ppm) represents typical performance,sthe weighted a for 

s 

the URAS (0.16 ppm) was greater than normal. This was not a serious hindrance 

to the testing, since a noise level for an individual measurement is an 

expression of a random error. In normal operation, as well as during these 

special tests, so many individual measurements are averaged that the noiseinduced individual errors of about 0.20 ppm are unimportant compared with 

longer term, systematic errors. 

The variance of the differences (URAS minus APC) of the 10-min average 

C0 2 concentrations determined by the two instruments measuring WA is approximately equal to the sum of the variances of the 10-min averages of each 1 

instrument. That is, o~ ~ [(oAPC) 2 + (oURAS) ]~. This suggests that the 

variability was largely uncorrelated and not closely related to changes in a 

common environment such as vibration, temperature, or electrical interference. 

Tests A, C, and F also included 10-min measurements during each cycle of 

ambient air from the SIO high-tower air intake line through common plumbing 

and cold trap. For this gas, TW, the analyzers gave a weighted average difference (URAS minus APC) of 0.12 ppm with a weighted average a of 0.026 ppm. 

The mean ambient air values of TW had higher variability (o =m0.10-0.37 ppm s 

per test) compared with the mean values of WA (o = 0.10-0.22 ppm per test). s 

This increased variability of their values is attributable to the combined 

instrumental and real air variability. The difference between the analyzers 

(URAS minus APC) appears to be significant (over 4 times a) . m 

In test D the difference (URAS minus APC) for ambient air was 0.15 ppm, 

with a = 0.024 ppm. Attempts in test E to cause this difference to reverse 

sign b~ interchanging plumbing but keeping the same air intake lines resulted 

in a URAS minus APC difference of 0.01 ppm with a = 0.025 ppm. m 

It was observed during the first part of test E that a negative-pointing 

spike occurred on the URAS strip chart recorder trace, at the start of each 

10-min sample of GMCC tower air. This spike was also found to have occurred 

on the APC chart recorder trace in test D, although it was much smaller, 

because of the larger sample cell of the APC analyzer compared with that of 

the URAS. The cause of this spike was found to be a faulty air pump in the 

110 
SIO plumbing system, used in test D to supply tower air to the AFC and in 

test E to supply tower air to the URAS. During the last 3 hours of test E, 

after replacement of the pump, the difference in ambient air values between 

the two systems (URAS minus AFC) rose to an average value of 0.15 ppm with 

a = 0.042 ppm, similar to test D. 

m 

The short "eavesdropping" comparison of test G presents only a small 

sample of the ongoing comparison between the NOAA and SIO C02 analyzers at 

MLO. The results indicated a difference of -0.02 ppm with a = 0.039 ppm. 

However, conclusions for this test will depend on final conc~ntrations for the 

different reference gases employed as station standards in the normal operation of the SIO and NOAA C0 2 programs at MLO. 

4. 12. 4 Summary 

Tests A, C, D, E, and F showed that the GMCC and SIO C02 systems gave the 

same measured ambient atmospheric air value to within about 0.15 ppm. For 

tests through common plumbing the difference (URAS minus AFC) on average was 

0.12 ppm with a = 0.026 ppm. For tests through different plumbing a similar 

difference of 0~15 ppm was observed, disregarding the period of faulty pump 

performance during test E. The weighted mean difference for all tests was 

0.138 ppm with a weighted a = 0.016 ppm. No single cause was discovered that 

accounted for these differeWces, which did not appear to correlate with 

permutations in plumbing except for the changes in pumps in test E. On 

average, no significant difference was observed when measuring C0 2 in air from 

a pressurized cylinder with common plumbing (URAS analyzer 0.01 ppm higher 

than the APC with a = 0.014 ppm). m 

The observed differences are smaller but of the same sign as the mean 

difference (URAS minus AFC) provisionally computed between the NOAA and SIO 

systems for calendar year 1983 (0.3 ppm). The overall level of agreement between the NOAA and SIO C0 2 records at MLO during the last decade has been 

provisonally determined at the 0.3- to 0.6-ppm level for monthly means, with a 

relative drift of about 0.08 ppm yr- 1 (NOAA minus SIO) from an initial difference of about -0.5 ppm in 1974 to +0.6 ppm in 1982 (fig. 84). Except for the 

period from mid-1980 to mid-1982, the NOAA-SIO difference has remained at or 

below 0.1% ($0.3 ppm). 

JI 

.I 

1 .4 

0 .2 

iii 

e Ol--~---f+-4--+-Nl--#+-W-,&.--'-ll"._...,~~~~~~4--I 

s. " E -.2 

~ -.4 z 

-.I 

-.e 

,~,~ ,~ ,~ ·~ ,~ ,~ ,~,~ ,~ ,~ 

YEAR 

111 

Figure 84.--Provisional selected 

monthly mean differences between 

NOAA and SIO for the common record 

of C0 2 sampling at MLO. 
4.13 The 1982-1983 El Nino-Southern Oscillation Event as Recorded in the 

Global Atmospheric C0 2 Distribution 

4.13.1 Introduction 

After the seasonal variation and the secular increase due to fossil fuel 

combustion are removed, the dominant residual signal in time series of atmospheric C02 concentration from background monitoring stations is a fluctuation 

inversely correlated with the SOI. This was first shown by Bacastow (1976) in 

the C0 2 records for MLO and SPO. Bacastow found the best correlation between 

the SOI and inverted C02 derivatives of the de-seasonalized, detrended MLO and 

SPO time series. An increase in atmospheric C0 2 was found to lag the SOI 

minimwn by two seasons at MLO and three seasons at SPO. Subsequent analyses 

by Bacastow and coworkers have extended this approach to stations in tropical 

latitudes (Fanning Is., MLO) and extratropical latitudes (Station P, SPO). 

These studies have confirmed the SOI signal in the C0 2 records corresponding 

to the ENSO events of 1965, 1969, 1972, and 1976 (Bacastow, 1977; Bacastow, 

1979; Bacastow et al., 1980). 

While Bacastow established the correlation of C0 2 anomalies with SOI, 

others studied SST, a parameter measurable in the C0 2 source and sink regions 

of the oceans. Various studies have shown relationships between atmospheric 

C0 2 variations and SST anomalies in the equatorial Pacific (Weare et al., 

1976; Newell and Weare, 1977; Newell et al., 1978), the northwest Pacific 

(Hanson et al., 1981), and the Pacific, north of 20°N (Schnell et al., 1981). 

Plotted in fig. 85 (Gammon et al., 1984a), are the year-to-year change in 

atmospheric C0 2 at MLO, adjusted to remove the fossil fuel increase, and the 

year-to-year change in the mean air temperature in the northern subtropical 

zone (Angell and Korshover, 1983). The empirical relationship between the 

interannual temperature change and the observed C02 change is ~0.8 ppm (°C)- 1 , 

similar to that reported by Schnell et al. (1981). 

The relative importance of anomalies in atmospheric circulation, SST, and 

biospheric activity associated with ENSO events in perturbing atmospheric C0 2 

levels remains an open question. For example, the reduced trade winds during 

El Nino imply reduced upwelling of C0 2 supersaturated deep wate r, hence a 

1.4 

1.0 

I r 

i .6 

a: a: ~< >W 

-> .2 

Q. ~-u Q. 0 

-.2 

-.8 

-1.0 

1955 1980 1985 1970 1975 1980 

YEAR 

1985 

112 

Figure 85.--A comparison of the HLO 

year-to-year change in atmospheric 

C0 2 , adjusted for fossil fuels 

( ·--·, SIO data; +---+, NOAA 

data) with the year-to-year temperature change in the northern subtropical zone, 10°-30°N (·----·). The 

heavy line is the C02 growth rate, 

calculated from fossil fuel production data, which has been subtracted 

from the observed growth rate at 

MLO. (From Gammon et al., 1984a.) 
weaker marine source of atmospheric C0 2 , while the simultaneot1s failure of the 

marine productivity in the upwelling regions implies a less-effective marine 

sink for C0 2 . Lower winds imply less-efficient air-sea C0 2 exchange, possibly 

affecting both source and sink regions, while warmer surface waters can 

accommodate less dissolved C02 in saturation equilibrium than cau colder 

waters. The role of changing wind stress and SST anomalies in extratropical 

latitudes may be more important in controlling global atmospheric C0 2 than was 

previously considered (Komhyr et al., 1983a). 

4.13.2 The 1982-1983 ENSO Event 

From the established correlation of the SOI witl1 anomalies in the C0 2 

growth rate, it was expected that the extreme ENSO event that began in mid1982 would measurably perturb the global atmospheric C02 distribution. This 

perturbation was observed in the GMCC global C0 2 data as an anomalously low 

rate of C0 2 increase in mid-1982 (Gammon and Komhyr, 1983; Gammon et al., 

1984a, 1984b). The prediction of a post-ENSO maximum in the C0 2 growth rate 

for late 1983-early 1984 of 2-3 ppm yr- 1 (Gammon and Komhyr, 1983) is confirmed by the latest results from the C0 2 flask network. The globally averaged year-to-year change in atmospheric C0 2 , plotted by quarters in fig. 86, 

clearly shows the effect of the 1982-1983 ENSO event on the global atmospheric 

burden of C0 2 over the period from mid-1982 to mid-1984. Because the past 5 

years have been a period of nearly constant global emission of ~s Gt yr- 1 of 

fossil fuel carbon to the atmosphere (Keeling, 1983), the zero growth rate 

from the third quarter of 1981 to the third quarter of 1982 implies that the 

equivalent of 5 Gt of fossil fuel carbon was removed from the atmosphere for 

temporary storage in the near-surface ocean and probably in the land biosphere 

as well. Now, more than a year after the SOI minimum was reached in January 

1983, this 5 Gt of carbon appears to have returned to the atmosphere; the 

year-to-year global average C0 2 increase peaked in the first quarter of 1984 

to 2.2 ± 0.3 ppm yr- 1 , well above the mean growth rate of 1.4 ppm yr- 1 for the 

past decade. Although previous investigators have focused on this high C0 2 

growth phase that lags the SOI minimum, the precursor phase of low C0 2 growth 

is equally prominent in the 1982-1983 event and may offer predictive possibilities. 

C02 PPM/YEAR 

1990 198 I 1982 1983 198'4 

113 

Figure 86.--The globally averaged 

C0 2 growth rate from the GMCC C02 

flask network data. The points are 

differences between quarterly global 

means in consecutive years, plotted 

in the forward year. 
A more detailed analysis of the latitude-dependent C0 2 response to the 

1982-]983 ENSO event can be made using the zonally averaged C0 2 concentration 

surface constructed from the C0 2 flask network data (sec. 3.1.2 and Komhyr et 

al., 1984). The representativeness of the surface has been verified by 

atmospheric C0 2 sampling aboard several cruises in 1982 and 1983 (Harris and 

Bodhaine, 1983, pp. 99-102; this report, secs. 4.11 and 4.16). In fig. 87a, 

several C0 2 anomalies precede or accompany the 1982-1983 ENSO event. First, 

the normal seasonal migration of the steep interhemispheric gradient near the 

Equator is perturbed in 1982, with the southern boundary of the gradient 

appearing far south of its normal position in the fall. A similar southward 

dislocation of the ITCZ, which represents a boundary between Northern and 

Southern Hemisphere air, has been reported by Philander (1983). 

Another anomaly seen in fig. 87a is the lack of a C0 2 increase from 1981 

to 1982, which is most easily discerned in the Southern Hemisphere. The 

year-to-year C0 2 changes by latitude are shown clearly in fig. 87b, which 

consists of the difference between concentration surfaces for two consecutive 

years, plotted in the forward year. The most striking feature of fig. 87b is 

the strength and location of the anomalous low-to-negative C0 2 year-to-year 

change in 1982, wl1ich clearly suggests that extratropical sinks in both 

hemispheres intensified in concert during this period. In the high southern 

latitudes, neither changes in the response of the land biosphere in 1982 nor 

the direct effects of stratospheric dust from El Chichon could have been 

responsible for the observed C0 2 decrease. Thus, a more effective southern 

ocean sink and a decrease in meridional transport of fossil fuel C0 2 from the 

north are the most likely explanations for this decrease. The interpretation 

of the negative C0 2 growth rate anomaly in the Northern Hemisphere is complicated both by the presence of the El Chichon dust veil and the unusual land 

plant activity observed in 1982. The Northern Hemisphere ocean sinks for C0 2 

were probably more effective during this period as a result of the extensive 

J 

r 

< 

.. YEAR 

Figure 87.--(a) A contour plot of the distribution of atmospheric C02 

in space and time, synthesized from the GMCC C0 2 flask network data. 

(This figure is the same as fig. 8, sec. 3.1, repeated here for convenience.) (b) The distribution of atmospheric C0 2 growth rates obtained 

by plotting in the forward year the differences between consecutive 

years in fig. 87a. Growth rates below 1.0 ppm yr- 1 are shaded with 

lines; growth rates greater than 2 ppm yr- 1 are shaded with dots; and 

values of 1-2 ppm yr 1 , typical growth rates for non-ENSO years, are not 

shaded. 

114 
and persistent negative SST anomalies (1-3°C) in the north Atlantic and 

northwest Pacific. As shown in fig. 88, the C0 2 growth rate anomalies appearert 

in phase at both northern subtropical and mid-to-high southern latitudes. 

This feature of the latitude dependence of the C0 2 response to the 1982-1983 

ENSO perturbation suggests that the C0 2 -ENSO signal is not generated at the 

Equator and propagated poleward, but rather appears nearly simultaneously in 

both hemispheres. 

The recovery from low C0 2 growth rates was observed first at southern 

tropical latitudes in early 1983, followed by a recovery in the northern 

tr~pics a few months later. Higher-than-normal C0 2 growth rates (2.0-3.0 ppm 

yr 1 ) peak in the fall of 1983 in the Northern Hemisphere and peak 2-3 months 

later in the Southern Hemisphere (fig. 87b). Although the data are incomplete, 

it appears that by mid-1984 the year-to-year C0 2 growth rates for the flask 

network are returning to normal values (1.5 ± 0.3 ppm yr- 1 ), signaling the end 

of the C02 -ENSO response. 

The effect of the 1982-1983 ENSO event on the latitude gradient of C0 2 

concentration is clearly demonstrated by a comparison of gradients for the 

years 1979-1983 (fig. 89). A prominent feature in the 1979-1981 gradients is 

a I-ppm equatorial enhancement in atmospheric C02 usually ascribed to an 

equatorial Pacific upwelling source (Keeling, 1983) and/or tropical deforestation. The obvious suppression of the local maximum in 1982 and its weak 

recovery in 1983 well south of its normal location constitutes the first 

well-documented case of an ENSO modulatiort of this feature. This result, 

together with the isotopic record (Keeling et al., 1984), essentially rules 

out tropical deforestation as a source for this feature, leaving upwelling in 

the equatorial Pacific as the most likely explanation. The suppression of 

this feature during the 1982-1983 event may have been caused by enhanced 

meridional mixing out of the equatorial zone by more active Hadley cell 

C02 PPH/YEAR 

r-~~~..--~~..--..--..--..--..--~..--..--~ ~..--~ 

-z 

a 

1980 198 I 1982 1983 

t<EY C26 N> 

HLO (29 N) 

KUH (20 N> 

AVl CIB N) 

1984 -z 

b 

19tl0 1981 1982 1983 

AHS C38 S> 

PSA t6S SJ 

SPO <90 Sl 

1994 

Figure 88.--C02 growth rates for flask network stations at (a) northern 

subtropical latitudes and (b) mid-to-high southern latitudes. The 

points are differences between quarterly means in successive years, 

plotted in the forward year. See table 7 for an explanation of network 

station codes. 

115 
i 

s 

z 

0 

!i1 

a: 

I-

~ u 

z 

0 

u 

. 

0 

u 

z 

:l 

,. 

~ 

"' ::.

z 

z 

"' 

34• 

3'2 

340 

336 -

33• ~- -- ------ ~--~ ~ SPO BO 60 40 20 EO 20 40 60 80 NP 

Soulh North 

LATITUDE 

Figure 89.--The latitudinal variation of annual mean atmospheric C02 

concentration using all available 

flask data, 1979-1983. 

circulation (C. Ramage; U. of Hawaii, Hilo; pe rsonal communication, 1984), as 

well as by a weakening of the normal upwelling that brings cold, C02 -saturated 

water to the surface in this regi on . 

4.14 Total S02 Observations at MLO 

Since the Eruption of El Chichon Volcano in 1982 

Sulfur dioxide in the atmosphere interferes with Dobson spectrophotometer 

total ozone observations, because it absorbs ultraviolet radiation at the 

Dobson instrument wavelengths. Concern has been expressed about the accuracy 

of total ozone observations made at MLO following the eruption of El Chichon 

volcano in late March-early April 1982, since the volcano probably spewed 

10 Mt of S02 into the stratosphere. 

It is possible to measure both total ozone and S02 with a Dobson spectrophotometer (Komhyr, 1980) if observations are made simultaneously on AD and AB 

wavelengths. Following the eruption of El Chichon, specially calibrated 

Dobson instrument no. 65 was put into operation at MLO on 17 May 1982. Results of 2 years of measurements since that time are shown in fig. 90. It 

appears that conversion of S02 to H2S04 occurred within several weeks after 

the eruption, because after about 1.5 months, the total S02 amount at MLO was 

slightly less than 2 milli-atm-cm. Since 17 May 1982, the S0 2 has continued 

to decrease slowly to a 30 May 1984 value of about 1.2 milli-atm-cm. The 

uncertainty in this value is probably ±1 milli-atm-cm, arising mostly from 

uncertainties in the absorption coefficients of S02 at the Dobson instrument 

wavelengths. This small amount of total atmospheric column S02 translates 

into total ozone measurement errors with a Dobson spectrophotometer of not 

more than about 1%. 

116 
nl 

0 

"' :c"' 

(_) 

I 

:c 

.... 

a: 

I 

_J 

_J 

:c 

i+----.~~B~2~r------,--,~~ ~-.-----.~~~ ~~---l 

Figure 90.--Total atmospheric 802 

measured at MLO with a Dobson spectrophotometer during 17 May 1982-

30 May 1984. 

'IE:RR 

4.15 Development of a Balloonborne 802 -sonde 

A balloonborne sonde for measuring the vertical distribution of 802 has 

been developed. The instrument, coupled to an NWS 1680-MHz radiosonde during 

flight, is a modification of the ECC ozonesonde developed by Komhyr (1969). 

When 802 is measured, ozone is prevented from entering the sensor with a 

rubber scrubber, while iodine is produced electrolytically within the cathode 

chamber of the cell. 802 -in-air entering the cell reduces iodine according to 

+ --7 so4 + 4H + 2e 

I2 + 2e --7 21 

One molecule of S02 , therefore, reduces one molecule of electrolyticallyproduced iodine to iodide. The fall in cell output current due to consumption 

of iodine by the sulfur dioxide is related coulometrically to the rate at 

which 802 enters the cell, and may be used to measure its concentration in 

air. S02 measurement sensitivities for the instrument are 0.7, 2.7, 15, and 

34 ppbv at 750, 200, 50, and 10 mb, respectively. 

The result of an 802 sounding made at State College, PA, on 25 February 

1983 is shown in fig. 91. The source of the S02 was a local powerplant stack, 

located several hundred yards away from the site from which the balloon was 

launched. 

117 
Temperature (°C) 

1s -10 -s o 5 10 15 20 25 30 Js 6 

4 \ 

I 

3. 

3.2 

3.0 

2.8 

2.6 

e 0 2.4 

...J 

~ 2.2 

QI i5 2.0 

~ QI 1.8 

-g 

~ 1.6 

1.4 

1.2 

1.0 

0.8 

0.6 

0.4 

0.2 

0 

' .. 1 Temperature 

,/ : 

I :~ _. Relative humidity I 

' I 

I 

I 

I 

I ·. I 

I 

I 

I .. I 

I " I 

'r-- ' I 

/ 802 ··· .... f-..L_ 

I --r---... .... '· ' '\ .• .• 

.. I 

I 

I 

\ 

\ J I I I 

I 

.. _/ 

/'" ,...--- 1, : ~ 

~ .. .... .... . ' \ 

..... 

10 20 30 40 50 60 70 80 90 100 

802 (PPBV) or relative humidity(%) 

Figure 91.--S02 , air temperature, 

and relative humidity vertical 

distribution data obtained with an 

S02-sonde on 25 February 1983 at 

State College, PA. 

4.16 C0 2 Measurements in Surface Ocean Waters 

Between 22 October and 5 December 1983, L. Waterman of the GMCC C0 2 Group 

participated in the SAGA Expedition aboard the U.S.S .R. research vessel 

AKADEMIK KOROLEV. The cruise track is shown in fig. 80b, sec. 4.11. The ship 

was at sea for 43.5 days with no ports of call. A modified Perkin-Elmer gas 

chromatograph (Weiss, 1981) was used for continuous monitoring of atmospheric 

carbon dioxide and methane. The condition of the surface ocean waters with 

respect to supersaturation or undersaturation of dissolved C02 and CH4 were 

also continuously monitored using a Weiss-design equilibrator. The apparatus 

is fully automatic and is programmed to make three atmospheric and three ocean 

surface measurements per hour. 

Atmospheric air was pumped continuously from intakes located on the bow 

of the ship and the top of the two forward cargo booms (starboard and port). 

The air lines were selected on the basis of wind speed, wind direction, and 

sea state. The airflow discharging into the laboratory was restricted to 

create a back-pressure in the line, which was needed for making periodic 

injections into the gas chromatograph (analyzer) col~1n. 

C0 2 in the surface waters was directly measured by circulating air in a 

closed loop between the analyzer and the equilibrator. This air was mixed in 

118 
460 

440 

422 

400 

'E 

0 

0 

'E 

460 

440 

420 

400 

• 

DO 

.fo 

0 

0 

0 0 0 

0 Org 00 

a. 38<l ! 380 ) 0 00 

~ 0 

~ 362 ~ 360 0 

u dJ c. 

3•a 

320 

330 

280 

"' ~ 

s "' "' "' "' "' LATITUOE Cdo g l 

"' "' "' "' "' T 

N 

Figure 92.--The concentration of co2 in surface ocean water as a function 

of latitude for the SAGA Expedition, 

leg 1, north to south. 

~ 

3<0 

320 

300 

280 

"' T 

5 

"' "' "' "' LATITUDE [degJ M '" 

Figure 93.--The concentration of co2 in surface ocean water as a function 

of latitude for the SAGA Expedition, 

leg 2, south to north. 

the equilibrator with a constantly renewed supply of ocean water pumped from a 

seachest located amidships and several meters below the water line of the 

vessel. This line was also equipped with a back-pressure regulator that 

served the same purpose as the one used in the atmospheric air line. 

Figures 92 and 93 show the preliminary ocean surface results from the 

SAGA north to south, run (25 October-1~ November) and the SAGA south to north, 

run (15 November-3 December) respectively. The mean atmospheric co2 concentration for the time interval is represented by a straight line in each 

case. This line is intended to be only a reference level for illustrating th e 

co2 undersaturation and supersaturation in the ocean surface waters. The 

entire track, 25 October-3 December, represents 921 hours of observations tha t 

are depicted as 3-h means. The ocean water measurements have been corrected 

to remove the effects of warming the water by the seachest pump and of the 

residence time in the transmission line and equilibrator chamber. 

The two SAGA equatorial crossings represent the eighth and ninth sections 

of a survey of the Pacific Ocean equatorial supersaturation feature. The 

survey began as part of the SIO Downwind Expedition during the International 

Geophysical Year (Keeling et al., 1965). A summary of all nine sections is 

given in table 32. 

A detailed report for the five crossings made during the Eastropac and 

Nova expeditions has not been published, although the data were considered in 

the determination of the general features of the distribution of co2 in the 

surface waters of the world's oceans (Keeling, 1968). 

119 
Table 32.--Equatorial crossings of research vessels measuring pC02 

Expedition Date Location & direction of crossing 

Downwind Oct-Dec 1957 130°w, N-S 

Monsoon Feb-Apr 1961 150°W, S-N 

Eastropac Jan-Mar 1967 -120°w, N-S; -125°w, S-N 

Nova Apr-Sep 1967 -175°w, N-S; -160°w, S-N; -178°w, N-S 

SAGA Oct-Dec 1983 155 °W, N-S; 133°W, S-N 

The overall patterns of supersaturation and undersaturation in the SAGA 

record (figures 94 and 95) resemble those found on the Downwind and Monsoon 

expeditions (Keeling et al., 1965). SAGA I (north to south) is closest to the 

Monsoon track in the region of the Equator, although the crossings occur 4 

months apart in time of year. The SAGA II (south to north) track closely 

parallels that of Downwind from 30°N to 30°S, and both expeditions occur in 

October-December. As was the case on all previous expeditions, the major 

features on the SAGA Expedition appear to be latitude dependent. 

The tropical maximum on SAGA I occurs at about 6°S and on SAGA II at the 

Equator. The SAGA I and Monsoon tracks were approximately the same near the 

Equator, but the crossing occurred in different seasons, which might explain 

the southward shift of the SAGA I maximum. However, since the SAGA II track 

was close to the Downwind track geographically, and the Equator crossings were 

.. DOWNWIND 

.,.. E.XPEDITION ....... 

"" v 10' 

.. 

-

... i:!,110 

... 

- .. .. .. .. "' 10 10 

•s LATITUOlt 

Figure 94.--Concentration of co2 near 

the ocean surface in the atmosphere 

(dots), and in sea water (squares), 

as a function of latitude for the 

Downwind Expedition, 21 October23 December 1957. The dashed line 

pertains to the northward part of the 

voyage. (From Keeling et al., 1965.) 

,.. 

WTH 

,.. .. ... 1•c1 

... 400 

.. ... ... .. . ... ... ~ 110 ,, .. , 

... ... HO 

Ml 10 10 10 I C ., LATITUDE 

Figure 95.--Concentration of co2 near 

the ocean surface in the atmosphere 

(dots), and in sea water (squares), 

as a function of latitude for the 

Monsoon Expedition, 31 January17 April 1961. The dashed line 

pertains to the southward part of the 

voyage. (From Keeling et al., 1965.) 

120 
made in the same month, one might expect to see more similarity than is 

actually present in these two data sets even if the tropical maximum had some 

longitudinal or seasonal dependency. 

Keeling et al. (1965) attributed the tropical supersaturation to the 

presence of the subsurface Cromwell current. Similar areas of surface water 

supersaturation of C02, albeit less pronounced than in the Pacific, have been 

observed in both the equatorial Atlantic and Indian Oceans over areas where 

subsurface currents are also known to be present (Keeling and Waterman, 1968). 

In the Indian Ocean, a band of high C0 2 extended over two-thirds of the 

equatorial zone during the northeast monsoon at the same time that a steady 

undercurrent was observed at depths of 50-200 m. The supersaturation was not 

present during the southwest monsoon when the current was found to be weak and 

variable or absent. The variations in the location of the maximum observed on 

these three expeditions suggest the high C02 feature in the equatorial Pacific 

may be related to meandering of the subsurface current. 

Outside the 10°N-10°S equatorial zone, the two SAGA data sets show much 

the same patterns of variability, and most of the areas are undersaturated. 

In the Northern Hemisphere, the same pattern seen at the beginning of SAGA I, 

a steady decline from equilibrium to about 20 ppm undersaturation followed by 

recovery to atmospheric level between 35° and 20°N, is repeated at the end of 

SAGA II between 15° and 30°N about a month later. This 5° displacement 

suggests some southward movement of a persistent undersaturated area. In the 

10°-30°N band, the SAGA plots bear more resemblence to Monsoon than to Downwind 

even though they are separated by 4 months. In the Southern Hemisphere, the 

closest retracing of the SAGA I record by the SAGA II record occurs between 

30°S and Tahiti (18°S) immediately following the ship's turning. All four 

plots show some degree of undersaturation in the 10°-30°S band. 

121 
5. COOPERATIVE PROGRAMS 

5 . 1 Air Mass Characteristics at BRW During AGASP 

W. E. Raatz 

NRC-NOAA Research Associate 

Geophysical Monitoring for Climatic Change, NOAA/ERL/ARL, Boulder, CO 80303 

During AGASP (March 1983), a major Arctic haze episode was recorded in 

the Alaskan Ar ctic. Thi s paper describes the occurrence of different air mass 

types at BRW during the period of 9-18 March, and characterizes air mass properties in terms of meteorological parameters, CN concentration, aerosol scattering extinction coefficient (a ), ozone, and C0 2 concentrations as measured 

at the baseline station. sp 

The overall synoptic conditi on over the Alaskan Arctic was determined by 

the gradual movement (both at the surface and at 500-mb) of the Arctic anticyclone out of the Laptev Sea, across the East Siberian Sea and into the 

Beaufort Sea area (Raatz, 1984). The assoc i ated change in air mass types 

present over BRW is reflected in the time-height cross sections of potential 

temperature and mixing ratio of water vapor (fig. 96). During the period 

9-10 March, the air mass is characterized by moist air and by relatively warm 

temperatures that gradually decrease. This may indicate the diminishing 

influence of marine Pacific air at low levels and the diminishing influence of 

an upper-level cyclone. During the period 11-13 March, a very cold and very 

dry air mass is present, with temperatures gradually increasing following this 

w 

a: 

::J 

CJ) 

CJ) 

w 

a: 

0.. 

320 

310 

300 

500 x 10-2

500 g/kg 

2.90 :0 

E 

- 600 20 

280 w 

700 a: 

::J 700 CJ) 

CJ) 

w 800 a: 

0.. 

9 10 11 12 13 14 15 16 

Figure 96.--Time-height cross sections of (left) potential temperature 

(K) and (right) water vapor mixing ratio (x 10- 2 g kg- 1 ), at BRW during 

March 1983 at 0000 GMT. 

122 
period. The cold and dry air is advected along the Arctic anticyclone (at low 

and upper levels) originating from the inner Arctic Basin and Siberia. 

Beginning 12 March, the advection occurs along a transport zone connecting 

western Eurasia with the Alaskan Arctic (Raatz, 1984; Harris, 1984). During 

the period 14-17 March, temperatures continue to increase and the near-surface 

layer contains moister air, whereas the upper layers remain dry. This warm 

and dry air aloft is the result of anticyclonic subsidence; the moisture in 

the low levels may be of local origin. During the period 17-19 March, temperatures below 700 mb decrease and moisture content increases dramatically. The 

near-surface flow probably carries the influence of marine Pacific air, 

whereas the upper levels still remain under anticyclonic influence. 

Surface-based CN and light-extinction data are shown in fig. 97 and have 

been discussed in detail by Bodhaine et al. (1984). The light-scattering data 

indicate background values of 2.3 x 10- 5 m- 1 during 9-11 and 17-18 March, with 

a maximum of 4.1 x 10- 5 m- 1 on 15-16 March. The variation in extinction is 

not caused by fluctuations in relative humidity, and the variations seen do 

not present a diurnal cycle due to temperature variations. Surface C0 2 

concentrations also seem to fall into three regimes similar to the lightextinction data (fig. 98). Background concentrations of about 348 ppm are 

recorded during 9-11 March and 16-18 March. Highest concentrations are measured within the Arctic haze episode during 12-15 March. In contrast, surfaceozone concentrations (fig. 99) show a variation different from those described 

for asp and C0 2 . During the period 9-10 March, concentrations vary from 5 

to 25 nb, followed by a period of low concentrations from 0 to 10 nb on 11-

12 March. On 13 March, ozone concentrations significantly increase and then 

steadily increase through the end of 18 March. 

In summary, the combination of time-height cross sections of potential 

temparture and mixing ratio is a powerful tool in identifying different types 

of air masses in terms of meteorological characteristics (Raatz, 1982). The 

Ill 

I 

0 

";; 4 

~ 

'e 

a. 2 ., 

l> 

<---'-~~~~--'- -'--~~ ~--'-~'--~ 

5.-----.--~.....----,~-.-~.--.- .....----,~-.-~,.---, 

.___,_~~ --'-~-'--~~ ~--'-~'--~ 

9 10 11 12 13 14 15 16 17 18 19 

MARCH 1983 

Figure 97.--(Top) Surface light 

extinction (a ) (x 10- 5 m- 1 ) and 

sp 

(bottom) surface CN concentration 

(cm- 3 ), at BRW during March 1983 

(Bodhaine et al., 1984). 

123 

...... 

E 

c. 

c. C02 ...... 

z 351 

0 

i= 

< a: 

~J Iz 349 

w 

u 

z 

0 

u 347 

9 10 11 12 13 14 15 16 17 18 19 

MARCH 1983 

Figure 98.--Surface C02 concentration (ppm) at BRW during March 1983 

(R. H. Gammon; NOAA/GMCC; personal 

communication, May 1984). 
35 

30 

,..., 

.0 

c: 

..... 25 

z 

~ 20 

<( 

a: 

Iz 15 

w 

(.) 

z 10 0 

(.) 

5 

OZONE 

9 10 11 12 13 14 15 16 17 18 19 

MARCH 1983 

Figure 99.--Surface ozone concentration (nb) at BRW during March 1983 

(S. J. Oltmans; NOAA/GMCC; personal 

conununication, May 1984). 

presence of Arctic haze is associated with an Arctic air mass characterized by 

enhanced a values and increased C02 concentrations. Ozone concentrations 

sp 

during Arctic haze are about normal. Prior to the Arctic haze episode, ozone 

concentrations are as low as 0 nb during the presence of a very cold and dry 

Arctic air mass. Such low ozone concentrations are unique to BRW (Oltmans, 

1981), and seem to occur frequently during February-April, a time when BRW 

experiences its coldest temperatures. 

5.2 Solar Radiation Measurements at BRW 

G. Wendler 

Geophysical Institute 

University of Alaska, Fairbanks, AK 99701 

The radiation measurements sponsored during 1982 by the University of 

Alaska were continued at BRW during 1983. Instrumentation for the following 

measurements is included in this program: (1) global radiation, (2) reflected 

short-wave radiation, (3) all-wave incoming radiation, (4) all-wave outgoing 

radiation, (5) sky radiation, (6) global radiation on the south slope inclined 

to latitude, and (7) global radiation on the south wall. The data are 

recorded on a Datel data logger. Some difficulties were experienced with the 

data logger as well as with the polyethylene covered domes of the all-wave 

radiation sensor. 

The amount of global radiation received at BRW is relatively high, with a 

mean annual flux of 103 W m- 2 It is about the same value as that found for 

Kodiak (108 W m- 2 ), which is located 14° farther south. At first glance this 

is astonishing, because both stations have nearly identical amounts of cloudiness. However, the clouds are much thicker at Kodiak, where the annual 

precipitation is more than 10 times the amount found at BRW. This can be 

explained by examining the values of the clearness index KT' which is the 

global radiation divided by the extraterrestrial radiation. The latter must 

124 
be corrected for Sun-Earth distance and reduced to the horizontal surface. 

This index yields much higher values for BRW than for Kodiak for overcast 

conditions. For clear days such a comparison was not possible, because not 

enough sunny days were observed. Besides the differences in cloud characteristics, the multiple reflection, which is of greater importance in BRW than in 

Kodiak, tends to increase the global radiation. This is discussed in Wendler 

(1983). 

5.3 Elemental Carbon Measurements at Whiteface Mountain 

R. Castillo 

Atmospheric Sciences Research Center 

State University of New York at Albany, Albany, NY 12222 

5.3.1 Introduction 

As part of a solar-chemical experiment at the ASRC field station, 

Whiteface Mountain, Wilmington, NY, a preliminary experiment was performed 

that attempted to measure the ambient total mass of organic and elemental 

carbon per unit volume in three different conditions: (1) clear air or haze, 

(2) the interstitial aerosol in a cloud (a mixture of cloud droplets and 

unactivated aerosol), and (3) the soluble and/or insoluble residue from cloud 

water. 

Ogren (1982) found that the median concentration of EC in the ambient 

aerosol was 4.9 μg m- 3 and in rainwater was 60 mg L- 1 . Generally accepted 

values of EC are 0.1-1 μg m- 3 and 10 μg m- 3 for rural sites and urban sites 

respectively. P. Chylek (ASRC, Albany, NY; personal communication, 1984) has 

obtained values of 6-23 μg L- 1 from snow samples. There is a decrease of EC 

with elevation greater than 1.1-3 km above sea level, by a factor of 3 to 4. 

5.3.2 Procedures 

Three different techniques were used to obtain samples for EC analysis. 

First, the clear air or haze aerosol was directly sampled in 1982 using a 

20 L min- 1 flow rate through two Whatman GF/A (glass microfiber) filters in 

series. Second, in 1983 the ambient aerosol was drawn through a Pallflex 

Quartz filter mounted on a Hi-Vol sampler (1.6 m3 min- 1 ). Third, the interstitial aerosol was obtained by impacting the cloud water into a glass fiber 

mesh (>90% collection efficiency for d ~ 10 μm) prior to the air stream 

flowing through a Pallflex Quartz filter. The latter system used a Hi-Vol 

sampler. The cloud water samples were prefiltered through a 0.4-μm Nuclepore 

filter to remove large insoluble material. The resulting liquid was either 

filtered (insoluble material), evaporated (insoluble and soluble), or freeze 

dried (insoluble and soluble), and all samples were then analyzed using a 

thermal-optical carbon technique. The results can be found in Huntzicker et 

al. (1982). 

5.3.3 Results and Discussion 

Under clear-air (visual range: 50 mi) to light-haze conditions (visual 

range: 20-30 mi), the total carbon varies from~ 2 to~ 37 μg m- 3 (table 33). 

125 
Table 33.--Clear air (C) and haze (H) carbon for sununer 1982, 

Whiteface Mountain, NY 

Visual Pollak Vol. 

Date range RH CN count Weather Carbon (I:!& m-3) sampled 

(mi) (%) (cm- 3) Organic Elemental Total (m3) 

08 Jul 20-30 (H) 83 2500 After cloud, 23.l 14.1 37.5 1.2 

pH = 4.0; 

SW trajectory 

12 Jul 20-25 (H) 81 3200 At end of warm 24.5 10. 1 34.6 1.2 

frontal passage; 

pH= 3.7; SW 

trajectory 

14 Jul 50 (C) 50 2100 Warm, dry air; 1. 9 BDL"' 1. 9 6.5 

calm all day 

20 Jul 50 (C) 64 Overcast; 2.2 BDL"' 2.2 4.8 

variablelight winds 

*Below detection limit . 

The EC varies from below detection limits to 10-14 μg m- 3 . These results are 

consistent with reported values. 

The EC for 1982 and 1983 found in the interstitial aerosol (external 

mixture of cloud droplets and unactivated aerosol) was indicative of a source 

dependency (table 34). For air masses originating in the southwest and 

northwest, the air pollution loading is approximately the same (Galvin et al. 

1983). Although the data set is not large, one is tempted to differentiate 

between the northwest and southwest, and the west EC loadings which differ by 

almost an order of magnitude. The haze aerosol EC from the southwest 

Table 34.--Summer interstitial aerosol carbon, Whiteface Mountain, NY 

Cld. H2 0 EC Vol. 

Da te Trajectory pH (μg m-3) sampled 

(m3) 

02-03 Aug 1982 NW 4 . 1 0.75 18.4 

04-05 Aug 1982 NW 3.5 0.64 8.] 

09-JO Aug 1982 SW 3.2 0. 13 13 . 2 

01-02 Jul 1983 SW 0. 18 2 x 10 3 

05 Jul 1983 SW 0 . 28 4.3 x 10 2 

19 Jul 1982 w 3.7 BDL'°' 4 . 8 

08-09 Jul 1983 w 0.049 8.3 x 10 2 

04 Aug 1983 1. 6 4.6 x 102 

05 Aug 1983 l. 3 1. 7 x 103 

.,.,Bel ow detec tion limit . 

126 
(table 33) is 1 order of magnitude larger than the northwest interstitial EC 

and 2 orders of magnitude larger than the corresponding southwest interstitial 

EC. 

Table 35 presents the carbon results for cloud water. The soluble and 

insoluble EC ranges from 0.06 to 0.66 mg L- 1 as compared with just the insoluble component, which ranges from 0.12 to 0.35 mg L- 1 These values are 

2 orders of magnitude lower than these reported by Ogren (1982) for an urban 

area. When the values are converted to an equivalent clear-air value, 

assuming a liquid water content of 0.7 g m- 3 for Whiteface Mountain stratiform, the values range from 0.1 to 0.46 μg m- 3 EC. 

Table 35.--Cloud water residue (soluble and/or insoluble) carbon for 

summers of 1982 and 1983, Whiteface Mountain, NY 

Vol. 

Carbon (μg) samp. EC 

Date Sampling method Organic Elemental Total (mL) (mg L- 1 ) 

Summer 1982 Filtered 131 35 168 100 0.35 

Composite 

Summer 1983 Filtered 92 12 104 100 0.12 

Composite 

Summer 1982 Freeze- 405 33 436 50 0.66 

Composite dried 

04 Aug 1982 Filtered 43 14 59 100 0 .14 

Composite 

28 Jul 1982 Evaporated 51 ~768 0.06 

Composite 

5.3.4 Conclusion 

These few comparisons suggest the following points. (1) It is possible 

for the interstitial and cloud water EC to be of the same magnitude and to 

exceed clear-air values. (2) There are instances of haze at this rural site 

with high EC (10-14 μg m- 3 ) similar to urban concentrations. (3) There is 

some indication of a source dependency of the amount of interstitial aerosol 

EC detected at this rural site. 

Acknowledgments 

I wish to acknowledge the support of J. DeLuisi of GMCC and the sample 

analysis of H. Rosen. 

127 
5.4. Aircraft and Surface Observations of Arctic Haze 

Near BRW, April 1983 

L. F. Radke, J. H. Lyons, D. A. Hegg, P. V. Hobbs, and I. H. Bailey* 

Atmospheric Sciences Department 

University of Washington, Seattle, WA 98195 

5.4.1 Introduction 

The polar regions are known to be sinks for many atmospheric trace 

constitutents. Recent studies (Rahn and Hiedam, 1981; Barrie et al., 1981; 

Rosen et al., 1981) have clearly established that episodes of anthropogenic 

pollution, which can cause hazes, are common at surface locations around the 

Arctic rim during winter. The hazes contain secondary aerosol (mainly acid 

sulfate), primary aerosol of industrial origins, and various soil and volcanic 

material. The goals of the more recent studies that are summarized here were 

to measure the vertical distributions of aerosol and trace gases in the Arctic 

atmosphere and to study their nature and origin. 

5.4.2 Measurements 

The University of Washington's B-23 research aircraft, which is instrumented for measurements of aerosol, trace gases, and cloud properties, was 

used to make 18 vertical soundings of the atmosphere to an elevation of <6 km 

within 400 km of BRW during 1-21 April 1983. The instrument package, described by Hobbs et al. (1976), Hegg and Hobbs (1980), Radke (1983), Radke and 

Whitby (1982), and Radke et al. (1984b), provides information on particle 

sizes of 0.01-4500 μm, particle characterization, and trace gas information. 

Three 47-mm filter packs, one 37-mm Teflon filter, and two seven-stage cascade 

impactors were exposed on each flight. 

Several optically dense haze layers were penetrated on each sounding. As 

many as 10 distinct haze layers were found on a single sounding. The haze 

layers were often abruptly discontinuous and frequently bounded by extremely 

clean air, with visibility near the Rayleigh limit. Some layers were thin (a 

few hundred meters) and usually did not extend more than 100 km in the horizontal. 

The particle spectra measured in haze and nonhaze conditions were quite 

similar (Radke et al., 1984a). Volume plots show peaks at particle diameters 

of -0.25, 0.6, 4.5 μm and at an indeterminate size >10 μm. The greatest 

contrast in the size spectra between haze and nonhaze conditions was in the 

accumulation mode (0.1-2.0 μm), where substantially higher concentrations of 

particles were found in haze. Light-scattering properties are clearly linked 

to this mode. The coarse particle mode was most dominant in samples made near 

the surface and in light haze. Unexpectedly large concentrations of giant 

particles (>2 μm) were found in all of the samples (Radke et al., 1984a; 

Bailey et al., 1984). 

*On leave from Western Australia Institute of Technology, Kent Street, 

Bentley, Western Australia 6102. 

128 
The nucleation mode (<0.1 μm) was difficult to size with confidence. The 

most successful technique for determining concentrations in the nucleation 

mode was a combination of a diffusion battery and a CN counter. Almost none 

of the nonhaze samples had measurable nucleation modes, whereas ~30% of the 

haze cases did have nucleation modes ~ The nucleation mode is most likely 

sustained by conversion of S02 to so4, since 80% of the nucleation modes that 

were detected during haze conditions were associated with S02 concentrations 

>1 ppb. None of the light haze or nonhaze cases were associated with such 

large S02 concentrations. Pa rticulate sulfate data support this conclusion. 

Filters and substrates were analyzed by ion chromatography for soluble 

sulfate, chloride, and nitrate using techniques similar to those described by 

Stevens et al. (1978). The results of this analysis for the cascade impactors 

is summarized in fig. 100. Most of the sulfate (81%) was in particles having 

diameters <1.0 μm . Chloride was uniformly distributed in size, except that 

little was found in particles with diameters <0.25 μm. Nitrate concentrations 

were quite low at all particle sizes. The fraction of total sulfate in the 

submicron range was largest (up to 100%) in samples from haze layers and 

smallest (up to 68%) in samples with little or no haze. Although the absence 

of small chloride particles is characteristic of the relatively unpolluted 

airmasses examined by Harrison and Pio (1983), the observed sulfate size 

distributions are similar to the polluted cases examined by them. Because the 

small chloride particles in the Harrison-Pio samples are most likely due to 

combusti on of high-chloride coal, which is by no means the coal usually 

employed by industry, we judge the ionic mass distributions of our samples to 

be in general agreement with the polluted cases of Harrison and Pio. 

The concentrations of the three ions and their relative abundances are 

summarized in table 36 . Impactors were exposed predominantly in regions of 

haze. Filter packs (~1 m3 sample) were distributed more uniformly with time 

and altitude and are therefore more representative of the average vertical 

column over which the aircraft flew. The increase in sulfate from nonhaze to 

haze conditions (0 . 5-1 . 8 μm m- 3 ) was virtually the same as the increase in the 

1.0 

-

~E 

J 

z 8 0 1 .. 

a: 

>-

z 

w 

u 

z 

0 

u 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

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~ --, I I 

.::c.:::.--::::i ! 

l 

L .-., 

! 

--so; 

---c1· 

-·-·- ·- NOj 

r- ~ 

I 

i 

I 

i 

I r - -- : - ·- ·-·_J 

1.0 

PARTICLE DIAMETER (iim) 

10 

Figure 100.--Size-segregated average 

concentrations of the soluble fractions of sulfate, chloride, and nitrate in aerosol collected primarily 

in the Arctic hazes. 

129 
Table 36.--Average ion concentrations (μg m-3) measured 

in the Arctic, April 1983 

Mea surement technique so4 Cl N03 Total 

Cascade impactor'°~ 1. 8 1.0 0.2 3.0 

Teflon filters (all)t 

All 1. 1 0.07 0.05 1. 2 

Haze (a > 2 x 10- 1 ) 

sp 

1. 8 0. 14 0.06 2.0 

Little or no haze 0.47 0.02 0.02 0.5 

(asp < 2 x 10- 1 ) 

Ground Teflon filters§ 2.6 0.23 0.03 2.9 

•'•Exposed from aircraft mainly in hazes. 

tExposed from aircraft in all haze conditions. 

§Exposed at BRW nearly daily. 

volume of the aerosol in the accumulation mode (Radke et al., 1984a). Similar 

results were found by Barrie et al. (1981) for surface measurements in the 

Canadian Arctic during winter. 

The higher-than-expected fraction of chloride on the impactors (compared 

with the filter packs and surface measurements) could indicate possible 

deposition of acid sulfate causing chlorine loss on the surface and on pack 

Teflon filters (Hitchcock et al., 1980). The particles on these filters were 

subject to much greater ventilation and hence greater potential losses than 

those on cascade impactor substrates. 

The submicron and supermicron chloride fractions are highly correlated 

with the supermicron sulfate (r = 0.8 and r = 0.9 respectively) whereas the 

submicron chloride and sulfate fractions are essentially uncorrelated 

(r = 0.08), suggesting that supermicron sulfate and all of the chloride have a 

common, probably oceanic, origin. A different origin for the submicron 

sulfate is suggested by the relatively low correlation between either supermicron chloride or sulfate, and submicron sulfate (r = 0.3 and 0.5 respectively). Separate origiris of submicron and supermicron sulfate are also 

suggested in the more numerous filter-pack samples. Samples from the little 

or nonhaze category show total sulfate and chloride modestly correlated 

(r = 0.6); in the haze category they were uncorrelated (r = -0.07). Total 

sulfate, submicron sulfate, and total soluble ion concentrations all correlate 

modestly with a (r = 0.6) whereas submicron chloride and nitrate are unsp 

correlated with a (r = -0.2 and= 0.2 respectively). sp 

Sulfate measured at the ground is found predominantly in submicron 

particles, while chloride spanned the submicron to supermicron particle size 

range. The particle size spectra for these ions are shown in fig. 101 where 

they can be compared with spectra measured at 0.3-1.2 km MSL 2 days later but 

under similar conditions. Sulfate was concentrated on submicron particles 

130 
10 

~ 

'e 

"' 3 

Vl 

':; 01 

::;; 

u 

z 

Q 

r - , I I 

I 

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--, I 

O.Ol '----'----'---1-L~-'-"<-l-J'-'--'---'-~-'---'---L.L..-'-'-U 

0 I 10 10 

DIAMETER (>'m) 

(o) 

10 

01 

I 

I 

I 

I 

-- - _J 

-- Surface cascade 1mpoctar (4/16/831 

- - - Airborne cascade impactor(4118/83) 

~~--y--, 

I 

I 

I 

I 

I 

0.01~-~~~~~~-~-~~~~_...J 

01 10 10 

DIAMETER l>'ml 

( b) 

Figure 101.--Comparison of particle spectra for (a) sulfate and 

(b) chloride ions measured at the surface and at 0.3-1.2 km MSL. 

both at the surface and aloft. Chloride was present in both submicron and 

supermicron particles at the surface and at higher altitudes, although at 

higher altitudes more of the chloride was found in submicron particles. 

Concentrations of sulfate measured at the ground at BRW were, on average, 

~z times greater than those measured 1-5 km above the BRW area. However, this 

difference was largely because the samples taken aloft were from both hazy and 

clear air, while the surface samples were taken entirely in haze, albeit at 

levels less intense than those aloft (visibility in one or more haze layers 

aloft was generally worse than at the surface [Radke et al., 1984a]). This is 

clear from the fact that the impactor samples and filter packs taken primarily 

in haze differ from the ground samples by much less than a factor of 2 

(table 36). Nevertheless, the generally higher sulfate levels and lower 

light-scattering coefficients on the ground compared with the airborne measurements strongly suggest that, in general, the sulfate concentrations measured 

aloft are not representative of the haze as defined by light scattering, but 

are rather systematically low. Support for this is provided by the one 

sulfate measurement obtained entirely in an intense haze layer. The sulfate 

concentration for this measurement was 13 μg m- 3 , substantially higher than 

either the airborne measurements in general, or the ground samples. 

Further comparisons of the airborne and ground sulfate measurements 

suggest that even though the thermal stability of the surface layer will tend 

to isolate it from haze -layers aloft, synoptic-scale variations can often 

provide a sufficient link so that surface measurements of sulfate are indicative of a change of air mass both at the surface and aloft, though not quantitatively representative of the air found aloft. For example, although a 

negative correlation coefficient of -0.65 was calculated for the 7 days when 

both aircraft and surface observations of sulfate were available, the anticorrelation is solely attributable to the data for 11 April when very high 

sulfate concentrations were measured by aircraft at 4 km, while surface values 

131 
6 13.0 μ.g m-3 

"? 

E 

C1' 

::I.. 

z 

0 

I-

<t 

a:: 

Iz 

w 

u 

z 

0 

u 

w 

~ LL. 

_J 

:::> 

(/) 

5 

4 

3 

- ESTER DOME 

SURFACE DATA 

ffiili!!!l!!l PT. BARROW 

SURFACE DATA 

11111111111 AIRBORNE DATA 

Figure 102.--Comparison of sulfate 

concentrations measured aloft near 

BRW and at Ester Dome near Fairbanks. 

31 I 5 10 

APRIL 1983 

were low. Exclusion 

correlation of 0.84. 

Ester Dome, AK (~750 

Mountain Range) were 

at BRW (fig. 102). 

5.4.3 Summary 

of this point from the correlation produces a positive 

Concentrations of sulfate measured at the surface at 

km south of BRW and on the other side of the Brooks 

less well correlated (r ~ 0.55) with surface measurements 

Airborne studies of haze layers in the Arctic have shown that their 

light-scattering properties are due primarily to sulfate particles in the 

acc1ITTulation mode (0.1-2 μm). Evidence was also obtained for the formation of 

aerosol particles in the nucleation mode (<0.1 μm) by gas-to-particle conversion of SOz. 

In optically clear regions, chloride was a significant fraction of the 

total aerosol and was correlated with sulfate at all altitudes, possibly 

indicating oceanic origins. The nucleation mode was not detected in these 

regions. Ground-based impaction samples contained sulfate and chloride in 

submicron- and supermicron-sized particles in similar proportions to those 

measured aloft. 

Acknowledgments 

We thank D. Beard, GMCC/BRW Station Chief, and G. Shaw, University of 

Alaska, for their assistance in providing surface filter data. Thanks also to 

K. Anlauf and S. E. Schwartz for information on the S02 filtration technique 

employed. This research was supported by NSF, Polar Programs Grant No. 

DPP 8209548. 

132 
5.5 The ASRC Aerosol Impactor-Concentrator 

A. W. Hogan 

Atmospheric Sciences Research Center 

State University of New York, Albany, NY 12222 

5.5.1 Introduction 

Aerosol concentrations in the polar regions are generally quite small, 

and advective events that transport midlatitude material to the polar regions 

are brief. Fenn and Weickmann (1959) found that the cascade impactor of May 

(1945) gave sufficient concentration of particulate material to facilitate 

analyses of Greenland aerosol with collection times of less than 30 minutes. 

For this study the Fenn-Weickmann-May techniques have been modified to permit 

aircraft sampling on substrates compatible with SEM analyses. The modified 

impactor was successfully used by Shapiro et al. (1984) during AGASP sampling. 

The May (1945) cascade impactor and its commercial descendants cause 

particles in four size ranges to be serially impacted on four microscope 

slides or glass disks. Experiments with May's device at SPO showed that a 

detectable impaction line could be collected on the submicron particle stage 

(May IV) in about 1 hour, but it was extremely difficult to detect particles 

on the collection disks for supermicron particles (May I, II, III). The 25-mm 

glass disks used as impaction substrates were difficult to clean and transport, 

and were not compatible with SEM analysis. 

The impaction jet of May's stage IV was fitted within a 10-cm diameter 

Delrin housing by W. Winters of ASRC, as shown in fig. 103. The features of 

133 

Figure 103.--Components of the 

Delrio housing for stage IV of the 

May (1945) impactor. This 10-cmdiameter housing seals the impactor 

to facilitate airborne use. 
this apparatus are the following: (1) A large inlet diameter allows still air 

sampling. (2) An interchangeable 0.953-cm tube inlet that is isokinetic in 

typical polar surface winds of 4-5 m s- 1 facilitates installation for aircraft 

sampling. (3) A conventional 25 x 75 x 1 mm microscope slide is used as a 

collecting substrate, but does not rely on slide dimensions to achieve the 

proper impaction distance. This allows gold foil or membrane substrates to be 

used, while maintaining the convenience of handling and storage of microscope 

slides. (4) The housing permits sealing of the entire impaction apparatus 

within a 10-cm Delrin cylinder and cover disk, thus facilitating both outdoor 

slide changes and aircraft use. (5) The single impaction stage causes the 

supermicron particles, which are few in number, to be collected along the same 

line as the submicron particles. This greatly enhances the probability of 

finding the larger particles during analysis. (6) Additional impactorconcentrator devices or filters can be connected in series with this impactor 

to allow selective removal of ice crystals or fog drops at the inlet, or to 

collect and concentrate the submicron particles passed by this impactor. 

5.5.2 Results of Experiments 

The ASRC impactor has been used with success in both polar regions. The 

results of a cooperative GMCC-ASRC aerosol experiment at SPO are shown in 

fig. 104. The upper panel shows particle area determined from nucleus counter 

0.3 

Q7 

0,1 

7 8 9 10 ,, 12 

6 ll/I 

1,0 

Q5 

JAM 11.7.1 

13 

"' ':t 

t'oj 

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0 

z 

< 

z 

ur 

z 

0 

N 

0 

"' "' <

:t 

UJ 

> 

;::: - < 

-' 

UJ 

ir 

134 

Figure 104.--Results of cooperative 

ASRC-GMCC aerosol sampling at SPO. 

(Top) Particle area determined by 

nucleus counter and diffusion 

battery data; (middle) Dasibi ozone 

data; and (bottom) impacted sulfur, 

crustal, and marine aerosol components normalized to scattering 

(nephelometer) mass. 
(Pollak) and diffusion battery data; the center panel, GMCC ozone data; and 

the lower panel, elemental fractions of impacted aerosol particles relative to 

the total scattering mass recorded by the nephelometer. Comparison of the 

aerosol and ozone concentrations given in fig. 104 with meteorological data 

shows the marine (Na + Cl) and· sulfur (S) components of the aerosol to be 

transported to the polar plateau in the warm advective phase of a storm, and 

the crustal (Al + Si) component to arrive during post-storm cold advection 

(Hogan et al., 1984). 

The impactor used by Shapiro et al. (1984) during AGASP is the same unit 

that was used in Greenland (Hogan et al., 1983) and Antarctica (Hogan et al., 

1984). Its first airborne use was by Shaw (G. Shaw; University of Alaska, 

Fairbanks; personal communication, 1980) in Antarctica in 1980. It has been 

operated at about 25-40 L min- 1 during these polar programs, which causes a 

greater velocity to occur in the jet than the 17.5 L min- 1 flow that was used 

in May's (1945) original calibration. Calculations using the data of May 

(1967) indicate that unit density spheres of 0.4-μm diameter should be impacted at the higher flow rates. SEM analysis of gold-coated membrane filter 

substrates impacted in the polar regions show that particles of 0.2-μm 

diameter were collected frequently. A series of experiments is currently in 

progress to calibrate the impaction efficiency of this impactor and accessory 

concentration devices. 

Spherical pigment grains with a density of approximately 2 g cm- 3 are 

diluted to a concentration of about 10 ppmm in distilled water. The pigment 

dispersion is aerosolized with a Collison atomizer (built at ASRC), and the 

atomizer output is diluted and dried with 30 L min- 1 of dry air. This technique produces a few clusters of pigment particles as great as 5-μm diameter, 

and many individual pigment grains of 0.05- to 0.5-μm diameter. The output 

flows through a 0.5-m3 plenum that houses the impactor, and exits through a 

pleated paper filter. Two atomizers are used with two types of pigment to 

produce more polydisperse aerosols. 

SEM analysis of gold-coated membrane filter substrates exposed in this 

manner show the supermicron particles to be collected along the edges of the 

main impaction line. Particles of 0.2- to 0.5-μm geometric diameter are 

confined to a line less than 200 μm wide. 

5.5.3 Conclusion 

A modification of May's (1945) impactor has been found useful for polar 

aerosol collection, in agreement with Fenn and Weickmann (1959). Experiments 

are in progress to extend the concentration capabilities of this device to 

0.01-μm particles for AGASP II. 

135 
5.6 Coarse Particle Soil Dust in Arctic Aerosols, Spring 1983 

J. W. Winchester, S. Li, and S. Fan 

Deptartment of Oceanography, Florida State University 

Tallahassee, FL 32306 

R. C. Schnell 

Cooperative Institute for Research in Environmental Sciences 

University of Colorado, Boulder, CO 80309 

B. A. Bodhaine 

Geophysical Monitoring for Climatic Change 

NOAA/ERL/ARL, Boulder, CO 80303 

In 6 out of 11 AGASP research flights, March-April 1983, particle size 

fractions collected by cascade impactors contained elemental constituents of 

soil dust--Al, Si, K, Ca, Ti, and Fe--primarily in the coarsest particles, 

>16-μm aerodynamic diameter (μmad), at concentrations much greater than in the 

samples of the remaining 5 flights. The relative concentrations of these 

elements were approximately those in average geochemical shale. They differed 

from concentrations of the average Earth by a several-fold depletion of Si in 

the aerosol samples, as well as from the composition of stratospheric samples 

of El Chichon volcanic dust, which had relatively higher K and Ti than did the 

Arctic haze aerosols. The results suggest two possible sources for these 

particles: (1) finely divided clay minerals generated at lower latitudes 

(e.g., in Asia during late winter), which are transported northward and, under 

suitable atmospheric conditions before sampling, may grow or coalesce as ice 

crystals or aqueous aerosols into much larger sizes; and (2) an eruption 

(probably not volcanic) of aerosol and water vapor into the Arctic troposphere. Some Cl of marine origin and some S from the oxidation of S02 may 

Table 37.--Earth crust elements in coarse particles > 2 μmad, 

summed over impactor stages 4-7 

Sample Concentration''( (ng m- 3

1 STP) Ratio 

no. Al Si K Ca Ti Fe Si/Al 

1 627 257 80 644 160 95 0.41 

2 40 65 17 17 <4 <14 1.62 

3 54 64 <14 31 <4 <18 1.18 

4 50 98 19 20 <12 <34 1.96 

5 951 639 263 411 46 446 0.67 

6 142 143 <48 ~74 <24 <92 1. 01 

7 530 153 52 137 14 226 0.29 

8 96 36 <6 ~6 <4 <14 0.38 

9 482 308 110 392 30 ~206 0.64 

10 208 111 28 ~44 5 48 0.69 

11 (160) (92) (36) (45) (5) (125) 0.58 

-/(Values in parentheses are approximate and include an estimate for missing 

stage 6. 

136 
PARTICLE SIZE CUT, 11mad 

1000,...-2-......-4-..-~B...,...-16...,...~_...2...,...-4....,..~B....,..l~B....,..__, 

ALUMINUM, AGASP 1983 

9 

a. 

I-

(/) 

,,; 

'e 

!Cl' 

c 10\ 

30 

.. :; 

II---

10 

7 

3 

4 5 6 7 4 5 6 7 

IMPACTOR STAGE 

Figure 105.--Distribution of coarse 

aerosol Al concentration in >2-μmad 

particle size fractions for six 

AGASP samples having highest dust 

loadings. In smaller size ranges, 

Al was below detection limit (indicated by~). Blank Al on vaselinecoated Kimfol film (stages 4-7) has 

been subtracted. For stage 10, data 

point in parentheses is approximate. 

Estimated uncertainties in concentrations from PIXE analysis (<20%) are 

less than those for determining 

airflow rate during sampling (~30%). 

0 

~ a:: 

I-

:c 

(!) 

w 

31: 

PARTICLE SIZE CUT, 11mod 

10 2 4 8 16 2 4 8 t6 

Si/Al, A GASP 1983 

3 .. CRUST 

·~ 

·~ 10 

3 

1-

II~ 

-SUM-" 

0.3 

0.1 4 5 6 7 4 5 6 7 

IMPACTOR STAGE 

Figure 106.--Distribution of Si/Al 

concentration ratio in >2-μmad 

particle size fractions for the six 

AGASP samples in fig. 105. For 

each, the ratio of the concentrations summed over stages 4-7 is indicated by horizontal lines. Ratios 

in average Earth crust and in average 

shale are indicated on the right. 

Aerosol Si/Al ratios are all much 

lower than in crust and also lower 

than in shales, but may approximate 

clay mineral composition. Upward 

arrow indicates point is at the 

lower limit of data; downward arrow, 

upper limit. 

also be taken up by the coarse particles as they interact with the haze. Data 

on which these conclusions are based are presented in tables 37 and 38 and in 

figs. 105 and 106. 

137 
Table 38.--Ratios of Earth crust elements in coarse particle size fractions 

Wt. ratio Weight ratios of sums of stages 4-7 (>2 μmad) 

stages 7 /6•'> Si/Al Si/Ca Si/Fe K/Al K/Ca K/Fe Ti/Fe 

Sample no.t 

1 2.6 0.41 0.40 2. 71 0. 128 0.124 0.84 l. 68 

5 5.4 0.67 1.55 1.43 0. 277 0.64 0.59 0.103 

7 11. 9 0.29 1. 12 0.68 0.098 0.38 0.23 0.062 

9 3.2 0.64 0.79 ~I.SO 0.228 0.28 0.53 0.146 

10 (>17.0) 0.69 2.52 2.31 0 .135 0.64 0 . 58 0.104 

11 0.58 2.04 0.74 0.225 0.80 0.29 0.040 

Median 5.4 0.61 1. 34 1. 46 0.180 0.51 0.56 0.104 

Shales§ 0.91 3.30 1. 55 0.333 1.204 0.564 0.097 

Earth crust,-r 3.41 7.64 5.54 0.318 0. 714 0.518 0.088 

Loess•'>•'r: 3.14 50.0 10 .15 0.225 2.69 0.55 0. 140 

Volcanic ashtt 0.541 1.463 2.548 0.323 

Median, sam- 1. 18 3.82 >1.5 <3.4 Nl,O 

pl es 2, 3' 

4, 6, 8§§ 

*Medians of six elements that are abundant in Earth crust minerals. 

tin other samples the soil dust elements in coarse fractions were near or 

below detection limits. 

§Averages of Turekian and Wedepohl (1961). 

,-rAverages of Mason and Moore (1982). 

**From Nanking, China (Heller and Liu, 1982; Taylor et al., 1983). 

ttStratospheric ash, May 1982, from El Chichon eruptions (Kotra et al., 

1983). 

§§From data in table 37. 

5.7 Particulate Sulfur and Chlorine in Arctic Aerosols, Spring 1983 

J. W. Winchester, S. Li, and S. Fan 

Department of Oceanography, Florida State University 

Tallahassee, FL 32306 

R. C. Schnell 

Cooperative Institute for Research in Environmental Sciences 

University of Colorado, Boulder, CO 80309 

B. A. Bodhaine 

Geophysical Monitoring for Climatic Change 

NOAA/ERL/ARL, Boulder, CO 80303 

In each of 11 AGASP flights, particulate S and Cl were determined by PlXE 

analysis of eight cascade impactor fractions from <0.25- to >16-μm aerodynamic 

diameter (μmad). Sulfur occurred mainly in fine aerosol sizes of <2 μmad, 

whereas Cl was mainly in coarser sizes. Two fine S modes could be identified, 

one being ultrafine (nuclei) <0.25 μmad, and the other being fine (accumulation) centered around the 0.5- to 1.0-μmad range; the relative abundances of 

the two modes apparently depended on flight location. This suggests that bot~ 

homogeneous gas phase and heteorogeneous liquid phase reactions led to sulfuric 

138 
4. 

,_ 

., 

.. 

'e 

"' c 

PARTICLE SIZE CUT, ~mad 

o.~ o.5 I 2 2~ O.~ 2 

SULFUR, A GASP 1983 

5 

9 

6~ 

30 10 

·:f\\ ''V\ It 

'"·~ 30 ·~ 10 0 j 2 3 0 I 2 3 

IMPACTOR STAGE 

0 I 2 3 

Figure 107.--Distribution of fine 

aerosol S concentrations in <2-μmad 

particle size fractions for AGASP 

samples 1-11. Blank S on Nuclepore 

filter (stage 0) and on paraffincoated Kimfol film (stages 1-3) has 

been subtracted. Estimated uncertainties in concentrations from 

PIXE analysis (<10%) are less than 

those for determining airflow rate 

during sampling (-30%). Concentration below detection limit is 

indicated by L 

acid formation in the haze. Qualitative comparisons of aerosol S and Cl 

distributions with particle size suggest that Cl may be volatilized by processes that depend on the presence of acidic reactants in the atmosphere. Data 

on which these conclusions are based are presented in figs. 107 and 108 and 

tables 39, 40, and 41. 

t 4 I II 

100 

30 

PARTIQ.E SIZE CUT, ~mad 

2:41lt0.S tZ"l'I 

CHLORINE, AGASP 1983 

10 '--~~--ts~s~1r----:4:t--rs--i;s---i;1,...--j2,....,3 ~:!:-+s-*s--i.,_J 

IMPACTOR STAGE 

139 

Figure 108.--Distribution of coarse 

aerosol Cl concentrations in >2-~nad 

particle size fractions (>O.S μmad 

for sample 10 and >1 μmad for 9 

and 11). In smaller size ranges Cl 

was below detection limit, indicated 

by~. Blank Cl on vaseline-coated 

(stages 4-7) and paraffin-coated 

(stages 1-3) Kimfol film has been 

subtracted. Estimated uncertainties 

in concentrations are the same as in 

fig. 107. 
Table 39.-Conditions of aerosol sampling by cascade impactor, 

March-April 19831( 

Air volume (m3) Starting time Haze in 

Sample Ambient 0°C, Date GMT Duration tropono. 1 atm (min) sphere 

1 0.336 0.233 11 Mar 2140 420 Moderate 

2 0.365 0.293 13 Mar 2023 457 Strong 

3 0.364 0.251 15 Mar 2025 455 Moderate 

4 0.228 0.125 17 Mar 2100 285 Light 

5 0.228 0.174 21 Mar 1200 475 Moderate 

6 0.095 0.047 23 Mar 1300 288 

7 0.402 0.280 28 Mar 1340 503 Lt. to Mod. 

8 0.460 0.303 31 Mar 0847 576 Strong 

9 0.459 0.341 04 Apr 0710 574 Moderate 

10 0.523 0.491 05 Apr 0848 513 Light 

11 0.504 0 .454 10 Apr 0750 495 Light 

*AGASP sample nos. 1-4 from Anchorage over Alaska to BRW and north; no. 5 

from Anchorage over Alaska and Arctic to Thule, Greenland; no. 6 

(stratospheric) from Thule south in El Chichon dust; no. 7 from Thule via 

Alert and Svalbard to Bod¢, Norway; nos. 8 and 9 from Bod~ over Greenland Sea 

to Svalbard; nos. 10 and 11 from Bod¢ west over Greenland Sea at low altitude. 

All sampling was tropospheric except no. 6 and part of no. 4. All flights 

were round trips from Anchorage, Thule, or Bod¢, except nos. 5 and 7. 

Table 40.--Aerosol sulfur in fine and coarse particle size fractions* 

Sample 

no. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

Impactor stage concentrations (ng 

0 1 2 3 4 5 

259 

247 

187 

62 

263 

<73 

106 

168 

193 

23 

70 

52 

97 

38 

29 

95 

<54 

60 

64 

213 

294 

362 

162 

103 

95 

178 

29 

<54 

117 

128 

130 

143 

131 

24 <12 <12 

15 <9 <9 

17 <11 <11 

83 <22 <22 

<14 <16 <16 

<54 <58 <58 

29 <10 <10 

17 <9 <9 

10 ~20 ~8 

16 ~15 ~6 

11 ~21 ~91 

STP) 

6 7 

34 28 

<9 <9 

<11 <11 

<22 <22 

<16 102 

<58 <58 

22 30 

<9 <9 

21 45 

9 23 

19 

Sum of stagest 

Fine Coarse 

0-3 6-7 

497 

462 

337 

352 

387 

<120 

312 

377 

551 

476 

574 

62 

<13 

<16 

<31 

102 

<82 

52 

<13 

66 

32 

(19) 

Coarse 

ratio 

7/6 

0.84 

<6.5 

1. 37 

2.11 

2.65 

*Aerodynamic diameter ranges: for impactor stage O, <0.25; 1, 0.25-0.5; 2, 

0.5-1; 3, 1-2; 4, 2-4; 5, 4-8; 6, 8-16; 7, >16 μmad; i.e., sizes of unit 

density spheres when sampled at 1 min- 1 airflow and 1 atm pressure. 

tMeans and standard deviations: 391 ± 73 for Alaska and Arctic samples 

1-5 and 7; 494 ± 89 for Greenland Sea samples 8-11; and 432 ± 92 ng m- 3 for 

all 10 tropospheric samples. 

140 
Table 41.--Aerosol chlorine in fine and coarse particle size fractions;'; 

Coarse 

Sample ImEactor stage concentrations ( ng m-3 STP) Sum of ratio 

no . 0 1 2 3 4 5 6 7 stages 7/6 

1 <60 <6 <6 <6 78 103 125 128 434 1. 02 

2 <48 <5 <5 <5 64 62 64 80 270 1.08 

3 <56 <6 <6 <6 59 73 79 75 286 0.95 

4 <112 <11 <11 <11 110 92 126 160 488 1. 27 

5 <81 <8 <8 <8 112 133 190 406 841 2.14 

6 <300 <30 <30 <30 401 358 420 560 1639 1. 33 

7 <SO <5 <5 <5 <5 <5 11 68 79 6.18 

8 <46 <5 <5 <5 <5 <5 <5 <5 <10 

9 <41 <4 <4 15 80 78 134 142 449 1.06 

10 >29 <3 13 111 85 48 11 43 311 3.91 

11 <31 <3 <3 14 39 12 26 (91) 

;'•See first footnote, table 40. 

5.8 Trace Gases in the Arctic: Indexes of Air Pollution 

5.8.1 Introduction 

M. A. K. Khalil and R. A. Rasmussen 

Oregon Graduate Center 

Beaverton, OR 97006 

Every spring for perhaps the last hundred years or more a haze consisting 

of fine particles has appeared over the Arctic (Schnell, 1984b). The origins 

and sources of the haze may have changed over the years, but at present the 

Arctic haze aerosol contains sulfate, soot, and organics and is believed to 

originate from the industrial regions of the world. Anthropogenic activities 

that produce the precursors of Arctic haze also produce dozens of trace gases 

that are more concentrated in the Arctic during the spring than at other 

times. The levels of the anthropogenic trace gases in the Arctic provide 

evidence for the origins of Arctic haze. Some gases--(C2Cl 3F2 , CF3Br, 

CF2BrCl) may identify the locations where Arctic pollution originates, whereas 

other tracers (C02 , N20, nonmethane hydrocarbons, CO, CH3Cl) are used to 

identify the types of sources such as powerplants that are common to all 

industrialized areas. 

Results are discussed here of measurements of trace gases taken over the 

past 4 years at BRW and more recently on board aircraft during AGASP (Khalil 

and Rasmussen, 1983a; Rasmussen and Khalil, 1982; Rasmussen et al., 1983). 

5.8.2 Seasonal, Vertical, and Spatial Variations of Tracers 

In our first experiment it was established that significantly higher 

levels of CHC1F2 (CFC-22), CH3CC1 3 , C2Cl 4 , C2HC1 3 , CC1 2F2 (CFC-12), and CC1 3F 

(CFC-11) exist in the Arctic during late winter and early spring (Khalil and 

141 
Rasmussen, 1983a). Statistical criteria were developed to detect the presence 

of higher springtime concentrations when the excess is not apparent. Many 

natural and anthropogenic trace gases are removed from the atmosphere by 

reacting with hydroxyl radicals (OH). In the Arctic, the concentration of OH 

must undergo large seasonal variations because of the variation of sunlight 

and water vapor that are needed to produce OH. In winter there may be no OH 

in the Arctic, and trace gases may thus accumulate; Lherefore, the high 

concentrations of some of the more reactive anthropogenic and natural trace 

gases may be explained entirely in terms of the natural variation of OH. This 

phenomenon of gases accumulating in the high northern latitudes during winter 

may itself contribute to the formation of Arctic haze as spring arrives and 

photochemical processes become active. The presence of higher concentrations 

of CFC-11 and CFC-12 suggests that more pollution is transported to the Arctic 

during winter than at other times, since these gases do not react with OH 

radicals. Moreover, calculations show that trace gases such as CH3CC1 3 , 

CFC-22, and some of the other chlorocarbons and hydrocarbons are much more 

abundant in the Arctic during winter than can be explained on the basis of 

their reactivity with OH (Khalil and Rasmussen, 1983a; Rasmussen et al., 

1983). 

After the occurrence of high concentrations of anthropogenic trace gases 

in the Arctic during winter and early spring was established, the vertical 

distribution of trace gases was investigated to detect the possible existence 

of layers within which the polluti on could be transported. Our first experiments consisted of flying in small aircraft from Point Barrow and obtaining 

air samples up to about 4 km. Statistical evidence of bulges in the vertical 

distributions of the mixing ratios of C2H2 , C2H6 , C3H8 , and C2Cl 4 were found 

(Rasmussen et al., 1983; Rasmussen and Khalil, 1982, 1983). These hydrocarbons 

were also much more abundant in the Arctic during late winter and spring than 

at other times. No significant vertical variations in the concentrations of 

the long-lived trace gases such as the fluorocarbons were detected. The 

background concentrations of long-lived trace gases are so high that small 

perturbations are extremely difficult to detect either in a seasonal time 

series or in vertical concentration distributions. More recently, these 

experiments were repeated on board the flights for the AGASP experiment. 

These early studies showed that anthropogenic trace gases are more 

abundant in the Arctic during winter and early spring and are probably transported in polluted layers. The tracers discussed here so far are emitted from 

all the major industrial regions of the world. To distinguish the various 

regions, several new tracers were chosen, namely, C2Cl 3F2 (CFC-113) and the 

fire-extinguishing compound CF3Br, which are used primarily in the United 

States, and CF2BrCl, which is used primarily in Europe. It is believed that 

none of these compounds is used in the U.S.S.R. The analytical procedures for 

measuring CF3Br and CF2BrCl at ambient concentrations of about 1 pptv have 

only just been refined, and some data have been obtained from BRW during the 

past year. Preliminary results suggest that CF2BrCl is slightly more abundant 

during winter than at other times, suggesting some contribution to Arctic 

pollution from Europe (Rasmussen and Khalil, 1984). 

A study of the spatial distribution of the gaseous tracers of Arctic haze 

was carried out to make certain that measurements taken at BRW represent the 

seasonal variations over the entire Arctic region where haze is observed, and 

to see if perhaps the locations of the source regions could be detected. 

During 1983 air samples were obtained from Spitzbergen, Norway (79°N). The 

142 
120 

70 

0 ~ 60 

<I 50 

40 

30 

20 

10 

0 

I 

-10 0 

-20 0,01 

C2Hs• fC2H2 

I I I I I I I I I I I I I I I I 

'"'"' C2Cl4 ~ I 

~c o il 1 I I I O I CH3CI 

' CH4 

CH3CCl3 

0,1 I 10 

Lifetime T 

• Spring 

o Summer 

F-11 

100 

(yrs) 

1000 

Figure 109.--Spatial variation of 

the gaseous tracers of Arctic haze. 

The relative difference ~ of concentrations C of trace gases observed 

at Sptizbergen, Norway, and at BRW 

are shown as a function of the 

average atmospheric lifetime of the 

trace gases. The open circles show 

~during summer (August-September); 

the dark circles represent ~ during 

spring (March-April). ~% = 100 x 

[C(Spitzbergen) - C(BRW)]/C(BRW). 

tracers followed similar seasonal cycles at both BRW and Spitzbergen sites 

with highest concentrations of trace gases during Spring (March-April) and 

lowest in summer (August-September). During spring, however, when Arctic haze 

is present, significantly higher concentrations of many hydrocarbons were 

observed at Spitzbergen compared with BRW (fig. 109). This could be either 

due to local pollution or because Spitzbergen is closer to the U.S.S.R. and 

Europe, which may be sources of Arctic pollution and haze. 

5.8.3 Tracers in Haze Layers 

During the flights for AGASP a large number of samples of air were 

obtained in both the polluted layers and the clean Arctic air on the same 

days. The results, summarized in table 42, showed that a large number of 

chlorofluorocarbons, chlorocarbons, hydrocarbons, and other trace gases were 

more abundant in the haze layers then outside the haze. As expected, the 

percent difference of concentrations in and out of the haze layers was much 

greater for short-lived species (Khalil and Rasmussen, 1984). The background 

concentrations of short-lived trace gases are extremely small; thus, polluted 

layers contain a relatively large excess. For long-lived trace gases the 

background concentration consists of accumulated amounts from many years, and 

thus the relative exces~ in the polluted layers is small. 

In the data analyzed (AGASP 8 and 9, flown 31 March and 4 April 1983, 

respectively) no clean air was encountered near the surface. It is possible 

that the concentrations of some short-lived gases decline with height, which 

would have led to underestimation of the background concentrations and therefore overestimation of the relative excess in the haze layers. The effect of 

such a possibility was investigated by reanalyzing the data after discarding 

measurements taken below 2 km. The remaining data, between 2 and 8 km, 

143 
Table 42. The estimated differences (6) of concentrations* and the 

associated 90% confidence limits (lower, upper) of trace 

gases in and out of Arctic haze 

Chlorofluorocarbons 

CC1 2 F2 (CFC-12) 

CC1 3F (CFC-II) 

CHCF 2 (CFC-22) 

C2Cl 3F3 (CFC-113) 

C2Cl 2 F4 (CFC-114) 

Chlorocarbons 

CH 3CC1 3 

C2Cl4 

CC1 4 

CH 3Cl 

CH2Cl 2 

CHC1 3 

C2HC1 3 

Hvdrocarbons 

CH4 (ppbv) 

CzH2 

C2H4 

C2 Hs 

C3H6 

C3Hs 

I-C4H10 

N-C4H10 

I-CsH12 

N-CsH12 

C6H6 

C1Hs 

CO, C02 , & NzO 

CO (ppbv) 

C02 (ppmv) 

N20 (ppbv) 

Other trace gases 

ocs 

CH 3 I 

CH2BrCl 

CH2Br 2 

C2H4 Br 2 

CF 3Br 

CH 3Br 

10 (5, 18) 

5 (3, 9) 

3 (0, IO) 

1.4 (0.5, 2.8) 

0 . 3 (-0.2, 0.7) 

15 (5 I 25) 

45 (21, 65) 

9 (6, 12) 

18 (-13, 38) 

8 (6, 13) 

8 (6, 14) 

10 (4, 16) 

41 

305 

41 

930 

5 

854 

253 

415 

107 

125 

164 

26 

(28' 49) 

(208, 442) 

(lo, 80) 

(560, 1400) 

(O I 44) 

(302, 1267) 

(92, 330) 

(ISO, 590) 

(47' 167) 

(72, 188) 

(68, 214) 

(0' 58) 

47 (27 I 66) 

3.5 (2, 5) 

1 (O I 2) 

97 

0. I 

0 

!. 7 

0 . 8 

0 

-0.3 

(47, 157) 

(O, 0 . 3) 

(-0.1, 0.2) 

(0.5, 2.3) 

(0.2, 1.2) 

(-0.1, 0.2) 

(-J J 0.6) 

*Units are pptv unless otherwise noted. 

2.7 (1.4, 5) 

2 (1.4, 4) 

3.8 ( 0, 13) 

6 (2, 12) 

3 (-2, 7) 

12 (4, 20) 

67 (±39) 

6 (±2) 

3 (-2, 6) 

33 (25, 54) 

35 (26, 61) 

167 (40, 800) 

2. 5 

66 

100 

40 

63 

120 

243 

256 

630 

1000 

5000 

200 

(1.7, 2) 

(±28) 

(25, 200) 

(22, 70) 

(0, 500) 

(±70) 

(±145) 

(±170) 

(>JOO)§ 

(>500)§ 

(>500)§ 

(---) 

36 (±15) 

I (±0 . 4) 

0.3 (±0 . 3) 

26 

142 

0 

68 

200 

0 

-3 

(11, 50) 

(0, 430) 

(-10, 20) 

(±40) 

(22, 1200) 

(-IO, 20) 

(-IO, 6) 

6 > O? 

yes 

yes 

no 

yes 

no 

yes 

yes 

yes 

no 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

no 

yes 

yes 

yes 

yes 

yes 

yes 

no 

yes 

yes 

no 

yes 

no 

no 

yes 

yes 

no 

no 

tData reanalyzed after discarding measurements taken below 2 km . 

§Lower confidence limit only; upper limit not determined. 

6't 

39 (19, 61) 

7 (4, 11) 

7 (4, 12) 

8 (0 . 7, 14) 

257 

39 

740 

0 

469 

154 

235 

86 

83 

127 

(53, 400) 

(7' 54) 

(300 I 1200) 

(-1, 21) 

(122, 1140) 

(30, 308) 

(48, 540) 

(21, 143) 

(30, 148) 

(12, 192) 

42 (10, 55) 

0.1 (O, 0 . 3) 

0.8 (0, 1.2) 

6'% 

58 (±38) 

31 (15 I 48) 

31 (15 I 49) 

138 (6' 242) 

56 (lo, 90) 

100 (18, 138) 

32 (13, 50) 

0 (---) 

66 (17, 160) 

148 (>20) 

145 (>20) 

540 (>60) 

630 (>100) 

4200 (>15) 

32 (8, 42) 

142 (0, --) 

200 (O, --) 

consisted of both clean and polluted air samples at each height. The results 

of the calculations show that while in some cases the estimated relative 

excess is slightly smaller, the conclusions remain the same. Most of the 

trace gases studied are much more concentrated in the haze layers than outside 

(see table 42). 

The results of these flights showed that many trace gases that originate 

from high-temperature combustion, such as in coal-fired powerplants and 

automobiles, were more abundant in the haze than outside the haze, including 

NzO and C0 2 . Excess CH 3Cl, the tracer of low-temperature biomass combustion, 

was not present. Moreover, excess concentrations of exotic manmade compounds 

such as CFC-113 and CF3Br, which would represent pollution from the United 

144 
States, and CF2BrCl, representing pollution from Europe, were also not observed. These findings suggested that the haze encountered on these two 

flights originated in the U.S.S.R. This conclusion was also obtained independently by trajectory analyses of air masses encountered during these flights. 

Measurements from the AGASP studies showed for the first time that the 

gaseous tracers are directly associated with the Arctic haze layers, whereas 

from ground-based measurements one could only infer such a relationship. 

5.8.4 Conclusions 

Studies of the gaseous tracers of Arctic haze have yielded valuable 

information. It has been demonstrated that many anthropogenic trace gases are 

more abundant in the Arctic during the time of haze and that these tracers are 

transported to the Arctic in polluted air that contains the Arctic haze 

aerosol. The tracers can be used to detect both the regions where Arctic 

pollution originates and the types of sources that might contribute to its 

formation. An extremely large array of gaseous tracers is available and can 

provide an exquisite characterization of sources and regions to advance 

further the usefulness of gaseous tracers in large-scale receptor models for a 

quantitative assessment of the sources, sinks, and effects of Arctic haze. 

5.9 Atmospheric Particulates at MLO and SPO 

C. M. Thompson, J. R. Parrington, G. Tuncel, and W. H. Zoller 

Department of Chemistry, University of Maryland 

College Park, MD 20742 

5.9.1 Introduction 

Particles have been collected on a weekly basis almost continuously at 

MLO since February 1979 and have been analyzed for about 40 elements at the 

University of Maryland. Results from the overall project are summarized below 

from Parrington (1983, abstract); data presented in the paper are summarized 

in fig. 110 and table 43. 

Mauna Loa Observatory, Hawaii, was selected as a remote northern 

hemisphere site from which to collect atmospheric particles for chemical 

analyses of background aerosols in the free troposphere of the northern 

hemisphere. An automatic digital sampling controller was designed and 

installed at this site to aid in the isolation of uncontaminated particles of the free troposphere, based on wind direction and speed, timeof-day and particle characteristics at the observatory. 

The three primary components measured on these background particles 

between 1979 and 1982 were sulfates, continentally derived crustal 

material and marine particles with average geometric mean concentrations 

of 240 ng/m3 , 50 ng/m3 , and 15 ng/m3 , respectively, during the months of 

July to mid-February. Other months showed a ten-fold increase in continental crustal material, geometric avg = 730 ng/m3 , (which has been traced 

to Asian deserts) and doubling of sulfate mass to 480 ng/m3 while the 

marine mass showed no significant changes. The average geometric mean 

concentration of local basalt was determined to be 15 ng/m3 in downslope 

winds and, thus, does not represent a major interference to most studies 

145 
Sea •odium 

10 

... 

.. 

E 

... 

Q 

.s 10 c 

~ 110 

~ 

c 

• u tlO c 

0 

CJ 

10 

Figure 110.--Weekly downslope marine sodium (as excess sodium) and aluminum concentrations (ng m- 3 ) for high-volume aerosol collections at MLO. 

(From Parrington et al., 1983.) 

Dust 

Dust 

Dust 

Dust 

at MLO as a majority of the crustal dust in the atmosphere, even in 

relatively clean periods, is transported over thousands of kilometers to 

the island from continents surrounding the Pacific Ocean. 

Several components, SO~, V, Co, Cu, Zn, As, Se, Ag, Sb, W and Au, 

show variations that suggest anthropogenic or volcanic sources during 

episodes throughout the year. Several of these major episodes have been 

traced to populated areas of Asia and North America and in one case 

emissions from copper smelters in the southwestern United States may have 

been transported to MLO. About 40% of the total yearly mass of sulfate 

(the major component by mass which reaches MLO in these episodes) is 

transported in these relatively short episodes. The major source of 

sulfate is apparently natural and may be due to biomethylation in the 

marine environment. 

Table 43.--Downslope concentrations of crustal and marine components, 

and calculated crustal and marine mass concentrations observed in dust 

and nondust periods of each year 

Concentration (ng m- 3 ) 

Material Total Total Marine Mass Mass 

aluminum sodium sodium marine crustal 

1979 115.0 ± 68.0 31.0 ± 22.0 8.6 ± 7.7 27 ± 24 1400 ± 830 

1980 57.0 ± 40.0 21.0 ± 11. 0 7.7 ± 6.3 24 ± 19 690 ± 490 

1981 61.0 ± 33.0 29.0 ± 3.0 15 .3 ± 8.7 46 ± 27 740 ± 400 

1982 46.0 ± 34.0 19.0 ± 6.0 6.5 ± 5.4 20 ± 17 560 ± 410 

Average dust 71.0 ± 51.0 25.0 ± 13.0 9.7 ± 7.5 30 ± 23 860 ± 620 

Nondust 1979 6.4 ± 2.0 17.0 ± 9.8 16.5 ± 9.7 51 ± 30 78 ± 24 

Nondust 1980 8.2 ± 2.2 9.0 ± 4.7 7.3 ± 5.4 23 ± 17 100 ± 27 

Nondust 1981 6.2 ± 2.5 9.6 ± 11. 0 8.4 ± 11. 3 26 ± 35 75 ± 30 

Nondust 1982 5.3 ± 4.0 6.9 ± 6.1 5.6 ± 5.5 17 ± 17 64 ± 49 

Average nondust 6.7 ± 2.3 11.0 ± 9.2 9.5 ± 9.2 29 ± 28 81 ± 28 

146 
Parrington et al. (1983, abstract) describe general features of the 

annual incursions of Asian dust to the Hawaiian Islands: 

Analyses of atmospheric particles collected at Mauna Loa Observatory 

in Hawaii from February . 1979 through September 1982 reveal strong influxes of Asian dust in the spring of each year. Concentrations of a 

typical crustal element, aluminum, are more than an order of magnitude 

greater between February and June than during the remainder of the year 

(71±51 versus 6.7±2.3 nanograms per cubic meter). The mass of crustal 

material transported during the relatively short dust episodes accounts 

for an average of 80 percent of the total yearly mass of atmospheric 

particles at 3400 meters on Mauna Loa. 

5.9.2 The Atmospheric Aerosol at MLO 

During the spring of 1982 and of 1983, size-fractioned atmospheric 

particulates were collected at MLO. The samples were collected during the 

clean downslope phase of the diurnal wind cycle at MLO, and are therefore 

typical of the midtroposphere at 3.4 km (Parrington and Zoller, 1984). These 

experiments were done to characterize the continentally derived material that 

is transported into the Pacific Basin during the spring (Parrington et al., 

1983; Bodhaine et al., 198lb). Many investigators (Parrington et al., 1983; 

Shaw, 1980; Duce et al., 1980; Darzi and Winchester, 1982) have concluded that 

this material has its origins on the Asian continent and is transported 

eastward by tropospheric flow during periods of high dust storm activity in 

central Asia. 

Five impactor sets from each sampling season were analyzed by instrumental neutron activation analysis to determine their elemental composition. 

Figure 111 shows the mass distributions determined for the suite of impactor 

data collected during each year. The mass is approximately log-normally 

distributed about 2-μm particle diameter with some mass on stage 1 and some on 

the backup filter (BU). The mass discontinuity at stage 2 suggests that the 

g. 

~ 

~ 

{ 

0 

0. 

~ 

. . 

0 

2 

ii 

~ 

il 

~ 

0.40 0 .40 

0.35 0.35 

g. 0.30 ~ 0.30 

~ 

0.2~ i 0.25 

... 0.20 ~ 0.20 . . 

0 

0.15 2 0.1~ 'ii 

c 

0 

0 .10 il 

~ 0.10 

0.05 0.05 

o.oo o.oo BU(<.5) 8(.5) 5(1) 4(2) 3(4) 2(8) 1 (1 6) BU(<.5) 8(.5) 5(1) 4(2) 3(4) 2(8) 1 (16) 

D No D No 

Figure 111.--Size distributions of particles bearing several elements at 

MLO under downslope conditions: (left) spring 1982; (right) spring 1983. 

BU is backup filter. 

147 
• 

4 

2 

0 

ll 

-

l ~a I BU I 5 4 (llU-4) 3 2 1 (3-1) sum BU ti S 4 (llU-4) 3 2 1 (3-1) sum 

IZZI Na ~"1;~ Sta'1m Mn IZZI No ~ct~ StagB Mn 

Figure 112.--Crustal enrichment factors for two MLO downslope impactor 

samples collected during Spring 1983: (left) aerosol DSl; (right) 

aerosol DS6. BU-4 is the small-particle stage; 3-1, the large-particle; 

Sum, the total mass on the impactor. The crustal enrichment factor of 

an element x with respect to Al is defined as the following: 

[atm. cone. (x)/atm. cone. (Al)]/[crust. cone. (x)/crust. cone. (Al)]. 

larger particles (stages 1, 2, and 3) may be of a different origin than the 

smaller particles (stages 4, 5, 6, and BU). This possibility was examined by 

using crustal enrichment factors (EF's) to compare the various size fractions . 

Figure 112 shows results from two typical impactor sets collected during the 

spring of 1983. The values of EF t for Na, Sc, and Mn are plotted vs. 

crus 

impactor stage, including the small-particle (BU-4) and large-particle (3-1) 

fractions and the total mass on the impactor (Sum). There are distinct 

differences between the two main size fractions (BU-4) and (3-1). Furthermore, the BU-4 fraction closely resembles the Sum, indicating that the smallparticle fraction is dominant. 

5.9.3 Atmospheric Aerosols at SPO 

Trace-element concentrations have been obtained from atmospheric particulates collected at SPO. Use of instrumental neutron activation analysis 

allows for collection of up to 40 elements on filter samples. Elements 

collected at SPO can be separated into three categories: those of crustal 

origin, those of marine origin, and those that are unusually enriched with 

respect to crustal and marine sources. Crustal and enriched elements can be 

easily distinguished from marine elements by their summer-winter behavior. 

The crustal and enriched elements usually have higher concentrations in the 

summer period. The high winter averages observed for most elements in 1978 

resulted from a large spike observed in the winter season. This is shown in 

fig. 113, where the Al concentrations observed over the period are plotted. 

Other crustal elements also show this regular cycle. They start to increase 

around September and drop back to low values around March. Enriched elements 

follow about the same cycle. Marine elements, on the other hand, follow a 

completely different pattern. They start to increase around May or June and 

148 
7 

..... 6 .., 

~ "li z 

z 

~ ' 

~ 3 u 

% 

8 2 

MJSDMJS 

1978 1'119 

SDMJSDMJSD • 

l'lll l'lil 1'112 

Figure 113.--Aluminum concentrations 

(ng m- 3 ) measured at SPO. 

drop quite rapidly in November and December. The period of high marine input 

overlaps with crustal input, so it is not possible to separate summer and 

winter distinctly by looking at fluctuations in the marine and crustal elements. 

Enriched elements follow a pattern similar to that of crustal elements. 

The easiest way to distinguish these enriched elements is by crustal enrichment factors. Arsenic, Se, Br, and Cl are enriched significantly (as are S, 

Cu, Zn, Ag, Sb, I, and Au). Most of these are believed to have natural 

sources. 

5.10 The Search for Particles of Cosmic Origin at SPO 

R. E. Witkowski and W. A. Cassidy 

University of Pittsburgh 

Pittsburgh, PA 15260 

G. W. Penney 

Carnegie-Mellon University 

Pittsburgh, PA 15213 

As part of the University of Pittsburgh Antarctic Search for Meteorites 

project, an atmospheric particle collector was designed, constructed, and 

installed at SPO during December 1983. Its operation is based on the 

electrostatic precipitation concept, whereby individual particles are 

electrically charged in an ionization chamber and subsequently collected on 

specimen plates maintained at an oppositely charged potential. The collector 

design parameters were so selected as to optimize particle collection in the 

size range of 0.01-1:0 μm with a maximum at 0.3 μm. 

The overall view of the particle collector is shown in fig. 114. Outside 

air enters the unit at the left inlet port and is drawn through the ionizer 

and collector regions at a flow rate of 300 ft min- 1 The combined ionizer 

and collector region is 10 in long and has a cross section of 6 x 3 in; the 

entire assembly is fabricated from Plexiglas. The ionizer is simply an 

149 
Figure 114.--Electrostatic particle 

collector. The specimen plates are 

clearly visible in the center section 

of the device. 

Figure 115.--Specimen plate transfer 

to the storage and transport container. 

electrically charged 0.006-in-diameter tungsten wire stretched perpendicular 

(axially) to the air sample. For this work at SPO, it was found that a 

potential of -12,000 V DC (35 μA) could be maintained; an even glow along the 

length of the tungsten wire was visible when the room was darkened. The 

collector region is made up of a series of stacked stainless steel specimen 

plates arranged in a 3 x 3 matrix configuration. Each 1.5- x 5-in plate is 

gold plated and has a 200-mesh copper grid coated with carbon attached to the 

active collector area. A +7,300-V DC potential is maintained. 

A special arrangement of shutters between the collector and the storage 

and transport container, shown in fig. 115, permits exposed specimen plates to 

be transferred directly to the laboratory for study using scanning transmission electron microscopy. No sample preparation or handling is required 

prior to analysis, thus minimizing contamination. 

The particle collector will operate throughout the 1984 year, and sample 

plates will be withdrawn at specific time intervals. The preliminary results 

obtained to date were from plates exposed for 168 hours. The data indicate 

that the collector has collected particles in the anticipated size range; 

preliminary energy-dispersive spectrometry analysis shows that, in addition to 

sulfur-rich material, particles composed of varying amounts of Mg, Si, K, Ca, 

and Fe have been isolated. Analysis will continue on samples obtained from 

plates exposed during December 1983 and January 1984 for periods up to 1000 

hours. The last set of plates, which is being exposed for various periods 

throughout the 1984 winter season (February-November), will be retrieved 

subsequently for study. 

Acknowledgments 

Much of the design and construction of the collector was provided by 

R. D. Sloss. This research has been supported by the Westinghouse Electric 

Corp. under an R&D Center Senate-sponsored project, and by NSF under Grant No. 

NSF/DPP 78 21104. 

150 
5.11 C0 2 and Other Air Chemistry Studies at Palmer Station 

E. Robinson and W. L. Bamesberger 

Laboratory for Atmospheric Research, College of 

Washington State University, Pullman, WA 

Engineering 

99164 

The second year of operation of the air chemistry facility at Palmer 

Station, Anvers Island, Antarctica, was completed in February 1984, and sampling results for C02 and other trace atmospheric constituents can be reported. 

A description of the station and its operation can be found in Robinson and 

Bamesberger (1982). 

The air chemistry facility is used as a base for gathering C0 2 flask 

samples for analysis in the GMCC laboratories. Also, gas-chromatographic 

instrumentation is operated to measure C02 and other trace constituents 

continuously. A Carle Model 211 automatic GC is used for C0 2 monitoring. The 

instrument is calibrated against standard C02 -in-air mixtures that in turn 

have been given a preliminary standardization check by the GMCC C02 laboratory. 

Table 44 shows the results of regression calculations on the concentration time trends. These data continue the general trends reported on the 

basis of the 1982 results. 

The values 0£ N20 concentrations at Palmer have shown an increase of 

about 3 ppb yr- 1 , or about 1%, compared with an average concentration of about 

300 ppb. This rate is higher than the 0.3%-0.4% observed at other stations 

and higher than the 0.4% long-term increase reported for SPO by Rasmussen et 

al. (1981) £or the period 1977-1981. The Palmer N20 data showed apparent 

seasonal fluctuations over the 1982-1983 2-yr period; thus the higher rate of 

Table 44.--Trace atmospheric constituent mixing ratio results*, 

Palmer Station, Antarctica 

Observed average CorreConstituent mixing ratio Annual lat ion Data period 

week of trendt coef. 

9 Jan 1983 

CCl3F 

(CFC-11) 189.8 ppt 8.9 ± 0.2 ppt yr- 1 (4.7%) 0.97 04 Apr 1982-11 

CCl2F2 

(CFC-12) 314.4 ppt 12.4 ± 0.2 ppt yr- 1 (3 . 9%) 0. 99 

CH3CCl3 118.6 ppt 7.8 ± 0.3 ppt yr- 1 (6 . 6%) 0.91 

CCl4 148.9 ppt 2.4 ± 0.2 ppt yr- 1 ( 1. 6%) 0 . 81 

N20 301.6 ppb 3.0 ± 0.2 ppb yr- 1 ( 1. 0%) 0.84 

04 Apr 1982-11 

04 Apr 1982-11 

04 Apr 1982-11 

04 Apr 1982-11 

C02 337.4 ppm ---§ 31 Jan 1982-11 

CH4 1. 51 ppm ---§ 31 Jan 1982-11 

co 57. 0 ppb ---§ 31 Jan 1982-11 

03 10-30 ppb (approx. annual range) 

CN 200-1000 cm- 3 (approx . annual range)1'* 

24 Jan 1982-11 

24 Jan 1982-11 

*Expressed on a dry-air basis. 

tBased on weekly average data; % calculated from observed data for week of 09 Jan 1983 . 

§Pronounced seasonal cycle precludes estimation of useful annual trend. 

ffNo samples for period 18 Jul 1982-18 Jan 1983. 

~"*CN expressed as concentration rather than mixing ratio. 

151 

Dec 1983 

Dec 1983 

Dec 1983 

Dec 1983 

Dec 1983 

Dec 1983ff 

Dec 1983 

Dec 1983 

Dec 1983 

Dec 1983 
l•• 

343 

3~2 

E )41 

a. 

a. 3-40 

339 N 

0 

I.) 338 

~36 

335 

: 

:·!.· • I \-. ·.I • • 

I '· "--/ N . . ~ N !!! . !!! ;;; ~ .. .. N 

.. 

~ Q 

"' 

~ N 

,...!-.,,, •• ,.. '-& 

"' • -r. . /. 

./ 

., 

"i • •f ··\ • I 

.. "<-(· 

"' 

~ 

"' 

.. 

'· . 

"' "' "' .. .. ~ N ~ "' 

... Q N 

I I I 

I 5 9 I~ 11212529333741454953576l 6H973 na1 899397 

WEEKSFigure 116.--Average weekly C02 

concentrations (ppm), 6 February 

1982-11 December 1983, Palmer 

Station, Antarctica. The curve is 

a subjective approximation of the 

apparent data trend. 

increase observed here may be due to the short sampling period and a lack of 

adequate compensation for the cyclical nature of the data. 

The C02 record described in table 44 covers the period from 31 January 

1982 to 11 December 1983, but with a break from 18 July 1982 to 18 January 

1983 due to instrumentation problems during the Antarctic winter. Figure 116 

shows a plot of the C02 record based on weekly average data. The data are 

expressed on a dry-gas basis (Pearman, 1975). The concentration trend and 

apparent seasonal cycle over this 2-yr period have been approximated by the 

subjectively drawn curve shown in the figure. The annual trend indicated by 

these data approximates the 1.2 ppm yr- 1 trend found for SPO data; however, 

the seasonal cycle as indicated by this curve is larger than what would be 

expected from the previous Southern Hemisphere data. The C02 data collection 

at Palmer is continuing, and more details on this apparent seasonal cycle 

should be provided in future analyses. The analyses of the seasonal data for 

CO and CH4 also show seasonal cycles similar in phase to the C02 pattern shown 

in fig. 116. 

5.12 Vertical Profiles of Carbon Particles in the Arctic 

H. Rosen and A. D. A. Hansen 

Lawrence Berkeley Laboratory 

University of California, Berkeley, CA 94720 

One of the major uncertainties in modeling the effects of the Arctic haze 

on the solar radiation balance has been the limited knowledge of the vertical 

distribution of the haze and, in particular, the vertical distribution of 

graphitic carbon particles and their associated absorption coefficients. The 

first measurements of such distributions in the Arctic atmosphere and, to the 

best of our knowledge, in the atmosphere in general are reported here. 

During March and April 1983 a series of flights (AGASP) organized by NOAA 

explored the vertical and horizontal distributions of the Arctic haze. One of 

the instruments used in this program was the aethalometer (Hansen et al., 

1982), which was developed at LBL and has the capability of determining 

graphitic carbon concentrations (Rosen and Novakov, 1983) on a real-time basis 

using the calibration of Gundel et al. (1984). 

152 
Vertical profiles were obtained by dividing the atmosphere into altitude 

bins and determining the average aethalometer response in each of these bins 

over the particular time periods of interest. The bin size was chosen so that 

the errors due to the minimum detection limit of the aethalometer were small 

compared with the average aethalometer response in the altitude bin. Error 

bars shown in the profiles are based on 3 times the minimum detectable limit 

of the aethalometer and correspond to a change in the transmission of the 

filter deposit of 0<075%. The error bars are different at different altitudes 

because they are inversely proportional to the volume of air sampled in a 

given altitude bin. 

In figs. 117 and 118 vertical profiles of graphitic carbon concentrations 

vs. altitude are shown for AGASP flights 8 and 10 respectively in the Norwegian 

Arctic. Flight 8 was essentially in a northerly direction over Bear Island to 

northern Spitzbergen at 80°N, 15°E; it then returned to Bod¢. The flight 

profile included a slow descent from 7 km to 0.1 km at 74°N, 25°E near Bear 

Island. The graphitic carbon concentrations as a function of altitude are 

shown for this descent in fig. 117. Also shown for comparison are the average 

ground-level concentrations found at BRW for April 1982, and the annual 

average ground-level concentrations found in various urban areas in the United 

States. It is clear from this figure that the vertical profile has considerable structure, with at least three layers located at approximately 1.0 km, 

2.5 km, and 4.5 km, and what appears to be a very narrow layer at 1.7 km. The 

haze layers can have sharp boundaries with dramatic changes in concentration 

over distances less than 100 m. The concentrations within these layers are 

large; the peak concentrations at 1 km are as large as typical ground-level 

concentrations in the United States (Berkeley, Denver, Gaithersburg) and only 

about a factor of 2.5 lower than those in New York City. The concentrations 

in this band are about a factor of 10 higher than the April 1982 ground-level 

3 

Barrow 

ground level 

April 1982 

! 

Berkeley 

lher burg 

Denver 

l Fremon1 Anaheim New Vork 

! 

Ground Level Annual Averages 

0'--~~-=-~~~~--'-~~~~~~~~~~~~~~~~--<~~~~~~~~........_~~~---J 

a 1000 2000 3000 ·IOOO 

Graphitic carbon concentration (ng/m ') 

Figure 117.--Ve~tical profile of graphitic carbon concentrations, expressed as ng m 3 , on AGASP flight 8, 31 March 1983 at ~74°N, 25°E. 

Shown for comparison are the annual average ground-level graphitic 

carbon concentrations at various urban locations in the United States 

and the average April 1982 ground-level values at BRW. See text for a 

discussion of the error bars. 

153 
(•) 

Graphillc carbon 

concentrallon (ng/m3) 

(b) 

0.5 O.! 

Mixing ratio (ppb) 

Figure 118.--Vertical profile of 

graphitic carbon concentrations on 

AGASP flight 10, S April 1983 at 

~70°N, 0°E, expressed (a) in ng m 3 

and (b) as a mixing ratio (ppb). 

concentrations at BRW (O.lS μg m- 3 ). The flight profile also indicates a 

relatively clean region at low altitudes, which is consistent with the BRW 

results (Hansen and Rosen, 1984) and the limited ground-level measurements 

made in the Norwegian Arctic. 

Flight 10 also originated in Bod¢, Norway, but flew west across the 

Norwegian Sea on 5 April 1983 to an area near 70°N, 0°E over the open ocean 

and then returned to Bod¢. The plane remained within 70° ± 2° latitude and 

ranged from S0 E to S0 W in longitude between 0914 and 1604 GMT. The average 

vertical profile of graphitic carbon concentrations for this period is shown 

in fig. 118a. This profile is quite distinct from the one shown in fig. 117; 

it has much less structure with only one sharp band at 3.75 km superimposed 

over an almost uniform haze layer, decreasing only slightly with altitude even 

close to the top of the troposphere. If this profile is plotted as a mixing 

ratio, as in fig. 118b, it is essentially flat to the top of the troposphere, 

with a very intense band located at about 3.7S km. This profile could indicate significant transport at high altitudes above the planetary boundary 

layer. However, it may also be indicative of changes in the vertical distribution that have occurred after the air mass has reached the Arctic. 

Acknowledgment 

This work was supported by the Director, Office of Energy Research, C0 2 

Research Division, DOE, under Contract DE-AC03-76SF00098. 

5.13 S02 , Ozone, and Aerosol Over MLO Since El Chichon 

W. F. J. Evans, G. M. Shah, and J. B. Kerr 

Atmospheric Environment Service 

Downsview, Ontario, M3H 5T4, Canada 

5.13.1 Introduction 

The El Chichon volcano in southern Mexico, which erupted between 28 March 

and 4 April 1982, injected enormous amounts of S02 , H2 0, fine ash, and other 

debris into the troposphere and stratosphere, and provided a unique measure154 
ment opportunity for the characterization of the distribution of the volcanic 

cloud and the assessment of its optical and radiative properties. 

In April 1982, after the eruption of El Chichon, the Experimental Studies 

Division at AES began a study of S02 , ozone, and aerosol optical depth in the 

atmosphere at several sites including MLO. During the same period, arrangements were made to make similar measurements on the NASA CV 990 flying laboratory on a latitude survey mission. The first flight was carried out in early 

May 1982. Subsequent flights were carried out in July and December 1982 and 

May 1983. 

This report presents the measurements of S02 , ozone, and aerosol optical 

thickness made at MLO between April 1982 and December 1983. 

5.13.2 Instrumentation 

The Brewer spectrophotometer (Brewer, 1973), calibrated against the 

standard Dobson spectrophotometer, was used to measure S0 2 and ozone. It is a 

remote sensing instrument that measures S02 and ozone by the absorption of the 

solar ultraviolet spectrum as it traverses the stratospheric layers. On the 

ground, the instrument is pointed at the Sun, and the intensity of light in 

the ultraviolet absorption spectrum of ozone at five wavelengths (306.3, 

310.1, 313.5, 316.8 and 320.1 nm) with a resolution of 0.6 nm is measured. 

Sulfur dioxide also has strong variable absorption in this spectral region. 

The optical depth measurements were made with a sunphotometer (Shah, 

1979), a small hand-held instrument that is manually pointed at the Sun. The 

spectral selection is obtained by manually switching through a sequence of 

narrowband (HBW 10 nm) interference filters centered at 380-, 500-, 862-, and 

935-nm wavelengths. The sunphotometer was calibrated by the Langley method in 

Boulder, CO, in December 1981 and at MLO in September 1982. 

5.13.3 Observations 

Figure 119 presents the monthly means of the apparent S02 column overburden measured at MLO from April 1982 to November 1983. Just after the 

11.1 

u 

I.I 

I.I 

I.I 

u 

u 

l.1 

u 

I.I 

I.I 

1982 

155 

Figure 119.--Monthly means of sulfur 

dioxide (milli-atm-cm) in the atmosphere measured with the Brewer spectrophotometer at MLO. 
eruption in May 1982, the S02 amount was over 4.0 milli-atm-cm and reached its 

maximum of 4.5 milli-atm-cm in August 1982. It decayed slowly with time, and 

by the end of the year, it had decreased to less than 0.5 milli-atm-cm (estimated threshold of detection). In 1983, the maximum S02 amount of about 

2.5 milli-atm-cm was found in July, and then it decreased to less than 

0.5 milli-atm-cm in October. 

On the basis of the latitudinal distribution of S02 from aircraft measurements and S02 column overburden measurements with time at Hawaii, Evans and 

Kerr (1983) have estimated the total amount of S02 injected by El Chichon to 

be over 13 Mt. This is consistent with total sulfate aerosol mass of 14 Mt 

estimated by Shah and Evans (1984) from aircraft measurements of optical 

depths. 

Figure 120 presents tbe monthly means of total ozone measured at MLO from 

April 1982 to December 1983. A maximum of 276 milli-atm-cm was found in April 

1982, and a minimum of 220 milli-atm-cm was found in January 1983. Total 

ozone again increased with a seasonal maximum of about 266 milli-atm-cm in 

June 1983. 

The total ozone values for the months of August 1982 to January 1983 are 

about 8% on an average lower than those found for the same period in 1983. 

This reduction in ozone is attributed to the El Chichon eruption cloud. 

Comparison of ozone data for August to January of 1980, 1981, and 1983, 

published by AES in cooperation with WMO (Ozone Data for the World, World 

Ozone Data Center, Atmospheric Environment Servi~4905 Dufferin Street, 

Downsview, Ontario M3H5T4), has indicated that the values were very similar 

for those periods. 

Figure 121 presents the monthly means of the aerosol optical thickness at 

500-nm wavelength calculated from the measurements of the extinction of solar 

radiation made at MLO from April 1982 to December 1983. targe increases in 

• 

"' 

"' 

1982 1983 

Figure 120.--Monthly means of total 

ozone (milli-atm-cm) in the atmosphere measured with the Brewer spectrophotometer at MLO. 

156 

u..-----------------~----. 

.. 

"' 

'" 

'-' 

1.1+---------------------4 

1982 198] 

Figure 121.--Monthly means of 

aerosol optical thickness in the 

atmosphere at 500-nm wavelength 

measured with the sunphotometer at 

MLO. 
I.BB t-------- -+---+--t---+-+--+-+ 

RPR 26 

B ~B 

B.2B JULY 

--~ 

~ B. IB DEC. G~ 

0~ 

0.B2 

B.01 ~-- ---+--+---+--<---+--+--+--I 

lllll 2BB IBBB 

MRVELEH6TH (NH) 

Figure 122.--Spectral dependence of 

monthly means of aerosol optical 

thickness t in 1982. 

RPR . 21 

B. ~B JULY 

DEC. 

B.2B 

~ e 1e 

B~ 

B.92 

B. Bl t---- - -+----+--->--+---.---+-+--+--1 

me 2BB ieee 

MRVELEN6TH (NH) 

Figure 123.--Spectral dependence of 

monthly means of aerosol optical 

thickness t in 1983. 

optical thickness were observed at all wavelengths just after the El Chichon 

eruption. The cloud had stabilized by the end of May 1982, and it decayed 

slowly to less than 0.1 in December 1982. The optical thickness continued to 

decrease, and by May 1983 it was below 0.05, nearly the background level. It 

remained at that level for the rest of the year. 

Figures 122 and 123 are plots of mean monthly aerosol optical thickness, 

t(A) vs. wavelength A on a log-log scale graph. From April 1982 to April 

1983, the spectral variation of optical thickness was essentially flat. In 

July 1983, a strong inflection was found at 500-run wavelength, and in December 

1983 log t(A) decreased monotonically with an increase in wavelength. 

5.13.4 Discussion 

The S02 measurement at MLO indicates the slow decrease of S02 over 

several months as the sulfate aerosol occurred by the conversion of S02 into 

H2S02 , and was removed by sedimentation and vertical transport. 

The time variation of optical depth at MLO demonstrates the morphology of 

the growth and decay of the resulting volcanic sulfate layer. The optical 

depth measurements show that the El Chichon eruption cloud produced the 

largest optical depth increase in the Northern Hemisphere since Krakatoa in 

1883. A perturbation of this size in the incident solar flux should be of 

interest to climatologists in future years. 

15 7 
The ground-based measurements at MLO together with the aircraft measurements of S02 have provided an estimate of the amount of S02 injected by 

El Chichon into the stratosphere. It is hoped that these measurements will 

provide a significant contribution to the data base for the most measured 

volcanic climate event in history. 

Acknowledgments 

We acknowledge the important contributions of the NOAA/GMCC staff in 

obtaining the ground measurements at MLO. We also acknowledge the cooperative 

efforts of the NASA staff in conducting the aircraft measurements. 

5 . 14 Optical and Chemical Features of Aerosol Present in the Arctic Snowpack 

A. D. Clarke and K. J. Noone 

Civil Engineering Department 

University of Washington, Seattle, WA 98195 

Since the early reports of banded-haze structures in the Arctic atmosphere (Mitchell, 1957), several investigators have identified relatively high 

concentrations of light-absorbing particles associated with these haze events 

at ground level (Barrie et al., 1981; Heintzenberg, 1982). Some of these 

measurements have identified elemental carbon (soot) as the primary absorber 

and suggest anthropogenic emissions as the primary source (Rosen et al., 

1981). The presence of aerosols with high specific absorption, such as soot, 

have raised questions about perturbations to the radiative fluxes in this 

region that are due to Arctic haze. Assessment of such perturbations can be 

gained through determination of the aerosol light-scattering coefficient and 

the aerosol light-absorption coefficient. Taken together, these coefficients 

define the single-scattering albedo, which determines their net effects in the 

equations that govern radiative transfer in the atmosphere. During the past 

2 years we have actively participated in NOAA-AGASP and University of 

Washington flight programs in the Arctic and measured these radiatively 

important parameters. Our results, recently reported elsewhere (Clarke et 

al., 1984), support evidence of combustion sources for the Arctic haze aerosol 

and indicate concentrations of light-absorbing aerosol of 1-2 orders of 

magnitude above tropospheric background values. These measurements also 

indicate possible aerosol heating rates on the order of 0.1°C day- 1 , values 

that are well above background but less than some other terms affecting 

atmospheric heating rates (Porch and MacCraken, 1982). 

In addition to the atmospheric aerosol measurements made under our Arctic 

haze program, we have initiated a wide-ranging study of the aerosol present in 

the Arctic snowpack. Because of the high surface albedo of uncontaminated 

fresh snow, trace concentrations of light-absorbing material (e.g., soot) in 

the snowpack can markedly effect its albedo and alter the amount of solar 

radiation absorbed at the surface (Warren and Wiscombe, 1980; Chylek et al., 

1983). In sufficient quantity, such soot could affect snowmelt rates and 

result in both primary and secondary effects on radiative climate parameters. 

Furthermore, once deposited on the snowpack, inert soot is likely to remain 

and accumulate on the surface during snowmelt and become exposed to the 

increased Arctic solar insolation even after elevated levels of springtime 

Arctic haze have dissipated. Consequently, our program attempts to collect 

snow from representative locations throughout the Arctic, and to determine the 

158 
Figure 124.--Map of Arctic sampling 

locations for the University of 

Washington atmospheric (black stars) 

aircraft samples and snowpack (white 

stars) samples for 1983-1984. 

amount of light-absorbing material in the snowpack and the fraction of absorption that can be attributed to soot. 

The network of stations providing snow samples for 1983-1985 are 

indicated in fig. 124, and the samples collected to date are indicated in 

table 45. Most samples were collected during winter months and kept frozen 

until analysis. This procedure minimizes possible losses of particulate 

material to the container walls (600-cm3 glass jar) and spurious effects due 

to algae growth or chemical reaction after sampling. Analysis began in March 

1984 on some randomly selected representative samples from each location. 

Initial extraction of particulates was accomplished by dual sequential 

filtration of meltwater obtained from rapid microwave melting of the sample. 

The filters were analyzed for visible light absorption at four wavelengths 

Table 45.--Arctic snow samples collected under the current 

University of Washington field program 

1983 1984 

BRW 11 6 

Spitzbergen (Norway) 9 6 

Re solute (Canada) 5 5 

Eureka (Canada) 4 4 

Alert (Canada) 4 4 

Mould Bay (Canada) 4 4 

Dye 3 (Greenland) 24 0 

Ice Floe 80°N (Greenland) 12 0 

Abisko (Sweden) 0 20 

Karesuando (Sweden) 0 3 

Kautokeno (Norway) 0 3 

Alta (Norway) 0 4 

Total 73 59 

159 
(475, 525, 660, 800 run) using either the integrating plate method (Lin et al., 

1973) and/or integrating sandwich method (Clarke, 1982). The filtrate was 

then measured for pH and conductivity before being refrozen or refrigerated 

for later measurement of major ions using ion chromatography. 

Results of the optical analysis for several random snow samples are 

indicated in fig. 125. To compare the behavior of samples with different 

concentrations, the absorption measured at each wavelength is divided by the 

550-nm value, and the normalized absorption wavelength dependence indicated is 

obtained. Four wavelengths are used to help discriminate absorption due to 

crustal aerosol compared with absorption due to soot. Figure 125 illustrates 

2.0 

EC 

·~::03 '-~~~~~~~~~-~~~~~~~ 

660 BOO 

WAVELENGTH IN NANOMETERS 

Figure 125.--Normalized wavelength 

dependence of particulate light 

absorption for Arctic snow samples 

in table 45. Heavy lines are for El 

Chichon volcanic ash (EC) and a prepared calibration soot, Monarch 71 

(M-71); the remaining samples are 

identified in table 46 and discussed 

in the text. 

the wavelength dependence of several samples compared with those characteristic of prepared submicron calibration soot (Monarch 71, Cabot Corp.) and 

crustal material (El Chichon volcanic ash), both emphasized by heavy lines in 

the same figure. The majority of these samples indicates that the light 

absorption due to particulates is dominated by soot in most locations, and 

that crustal material is present but generally of secondary importance. It 

should be noted that the greatest crustal influence appears in the sample from 

Resolute, Canada (C-03). This sample was collected close to the local airport 

where low precipitation and substantial exposed soil was noted. In contrast, 

the clearest soot signatures are present in the most remote samples collected 

160 
on ice floes at 80°N (I-10) and for the samples from BRW (B-01, B-06). The 

wavelength dependence of absorption is similar for the Greenland (G-01, G-07) 

and Spitzbergen (S-02, S-05) samples and suggests absorption due to both soot 

and crustal components, with the former slightly dominant. It is of interest 

to note that the mixing ratios measured in the snow samples (average 2 x 10- 8 ) 

are consistent with those expected from applying scavenging ratios (Barrie and 

Neustadter, 1983) to the typical atmospheric concentrations of elemental 

carbon c~2 x 10- 7 g m- 3 ) obtained during our 1983 aircraft measurements 

(Clarke et al., 1984). 

The slope of the wavelength dependence in fig. 125 can be used to provide 

an approximate estimate of the relative contribution of soot to particulate 

light absorption. This estimate has been used in conjunction with the measured light absorption values at 550 run to obtain the apparent soot mass per 

mass of liquid water in each sample. Recent model calculations (S. Warren; 

University of Washington, Seattle; personal communication, April 1984) indicate that a 1% change in snow albedo (a minimum detectable effect relative 

Table 46.--Arctic haze snow sample data 

Concentration in snow melt (EEm) 

NA+ NH! K+ NO; 

[C (g)/ 

so:; H20 (~}I pH Cond. 

I.D. Date Location Type (depth) (12%)* (50%)'~ (50%)* (14%)* (8%)* x 10 (umho) 

B-01 830413 BRW Old (1-15 cm) ? 8.96 12 6.10 2500 

B-02 830413 BRW Old (2-4 cm) ? 6.06 13 6.15 ? 

B-04 830413 BRW Old (3-15 cm) 33.8 2.0 0.39 8.20 32 5.50 366 

B-OS 830413 BRW Old (15-30 cm) 60 .5 5 . 3 0.28 4.82 16 S.60 764 

B-06 830420 BRW Fresh (surface) 19.2 0.40 2.7S 52 S.50 221 

C-03 830311 Resolute Fresh (surface) ? 0.14 6.30 

C-06 831117 Mould Bay Fresh (surface) 0.3S 0.38 0.11 0.20 35 6.12 11.3 

IF-01 830715 Ice Floe Fresh (surface) 0.54 0.75 0.06 O.lS 3 6.55 9.5 

IF-10 830717 Ice Floe Old (5-20 cm) 0.95 9 S.6 

G-01 830516 Greenland Recent (0-12 cm) 0 . 24 0 .14 o. 12 0.18 0.09 21 5.92 3.1 

G-03 830216 Greenland Old (12-22 cm) 0 .57 0. 14 0 . 12 ? 10 S.7 3.3 

G-11 830423 Greenland Fresh (surface) 0 . 46 0.01 0.20 o.os 11 6 . 0 

S-02 830516 Spitzbergen Old (10-20 cm) 1.29 0.56 0.09 0.88 SS 6.05 14.8 

S-05 840108 Spitzbergen Fresh (0-10 cm) 0.S6 0.03 0.12 0.08 0.43 2S 6.0 4.5 

SS-02 840308 Spitzbergen Fresh (surface) 0.53 o.os 0. lS 0.64 6 5 .10 22.8 

Note: ? means not measured;-- means below detection limit . 

* % uncertainty in analytic measurement. 

to pure snow) could be expected for ~1 x 10- 8 mass fraction of soot in fresh 

snow and 0.3 x 10- 8 in coarse-grained, aged snow. Estimated soot mass fractions obtained from the slopes for fig. 125 samples are included in the data 

swnmary found in table 46. The range of values is ~(0.3-5.5) x 10- 8 for this 

limited data set. If these values are typical of the samples that remain to 

be analyzed (~100), then soot appears to be common in concentrations capable 

of reducing fresh snow albedo by 1%-3% (a measureable effect). This reduction 

for a given initial soot mass fraction in fresh snow may increase during a 

season to as much as 10% for some of these samples because of snow ablation, 

melting, and morphological changes in grain size (S. Warren; University of 

Washington, Seattle; personal communication, April 1984). The lowest mass 

fraction is seen in a fresh summer snowfall (IF-01) and is approximately an 

161 
order of magnitude lower than average winter values. This is consistent with 

an order of magnitude winter-summer variability seen in other atmospheric 

aerosol measurements (Heintzenberg, 1982). 

Chemical data reported in table 46 were obtained from the meltwater 

filtrate subsequent to the extraction of insoluble components. The random 

selection of these samples makes any interpretation of chemical signatures 

premature. This is particularly true of older snow where soluble ions may 

have migrated during periods of partial melting. However, the BRW samples 

(including fresh snow) clearly have major ion concentrations and conductivity 

up to 2 orders of magnitude higher than other samples. Because the mass 

mixing ratio of carbon is not greatly elevated for the BRW samples, it is 

likely that a natural aerosol such as seasalt may be primarily responsible. 

The lowest concentrations of major ions and light-absorbing aerosol is found 

for the Ice Floe (80°N, 4°W) and at Dye 3 in Greenland. If one observes the 

relationship of pH to conductivity (Winkler, 1980), the deduced free acidity 

of these samples appears to be less than 5%. We intend to improve on the 

above oata through the more complete analysis of the entire sample set that is 

currently under way. 

In summary, climatic impacts may arise from the scavenging and accumulation of absorbing material into the Arctic snowpack to result in a reduced 

surface snow albedo. Measurements are reported here on the aerosol deposited 

to the snowpack at diverse Arctic sites including visible light absorption at 

four wavelengths. Preliminary data on the wavelength dependence of absorption 

(430-800 nm) indicate that soot is primarily responsible for aerosol light 

absorption in snow at most locations under investigation and is present at 

concentrations that may appreciably affect snow albedo. Crustally derived 

material in the snow pack appears as a minor contributor to visible light 

absorption at most locations but may play a secondary role at several others. 

More extensive measurements are presently being assessed throughout the Arctic 

under the snow sampling program currently under way. After the remaining 

samples are analyzed, it is hoped that information can be obtained about the 

areal distribution of soot in the snowpack and its relationship to other 

measured chemical features. Spatial and temporal effects of these concentrations on snow albedo will be modeled to determine the possible impact on 

Arctic radiative transfer and climate. 

Acknowledgments 

This research received principal support from NSF through the Division of 

Polar Program Grant No. DPP-8213425. We are particularly grateful to all 

those individuals who contributed to our field sampling and collection program. We extend special thanks to L. Barrie and D. Stossel (AES); V. Vitosl 

(NIAR); D. Beard (GMCC/BRW); C. Davidson (Carnegie-Mellon University); and 

T. Grenfell (University of Washington). 

162 
5.15 Global Atmospheric Measurements of CH4 and C0 2 

by Gas Chromatography 

L. P. Steele 

NRC-NOAA Research Associate 

Geophysical Monitoring for Climatic Change, NOAA/ERL/ARL, Boulder, CO 80303 

P. J. Fraser* 

Research Assoc., Cooperative Institute for Research in Environmental Sciences 

University of Colorado, Boulder, CO 80309 

R. A. Rasmussen, M. A. K. Khalil, and A. J. Crawford 

Oregon Graduate Center 

Beaverton, OR 97006 

T. J. Conway and R. H. Gammon 

Geophysical Monitoring for Climatic Change 

NOAA/ERL/ARL, Boulder, CO 80303 

During 1983 a cooperative program between CSIRO, NOAA/GMCC, and OGC was 

initiated by P. Fraser of CSIRO while visiting GMCC for 1 year as a CIRES 

Research Associate. The major purpose of the program is to investigate any 

possible relationship between the observed seasonal cycles of both methane 

(CH4 ) and C02 in the atmosphere. 

This program uses the existing NOAA/GMCC global network of flask sampling 

sites to provide samples of air for analysis by gas chromatography for its CH4 

and C0 2 content. The gas chromatographic procedures adopted are similar to 

those described by Rasmussen and Khalil (1981) using Carle model 211-M gas 

chromatographs fitted with flame ionization detectors. One of the gas chromatographic systems used in this work has been loaned to NOAA/GMCC by 

R. Rasmussen of OGC. About 500 flask samples taken at approximately weekly 

intervals at 20 sites were analyzed during 1983. The gas chromatographic 

analysis is carried out on only one of the pair of flasks normally filled 

using the P3 sampler, and is performed prior to the analysis of both members 

of each pair for the C0 2 concentration by the method of infrared absorption. 

This procedure is possible because of the slight pressure above ambient that 

is achieved in the flasks at the time of sampling. The excess pressure is 

used to purge the low-volume sampling system of the chromatograph, including 

the sample loop itself, which has a volume of about 2 mL. This purging and 

filling procedure consumes only small quantities (-20 mL) of air sample. The 

analysis of every flask air sample is bracketed by the analysis of a sample of 

calibration gas. 

The calibration gases used in the program are those supplied by R. 

Rasmussen, and are regularly intercalibrated with a suite of CH 4 standards 

maintained by him at OGC. In addition, routine intercalibrations with an NBS 

CH4 -in-air standard gas with a nominal concentration of 1 ppm are performed. 

To date, no significant drift in the CH4 concentration of the calibration 

*On leave from Division of Atmospheric Research, CSIRO, Mordialloc, Victoria, 

3195 Australia. 

163 
gases has been detected. 

checked routinely against 

of infrared absorption. 

The C02 concentration of these calibration gases is 

standards maintained at NOAA/GMCC using the method 

To check the reliability of CH4 concentrations in air samples collected 

in the 500 cm3 glass flasks with greased (Apiezon N) stopcocks, a number of 

storage tests have been performed. In one test, air samples were analyzed as 

soon as the flasks arrived in Boulder, and a selection of those flasks with 

sufficient remaining pressure was set aside for periods of time ranging from a 

few days to several weeks, and then analyzed again. In another test, flasks 

were filled to a pressure a little above ambient with a known CH4 -in-air 

calibration gas from a cylinder. Some of these flasks were analyzed immediately, while others were set aside for periods up to 6 months, and then 

analyzed. The results of all these tests indicate that CH4 is remarkably 

stable in these glass flasks, with no evidence of either a loss or a gain in 

concentration. This appears to be so whether the air sample in the flask is 

dry or not. 

The routine precision of these gas chromatographic measurements can be 

estimated readily since, whenever possible, at least two aliquots are taken 

from each flask for analysis . Histograms of differences between the concentration in the first and second aliquot show no significant bias for either 

CH4 or C0 2 • These histograms also show the distribution of these differences 

to be approximately normal, yielding an estimate of the standard deviation 

(based on several hundred samples) of 4 ppbv for CH4 and 0.8 ppm for C0 2 . 

This level of precision for CH4 is very good, but for C02 is significantly 

worse than that routinely achieved at NOAA/GMCC with the method of infrared 

absorption. 

Since the C02 concentration is determined in these flasks by two different methods of analysis, the results have been compared by means of a histogram of differences in concentration obtained from both methods. The histogram obtained from several hundred samples is approximately normal, but with a 

mean value of 0.6 ppm and a standard deviation of 0.9 ppm. The gas chromatographic estimate is almost always larger than that found by the infrared 

method. This surprising result cannot be explained by calibration errors, 

since both types of measurements are referenced to the same calibration 

standards. 

Although the NOAA/GMCC flask sampl i ng network gives relatively good 

global coverage, it was decided to supplement these samples with data from 

oceanographic cruises. The results so far from this type of comparison 

indicate that in general the network gives a very reliable guide to the 

background concentration of both CH4 and C02 . This is illustrated in fig. 126 

which shows the monthly mean CH4 concentratio~s for November 1983 at a number 

of the network sampling sites, together with flask samples taken by 1. Waterman 

on the cruise of the AKADEMIK KOROLEV during 25 October-14 November 1983 in 

the mid-Pacific. It should be noted, however, that the location of the very 

abrupt change in concentration near the Equator is not detected in data from 

the network alone because of the scarcity of sites in this latitude band. 

Given the early stage in the development of this program, it is too 

soon to evaluate the data fully. However, several features are already 

apparent. The latitudinal gradients of CH4 (see fig. 126) confirm the results 

of previous measurements (e.g., Khalil and Rasmussen, 1983b) and are the most 

164 
1700 

·1 · > . , .. 1 16'50 .,. 

..,. IECD 

i5 .. . .... t •• t ........ 

15'11 

i, ~ ti ~ g ~ ~ ~ ~ ~ ~ 

0.8 0.6 0.1 0.2 0.0 -{).2 -0. 1 

511\E CT L..ATin.cE 

!! I . 

~~ H 

-{).6 -{).8 

Figure 126.--Monthly mean CH4 concentrations for November 1983 determined from NOAA flask sampling sites 

(dots). Error bars indicated are 

1 standard deviation from the mean 

value. Data indicated by x are individual flask values taken on the 

cruise of the AKADEMIK KOROLEV 

during 25 October-14 November 1983 

in the mid-Pacific. 

detailed of any available at this time. Measurements of CH4 in the Southern 

Hemisphere are in excellent agreement with previously published data (Fraser 

et al., 1984), but for the first time the remarkable uniformity of background 

CH4 concentrations over most of this hemisphere has been demonstrated. The 

time series of CH4 at most sites in the Northern Hemisphere also show good 

agreement with the type of seasonal behavior described by Khalil and Rasmussen 

(1983b), that is, a strong minimum during the northern summer. 

165 
6. INTERNATIONAL ACTIVITIES 

In June 1983, GMCC hosted a WMO meeting of experts on C0 2 concentrations 

from pre-industrial time to the IGY. Fourteen international experts participated in the discussion. A summary of the meeting, presented by W. Elliott in 

EOS (26 June 1984), was entitled "The Pre-1958 Atmospheric Concentration of 

Carbon Dioxide." 

J. Peterson participated in the WMO Technical Conference on Observation 

and Measurement of Atmospheric Contaminants held in Vienna, Austria, during 

October 1983. He presented papers with W. Komhyr on C0 2 measurements at BRW, 

with R. Schnell on AGASP, and with J. DeLuisi, E. Dutt.on, and E. Flowers on 

NOAA turbidity measurements. He also gave a summary report to conclude the 

conference. All of these reports will be presented in a WMO document on the 

conference proceedings. 

W. Komhyr and R. Evans visited Haute Provence Observatory, France, during 

late August-early September 1983 to install automated Dobson instrument no. 85 

at the observatory and implement a program of total ozone and Umkehr observations. Haute Provence Observatory is one of seven global sites where Umkehr 

observations will be made on a long-term basis using automated Dobson instruments to monitor possible atmospheric ozone depletion by halocarbons near 

40-km altitude. 

W. Komhyr visited Aire Sur L'Adour, France, 2-17 September 1983 to 

participate in MAP/GLOBUS balloon ozone instrument comparisons. Successful 

experiments were conducted on two occasions. 

CIRES Research Assistant, A. Chopra of the Indian Meteorological Service, 

New Delhi, India, completed his assignment with GMCC and returned to India in 

December 1983. While in Boulder, Chopra assisted with ECC ozonesonde evaluations, the 1983 MLO ECC ozonesonde observations program, and special ozone and 

S02 observations made at MLO following the eruption of El Chichon in late 

March-early April 1982. 

Huancayo, Peru, Dobson instrument no. 87 was modernized, optically 

aligned, and recalibrated in August 1983, in preparation for automation of 

the instrument and its reestablishment in Huancayo for long-term Umkehr 

observations. 

R. Gammon traveled to Leningrad, U.S.S.R., in July 1983 to participate in 

a meeting of experts on anthropogenic climatic change. The travel was under 

the auspices of the U.S.-U.S.S.R. bilateral scientific exchange agreement, 

Working Group VIII. He gave a talk entitled "Global Atmospheric C0 2 , 1968-

1983: Summary of the United States/NOAA Monitoring Program." 

R. Gammon also attended the IAMAP/IUGG Symposium in Hamburg, F.R.G., in 

August 1983. He gave two papers: the first, by Gammon and Komhyr, was entitled "Response of the Global Atmospheric C0 2 Distribution to the Atmospheric/ 

Oceanic Circulation Perturbations in 1982"; the second, by Komhyr, Gammon, and 

Gillette was "The Southern Ocean Sink for Atmospheric C0 2 ." 

R. Gammon also participated in the oceanographic cruise of the ship KNORR 

based out of Woods Hole Oceanographic Institution. The ship sailed from 

Dakar, Senegal, to Recife, Brazil. This cruise was part of the tropical 

166 
Atlantic study of the Transient Tracers in the Ocean Program. One of the 

objectives was to measure chlorofluorocarbons in the ocean, which are very 

useful as an index of ocean circulation. 

Flask sampling for C0 2 analysis at Halley Bay, Antarctica (75°S, 27°W), 

began in 1983 in cooperation with the British Antarctic Survey. In June a 

second year's supply of flasks was shipped to England for transshipment to 

Halley Bay for sampling in 1984. The 1983 samples will return to Boulder for 

analysis during the summer of 1984. Initial inquiries were made to D. Walton 

of BAS concerning the possibility of obtaining flask samples at South Georgia 

Island, as a replacement for the discontinued Falkland Islands site. 

Agreements were reached with C. Keeling of SIO to begin flask sampling at 

Christmas Island (2°N, 175°W) and with P. Fraser of CSIRO to begin sampling at 

Cape Grim, Tasmania (41°S, 145°E). Both programs, scheduled to start in 1984, 

will fill existing gaps in the GMCC C02 flask network coverage and will 

provide interlaboratory comparison data. 

From 22 October to 5 December, L. Waterman participated in the SovietAmerican Gases and Aerosols Expedition aboard the Soviet research vessel 

AKADEMIK KOROLEV. Measurements of C0 2 and CH4 in the atmosphere, and pC02 and 

pCH4 in surface waters were made by the method of gas chromatography, between 

40°N and 30°S in the mid-Pacific Ocean. The joint cruise was organized 

through the U.S.-U.S.S.R. Working Group VIII Committee on the Environment and 

included measurements of several gases, aerosols, and oceanographic parameters 

by Soviet and American scientists using a variety of techniques. 

A noncontaminating gas transfer pump used for analyzing flask air samples 

for C02 concentration (Komhyr et al., 1983b) was built for C.S. Wong of the 

Institute for Ocean Sciences, British Columbia. In conjunction with this 

transfer of technology, G. Smith of IOS visited GMCC for a week in August for 

discussions of C0 2 measurement systems and testing of the new transfer pump. 

N. Trivett of Environment Canada, AES, Downsview, Ontario, visited GMCC 

for 2 days in October to discuss AES plans to begin in situ continuous monitoring of atmospheric C02 by NDIR analysis at Alert, Northwest Territory. AES 

is planning a comprehensive measurement program at Alert similar to those at 

the GMCC baseline observatories. 

J. DeLuisi issued a call to lidar research scientists having sites in the 

United States, Japan, Europe, South America, and Australia for a collaborative 

global stratospheric aerosol monitoring program to support Umkehr observations 

of stratospheric ozone profiles. The lidar data will be used to improve the 

quality of the Umkehr measurements because of their susceptibility to errors 

caused by stratospheric aerosols. All responses to the call were positive. 

Arrangements are being made to archive data in the Canadian-issued book, 

Ozone Data for the World. DeLuisi submitted to the WMO a preliminary lidar 

data archiving format. He arranged a meeting of lidar scientists at the 

Twelfth International Radar Conference to formulate activities of the group 

and discuss the preliminary data format. He also prepared a paper (given by 

P. McCormick of NASA/Langley at that conference) on the application of lidar 

measurements for correction of Umkehr measurements. 

R. Schnell, director of AGASP, traveled to Alaska, Canadian Arctic, 

Greenland, and Norway with 40 people in the field operation. He also helped 

167 
organize and conduct the Ringberg Castle Arctic Haze Symposium, Kreuth, 

F.R.G., 5-9 September 1983. AGASP supported nine scientists attending this 

meeting. 

B. Bodhaine also traveled to Kreuth, F.R.G., to participate in the 

Ringberg Castle Arctic Haze Meeting. This meeting provided the participants a 

first opportunity to discuss and compare Arctic haze data obtained during the 

AGASP flight program in March-April 1983. In addition to giving presentations 

of preliminary data, the attendees discussed plans for comprehensive publication of the AGASP data. 

P. Steele, visiting scientist from Australia, continued his appointment 

at GMCC as an NRC-NOAA Research Associate during 1983. His work continued on 

the modeling of the global carbon cycle. He also became heavily involved in 

the cooperative program between CSIRO, NOAA/GMCC, and OGC to use gas chromatographic methods to measure CH4 and C0 2 concentrations in the flask air samples 

routinely received from the GMCC global flask sampling network. 

P. Fraser of CSIRO, Division of Atmospheric Research, finished a 1-yr 

position as a CIRES Research Associate sponsored by GMCC, departing in 

November 1983. His appointment continued an informal, reciprocal arrangement 

for cooperative research by the staffs of NOAA and CSIRO. During his visit, 

he undertook a detailed comparison of gas chromatographic and infrared absorption techniques for the measurement of C02 concentrations in the atmosphere. 

His major contribution was an investigation into the feasibility of measuring 

methane and C02 by gas chromatographic techniques from the 0.5-L glass flasks 

routinely collected for the C02 program. By conducting an extensive series of 

laboratory tests, he determined that a small volume of air could be taken from 

the flasks prior to C02 analysis without influencing the gas concentrations 

within the flask. Largely through his efforts, a pilot program was begun for 

routine global-scale CH4 measurements based on flask analyses. Some preliminary results are presented in sec. 5.15. 

W. Raatz from the F.R.G. began a 1-yr term as an NRC-NOAA Research 

Associate on 15 September 1983. He had participated in the AGASP project 

during spring 198~, and his objective is to continue work on the meteorological aspects of long-range transport leading to the presence of Arctic 

haze. 

R. Boonprakai, a meteorologist in the Meteorological Department in 

Bangkok, Thailand, was a guest worker with the GMCC Division in Boulder, CO, 

from 14 April 1983 to 14 October 1983. Boonprakai was on a WMO training 

fellowship to receive technical training and experience in making atmospheric 

ozone and turbidity measurements. While here, she was trained on the Dobson 

spectrophotometer and the GMCC turbidity instruments. She participated in an 

international sunphotometer comparison and calibration workshop. 

168 
7. PUBLICATIONS AND PRESENTATIONS BY GMCC STAFF, 1983 

Bodhaine, B. A. Aerosol measurements at four background sites. J. Geophys. 

Res. 88(C15):10753-10768. 

Bodhaine, B. A. Surface aerosol measurements at Barrow. Paper presented 

at the Ringberg Castle Arctic Haze Workshop, Kreuth, F.R.G., 5-9 September 1983. 

Bodhaine, B. A., J. J. DeLuisi, J.M. Harris, and R. C. Castillo. Aerosol 

light scattering, condensation nuclei, and air mass trajectories at 

Whiteface Mountain. Paper A12-05 presented at the AGU Spring Meeting, 

Baltimore, MD, 30 May-3 June 1983. 

Bodhaine, B. A., J. J. DeLuisi, J.M. Harris, and R. C. Castillo. Light 

scattering, condensation nuclei, and air mass trajectories at Whiteface 

Mountain: Summer 1982. NOAA Data Rep. ERL ARL-3, NOAA Environmental 

Research Laboratories, Boulder, CO, 69 pp. 

Bullister, J., R. Weiss, and R. Gammon. Freon transient tracer distributions 

in the tropical Atlantic Ocean. Paper presented at the AGU Fall Meeting, 

San Francisco, CA, December 1983. 

DeLuisi, J. J., and J.M. Harris. A determination of the absolute radiant 

energy of a Robertson-Berger meter sunburn unit. Atmos. Environ. 

17(4):751-758. 

DeLuisi, J. J., E. G. Dutton, K. L. Coulson, T. E. Defoor, and B. G. Mendonca. 

On some radiative features of the El Chichon volcanic stratospheric dust 

cloud and a cloud of unknown origin observed at Mauna Loa. J. Geophys. 

Res. 88(Cll):6769-6772. 

DeLuisi, J., E. Dutton, E. Flowers, and J. Peterson. Recent developments 

in atmospheric turbidity measurements in the NOAA Geophysical Monitoring 

for Climatic Change Program. Paper presented at the WMO TECOMAC 

Conference, Vienna, Austria, October 1983. 

DeLuisi, J. J., B. G. Mendonca, E. G. Dutton, M. A. Box, and B. M. Herman. 

Radiative properties of the stratospheric dust cloud from the May 18, 

1980, eruption of Mount St. Helens. ~ Geophys. Res. 88(C9):5290-5298. 

Dutton, E. G., and J . J. DeLuisi. Optical thickness features of the El 

Chichon stratospheric debris cloud. Paper presented at the Fifth 

Conference on Atmospheric Radiation, Baltimore, MD, 31 October4 November 1983. 

Dutton, E. G., and J. J. DeLuisi. Spectral extinction of direct solar 

radiation by the El Chichon cloud during December 1982. Geophys. Res. 

Lett. 10:1013-1016. 

Gammon, R. Global atmospheric C02 , 1968-83: Summary of the United States/ 

NOAA monitoring program. Paper presented at the Meeting of Experts on 

Anthropogenic Climatic Change, Leningrad, U.S.S.R., 3-9 July 1983. 

169 
Gammon, R. Global carbon dioxide distributions from the NOAA monitoring 

program: Implications for the global carbon cycle. Paper presented in 

the Climate Seminar Series, National Center for Atmospheric Research, 

Boulder, CO, December 1983. 

Gammon, R., and W. Komhyr. Response of the global atmospheric C02 distribution 

to the atmospheric/oceanic circulation perturbations in 1982 (El ChichonEl Nino). Paper presented at the IAMAP/IUGG Symposium, Hamburg, F.R.G., 

August 1983. 

Gammon, R., W. Komhyr, and J. Peterson. The global atmospheric C02 

distribution 1968-83: Interpretation of the results of the NOAA/GMCC 

measurement program. Paper presented at the Sixth Oak Ridge National 

Laboratory Life Sciences Symposium on the Global Carbon Cycle: Analysis 

of the National Cycle and Implications of Anthropogenic Alterations for 

the Next Century, Knoxville, TN, 31 October-3 November 1983, Dept. of 

Energy. 

Gillette, D. A. Future research in resuspension. Proceedings, Fourth International Conference on Precipitation Scavenging, Dry Deposition, and 

Resuspension, Santa Monica, CA, 29 November-3 December 1982, 

H. R. Pruppacher, R. G. Semonin, and W. G. N. Slinn (eds.), Vol. 2, 

Elsevier, NY, 1443-1445. 

Gillette, D. A. The concept of resuspension rates applied to problems of fugitive dust emissions and wind erosions. Proceedings, Fourth International 

Conference on Precipitation Scavenging, Dry Deposition, and Resuspension, 

Santa Monica, CA, 29 November-3 December 1982, H. R. Pruppacher, 

R. G. Semonin, and W. G. N. Slinn (eds.), Vol. 2, Elsevier, NY, 1059-1072. 

Gillette, D. A. Threshold velocities for wind erosion on natural terrestrial 

arid surfaces (A summary). Proceedings, Fourth International Conference 

on Precipitation Scavenging, Dry Deposition, and Resuspension, Santa 

Monica, CA, 29 November-3 December 1982, H. R. Pruppacher, R. G. Semonin, 

and W. G. N. Slinn (eds.), Vol. 2, Elsevier, NY, 1047-1057. 

Gillette, D. A., and K .. J. Hanson. Sampling strategy to obtain data used in 

models of global annual C0 2 increase and global carbon cycle. J. Geophys. 

Res. 88(C2):1345-1348. 

Gillette, D. A., and A. T. Steele. Selection of C0 2 concentration data from 

whole-air sampling at three locations between 1968 and 1974. J. Geophys. 

Res. 88(C2):1349-1359. 

Halter, B., and J. M. Harris. On the variability of atmospheric carbon 

dioxide concentration at Barrow, Alaska, during winter. J. Geophys. Res. 

88(C11):6858-6864. 

Harris, J.M., and B. A. Bodhaine. Air mass trajectories in the Arctic. 

Paper presented (by Bodhaine) at the Ringberg Castle Arctic Haze Workshop, Kreuth, F.R.G., 5-9 September 1983. 

Harris, J.M., and B. A. Bodhaine (eds.). Geophysical Monitoring for 

Climatic Change, No. 11: Summary Report 1982. NOAA Environmental 

Research Laboratories, Boulder, CO, 160 pp. 

170 
Komhyr, W. D. An aerosol and gas sampling apparatus for remote observatory 

use. J. Geophys. Res. 88(C6):3913-3918. 

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Rosen, H., and T. Novakov, 1983. Combustion-generated carbon particles in the 

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9. GMCC STAFF, 1983 

Director's Office 

James Peterson, Director 

Bernard Mendonca, Deputy Director 

Jeanne Kelsey, Secretary 

Joanne Edwards, CIRES 

Carol Fee, Computer Programmer 

Paul Fraser, Guest Scientist, CSIRO 

Dale Gillette, Physical Scientist 

Everett Nickerson, Meteorologist 

Rita Rosson, Clerk-Typist 

Russell Schnell, CIRES 

Chandra Shastri, CIRES 

Gregory Siedelberg, Electronic Technician 

Paul Steele, Guest Scientist 

Acquisition and Data Management Group 

Gary Herbert, Chief 

Bonnie Hill, Secretary 

Richard Clark, Computer Programmer 

Edward Green, CIRES 

Joyce Harris, Computer Specialist 

Troy Higgins, Jr. Fellow 

Gloria Koenig, Computer Programmer 

Kenneth Thaut, Electronic Technician 

Monitoring Trace Gases G,rour> 

Walter Komhyr, Chief 

Susan Dozier, Secretary 

Amar Chopra, CIRES 

Robert Evans, CIRES 

Robert Grass, Physicist 

Kent Leonard, CIRES 

Samuel Oltmans, Physicist 

Frank Polacek, III, Meteorological Technician 

Thayne Thompson, Physicist 

Aerosols and Radiation Monitoring Group 

John DeLuisi, Chief 

Bonnie Hill, Secretary 

Barry Bodhaine, Meteorologist 

Forrest Cook, Electronic Technician 

Ellsworth Dutton, Meteorologist 

Stuart Naegele, CIRES 

Kenneth Thorne, CIRES 

Wolfgang Raatz, NRC Postdoctoral Research Associate 

Carbon Dioxide Group 

Richard Gammon, Chief 

Susan Dozier, Secretary 

Thomas Conway, CIRES 

Bradley Halter, Meteorologist 

Kenneth Masarie, CIRES 

Steven Rush, CIRES 

Kirk Thouing, CIRES 

Lee Waterman, Chemist 

183 
Mauna Loa Observato ry 

Kinsell Coulson, Director 

Judith Pereira, Secretary 

Arnold Austring, Physical Scientist 

John Chin, Physicist 

Thomas DeFoor, Electrical Engineer 

Thomas Garcia, Physical Science Aid 

Darryl Kuniyuki, Jr. Fellow 

Cynthia McFee, NOAA Corps 

Mamoru Shibata, Electonic Technician 

Alan Yoshinaga, Chemist 

Barrow Observatory 

Randy Fox, Station Chief 

Daniel Beard, Station Chief 

Timothy Wolfe, Electronic Technician 

Samoa Observatory 

Donald Nelson, Station Chief 

Roger Williams, Electronic Technician 

Efaraima Peau, W. G. Laborer 

South Pole Observatory 

Rusty Brainard, NOAA Corps, Station Chief 

Steven Fahnenstiel, Physicist 

Frank Migaiolo, NOAA Corps, Station Chief 

Robert Platzer, Engineer 

*u.s. GOVERNMENT PRINTING OFFICE:1988-676-002/40017 

184