Su larl Report 1987 

U.S. DEPARTMENT 

OF COMMERCE 

NATIONAL 

OCEANIC AND 

ATMOSPHERIC 

ADMINISTRATION 

ENVIRONMENTAL 

RESEARCH 

LABORATORIES 

• 

• 

• 

• 
Geophysical Monitoring 

for Climactic Change 

No. 16 

Summary Report 1987 

Barry A. Bodhaine, Editor 

Rita M. Rosson, Assistant Editor 

Air Resou rces Laboratory 

Geophysical Monitoring for Climatic Change 

Boulder, Colorado 

December 1988 

u.s. DEPARTMENT DF COMMERCE 

C. William Verity, Secretary 

National Oceanic and Atmospheric Administration 

William E. Evans, Under Secretary ior Oceans and Atmosphere / Administrator 

Environmental Research Laboratories 

Vernon E. Derr, Director 
ii 

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 Ihe tests of such 

producls is not authorized. 

For sale b)' the Nallonal Technic::lllnrorm:lIlOn Ser'lce, S:::8S Pon Royal Road 

Spnngfield, VA ;!2161 
iii 

Contents 

GMCC Staff. 1987 vi 

GMCC Station Infonnation .. ...................... ......................................... ..... ....... ................................................ .......... vii 

I. Summary .......................................................................................................................................................... . 

2. ObservaLOry Reports .......................... .................................................. .................................................. ........... 3 

2.1. Mauna Loa ...... ........................ ......................................... ......................................................... ... .......... 3 

2.2. 

2.3. 

2.4. 

2.5. 

2. I. I. Facilities ...................... ""."." ... " ... " .. ""."".""".".".. ............................................................... 3 

2. 1.2. Programs ........................... ... .................................... ......... ..... .......... ..................... ..... ............... 3 

Barrow 

2.2.1. 

2.2.2. 

Facil ities ........................................................................................................................... ....... . 

Programs ..... ............................................................................................................................ . 

Samoa ......................................................................................................................................... .. .......... . 

2.3.1. Facil ities .................................................................................................................................. . 

2.3.2. Programs ........................................................................................ ......................................... . 

South Pole ..................................................................................................................... ........................ . 

2.4.1. F acilitics .................................................................................................................................. . 

2.4 .2. Programs ................................................................................................................................ .. 

References ............................................................................................................................................. . 

7 

7 

8 

10 

10 

10 

12 

12 

12 

IS 

3. Aerosols and Radiation Monitoring Group ...................................................................................................... 16 

3.1. Continuing Programs ..................... ...................... ............................... ................................................... 16 

3.1.1. Surface Aerosols .................................... .................................................................................. 16 

3.1.2. Solar and Thennal Radiation ................................................................................................... 19 

3.1.3. Solar Radiation Facility ............... ............ .............................................. .................................. 22 

3.1.4. Turbidity...................................... ..... ..... ..................................................... ............................. 22 

3.2. Special Projects ...................................................................................................................................... 26 

3.2.1. Zenith-Sky Cloud Detection for Automated Dobson Umkehr Measurements ........................ 26 

3.2.2. An Objective Method of Correcting Umkehr Measurements for Volcanic Aerosol Error ...... 26 

3.3. References ....... ............ ........................................... ...................................................................... .......... 29 

4. Carbon Cycle Group ......................................................................................................................................... 30 

4.1. Continuing Programs ............................................................................................................................. 30 

4.1.1. Continuous In-Situ CO2 Measurements .................................................................................. 30 

4.1.2. Flask Sample CO2 Measurements .......................................... """"""""""""""""""'" .......... 30 

4.1.3. Model Development .......................................... ...................................................................... 31 

4.1.4. Flask Sample Methane Measurements ......... ..... ...................................................................... 31 

4.1.5. In Situ Methane Measurements at BRW ................................................................................. 32 

4.1.6. In Situ Methane Measurements at MLO .......................................................................... ........ 32 

4.2. Special Projects ................................................................ ..................... ........ ........................ ................. 33 

4.2.1. SAG A II Expedition ........... ................ .......... ..... ..................................................... ......... ........ 33 

4.2.2. Egypt Project ..... ................................................................................................................. ..... 33 

4.3. References................... ................................................................................................................... ........ 33 

5. Monitoring Trace Gases Group ........................................................................................................................ 35 

5.1. Continuing Programs .. ........................................... ................. ............................. ..... ............................. 35 

5.1. I. Total Ozone ............................................ ............ ............................................. ........ ............... 35 

5.1.2. Ozone Vertical Distribution ..................... ................. .......................... ........................ ............. 39 

5.1.3. Tropospheric Ozone ................................................................................................................. 43 

5.1.4. Stratospheric Water Vapor .................. ............... ....... ............................................................... 43 

5.2. References .......................................................................... "............... ............................... .......... .......... 49 
iv 

6. Acquisition and Data Management Group ....................... ................................................................................ 50 

6.1. Continuing Programs ............................................. ...................... .......................................................... 50 

6.1. 1. Station Climatology ................................................................................................................. 50 

6.1 .2. Data Management ....... ... ..................... .................................... ..... ...................... ....................... 55 

6.2. Special Projects .................................................................. .. .................................................................. 55 

6.2.1. Atmospheric Trajectories ................ .... ...................... .............. ...................... ........................... 55 

6.3. References .......................... ... ............................ ...................... .............. ........................ ......................... 60 

7. Air Quality Group .............................................................................. ............................................................... 61 

7. 1. Continuing Programs ......................................................... .................................................................... 61 

7.1.1. Introduction .............................................................................................................................. 61 

7.1.2. National Acid Precipitation Assessment Program ................................................................... 61 

7.1.3. Western Atlantic Ocean Experiment ....................................................................................... 61 

7. 1.4. Processing of Emissions by Clouds and Precipitation ............................................................. 61 

7.1.5. Central U.S. RADM Test and Assessment Intensives ........ ............................... ...................... 61 

7. 1.6. Across North America Tracer Experiment ..... .......... ............ ....... ............................................ 63 

7.1.7. RADM Evaluation Experiment ............................................................................................ ... 63 

7. 1.8. Radiatively Important Trace Species .............................................. ......................................... 64 

7.1.9. Use of an Airborne Air Sampling Platform for Regional Air Quality Studies ......... .. ........ .. ... 64 

7.2. Special Projects . ..... ..... .......... ..................... ... ......... ....... .......... .. .......... ............ ....... ....... .......... ..... .......... 65 

7.2.1. Natural Sulfur Flux From the Gulf of Mexico: Dimethyl Sulfide, Carbonyl Sulfide, 

and Sulfur Dioxide ................................................................................................................... 65 

7.3. References ......... .............. .............................................. ..... .................................................................... 65 

8. Nitrous Oxide and Halocarbons Group ............................................................................................................ 67 

8.1. Continuing Programs .................................................... .................... .................................... ................. 67 

8. 1.1 . Samples ................... .......... ....................... ................. .................................................. ............. 67 

8.1.2. RITS Continuous Gas Chromatograph Systems at GMCC Baseline Stations ........................ 71 

8.1.3. Low Elcctron Attachment Potential Species ....... .............................................. .. ... ................. 72 

8.1 .4. Gravimetric Standards ............................................................................................................. 72 

8.2. Special Projccts ...................................................................................................................................... 72 

8.2.1. Soviet-American Gas and Aerosol Experiment ....................................................................... 72 

8.2.2. FT-IR Spectrometer Archive Project ....................................................................................... 75 

8.3. References ....................................................... ....... ........................ ................... ..................................... 75 

9. Director's Office ............................................................................................................................................... 77 

9.1. Alkaline Aerosols Program: Dust Emissions Modeling ............................ ........................... ................. 77 

9. 1.1 . Introduction ....................................... ....................................................................................... 77 

9. 1.2. Basis of the Dust Production Model .................................................................. ...................... 77 

9.1.3. Calibration of the Model .. ...................... .......................... ... ..................................................... 77 

9. 1.4. Results of the Model ................................................... ....... .............................................. ........ 77 

9.1.5. Conclusions .................................................................... .. .. .................... ................................... 78 

9.2. Arctic Gas and Aerosol Sampling Program: Springtime Tropospheric Ozone Destruction 

in the High Arctic ........................... ........................................................................ ....... ... ......... .. ........... 78 

9.2. 1. Introduction ... ...................... ........................................ ..................................................... ........ 78 

9.2.2. Vertical Extent of the Ozone Depletion ...................... ............................................................. 79 

9.2.3. Seasonal Pattern of Solar Insolation and Ozone Concentrations at BRW ............................... 79 

9.2.4. Ozone Destruction and Filterable Bromine Formation ............................................................ 80 

9.2.5. Vertical and Areal Distribution of Filterable Bromine in the Arctic ....................................... 80 

9.2.6. Discussion and Concluding Remarks ..................................................................... ................. 81 

9.3. References .......................... .................................................................................................................... 81 

10. Cooperative Programs ...................................................................................................................................... 83 

Aerosol Black Carbon Measurements at the South Pole: Initial Results, 1986-1987 

AD.A. Hansen , B.A. Bodhaine, E.G. Dutton, and R.C. Schnell .............................................. 83 
Global Distributions of Anthropogenic Chlorocarbons: A Comparison of CFC-II, CFC-12, CFC-22, 

CFC-I13, CCl., and CH3CCl3 From an Ocean Cruise and From Land-Based Sampling Sites 

MA.K. Khalil andR.A. Rasmussen ........................................................................................ . 85 

Some Characteristics of Aerosol Size Distributions at MLO 

Antony D. Clarke ..................................................................................................................... 87 

Snowfall Measurements in the Arctic 

George Clagell ..... .. ..... ..... ............................... ... ..... ...................................... ....... ....... ............. 90 

Resolution and Geochemistry of Ionic Components in the Late Winter Aerosol at Barrow Station 

During AGASP-II 

Shao-meng Li and John W. Winchester ................................................................................... 93 

The Global Precipitation Chemistry Project 

William C. Keene, James N. Galloway, Gene E. Likens, and John M. Miller ........................ 95 

Radioactivity in the Surface Air at BRW, MLO, SMO, and SPO 

Richard Larsen and Colin Sanderson ...................................................................................... 97 

Precipitation Chemistry 

R.S. Artz ................................................................................................................................... 99 

UVB Monitoring Data From Mauna Loa, Boulder, and Rockville 

David L. Correll .................. ................ .............................................. ..... ............ ......... ... ....... .... 102 

Nitric Acid and Aerosol Nitrate Variations at Mauna Loa 

BJ. Huebert and W.M. Warren ............................... ................................................... .......... .... 103 

II. International Activities, 1987 ........................................................................................................................... 105 

12. Publications and Presentations by GMCC Staff, 1987 ..................................................................................... 106 

13. Acronyms and Abbreviations 108 

v 
vi 

Director'S Office 

James Peterson, Director 

Bernard Mendonca. Deputy Director 

Ellen Hardman, Secretary 

Howard Bridgman. Guest Scientist 

Dale Gillene, Physical Scientist 

Jon Kahl, i\TR,C Post Doctorate 

Evereu C. Nickerson, Meteorologist 

Dana Roper, Summer Aid 

Rita Rosson, Oerk-Typist 

Pedro Sancho, Guest Scientist 

Russell Schnell, ORES 

Patrick Sheridan. hTRC Post Doctorate 

Elizabeth Shuey, Scientific Data Clerk 

Paul Stockton, Physical Science Technician 

Denise Theedc, Program Clerk 

Thomas Watson, Physical Science Aid 

Chi Zhou, CIRES 

Acqulsltlon and Data Management 

Group 

Gary Herbert, COief 

Dee Dee Giebelhaus. Secretary 

Richard Clark, Computer Programmer 

Richard Cook, Physical Science Aid 

Michael Ellis, Physical Science Aid 

Joyce Harris, Computer Spec ialist 

Steve Roughton, Computer Assistant 

Kenneth ThauI, Electronic Technician 

Aerosols and Radiation Monitoring 

Group 

John DeLuisi, Olief 

Marilyn Van Asche, Secretary 

Christa Anderson, Physical Science Aid 

Barry Bodhaine, Meteorologist 

Mickey Cronin, Physical Science Aid 

Ellsworth Dutton, Meteorologist 

Rudy Haas, Mathematician 

Bradley Halter, Meteorologist 

David Kanzer, Physical Science Aid 

Fred Kreiner, Physical Science Aid 

David Longenecker, CIRES 

David Massey, Physical Science Aid 

Donald Nelson, Meteorologist 

Timothy Quakenbush, Physical Science Aid 

Patrick Reddy, CIRES 

Michael Shanahan, Physical Science Aid 

Lois Steams, Meteorologist 

Raben Stone, ClRES 

GMCC Staff, 1987 

Air Quality Group 

Joseph Boatman, Olicf 

Dee Dee Giebelhaus, Secretary 

M"k Cichy, CO-OP 

Laureen Gunter, Meteorologist 

Helmut Horvath, Guest Scientist 

Young Kim, CIRES 

Menachem Luria, J'I..~C Post Doctorate 

John Ray, cmES 

Herman Sievering, CIRES 

Kurt Shallenberger, CIRES 

Karen Stamm inger, Physical Science Aid 

Charles Van Valin, Research Olemist 

Dennis Wellman, Engineer 

Stan Wilkison, Computer Programmer 

Carbon Cycle Group 

Pieter Tans, CIRES 

Lee Prendergast, Secretary 

Craig Averman, CO·OP 

Thomas Conway, Research Olemist 

Ronald Garrett, Physical Science Aid 

Thomas Greaney, ClRES 

Darryl Kaurin, CO·OP 

Duane Kitzis, CIRES 

Patricia Lang, CIRES 

Russell Martin, CIRES 

Kenneth Masarie, CIRES 

Paul Novelli, CIRES 

Vernon Preston, CO·OP 

L. Paul Steele, OR ES 

John Taylor, CIRES 

Kirk Thoning, CIRES 

James Todd, CIRES 

Lee Waterman, Research Chemist 

Glen Weiler, Physical Science Aid 

Monitoring Trace Gases Group 

Walter Komhyr, Chief 

Lee Prendergast, Secretary 

Mark Anderson, Physical Science Aid 

Maureen Ballard, CIRES 

Sean Coleman, Physical Science Aid 

Raben Evans, CIRES 

Leigh Fanning, Physical Science Aid 

Paul Franchois, ClRES 

Rabert Grass, Physicist 

Timothy Kauffman, Physical Science Aid 

Gloria Koenig, Computer Programmer 

Laura Landrum, CIRES 

Kent Leona rd, CIRES 

Michael O'Neill, CO·OP 

Samuel Oltmans, Physicist 

Frank Polacek, m, Meteorological 

Technician 

Ronald Thome, Engineering Technician 

LaRae Williams, Physical Science Aid 

Nitrous Oxide and Halocarbons Group 

James Elkins, Olief 

Marilyn Van Asche, Secretary 

Christina Brunson, Physical Science Aid 

James Butler, CIRES 

EUen DeMoney, CIR.ES 

Keith Egan, CIRES 

Brad HaU, Physical Science Technician 

Thayne Thompson, Physicist 

Barrow Observatory 

Daniel Endres, Station Olief 

James WendeU, Electronic Technician 

Mauna Loa Observatory 

Elmer Robinson, Director 

Judith Pereira, Program Suppon Technician 

Arne Austring, Physical Scientist 

Lynne Bannan, Physical Science Aid 

John Chin, Physicist 

Thomas DeFoor, Electronic Engineer 

lbomas Garcia, Meteorological Technician 

Barbara Kereanan, Data Oerk 

Darryl Kuniyuki, NOAA Jr. Fellow 

Mamoru Shibata, Electronic Technician 

Alan Yoshinaga, Chemist 

Samoa Observatory 

Steven Ryan, Station Olid 

M. Emily Wilson, Electronic Technician 

South Pole Observatory 

Clifford Wilson, NOAA Corps, 

Station Olid 

SCOlt Kuester, NOAA Corps, Station Chief 

Ted Mullen, Electronic Technician 

Patrick Reitelbach, Electronic Technician 
Name: 

Latitude: 

Longitude: 

Elevation: 

Time Zone: 

Office Hours: 

Telephone 

Office hours: 

After hours: 

Postal Address: 

Freight Address: 

Name: 

Latitude: 

Longitude: 

Elevation: 

Time Zone: 

Officc Hours: 

Telephone: 

Office hours: 

After hours: 

Postal Address: 

GMCC Station Information 

Barrow (BRW) 

71.3233 

156.6067 

Okm 

GMT-9 

8:00 am-5:oo pm 

(907) 852-6500 

(907) 852-6500 

Officer in Charge 

NOAA/ERijARijGMCC 

Pouch 8888 

Barrow, AK 99723 

Samoa-(SMO) 

-14.2522 

170.5628 

0.03 km 

GMT -11 

8:00 am-5:oo pm 

011-(684) 622-7455 

011-(684) 699-9953 

U.S . Dept. of Commerce 

NOAA - GMCC Samoa Observatory 

P.O. Box 2568 

Pago Pago, American Samoa 96799 

Mauna Loa (MLO) 

19.533 

155.578 

3.4km 

GMT-IO 

8:00 am-5:00 pm 

(808) 961-3788 

(808) 961-3788 

U.S. Dept. of Commerce 

NOAA - Mauna Loa Observatory 

P.O. Box 275 

Hilo, HI 96720 

U.S, Dept. of Commerce 

NOAA· Mauna Loa Observatory 

154 Waianuenue Ave. 

Hilo, HI 96720 

South Pole (SPO) 

-90.000 

0.000 

2.8km 

GMT +12 

8:00 am - 5:00 pm 

Relayed through GMCC Boulder 

Officer in Charge. GMCC Program 

Box 400 USARP 

C/O NA VSUPPFORANT ARCTICA 

FPO San Francisco, CA 96692 

ATTN: South Pole #S-257 

E. CrozeT 

vii 

GEOPHYSICAL MONITORING FOR CLIMATIC CHANGE 

NO. 16 

SUMMARY REPORT 1987 

1. Summary 

At MLO. major additions were gas chromatographs for 

continuow in situ measurements of methane and certain 

halocarbons. The staff supported 24 cooperative projects from 

university and other· agency investigators. Lidar measurements 

of stratospheric aerosol showed continued decay toward 

background and no major new injections of volcanic dust. At 

BRW, the frequency of ozonesonde balloon profiles was 

enhanced during winter-spring to look for stratospheric ozone 

depletion. Numerous improvements were made to facilities at 

BR\V. SMO. and SPO. The major change at spa was to raise 

the Clean Air Facility by about 3.7 m, thus lengthening its 

lifetime by some 10 years before it becomes covered by drifting 

snow. 

The ongoing GMCC core measurement programs continued. 

They include CO2 and CH4 from the nask network and 

observatories; total column ozone; ozone vertical distribution by 

ECC sonde and Umkehr technique; surface ozone; sLTatospheric 

wat~r vapor by balloon soundings at Boulder; CFC-ll, CFC-12 

and N20 from nask samples and observatory analyzers; 

stratospheric aerosols at MLO using lidar; aerosol light 

scattering; CN concentration; direct and diffuse solar and 

infrared radiation; meteorological variables; and chemistry of 

precipitation. 

In the Aerosols and Radiation Monitoring Group, linear 

LTends of CN concentration and particle scattering for the full 

records (up to 14 years in length) at the four observatories are 

all not statistically significant from zero. The major features in 

the measurements of aerosol optical depth. turbidity and 

incident solar radiation over the last 10 years are the very 

notable effects beginning in 1982 from the eruption of EI 

Chichon. Two active cavity radiometers were characterized for 

U.S. representation in the world standard group maintained by 

WMO. An objective method of calculating errors to Umkehr 

ozone profiles due to stratospheric aerosol interference was 

developed and applied to a selected set of global Umkehr data. 

Results from the analysis, which are in agreement with 

theoretical model output from Lawrence Livermore Laboratory, 

show average ozone depletion at 35 km altitude for the period 

1979-1986 of about 8%. 

The Carbon Cycle Group continued regular aunospheric 

sampling of CO2 and CH4 at the observatories and another 22 

cooperative sites with in situ analyzers and flask samples. 

Concentrations in 1987 increased compared with 1986, by about 

1.7 ppm and 12 ppb for CO2 and CH4, respectively. Continuous 

measurements of CH4 at BRW during springtime showed it to 

be correlated with CO2 and aerosol black carbon, suggesting a 

conunon source or source region for all three species. Installation of an in situ CH4 analyzer at MLO yielded intriguing 

results, showing rather large variability corresponding to time 

periods of 12-14 days. 

The Monitoring Trace Gases Group continued Dobson total 

ozone measurements at 16 sites and international Dobson 

calibration work. Assessment of the calibration history of the 

World Primary Standard Dobson instrument showed very rugh 

stability since 1976, having calibration uncenainly of only ± 

0.5%. Reassessment of the complete Dobson record from MLO 

showed increasing total ozone from 1964 to 1974 at about 

0.37% per year, and decreasing amounts since then at about the 

same rate. Ozonesonde and total ozone measurements from 

SPO throughout the year gave clear definition of the Antarctic 

ozone hole; record low total ozone amounts were measured 

during September-November. The Group also continued regular 

balloon ozonesonde profiles at BRW, MLO, SMO, and Boulder; 

Umkehr ozone profiles at six locations; surface ozone at the 

observatories; and in situ stratospheric water vapor profiles at 

Boulder. 

The Acquisition and Data Management Group continued 

regular meteorological measurements at the observatories. 

Annual surface wind rose patterns were similar to long-term 

climatologies, but the mature stage of the 1987 ENSO event 

evidently did cause some anomalous weatller patterns and 

extreme events at the observatories. Numerous isobaric and 

isentropic air mass trajectories were calculated for NOAA and 

affiliate researchers. A special trajectory project supported the 

SPO aerosol study whereby measured aerosol variability was 

clearly linked to changes in air mass transport over Antarctica. 

The Air Quali[)! Group continued participation in the 

National Acid Precipitation Assessment Program and several 

other field programs making use of their NOAA King Air 

icsearch aircraft, which they have extensively modified and 

modernized for meteorological and chemical airborne research. 

High1ights included new characterization of H20 2 concentrations by long latitudinal sampling profiles and measurements of 

DMS over the Gulf of Mexico and southern United States that 

suggested DMS is the principal source of S02 in the marine 

atmosphere. 

The Nitrous Oxide and Halocarbons Group continued flask 

sampling of CFC·ll, CFC-12, and N20, and improvement of 

performance of newly installed automated gas chromatographs 

for in situ sampling of halocarbons and N20 at the observatories. The ratc of increase of CFC-Il and CFC-12 

continued at about 4% per year. The Group undertook a major 

expeditionary effort through participation in SAGA IT, a joint 

US-USSR sea cruise over the western Pacific and Indian 
2 

Oceans. More lhan 1000 measurements were made of a variety 

of trace gases in the air and surface water, yielding a highquality data set that is giving new infonnation on the spatial 

distribution and air-sea exchange of these species. 

Within the Director's Office, NAPAP research included 

development of a model 10 estimate the flux of dust to the 

aunospherc, primarily via wind erosion. for use in an inventory 

of alkaline elements in acid/base balance studies of precipitation. Areas of maximum dust production in the United States 

include the region from western Texas to western Nebraska, the 

valley of the Red River of lhe North, and northern Montana. 

Analyses of AGASP measurements led to numerous publications. A follow-on study incorporating BRW surface ozone and 

solar radiation data indicated that bromine plays an important 

role in Arctic ozone photochemistry and the very low ozone 

measured there during March-May. Many scientists used the 

observatories for cooperative research; several of their projects 

are swnmarized. 
3 

2. Observatory RepOIts 

2.1. MAUNA LOA 

2.1.1. F AClLrms 

The 1987 observational year was especially notable for 

several important upgrades of observatory instrumentation. In 

April an automated Carle GC was installed to provide ambient 

air samples each 24 minutes for CH4• CO, and CO2, A second 

complex automated halocarbon GC system was installed in June 

for 3-hourly concentration measurements of the halocarbons 

CFC·ll. CFC·12. CCl,. and CH,CC1,. as well as [or N,O. TI,e 

Carle GC system replaced an earlier GC that provided only CO2 

and CH4 concentration measurements. The halocarbon-NzO 

system supplements the ongoing weekly flask sampling 

program, which has provided data since 1977. 

The MLO CO2 sampling program was upgraded in August 

when a Siemens Ultramat-3 replaced the URAS-2 instrument 

system. The Siemens system is also a nondispersivc infrared 

system, but with improved design and electronic systems it 

provides a much improvcd CO2 concentration record. Thc 

URAS-2 had been in essenti ally continuous operation at MLO 

since the spring of 1974. 

In September an electronic engineer joined the MLO staff. 

He is responsible for ozonesonde operations and for the 

calibration and maintenance of the MLO Dobson spectrophotometer and the Dasibi surface ozone system; he also has 

observing and engineering duties. 

Data tapes from the three main CAMS units arc changed 

once or twice a monlh. Before these tapes arc sent to GMCC 

Boulder, copies are made and kept at MLO. The copies are used 

to prepare monthly plots of hourly provisional CAMS data. 

These provisional data plots provide a "quick look" review of 

the month 's data from which the general trends of the observations can be ascertained and periods warranting special review 

can be identified. The plots of provisional data arc included in 

the MLO monthly activity reports, but they arc not for general 

publication. 

Lidar operations and ozoncsonde flights were carried out on 

an approximately weekly schedule. Both programs provide 

ground-trulh data for NOAA NESDIS satellite observational 

systcms. The lidar data showed that stratospheric aerosol 

concentrations gradually decreased during lhe year and that 

there were no identifiable new volcanic episodes. 

1n late April lhe Soviet oceanographic research ship 

Akademik Korolev callcd at Hilo to load a contingent of 

American aunospheric and oceanographic scientists for a joint 

U.S.-U.S.S.R. scientific study. The U.S. scientific party 

included GMCC and other NOAA scientists as well as a number 

of univcrsity researchers. After about a 3-mo cruise with port 

calls in Wellington, New Zealand. and Singapore, the Korolev 

returned to Hila in late July to disembark the U.S. scientific 

team and their equipment. 

The installation and instrumentation of the 40-m tower at 

tv1 LO has resulted in considerable reconfiguration of the air 

sampl ing intake lines to variolls monitoring instruments. Table 

2.1 shows the number. location. and composition of the inlet 

lines for the GMCC and SIO monitoring instruments. For most 

instruments sampling from the 40-m tower, inlet lines of 

Dekoron 3!8-in-OD tubing have replaced lhe aluminum tubing 

previously used. The MLO air intake stack has becn described 

by Komhyr (1983). 

2. 1.2. PROGRAMS 

The principal programs conducted at MLO duri ng 1987 are 

listed in Table 2.2. The programs that are carried out at MLO 

for non-Gl\1CC scientists are listed under CoolXrati ve 

Programs. Brief comments on some of the individual GMCC 

programs follow. 

TAB LE 2.1. MLO Air Sampling Intake Lines, Locations and 

Composition (as of early 1988) 

No. 

I 

2 

I 

2t 

3; 

4 

5 

lIeight Localion 

GMCC Siemens CO2 Analyur 

40m(126fl) Esidcoftower 

24 m (80 fl) NE comer of tower 

SIO Appied Physics CO2 Analyzer 

24 m (80 fI) 

6m(20fl) 

15 m (50rl) 

40m(126f1) 

24 m (80 fI) 

i\E comcr of lowcr 

300 m W of building 

150 m SE of building 

E side of lower 

NE comcr of tower 

Composilion 

Dekoron" 

Dckoron" 

Dckoran" 

Dckoron" 

Dckoron" 

Dekoron" 

Aluminum 

Carle CII4-CO-C02 Gas Chromalograph 

1. 2 40 m ( 126 ft) NE comcr of tower Dekoron" 

lIalocarbon-NzO Gas Chromalograph 

12.2 m (40 ft) GMCC mai n building 

stain less-steel stack 

Oasibi OJ Analyzer 

12.2 m (40 ft) GMCC mai n building 

stainless-steel stack 

G.£. CNC 

12.2 m (40 fl) GMCC main bu ilding 

aluminum stack 

Four-Wavelenglh Nepheiomeler 

12.2 m (40 rt) GMCC main building 

aluminum stack 

Stainlcss stcel 

Teflon tube 

Teflon tube 

1 Sin·DD plastic 

inlct 

"Dekoron refe rs to Eaton Dekoron Typ: 1300, 3/8-in-OD lubing. 'rne 

outer su rface is a rugged plaslic; insidc is a light aluminum tube lined 

with a thin plastic materia1. The Dckoron lines appear to be nonreactive for thc gaseous constitucnts samplcd at MLO. 

t Daytimc intake. 

;Nighttime intake. 
4 

Gases 

CO, 

Program 

CH •. CO. CO, 

Surface 0) 

Total 0) 

0] profile 

crc·l l. CrC·12. N,o. 

crc·ll. CFC·12, N,O 

C04• CH3CC13 

N10 

S0, 

Aerosols 

Condensation nuclei 

Optical properties 

Stratospheric aerosols 

Solar Radiation 

Global irradiance 

Direct irradiance 

Diffuse irradiance 

Turbidity 

Meteorology 

Air temperature 

Temperature gradient 

Dewpoinllcmpcrature 

Relative humidity 

Pressure 

Wind (speed and direction) 

Precipitation 

Total precipitable water 

TABLE 2.2. Summary of Sampling Programs at MLO in 1987 

Instrument 

URAS·2 IR analyzer' 

Siemens Ultramat-3 IR analyzer* 

3-t glass flasks 

O.S-L glass flasks, through analyzer 

O.S-L glass flasks, pl 

GC 

Carle automated GC 

Dasibi ozone meter* 

Dobson spectrophotometer no. 76 

Dobson spectrophotometer no. 76 

Ballooobome ECC sonde 

3()(}.mL stainless steel flasks 

HP5890 automated GC 

Shimadzu automated GC 

Flame photometric analyzer 

Pollak CNC 

G.E. CNC· 

Four-wavelength nephclometer* 

Lidar 

Eppley pynnometers (3) with Q. 

OG I, and RG8 filters· 

Eppley pyrheliomcters (2) with Q 

mter' 

Eppley pyrheliometer with Q. OG I, 

RG2, and RG8 filters 

Eppley !Kendall active cavity 

radiometer 

Eppley pyranometer with shading disk 

and Q mter' 

J·series sunphotometcrs. J-202 

and )·314 

Sampling Frequency 

Continuous 

Continuous 

1 pair wk-I 

1 pair wk'! 

1 pair wk'! 

Continuous 

1 sample (24 min)·l 

Continuous 

3 day·1 

2 day" 

1 wk-! 

1 pair wk-I 

1 sample (3 hr)'! 

1 sample (3 hr)-l 

Continuous 

I day" 

Continuous 

Continuous 

Discrete 

Continuou s 

Continuous 

Continuous 

3 day" 

Maim. n sunphotometer, Ml19 and Ml20 3 day' I 

PMOD three-wavelength sunphotometer* Continuous 

Aspirated thennistor* Continuous 

Max.-min. thermometers 1 day·l 

Hygrothermograph Continuous 

Aspirated thermistors· Continuous 

Depolo! hygrometc'" Continuous 

HygrOlhcnnograph Continuous 

Capacitance tran sducer* Continuous 

Microbarograph Continuous 

Mccurial barometer I day" 

Bendix Acrovane· Continuous 

Rain gauge, 8-in I day" 

Rain gauge, 8-in 1 wk 1 

Rain gauge, weighing bucket Continuous 

Rain gauge, tipping bucket· Continuous 

Foskett IR hygromete'" Continuous 

HAO IR hygromete'" Continuous 

Remarks 

MLO; discontinued Aug. 5 

MLO; installed Aug. 5 

MLO and Kwnukahi 

MW 

MLO and Kwnukahi 

MLO; discootinued April 

MLO; installed April 

MLO 

Weekdays 

Umkehr method 

From Hilo Airport 

MW 

MLO; installed June 

MLO; installed June 

MLO; Installed Aug. 

Weekdays 

450,550,700,850 run 

694.3 nm; average I profile 

wk-i 

380, 500, 778, 862 nm; 

narrowband; discontinued 

July 

380,412,500,675, 862 nm; 

Ml19 operational July-Oct.; 

MI20 installed OCI. 

380,500,778 run; 

narrowband 

2- and 40-m heights 

Standard sheller 

MLO and Kulani Mauka 

2- and 40-m heights 

2-m height 

MLO and Kulani Mauka 

8.5- and 40-m heights 

Kulani Mauka 

Weekly chart record 

Discontinued July 
5 

TABLE 2.2. (continued) 

Program InslrUment 

Precipilation Chemistry 

pH pH meter, Hila lab. 

Conductivity Conductivity bridge, Hila lab. 

Chemical components Ion chromatograph, Hila lab. 

Cooperative Programs 

CO, (SID) IR analyzer (Applied Physics) 

CO" '3(;, N,O (SID) S-L evacuated glass flasks 

Surface SO, (EPA) Chemical bubbler system 

CO" CO, CH" '3(;1'3(; Pressurized glass flask sample 

(CSIRO) 

CO2, CH4• and other lr1.ce Evacuated stainless steel flasks 

gases (NCAR) 

Total suspended particles High-volume sampler 

(ODE) 

Total 03' SOl Brewer spectrophotometer, MK-I 

(AES Canada) 

Brewer spectrophOlometer, MK-II; 

Umkehr-automated 

Turbidity Sonotek sunphOlometer no. 5698 

(AES Canada) 

CII, ('3(;/'3(;) 35-L evacuated flask 

(Univ. of Washington) 

Total suspended particles High-volume sampler 

(EPA) 

Ultraviolct radiation UV radiometer (erythema) 

(Temple Univ.) 

Ultraviolet radiation 8-wavclength UV radiometer 

(Smithsonian) 

Solar variability Solar spectroradiometer 

(Univ. of Arizona) 

Solar aureole intensity Multi-aperture tracking photometer 

(CSU) 

Precipitation ooUcction Exposed collection pails 

(ODE) 

Precipitation ooUcction Aerochemctric automatic collector 

OSWS) 

Precipitation oollcction Aerochemetric automatic collector 

(Univ. of Virginia) 

Wet-dry deposition Aerochemetric automatic collector 

OSWS) 

Aerosol chemistry Nuc1epore filters 

(Univ. of Washington) 

13C (USGS, Denver) ID·L stainless steel flasks 

Various trace gases Stainless steel flasks 

(OGC) 

HN03, HO vapor, Filter system 

and aerosols (URI) 

IR. solar spectra Interferometer 

(Univ. of Denver) 

Su nphotometery SunphOlometer calibrations 

(NASA Goddard) 

*Data from this instrument recorded and processed by CAMS. 

Carbon Dioxide 

The GMCC and the SIO Applied Physics NDIR analyzers 

were operated in paraUel without major problems during the 

year. The average CO2 concentration for the year was about 

348.6 ppm, and the rale of CO2 increase was approximately 1.9 

ppm yrl. This provisional value is noticeably larger than the 

Sampling Frequency Remarks 

Weekly Rainwater coUections, 

3 sites 

Weekly Rainwater coUcctions, 

3 sites 

Weekly Rainwater coUcclions, 

3 sites 

Continuous 

1 pair wk-l MLO and Kwnukahi 

Every 12 days 24·h (0000·2400) .ample 

1 mo·l MLO 

1 pair wk-I MLO and Kumukahi 

Continuous 1 ftlltT wk-I 

1-3 day·l MLO, discontinued March 

Continuous MLO, installed March 

1-3 day'! MLO 

1 mo'! MLO 

Every 12 days 24·h (0000·2400) .. mplc 

Continuous Radiation responsible for 

sunburnin g of sk in 

Continuous 290-325 lUll, lIarruwbamJ 

Discrete Program began Sept. 1985 

Continuous 2,5,10,20,30' fields 

of view 

Continuous MLO 

Continuous Analysis for 7Be and lOBe 

Continuous Organic acid analysis 

Continuous NADP 

Continuous Upslope-downslope 

discrimination 

Biweekly MLO 

1 set wk'! MLO and Kumukahi 

(3 flasks) 

Four 2·wk periods yr-l MLO 

Feb. and July 1987 MLO 

1 wk each 

Oct. 1987, I wk MLO 

long-tenn MLO CO2 rate of increase of 1.42 ppm yrl [Schnell 

and Rosson, 1987). 

A Siemens Ultramat-3 IR analyzer replaced the URAS·2 IR 

analyzer on August 5, 1988. The URAS·2 analyzer had been in 

use at MLO since May 1974. A series of comparisons between 

the two analyzers was performed before the removal of the 
6 

URAS-2 analyzer. The analyzers were fITSt operated 

independently but using the same synthetic air as reference 

gases, sharing the same 25-m (80-f1) air intake, and using the 

same freeze trap at -60' to -70·C. After this side-by-side 

operation indicated a possible accuracy problem, a second test 

was run using a double freeze trap connected in series. In these 

tests URAS-2 values were 0,3 ppm higher than the Siemens 

values. When the analyzers were interchanged with all the 

plumbing configuration remaining untouched, the URAS-2 

values were still consistently 0.3 ppm higher than the Siemens'. 

However, when a set of natural air standards was used to replace 

the usual operational synthetic air as the reference gases, the 

Siemens and URAS-2 values showed no consistent 

concentration difference, Experiments are being undertaken in 

Boulder GMCC laboratories to explain the differences in 

ambient air response observed for the two insLrUments. 

The weekly CO, nask samplings al MLO and Cape 

Kumukahi were continued without problems and with no 

changes in protocol. 

As in previous years, outgassing from several volcanic vents 

ncar the summit and along the northeast rift of Mauna Loa 

caused observable disturbances in some of the COl records. 

These occur during the nocturnal downslope wind regime. most 

frequently belween 0000 and 0800 LST. Visual scanning of the 

recorder chart records showed the frequency of disturbed 

periods; these have been accumulated into monthly totals (fable 

2.3). Note that these frequencies indicate only the number of 

days of occurrence and not the number or percentage of hours of 

data that are affected. Periods when the MLO COl record is 

affected in this manner by volcanic events are not included in 

the determination of background Cal concentrations. 

The 1987 average frequency of outgassing episodes was 

38%, which continues me downward trend of venting influences 

seen in prior years (e.g., 1984,61%; 1985,48%; 1986,44%). 

The 5-yr average prior to the March 25. 1984, Mauna Loa 

eruption was 27%. The lower frequencies observed in February 

and March are probably due to lower frequencies of 

southeasterly winds during those 2 months. 

Surface Ozone 

The Dasibi ozone monitor samples directly from the air 

inlake slack and is recorded by the CAMS. In 1987 the 

instrument was oul of service from April 10 to July 25 because 

of the nonavailability of replacement electronic components. 

Otherwise continuous ambient data were obtained. 

TOla/ Ozone 

The regular program of Dobson measurements and Umkehr 

profiles using Dobson spectrophotometer no. 76 was augmented 

in May, June, and July by a program of Langley plot calibrations of the WMO world standard Dobson instrument, no. 83. 

During this calibration program, intercomparison calibrations 

with no. 83 were also carried out on the MLO Dobson no. 76 

and the SMa Dobson no. 42. 

Ozone Profiles 

In the MLO ozoncsonde program there were 53 launches, 

approximately weekly, from the NWS Hilo airport stalion. Of 

Lhcse. 48 produced satisfactory profile data. Of the five Lhat 

were unsuccessful, four were due to instrument failure after 

launch and one was due to the weather. The average flight 

allilude for the 48 successful nights was 41.4 km (2.5 mb) and 

ranged belween 39.6 km (3.3 mb) and 44.9 km (1.6 mb). All 

but three of the 48 profiles exceeded the target altitude of 40 km 

(3.0 mb). 

Aerosols 

As in prior years, the MLO aerosol program consisted of 

both surface and stratospheric aerosol measurements. 

Continuous measurements of CN concentration and aerosol 

scattering extinction were made by Lhe O.E. CNC and the 

four-wavelength nephelometer, respectively. Both systems were 

recorded by Lhe CAMS. Operation of both instruments was 

essentially continuous through the year, having only minor 

periods of downtime. The Pollak CNC was opera led daily 10 

provide a calibration check for the a.E. eNe. 

Lidar data were obtained on 45 nights during the year. 

Wealher permitting, observations were coordinated with 

overpasses of the SAGE II satellite. Stratospheric aerosol 

concentrations continued to decay toward backgroWld, as shown 

by the decrease in average non-Rayleigh backscatter (NRBS) 

from an average of 1.4 x 10'" Sr"I in January 1987 to an average 

value of 1.0 x IO'4 sri in December. Prior to the eruption of the 

Columbian volcano Ruiz in November 1985, the NRBS was 

averaging 1.1 x 104 sri. No new volcanic stratospheric aerosol 

clouds were observed by the MLO lidar in 1987. 

Solar Radialion 

In July Lhe older J-series sunphotometers were replaced with 

a single Mainz II (Ml19) five-channel sunphotometer. The new 

instrument is easier to use and has more accurate aiming optics 

than the J-series units. The five filters in the Mainz II units are 

narrowband fillers al approximalely 380, 412, 500, 675, and 862 

run. In October, a Mainz II M 120 replaced the M 119 when the 

filter rOlation mechanism malfunctioned. 

The other components of the MLO solar radiation program 

were continued with little change from the previous year. 

These, as shown in Table 2.2, include normal incidence 

pyrhcliometers and global pyranometers for total and diffuse 

radiation measurements. In the solar dome a variety of solar 

TABLE 2.3. Monthly Occurrences of Outgassing from Volcanic Vents on Mauna Loa 

Number of days 

Percent of days 

Jan. Feb. 

10 

32 

2 

7 

March April May June 

5 

16 

9 

30 

8 

26 

12 

40 

July 

18 

58 

Aug. Sept. Oct. Nov. 

19 

61 

10 

33 

16 

52 

11 

37 

Dec. 

18 

30 

Year 

138 

38 
measurement instruments were mounted on the active solartracking spar. The dome and shutter controllers malfunctioned 

occasionally, but repairs could generally be made readily and 

downtime was kept to a minimum. 

The MLO solar radiation program was used frequently by 

non-OMCC groups for assistance in instrument calibrations and 

as a source for information to assist in data interpretation. 

Specialized long-term cooperative programs, especially in the 

shorter wavelength bands, augmented the MLO radiation 

program. 

Meteorology 

The MLO program of meteorological measurements was 

continued without major problems other than a I-mo period of 

downtime for the dewpoint hygrometer. The CAMS record of 

weather factors was expanded with the addition of the 

temperature gradient between 2 m and the top of the 40-m tower 

and of the wind gradients between 8.5 m and 40 m; thus a 

continuous measure of boundary layer stability is now available 

for use in data interpretation. 

Precipitatjon Chemjstry 

The 1987 precipitation chemistry program consisted of 

collections from three local sites: Hilo, 22-mile on the Saddle 

Road, and MLO. Collections and collector equipment changes 

were made at each of these sites each weekday to provide an 

approximation of precipitation event sampling. These samples 

plw rain and snow samples from the other three OMCC 

observatories were analyzed in the MLO Hilo laboratory. As 

shown in Table 2.2, the precipitation analysis protocol includes 

pH, conductivity, and a variety of anions and cations. Ion 

chromatography is used for the latter analysis. Several 

cooperative programs in precipitation chemistry are also carried 

out at MLO and serve to augment the GMCC program. 

Cooperative Programs 

Table 2.2 lists 24 cooperative projects supported by the 

GMeC MLO program. Most of these programs are long-tenn 

monitoring and sampling studies in which MLO staff assume 

the rudimentary housekeeping chores to maintain the operations, 

and the P.I. does the sample and data analysis. Classic in this 

cooperation between P.1. and MLO staff is the S10 CO2 

program involving both flask samples and the operation of a 

CO2 analyzer. This program completes 30 years of operation at 

MLO in 1988, and thus this program predates the establishment 

of the GMCC program in 1972. The other type of cooperative 

program is one in which the P.1. and colleagues use MLO 

facilities to carry out specific short-tenn studies without any 

significant involvement of MLO staff members. The 1987 URr 

studies of HN03 and HCl, and the University of Denver IR solar 

spectra research are examples of this laner type of program. 

All of the MLO cooperative programs listed in the 1986 

Summary Report [Schnell aruJ Rosson, 1987] were active in 

1987. The SID CO2 analyzer was upgraded with the addition of 

a new data acquisition system and new sample lines. The inlct 

line that had been on the old high (25-m) tower was moved to a 

similar height on lhe new 40-m tower (see Table 2.1). The 

Canadian Atmospheric Environment Service program of total 

7 

ozone and 502 measurements using the Brewer 

spectrophotometer was upgraded in March with the installation 

of a fully automated Brewer MK-II in place of the older, 

manually oriented and initiated Brewer MK-I instrument. The 

MK-I had been in operation at MLO since April 1982. 

The program of infrared solar absorption spectra 

measurements made by the University of Denver in February 

and July showed that MLO is a favorable site for this type of 

measurement {Rinsland et al., 1988]. The results of this 

program provided total vertical column amounts of 13 

aunospheric gases and average tropospheric concentrations of 

CO,. N,o. CH,. and CHCIF, (CFC-22). The diurnal variations 

of the total column amounts of NO and NOz were also obtained. 

Spectral measurements of this type provide a permanent record 

of the observed atmospheric solar spectra and can be compared 

with spectra taken at other times and in other locations. Such 

comparisons can provide geographic distributions and temporal 

trends of a wide variety of minor and trace aunospheric 

constituents. As more basic information becomes available on 

the IR spectra of other trace constituents such as the CFCs these 

spectra can be reanalyzed to provide additional information. 

The sampler used by URI for aerosol particle studies was 

moved from a surface location to the 23-m level on the new 

tower. Boundary layer profiles and possible surface deposition 

effects will be examined in this continuing program. 

2.2. BARROW 

2.2. 1. FACILITIES 

Another year of data was successfully col1ected at BRW in 

1987. Scientific interest in BRW and the Arctic increased in 

1987. This was manifested by visits to B R W by the NOAA 

Administrator in February, the NSF Polar Research Board in 

April and September, the Director of the Geophysical Institute 

of the University of Alaska in February, and others throughout 

the year who looked into ways to increase U.S. involvement in 

Arctic science. The visits focused on reviewing present Arctic 

research and in determining what more is needed and could be 

done in the Arctic in the future. 

Station personnel were called on several times by the North 

Slope Borough/Wildlife Management for technical expertise. 

On several occasions GMCC personnel were also used by NWS 

to repair equipment. There was a change in the GMCC slafr in 

December when one staff member was temporarily assigned to 

Boulder; a new electronics technician was recruited and was 

assigned to BRW in his place. BRW's administrative support 

was transferred from W ASC in Seattle to MASC in Boulder at 

the beginning of 1987. This included hooking BRW up to the 

FlOO communication network in ERL, Boulder. 

The BRW vehicles underwent major changes in 1987. The 

GSA Dodge truck was relegated to standby status early in the 

year after numerous problems made it too umeliable. In the 

summer it was replaced by a new 1985 Chevrolet Suburban 

provided by GSA. At year's end the new Suburban was still 

working well. A new Skandic 503 snowmobile was purchased 

in February. By the end of the year, all the old snowmobiles 
8 

and the historic Bombi were excessed and removed from the 

station inventory. The 1979 GMC truck, which has served as 

the most durable observatory lransp:>rtation vehicle, received a 

new engine in February but needed further repairs. By the end 

of the year, thanks to a lhird-party support agreement wilh the 

Dew Line Station for vehicle maintenance on a noninterference 

basis, it was running bener. 

The Dew Line Station supply of electrical power to BRW 

observatory was cut off in April 1987 when a ftre at the Dew 

Line Station destroyed more than one-wrd of its electrical 

power plant. Emergency action was required to locate and hook 

up an alternate power supply to the GMCC observatory. In a 

matter of days JXlwer was obtained to continue the measurements at BRW with minimum instrument downtime, and in a 

matter of months a working agreement was in place to receive 

commercial power from the Eskimo Corporation (VIC), which 

had taken over the day-to-day operation of NARL. By the end 

of the year, good and reliable power was still being supplied to 

BRW by VIC through NARL using the Barrow Borough Power 

Plant. 

The phone lines 10 the observatory continue to work 

marginally. Every spring. during breakup, water can infillrate 

into the lines feeding to the observatory and cause noisy 

conditions. GTE has worked on the lines several times during 

the year to bring temporary relief, but the problem remains. The 

observatory computer continues to be used as an alternate 

communication link with Boulder. Computer data transfer 

between BRW and Boulder is being planned. 

The clean room at the observatory had acoustic foam 

installed on the remaining walls this year, helping with the noise 

problem at the station. The clean room was also rearranged to 

make bener use of the small amount of room left for expansion. 

An air conditioning unit arrived to help with the cooling! 

humidity problems at the station. 

The arrangement between NWS and GMCC for shared 

housing in BRW continued throughout 1987. Several upgrades 

and repairs were done in the units occupied by GMCC staff. A 

water heater was installed, along with a new front door, in the 

double~wide housing unit. Corroded fixtures were replaced in 

both houses. The heater system in the double~wide unit is 

marginal and is scheduled for replacement. 

2.2.2. PROGRAMS 

Table 2.4 summarizes the programs at BRW. Further 

discussion of some of the programs follows. 

Carbon Dioxide 

Several problems this year were power related and solved 

with simple restarts. Tanks of compressed gas were sent to 

BRW on the cool barge; this continues to be a good system for 

shipping large amounts of heavy goods to the station. 

Melhane 

The methanizer was reconditioned early in the year and 

replaced in May. The HP integrator locked up twice and had to 

be replaced. The pure air generator also died and was replaced 

with canned air sent from Boulder. The results seem to be betler 

using the canned air, so we may continue using it. The stream 

selection valve had to be replaced when it stopped flow on 

channel 3. 

Sur/ace Ozone 

A new lamp was installed in the Dasibi ozone meter along 

with a different LED display. The old display had several 

burned out segments, making it hard to read. The only other 

occurrence of note was replacement of the pump. 

TOlalOzone 

Observations continued without any major problems this 

year. 

Ozone Profiles 

The ozonesonde program in BRW was enhanced this spring 

to look for stratospheric depletion of ozone in the Arctic. A 

total of 54 balloons were launched this year. A member of the 

MTG Group was here from Boulder during the spring to launch 

ozonesondes during the spring Arctic haze episode. 

Halocarbons and Nitrous Oxide 

A new Epson printer was installed to replace the troublesome 

HP Think-jet printer. Bad power led to several problems this 

year. Several times outages were long enough that the UPS 

could not keep things running. The problems were solved by 

use of the town power. A new disk drive was installed because 

the old one tried to write continually to the disk even though 

there was nothing to write. A member of the NOAH group 

came from Boulder to upgrade the RITS GC and make some 

programming changes. He installed a Shimadzu GC, the 

plwnbing to run it, and two tanks of calibration gas. Earlier in 

the year a new compressor was installed to take the place of the 

tanks of compressed air that tum the pneumatic valves in the 

GC. 

Aerosols 

The vacuum pump for the GE CNC was rebuilt this year. A 

cracked O-ring was found in the GE CNC causing erroneous 

readings. This was repaired and the unit ran properly the rest of 

the year. The Pollak CNC operated nonnally all year. The print 

head in the Leeds and Northrup recorder started sticking and 

causing poor-quality chart records. The trouble was traced to a 

worn bearing in the print head carriage; a new one was ordered 

and sent from Boulder. 

Solar and T erestrial Radiation 

The sun rose on January 24 and set on November 18, both as 

expected. A Teflon cable was installed on the Li-Cor tracker 

because the old plastic one had cracked. The HP data acquisition system was moved to a rack this year to make more space 

in the clean room. 

Meteorology 

This year's weather at BRW was characterized by extremes. 

Blizzards and blowing snow closed the observatory road for 

portions of January, February, March, and April. A new 24~h 

rainfall record was set in July: 1.48 in. The old record was 1 in 

set in October 1926. A new 24-h snowfall record was also set 
Table 2.4. Summary of Sampling Programs at BRW in 1987 

Gases 

CO, 

Progrun 

CO"Cll, 

CH" CO, CO, 

Surface 0) 

Total 0, 

0) proftle 

CrC·II, CrC·12, N,o 

CrC·II, CFC·12, N,o, 

C04• CHJCCl] 

NaO 

Aerosols 

Condensation nuclei 

Optical properties 

Solar and Terrreslriai Radiation 

Albedo 

Global irradiancc 

Direct irradiance 

Terrestrial (IR) mdiation 

Turbidity 

Meteorology 

A ir temperature 

Dewpoint temperature 

Pressure 

Wind (speed and direction) 

Precipitation 

Precipitation Chemistry 

pH 

Conductivity 

Cooperative Programs 

Total surface particulates (DOE) 

Aerosol chemistry (URI) 

Aerosol chemistry (Univ. of Alaska) 

Ultraviolet radiation ([emplc Univ.) 

Precipitation gauge (ASCS) 

Magnetic fields (USGS) 

t'C (USGS) 

Various trace gases (OGC) 

COl' CH4 and Olher trace gases (NCAR) 

''C, ''0, CO, (CS[RO) 

CO" "c, N,o (SIO) 

Halocarbon monitoring (Univ. of 

Calif., Irvine) 

Earthquake detection 

(Univ. of Alaska) 

13CH4 (l3(:p.C) (Uoiv. of Washington) 

Atmosphcric tracer experiment 

(ARLJIdaho Falls) 

lnsl.rUJt\cnt 

URAS-2T 1R analyzer 

3-L glass flasks 

O.S-L glass flasks, through analyzer 

O.S-L glass flasks, pJ 

Carle automated GC 

Dasibi ozone metcr 

Dobson spectrophotometer no. 91 

Balloonbome ECC sonde 

300-mL stainless steel flasks 

HP5890 automated GC 

Shirnadzu automated GC 

Pollak CNC 

G.E. CNC 

Four-wavelength nephelometer 

Eppley pyranomter 

Eppley pyranometers with Q and RG8 ruters 

Tracking NIP 

Eppley pymeliomeler with Q, 001, 

RG2, and RG8 filters 

Eppley pyrgeomeler 

SunphOlometers with 380-, 500-, 778-, 

and 862'nm narrowband ruters 

Thermistor, 2 levels 

Max.-min. thermometers 

Dewpoint hygrometer 

Capacitance transducer 

Mercurial barometer 

Bendix Aerovane 

Rain gauge, tipping bucket 

pH meter (samples analy:z.ed at MLO) 

Conductivity bridge (samples analyzed at MLO) 

High-volume sampler (1 filter wk'\) 

High-volume sampler (2 filters wk'!) 

Hi-volume filters Ctlters wk'! 

UV radiometer 

Wyoming shielded precipitation gauge 

Magnetometer 

IO-L stainless steel flasks 

Stainless steel flasks 

3-L stainless steel flasks 

5·L glass flasks 

S-L evacuated gJass flasks 

Various stainless steel flasks 

Seismograph 

3S-L stainless steel flasks 

Air sample 

Sampling Frequency 

Continuous 

1 pair wk· t 

I pair wk'! 

1 pair wk-i 

1 samplc (24 min)-l 

Continuous 

3 day·' 

I wk'\ 

I pair wk-i 

I sample (3 hr)·l 

I sample (3 hr)-l 

I day-! 

Continuous 

Continuous 

Continuous 

Continuous 

Continuous 

Discrete 

Continuous 

Discrete 

Continuous 

1 day·1 

Continuous 

Continuous 

Discrete 

Continuous 

Discrete 

2mo'\ 

Continuous 

Continuous 

Continuous 

Continuous 

2mo-\ 

1 station check wk·l ) 

I pair mo· t 

I set wk· i (3 flasks set· l ) 

1 pair wk·l 

1 pair (2 wk)·1 

1 pair wk-I 

I set (3 mo)·1 

Continuous; 

check site 1 wk·l 

change tape I mo'! 

I (2 wk)"' 

I wk-! 

9 
10 

this year: 5.2 in in September. The old record was 5.0 in. The 

total for September was 16.2 in. beating lhe old September 

record of 12.9 in. Several new low-temperature records were 

also set. Routine calibrations were performed. and all instruments operated normally during the year. 

Precipitation Chemistry 

Precipitation samples were collected this year according to 

instructions from ARL. After collection they were sent to MLO 

for analysis. 

Cooperalive Programs 

Afler running for only 7 months, the pump for the DOE filter 

collector seized a bearing and had to be replaced. 

The ANATEX project was run in cooperation with ARU 

Field Research. 

The USGS equipment was checked on a regular basis. A 

CRT was installed to replace the one that stopped working this 

year. 

The University of California, Irvine continues to send a 

person to BRW four times per year to collect air samples for 

CH4 analysis. 

The Soil Conservation Service rain gauge continues to 

operate, although it needs some repairs. 

A flag was flown for NWS to check the wear resistance. The 

OMCC site was chosen because it is far enough away from town 

to detennine a more accurate wear rate. 

The Temple University UV meter was calibrated this year. 

Some repairs were made in September to the University of 

Alaska filler hut. 

A long-standing problem wilh shipping lhe CSIRO flasks has 

fmally been solved. The flasks will be sent 10 MLO and lhen 

mailed lO BRW. This solves lhe problems with customs in 

Anchorage. 

2.3. SAMOA 

2.3.1. FACll.ITIES 

SMO had a year of fairly trouble-free operation in 1987. and 

several construction and upgrade projects were completed. In 

May, a 24-ft square carport was built in front of lhe observatory 

entrance, providing shelter for lhe government vehicles during 

the day and making freight and mail loading easier during rainy 

periods. The upper sampling tower was primed and painted in 

July. Both of these projects provided jobs for people of nearby 

Tula village. 

The station's main air conditioner was replaced in April, and 

a second small air conditioner was installed in lhe OMCC room 

of the EKTO building in May. With the recent addition of a gas 

chromatograph. the single EKTO air conditioner was unable to 

maintain room temperature on the hottest days; with the two 

units working together the room temperature can be kept stable 

10 wilhin 2'F. 

As the solar pholOvoltaic system entered its fourth year of 

operation, a few of the 60 battery cells began to fail, and two 

six-cell replacement batteries were ordered to replace them. 

Apart from this, the system continued to perfonn well throughout the year. 

Other projccts included the paneling of the Dobson dome in 

August, application of wood preservative lO the shingles of 

housing unit T-7, and installation of a plastic bed liner in the 

Toyota pickup. Concrete landings were poured in front of both 

EKTO building doors in November. In December, a sump 

pump was installed in series with the observatory pressure pump 

to eliminate the occasional priming problems with that pump. 

Both the Ford van and the Toyota gave a year of trouble-free 

service. 

On January 17, a hundred-year hurricane devastated the 

Manua Islands 70 mi to the east, leaving over 90% of the 

residents homeless, and stripping all of the vegetation down to 

ground level. Luckily, Tutuila Island was spared, and the 

observalOry escaped damage. 

2.3.2. PROGRAMS 

Table 2.5 summarizes the programs for 1987. New programs 

this year include the addition of a Shimadzu automated OC by 

GMCC to improve N20 measurements, and the initiation of 

flask sampling for the U.S. Bureau of Mines to measure 

aunospheric helium. 

Carbon Dioxide 

The URAS-2T analyzer and its system operated without 

problems all year with the exception of the Cryocool freezer. 

The old unit and two spares were used throughout the year, 

maintaining -6WC or cooler temperatures except for a period in 

June and July. when lhe trap warmed 10 -30'C. By early 1988. a 

heavy-duty Cincinnati Sub Zero freezer was delivered; it has 

maintained -80'C temperatures. An experiment was performed 

in May to compare the effect of using a small, low-flow-volume 

glass freezeout trap with that of a larger, high-flow-volume trap. 

In September, a special intercomparison was conducted 

between O.5-L p3 flasks with greased stopcocks and with 

SlOpcocks having a new type of a -ring. 

Surface Ozone 

In January, the Teflon intake line was shortened and wrapped 

with heat tape to eliminate condensation. Dasibi ozone meter 

no. 1326 was replaced by no. 1323 in October, resulting in a 

much improved data set. 

TOlalOzone 

After spending 1 year in Samoa, Dobson instrument no. 65 

was returned to Boulder in July and replaced by no. 42. Dobson 

no. 42 arrived in May, and a side-by-side comparison with no. 

65 was run for 3 weeks. In early July, no. 42 was sent to MLO 

where it was calibrated against the world standard instnunent 

before being returned to service in Samoa on July 29. The 

frequency of daily observations was increased to 4-5 per day in 

1987. 

Ozone Profiles 

Weekly ozonesonde flights from the NWS facili ty in Tafuna 

continued in 1987, resulting in 43 lOtal launches and a 96% 
Program 

Gases 

CO, 

CO2.CH .. 

Surface 0) 

Total OJ 

0 ) profile 

CFC·II. CFC· 12. N,O 

CFC·II. CFC· 12. N,o. CO,. 

CH,CCI, 

N,O 

Aerosols 

Condensation nucl ei 

Optical properties 

Solar Radiation 

Global irradiance 

Direct irradiance 

Turbidity 

Meteorology 

Air temperature 

Pressure 

Wind (speed and direction) 

Precipitation 

Precipitation Chemistry 

pH 

Conductivity 

Cooperati'lle Programs 

CO, . tlC. N,O (510) 

ALE project: ere·tl, CFC- 12, 

N,o. CH,CCI,. CO, (OGC) 

Various trace gases (OGe) 

tlC. "A. CO, (CStRO) 

t'C (USGS) 

Wet-dry deposition (NADP) 

Bulk deposition (EML) 

Hi-vol sampler (EML) 

Hi -vol sampler (SEASPAN Project) 

CO2, CH". lrace gases (NCAR) 

13(:, nCII4 (Argonne Lab.) 

"He (U.S. Bureau of Mines) 

TABLE 2.5. Sununary of Sampling Programs at SMO in 1987 

Instrument 

URAS-2T IR analyzer 

3-L gla ss flasks 

O.5-L glass n asks, through analyzer 

O.S-L glass fl asks, p3 

Dasibi ozone meter 

Dobson spectrophotomcter no. 42 or 65 

Balloon bomc ECC sonde 

300·mL stainless steel flasks 

HP5890 automated GC 

Shimadzu automated GC 

Pollak CNC 

G.E. CNC 

Four-wavelength nephelometer 

Eppley pyranometers with Q and RG8 rulers 

Eppley pyranometers with Q fillers on tilled mounts 

Eppley pyrheliomctcr wit h Q filtc r 

Eppley pyrheliomcler with Q, OG I, 

RG2 , and RG8 filt ers 

SunphOlometers with 380·, 500-,778·, 

and 862-nm narrowband filters 

Thermistors (2) 

Max.-min. thermometers 

Capacitance tran sduccr 

Microbarograph 

Mercurial baromcter 

Bendix Aerovane 

Rain gau ge, weighing bucket 

Rain guage tipping bucket 

Plastic bulk rain guage 

Fisher model 805 mete r 

Beckman model RC-I6C meter 

5-L evacuated glass flasks 

IIP5880 gas chromatograph 

Stainless steel flask s 

5-L glass flasks 

ID-L stainless stccl flasks 

IIASL Chemetrics wCHlry coUcctor 

Plastic bucket 

Hi-volume sampler 

Hi-volume samplc r 

Evacuated stainless stecl flasks 

30-L evacuated steel cylindc rs 

I-L pressurizcd stcel cylinder 

Sampling Frequency 

Continuous 

1 pair wk-i 

I pair wk-I 

1 pair wk-l 

Continuous 

3 day-l 

I wk-I 

I pair wk-! 

1 sample (3 hr)-l 

1 sample (3 hr)·t 

I day-! 

Continuous 

Continuous 

Continuous 

Continuous 

Con tinuous 

Discrcte 

Discrete 

Continuous 

I day-I 

Continuous 

Discrete 

1 wk-I 

Continuous 

Continuous 

Continuous 

I day-I 

I day" (GMCC); 

I wk-! (NADP) 

I day" (GMCC); 

I wk" (NADP) 

3 flasks wk-! 

(3 flasks SCI-I) 

I pair mo- I 

2 pair moo! 

I wk"!, wct; 

discrete, dry 

Continuous (I bucket lOa-I) 

Continuous (1 filtc r wk'!) 

Continuous (1 filter wk-!) 

1 pair wk-I 

1 pair discrete 

2 yr-i 

11 
12 

launch success rate. The program at SMO has been standardized with 2000-g balloons that reach typical heights of 6·8 mb. 

In July, hypsometcr radiosondes began to be used to improve 

pressure determinations at high altitudes. 

Halocarbons and Nitrous Oxide 

The GMCC halocarbon program continued to be upgraded in 

1987. An HP5890 GC operated throughout the year and was 

augmented in June by a Shimadzu GC. At the same time, the 

system was converted from using one calibration gas to using 

two and had a software upgrade installed. 

Flask sampling continued on a weekly basis. Once per 

month, flask pairs were filled through a chemical dryer to test 

the effect of humidity in the exposed flasks. 

Aerosols 

Condensation nuclei were measured continuously except for 

a 6-wk period centered around November when the GE CNC 

was sent to Boulder for repair. The four-wavelength 

nephelometer ran well all year until November, when a board 

replacement and microswilCh contacts on a rotary valve needed 

adjustment. 

Solar and Terrestrial Radiation 

The solar radiation program at SMO continued without any 

changes in 1987. The program consists of a continuous tracking 

pyrheliometer, global pyranometers at two wavelengths, a 

pyrheliometer at four wavelengths for making discrete 

measurements, and sun photometers at four wavelengths. 

Meteorology 

The complement of meteorological measurements continued 

in 1987 with the exception of dewpoint temperature. In April, 

the standard plastic rain gauge at the observatory was relocated 

when it was discovered that droplets could bounce off a nearby 

wall into the gauge, causing an average 14% increase in the 

measured amounts when compared with measurements at an 

unsheltered location. 

Precipitation Chemistry 

Collection of samples, using a plastic funnel and bottle, was 

carried out on a daily basis. After on-site measurement of pH 

and conductivity, selected samples were sent to the MLO Hila 

laboratory for further analyses. 

Cooperative Programs 

Table 2.5 lists 14 cooperative projects supported by the 

GMCC SMO program. The U.S. Bureau of Mines aunospheric 

hcliwn program involved the pressurization of a small steel 

cylinder and was conducted twice in 1987. 

The largest cooperative project at SMO is the ALE project 

run by OGC consisting of an HP5880 gas chromatograph and 

associated equipment. In March. a new UPS was installed for 

the project. along with a compressor pnewnatic air source and a 

new version of software for the IBM PC data acquisition 

system. A second upgrade to the software was installed in 

October. The IBM PC suffered several periods of down time 

during the year due to program and communication problems. 

In May, an SIO scientist visited to discover the cause of 

excessive scatter between the CO2 concentrations measured 

during the three weekly 5-L glass flask exposures. The problem 

was found to be caused by sunlight striking the grease in the 

glass stopcocks, liberating trace amounts of CO2, Canvas 

"boots" sent from La 1011a to cover the stopcocks while the 

flasks are carried from the observatory to the exposure point and 

back corrected the problem. 

2.4. SOUTII POLE 

2.4.1. F ACILITES 

The GMCC SPO program is situated in the NSF's CAF 

(Figure 2.1), After an unsuccessful attempt to raise the CAF 

building during the sununer of 1985-1986, it was raised 3.7 m 

during December 1986. A hydraulic jacking system composed 

of a central pumping station, ten jacks, and associated hosing 

was used. The only major incident that occurred during the 

building raising involved the main CAF power cable, which was 

gouged by a bulldozer. Power to the CAP was not lost. 

however, and the cable was spliced later. A new stairway was 

constructed of timber and alwninum to reach from the CAF 

front porch to the snow surface, and a new iron ladder was 

constructed to reach from the CAP back porch to the snow 

surface. 

Electric power was very reliable this year except for a few 

concentrated, problematical periods. Once again frequency 

fluctuations were virtually nonexistent. 

SPO operations continued to be good this year. Three new 

projects were undertaken: a special aerosol measurement 

program, a Smithsonian-NOAA cooperative project to monitor 

and record UV radiation levels, and a U.S. Department of 

Interior cooperative project to collect a single sample of air for 

eventual 'He content analyses. The most significant operating 

problem encountered during the year was with the halocarbon 

program's GC. Additionally the surface ozone program's 

Dasibi ozone monitor was inoperable at various times. 

The CAMS units worked very well again this year. One 

BRAM loss was due to equipment failure. All other BRAM 

losses were due to maintenance. The ASR automatically 

restarted frequently (and inexplicably) in periods of high winds. 

The M03 did not always resume logging surface ozone data 

after scheduled calibrations. The root of this problem was never 

detennined. On all occasions all three CAMS systems 

automatically restarted following power outages and failures. 

Data transfer by satellite continued this year in much the 

same form as initiated last year. There were some losses of 

message traffic. which hampered some programs. Most of these 

losses were due to an addressing problem, which was subsequently discovered and corrected. At the SPO end of communication, high winds and auroral activity disrupted message 

receipt and transmission capabilities at times. 

2.4.2. PROORAMS 

Table 2.6 lists the sampling programs carried out during 
~---Grid Norlh 

Ladder 

to Snow 

Sudace 

I 

13 

Platform 

GC 

Halocarbon~\ ,LsamPling Slacks Cosmic 

Gas Aerosol Shelves Dust ~ C14 ODE Dobson Parts 

~~-=~ "O? pn \ ~ ~~~.~~~-----P~ 0 0 boo "0 rl ~, 

7p;j'ak L\J 

Nephelometer Sudace High Volume 

. GECNC Ozone & Sampling Pumps 

Table C14 Sphere 

7. St(lIage 

Nitrogen Tanks §2 Smilhsonian I 

CO2 Tanks 12 Shelves/' t::!::J 

NSF Shelves 

""-10 Table-:-

OGC & CSIRO ~~ J.:-

Storage ~O CSIRO ::::~;==!::!:=;;~:;:::!:;r=:!:::=~ 

Cryocoot~ 10 MerC~ia' 

Ta~ CAM;r; NOAA/ GMCC Solar R~ 

C. 

File Desk 

Common 

Storage 

& 

DUlce 

....;---UPS 

batleries . 

'" -. 

u 

r.:::=~:::-:l-;::=:-:-I- DObson Room 

\':=='=='io;;;;;"I,,;S;;;h;;.r, ••• s .. --,,N'!!~!QI!CC .. 0 Nitrogen and 

Repair 

Bench 

Parts Y 

Drawers 

Desk D 

Solar 

Radiation 

Room 

Table 

O. ___ CO, 

0"""1 Siorage 

o Friedman 

o Flask 

o Sto,age 

FW NIP 

= 

Deck L--K'-'-lin-g F~'a~s'k~.,-r~,.~~.,~~~----, 

Clean Air Facility 

South Pole, Antarctica 

1987 

C14 Sphere 

Storage 

SlaifS 10 

Snow Sulface 

Fig. 2.1. Oean Air Facility at SPO, 1987 

1987. Conunents on some of the programs follow. 

Carbon Dioxide 

There were a few problems with this program last year; 

perhaps most significant was the apparent deterioration of the IR 

light source and heaterlblower unit in the analyzer. Both units 

were replaced, and after a period of internal temperature 

stabilization, the analyzer resumed normal operation. 

Surface Ozone 

Problems with this program included logging difficulties in 

the M03 CAMS and the failure of the Dasibi ozone meter on 

August 4. The logging problem seemed to be in the CAMS 

hardware and/or software. The Dasibi logic/display board failed 

and could not be replaced until opening flight. Therefore, no 

surface ozone data were collected from August 4 until after 

station opening. 

Ozone Profiles 

The ozonesonde program continued this year as a major 

element of GMeC. The biggest problem encountered with this 

program was high wind. When winds were in excess of 

approximately 15 knots, it was virtually impossible to launch 

successfully. A sustained period of high winds permitted only 

three successful launches in April 1987; otherwise. there were 

more than 60 successful launches through the year, with a 

concentration in the austral spring. The standard balloon used 

was a 19,OOO-ft3 plastic balloon, but 3OOO-g rubber and 

141,770-ft3 plastic balloons were also used occasionally. 

Halocarboru and Nitrous Oxide 

The most significant operating problem encountered this year 

was with this program. After a period of variable data quality, 

the gas chromatograph failed in February 1987, Despite 

considerable effort made to return the instrument to operation, it 

was still not o~rating when the station opened the following 

November. 

Aerosols 

The Pollak eNe, GE eNe, and nephelomeler performed 

well all year. The GE CNC required the usual maintenance; 

problems with this instrument nonnally occurred very shortly 

after maintenance, having resulted fTOm overgreasmg the valves, 

etc. 

The equipment for the special aerosol project consisted of 

two stepping streakers, a diffusion battery with a TSI eN 

counter, and an aethelometer. The project was designed to 

investigate aerosol chemistry, size, concentration, and scattering 

properties in relation to large-scale meteorology in order to 

understand source regions and transport paths to the South Pole, 
14 

Program 

Gases 

CO, 

CO"CH, 

Surface 0) 

Total 0, 

Ozone prome 

CFC·II, CFC· 12, N,O 

CFC·II, CFC· 12, N,O 

Aerosols 

Condensation nuclei 

Optica1 propenics 

Carbon aerosols 

Aerosol chemistry 

Solar and Terrestrial Radiation 

Global irradiance 

Direct irradiance 

Turbidity 

Albedo 

Terrestrial (JR.) radiation 

Meteorology 

Air temperature 

Snow temperature 

Pressure 

Wind (speed and direction) 

Cooperative Programs 

CO" "C, N,O (SIO) 

TOlal surface particulates 

(DOE) 

Aerosol physical properileS 

(SUNYA) 

Various trace gases (OGC) 

''C/''C, CH, (USGS) 

''C (NOAA/ARL) 

Snow acidity (NOANARL) 

Interhemispheric IlC/l4(: 

(CSmO) 

NO" 0, (NZARP) 

He (Dept of Interior) 

CH" CO" CO (NCAR) 

Ultraviolct radiation 

(Smithsonian-NOAA) 

TABLE 2.6. Summary of Sampling Programs at SPO in 1987 

Insuument 

VRAS-2T IR analyzer 

O.S-L glass fl asks, through analyzer 

O.5-L glass flasks, pl 

Dasibi ozone meter 

Dobson spectrophotometer no. 82 

Balloonbome ECC sonde 

300-mL sta inless steel flasks 

Shimadzu automated GC 

Pollak CNC 

G.E.CNC 

Four-wavelength nephelometer 

Aethalomcter 

Stepping streakers 

Eppley pyranomclers with Q and RGS fLlten 

Eppley pyrheliometer with Q. OG I. RG2, 

and RGS filters 

Sunphotometers with 380-, 500-, TI8-, 

and 862-nm narrowband nIters 

Eppley pyranometers with Q and RG8 

filters, downward-facing 

Eppley pyrgeometers, upward- and 

downward-facing 

P1atinum resistor, 2- and 2O'm heights 

P1atinurn resistor, 0,5 em 

Capacitance tran sducer 

Mercurial barometer 

Bendix Aerovane 

SOl evacuated glass flasks 

High-volume sampler 

Pollak CNC with diffusion battery 

Nuc1epore filters 

Stainless steel flasks 

lO-L stainless steel cylinder 

3,000 psi spheres 

12S-mL Nalgene fl asks 

Sol glass fl asks 

Spectrophotometer, data logger 

l-L steel cylinder 

2,S-L steel flasks 

UV radiometer, data logger 

Sampling Frequency 

Continuous 

1 pair twice mo'! 

I pair twice mo·l 

Continuous 

3 day" 

1 wk-l summer, autumn, winter 

1 (3 day}} spring 

3 wk- l summer 

2 analyses wk-l 

2 day" 

Continuous 

Continuous 

Continuous 

I sample day'} 

Continuous, summer 

Discrete, summer 

Discrete, summer 

Continuous, summer 

Continuous 

Continuous 

Continuous 

Continuous 

2 limes wk-! 

Continuous 

2 moot (3 fla sks sample'l) 

Continuous 

(4 filte rs mo-I) 

Discrete 

Continuous 

Twice moot (3 flasks set)'I) 

1 mo'l (2 cylinders sample-t) 

SOO psi day-t 

I (2 wk)" 

1 or 2 fl asks mo·t 

Continuous for 6 wk 

at sunrise and sun set, 

and control periods in summcr 

One time 

Daily (seasonally) 

Continuous, summer 

Solar and Terrestrilll RadiaJion 

Once again there were a few problems associated with 

pre-amps, but downtime was short. All cables with the 

ex.ception of one leading from CAF to the albedo rack were 

replaced with single-run, longer cables to facilitate the raising of 

the eAF building. Additionally, the cables were suspended 

above the snow surface to prevent their future burial by blowing 

snow. 

Meteorology 

The problems encountered with this program were relatively 

minor and infrequent. An extended period of data loss occurred 
when the wires near the snow temperature sensor probe broke 

and went unnoticed for approximately 3 months. This affected 

only the snow surface temperature readings. 

Cooperative Programs 

Most of the cooperative programs listed in Table 2.6 were 

continued from previous years. However, two new projects 

began. One, the Smithsonian-NOAA UV radiometer project 

will be an ongoing program; the other, a U.S. Department of 

Interior project to reassess global 4He levels, was a one-time 

sample. The Smithsonian-NOAA instrument went omine due 

to a failed tape-drive unit, but a new unit was received by 

15 

airdrop and the system was returned to operation. 

2.5. REFERENCES 

Komhyr, W. D., An aerosol and gas sampling apparatus for remote 

observatory usc, J. Geophys. Res .• 88, 3913-3918, 1983. 

Rinsland, C. P., A. Goldman. F. J. Murcray, R. D. Dlatherwick, P. H. 

Murcray, and D. G. Murcray, Infrared measurements of atmospheric 

gases above Mauna Loa, Hawaii, in February 1987.1. Geop/iys. Res., 

1988. 

Schnell, R. c., and R. M. Rosson (Eds.), Geophysical Monitoring for 

Climalic Change No. 15, Swnmary Reporl 1986, 155 pp., NOAA 

Environmental Research Laboratories, Boulder, Colo. 1987. 
16 

3. Aerosols and Radiation Monitoring Group 

3.1. CONTINUING PROGRAMS 

3.1.1. SURFACE AEROSOLS 

The GMCC aerosol monitoring program continued during 

1987 as in previous years. eN concentration and aerosol 

scattering extinction coefficient (cr~ were measured continuously at BRW. MLO. SMO, and SPO. A G.E. automatic CN 

counter operates continuously, and a Pollak eN counter 

provides daily calibration points for lhe automatic eN counter at 

each station. A four-wavelength nephelometer at each station 

continuowly measures O"rp at 450-, 550-, 700-, and SSO-run 

wavelengths. 

No major changes were made to the routine monitoring 

program at the GMCC stations during 1987. The MLO 

nephelometer exhibited low sensitivity on channel four (850 

run) during the early part of 1987. Therefore. only 450-.550-. 

and 700-nm scattering extinction data for MLO are shown here 

until September 5 (DOY 248), the date when the photomultiplier 

tube in the MLO nephelometer was replaced. The BRW, SMO, 

and SPO aerosol monitoring programs operated essentially 

trouble free during 1987. 

A special aerosol experiment was conducted at SPO during 

1987. A Nuclepore·filter diffusion battery apparatus for 

measurement of particle size distribution in the Aitken size 

range, a TSI alcohol-based CN counter, an aethalometer for the 

measurement of soot carbon, two stepping streaker samplers, 

and an HP data acquisition and control system were installed in 

the Clean Air Facility. The streaker samplers were programmed 

to take 24-h filter samples for each day of the year for subsequent aerosol chemistry analysis using the PIXE technique. 

Monthly geometric means of the data for 1987 are listed in 

Table 3.1. Figure 3.1 shows daily geometric means of CN 

concentration (lower portion of each plot), Oop (middle portion 

of each plot), and Angstrom exponcnt (upper portion of each 

plot) at the GMCC stations for 1987. Three independent values 

of Angstrom exp:ment were calculated from the o.p data. 

Monthly geometric means of the entire data rccord for each 

station are shown in Figure 3.2. 

The BRW data in Figure 3.1 show a maximum in O'.p of about 

2 x lO-s mol during the middle of March, typical of the well· 

known springtime Arctic haze. Afler a decrease during the last 

week of March, the Oop data again show high Arctic haze values 

during the first 3 weeks of April 1987. The high springtime 

values of o.p decrease rapidly in May and June, reaching values 

well below 10-6 mol . The BRW long-term record presented in 

Figure 3.2 clearly shows this annual cycle in O'JP' having 

monthly means above lO-s m·l in the spring and occasionally 

below 10-6 mol in the summer. The BRW CN data in Figure 3.1 

show an apparent semiannual cycle and a secondary maximum 

TABLE 3.1. Monthly Geometric Means of CN Concentration (em") and crop (m· l ) at 450, 550. 700, 

and 850 run for BRW. MLO. SMO. and SPO During 1987 

JaD . rob. March April May Ju"" July A"". Sapt . oct. No.,. Dae. 

.... eN 251 2.2 .,. 321 101 145 330 347 100 lBl .. 157 

cr., (.50) 1.07-05 1.37-05 1.50-05 1.96-05 1.09-05 3.57-06 2.76-06 2.80-06 3.63-06 4.74-06 6.B2-06 1.11-05 

cr., (550) 1.00-05 1.28-05 1.34-05 1.66-05 B.90-06 3.11-06 2.50-06 2.74-063.55-06 4.50-06 5.81-06 1.08-05 

cr., (700) 7.2B-06 9.09-06 8.90-06 1.03-05 5.23-06 2.06-06 1 . 84-06 2.18-06 2.B1-06 3.50-06 3.BO-06 8.26-06 

cr., (850) 5 .• 2-06 6.69-06 6.29-015 6.90-015 3.39--06 1.409-015 1.40-06 1.B5-015 2.30-015 2.i2-06 2.65-06 6.U-06 

MLO 

ClI 2.2 250 252 2" 271 320 205 203 25B 252 247 207 

cr., (450, 3.U-06 2.33-06 2.66-06 2 .• 7-06 1.75-06 2.47-06 1 . 36-06 1.10-06 1.21-06 

cr., (550, 2.97-06 1.84-06 2 . 015-06 1.B3-06 1.2B-06 1.80-06 9.79-07 7.99-07 B. 98-07 

cr., (700) 2.77-06 1. 52-06 1 . 66-015 1.42-06 9.B6-07 1. 22-06 6.76-07 5.39-07 6.11-07 

crop (850) 9.95-07 6.25-07 5.17-07 5. B7-07 

B"" 

eN 310 255 234 lOB 233 107 100 211 20. 218 303 

crop (450) 1.10-05 B.66-06 1.50-05 1.BB-05 1.31-05 1.18-05 1 . 02-05 1.69-05 1.31-05 2.00-05 1. i6-05 2.U-05 

cr., (550) 1.06-05 B.40-06 1.41-05 1.84-05 1.30-05 1.lB-05 1.02-05 1.73-05 1.29-05 2.03-05 1.BO-05 2 . 36-05 

crop (700) 1.06-05 8.59--06 1.41-05 1.91-05 1.34-05 1 .21-05 1.05-05 1.B2-05 1.32-05 2.13-05 1.74-05 2.36-05 

crop (B50, 1.14-05 9.09-015 1.47-05 2.05-05 1.43-05 1.30-05 1.11-05 1.518-05 1..7-05 2.34-05 1.BO-05 2.47-05 

B'O 

eN 100 100 102 32 24 16 11 15 27 B' 121 115 

crop (4501 4.49-07 3.04-07 3.35-07 2.53-07 2 .45-07 3 . 93-07 3.49-07 5.02-07 3.BS-07 5.52-07 5.37-07 

cr., (550) 2.66-07 1.84-07 2.18-07 1.67-07 1. 61-07 2 .65-07 2.55-07 4.03-07 3.12-07 4.31-07 3.75-07 

crop (700) 1.19-07 7 . 7B-OB 1.19-07 B.91-0B 51.29-08 1.56-07 1.36-07 2.5B-07 1.B5-07 2.6B-07 2.21-07 

cr., (B50) 15.40-0B 4.15-0B 6.10-08 5.60-0B 5.U-OB B . 61-0B B.37-0B 1.72-07 1.22-07 1.78-07 1.45-07 

A c.ompact exponential fonnat is used for aop such thai 1.07·05 = 1.07 x 10-

5. 
AEROSOL DATA F'OR BARROW 

JAN fEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

li+>1 41- I;PkJd ,JMI 'kl 

I .• 11 ,M l;c ' . 

11' '\,} \ 

' , '- ~l 10/ Ik .pi 'i,' ., , , ;\!, ~ J " " '\'I :-.it: ,~ 

.l 

. 

I I 

~ 1/) J ~\,~ M ~. ,!,.. lM ~~~ ~ ,if ,f I I)' 'II rl

i 

JAN F'EB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

1987 

AEROSOL DATA F'OR SAMOA 

JAN F'EB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

0 

N~ • 

~ 

.< 

+ 

7 

~ .s 

" ~ 0" 

~ 

.3 

~ 

M 

, 

0 E 

-" 

z 

u 

M 

.3 

, ~7 kh t:~lll JL I : I I,J :1 U , 

, 

, 

r ., : 

M • l" I.N'\ .1 I,; '!vII' G,." r-\ N~ 

cvr [\1T fIT " 

iwJ Vw~ !d IJ, \1'\ 1.fJ" Mv '1"1 ~ «11 

JAN F'EB MAR APR MAY JUN JUL AUG SEP ocr NOV DEC 

1967 

" .0 

,~ 

.3 

.0 

.eN 

E-_ 

<. 

~ , 

, 

g"i' 

~ 

O. 

~, 

.3 

~ 

n-

, 

Eo 

-" 

z 

U 

~N 

.3 

AEROSOL DATA F'OR MAUNA LDA 

JAN F'EB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

I I 1 1 r PI; 1 I;+}-I :1 

i U!i,r' . 'f " II, Ii l!i ' j , 

I , 'P - l, 1\ 

~1,~ ~W M ~~ ~. I~ ." . Lt , ,I.. , j 

-Y' It 

1" "r/ ~ , I 

JAN F'EB MAR APR MAY JUN JUL Aue SEP OCT NOV DEC 

1987 

AEROSOL DATA FOR SOUTH POLE 

JAN ~tl} MAJ~ APR MAY J~N JUL Aue SEP ocr NOV DEC 

1: j " 

E-- ) <. 

n 

, 

, 

. 

EN 

"" z 

u 

~ 

.3 

" 

JAN 

, I "" ~, 

N I. ~ " VI~ 1 1 '1' 

IL ~Ml-rt r~ 

F'EB MAR APR MAY JUN JUL Aue SEP ocr NOV OEC 

1967 

17 

" • 0 'M 

.3 

M 

, 

NE 

-" 

z 

u 

~ 

.3 

Figure 3.1. DaiJy geometric means of a and eN data at BRW, MLO, SMO, and SPO for 1987. Data for MLO are induded only for 0000-0800 

LST. For each station, a T concentration (fower) is shown as a solid line. a data (middle) are shown for 450 (dotted), 550 (solid), 700 (dashed), and 

850 nm Oong-dashed). Angstrom exponents (alpha) were calculated from 450- and 550-run (dotted), 550- and 700-nm (solid), and 700- and 850-nm 

(dashed) alP data. aap data for 850 nm and Angstrom exponent data for 700-850 nm are not shown for MLO. 

in July-August. The BRW long-Ienn CN record shows a more 

variable semiannual cycle, having maxima usually in March and 

August, and minima usually in June and November. Quakenbush and Bodhaine (1987] presented the Barrow aerosol record 

graphically in the fonn of hourly means for 1976-1986. 

The MLO arp data shown in Figure 3.1 are fairly typical for 

MLO but do not clearly show the expected annual cycle because 

of instrument problems and missing data. A maximum is 

expected in April-May that is caused by the long-range transport 

of Asian desert dust in the upper troposphere to the vicinity of 

Hawaii. The Angstrom exponent data show a minimum in 

April-May, indicating larger particle sizes during that time. The 

MLO CN data shown in Figures 3.1 and 3.2 average about 250 

cm·3 and are probably representative of the background 

troposphere in this region. The desert dust events in the spring 

do not significantly affect the eN concentration because the dust 

particles contribute only a small percentage to the total numbers. 

However, because of their larger size, they contribute significantly to the scattering coefficient. The MLO long-tenn 

aerosol record presented in Figure 3.2 shows significantly 

higher wintertime values during 1985-1987 than during 

1974-1980. ]t is not known whether this is a real change or if it 
18 

AEROSOL DATA FOR BARROW • w • • • • • aM. . . , I I; l'¥i·4'ls**44-,f4 

\.. I. I, h tt. l-, IA , fi I'H f\j! Rd 1'10 .- . 11, I 1M \P4 '* \t' iM:: , " i , " I , 

n. 

N~ 

-.9-

.< 

7 

'?.§. ~ 

• b '", 

.9 

, 

AEROSOL DATA FOR MAUNA LOA M ~ ~ n ~ ~ ~ 81 ~ ~ ~ M M ~ 

1·'$,kl5?Hvf 1 1 1 14-.],1 

I. ~ . II:: lri. Ilc I~ I~ · I", 

F\1 r~ ~ ,'r til -: w' L ,; .. 

" : ': . , \.: 

7 

~.s 

~ , b 

'", 

.9 

AEROSOL DATA FOR SAMOA AEROSOL DATA FOR SOUTH POLE 

i~ln4: I:I·liJ· lal:l~l·fl~i i~" ~. w ••••• aM ... ~i 

};I i4~ ~d+J44AH) }~ ~} 

1kt I rn±fdiWl tM4##nrlJ 

I 1 1 1 1 hi HH'4¥fM 

bN . j l .' ' ... ~It ./{" k#, ., , .if; 

.' .. .' 

77 78 7'i eo 81 1!2 63 84 85 06 87 7.~7677787l1eo8 82e::J848:i(MItn 

Y~R Y~R 

Figure 3.2. MOnl.hly geometric means of a~ and CN data for the enli~ data record, as in Figure 3.1. Details of the trend lines are given in Table 3.2. 

is because of the new nephelometer installed at MLO in 

1985. 

The SMO "op and CN data (Figures 3.1 and 3.2) continue as 

in previous years, showing no significant annual cycle or 

long-tcnn trend. The SMO aerosol is representative of the 

background marine boundary layer in this region. The 10nglenn mean at SMO is about 1.5 x 10-:5 mol for 0sp and about 270 

cm-) for CN concentration. A detailed analysis of the entire 

SMO dala record was presented by Bodhaine and DeLuisi 

[1985). 

The SPO "op da,a (Figures 3.1 and 3.2) show intennedia,e 

values in the summer, a minimum in May, and a record 

dominated by large events, sometimes exceeding 10-

6 m·l

, in 

late winter. These large aerosol events are caused by the 

transport of sea salt in the middle troposphere from stonny 

regions near the coast to the interior of the continent. Analyses 

of \he SPO d.,. were presen,ed by Bodlwine et al. [1986, 1987]. 

The SPO CN da" show an annual cycle strikingly different 

from that of the 0sp data. The CN data show a strong annual 

cycle, reaching a maxirnwn of about 200 em3 in the austral 

summer and a minimwn of about 10 cm·3 in the winter. 

Preliminary results from the 1987 SPO aerosol experiment 

show that aerosol carbon has an annual cycle with a minimum 

concentration of about 0.1 ng m·

3 in May and a maximum of 

about 10 ng mol in the austral summer. The general shape and 

phase of the carbon annual cycle most resembles that of a lP' 

Time-height cross sections of temperature show no surface 

temperature inversion in summer and a strong. shallow 

inversion in winter. Large surface aerosol events often occur 

during a decrease in the strength of the surface temperature 

inversion. Trajectories calculated backward from the South 

Pole show periods of rapid transport from the Weddell and Ross 

Seas corresponding to sea-salt events in the aerosol data, This 

experiment was described in more detail by Bodhaine eI al. 

[1988) and Hansen et 01. [19 88). 

The least-squares trend lines shown in Figure 3.2 were 

calculated using the common logaritluns of the monthly means 

of the entire data record. and the results are given in Table 3.2. 

Similar trend lines have been calculated and presented in 

previous GMCC Summary Reports. The long-term trends are 
TABLE 3.2. Least-Squares Trend Analysis of the Common 

Logaritluns of Ihe Data Shown in Figure 3.2-

Parameter Slope Intercept S.E. Trend (% yt"l) 

BRW eN 0.0164 0.954 0.290 3.9 

"", 0.00553 -5.70 0.370 1.3 

MLO eN -{J.00457 2.79 0.127 -1.05 

"", 0.0210 -7.81 0.321 5.0 

SMO eN -{J.0113 3.38 0.113 -2.6 

"", -0.0107 -3.94 0.116 -2.4 

SPO eN -{J.00917 2.39 0.432 -2.1 

"", 0.0124 -7.58 0.187 2.9 

-The time axis is in fractional years, with a dala point centered at the 

middle of a month; e.g., Jan. 1974 = 74.042. Feb. 1914 = 74.125, etc. 

not statistically significant compared with the standard error 

about the regression line, suggesting that there is no long-term 

trend in the background aerosol measured at these four stations. 

3.1.2. SOlAR AND THERMAL RADIATION 

The purpose of Ihe OMCC solar and Ihennal radiation 

measurement project is to establish the surface radiation budget 

components at the GMCC sites. From this data set two major 

research areas are addressed: (1) the explanation of observed 

variations on multiple time scales and (2) understanding the 

influence of surface radiation budget variations on global and 

regional climate. A major effort in the project is spent on the 

acquisition and quality control of the radiation data. thereby 

facilitating a research-quality data base. In addition to measurements of the principal components of the radiation budget. 

assorted spectral radiation measurements are made at solar 

wavelengths. These spectral measurements, obtained by 

remote-sensing techniques, support radiation budget research by 

providing data on different aunospheric constituents, such as 

water vapor and aerosols. 

Current Measurenumls 

Table 3.3 shows the radiation measurements currently being 

made at the four GMCC observatories. This suite of measurements has remained unchanged for the previous 3 years. The 

long-term goal of the measurements is to provide an understanding of phenomena on a multiyear time scale. 

Filter Wheel NIP Analysis 

Two sources of day-to-day and long term variations in the 

radiation budget are water vapor and to a lesser extent aerosols. 

Recently the ll-yr records of the FWNlPs from all four sites 

were analyzed in an effort to determine the aerosol optical depth 

and precipitable water information contained in the observation 

results. This analysis was accomplished, observation-byobservation. by repeatedly adjusting the aerosol and water vapor 

amounts in a spectral atmospheric transmission model [Bird and 

Riordan. 1986] until agreement with the observations in several 

19 

TABLE 3.3. Current Radiation Measurements 

at GMCC Observatories 

SWD SWU LWD LWU RG8D D1RQ FWNlP SPIITM Mise 

BRW X X X X X X X X a 

MLa X a a a X X X X X 

SMa X a a a X X X X a 

SPO X X X X X X X X X 

X, measurements made; 0, measurements not made; SWD. downward 

solar irradiance; SWU, upward (renccted) solar; LWD, downward 

long wave (sky emitted); LWU, upward longwavc (earth emitted); 

RG8D, downward solar (RG8 mter, 0.7 to 3.0 ~m) irradiance; DIRQ, 

direct solar; FWNIP, fllter wheel normal incidence pymeliometer 

(discrete observations, four solar bands); SPHTM, multi-wavelength 

sunphotometer; MlSC, misceUaneous-MLO: global diffuse solar, 

downward solar (OGI filter, 0.53 to 3.0 ~), 2-channel sunphotometer 

(water vapor), 3-channel sunpholometer (calibration standard); SPO: 

RG8 albedo, direct sun (RG8 filter). 

spectral bands was achieved. Preliminary results from this 

effort are shown in Figures 3.3 and 3.4. Identical scales were 

used for the different locations in Figures 3.3 and 3.4 for easy 

comparison. Only SPO water vapor values, which range from 

0.02 to about 0.1 cm with an average of 0.05 cm, are not easily 

discernible on the plots. The uncertainty in these results is 

larger than in results from more traditional techniques for 

measuring these quantities. Although it is difficult to estimate 

the magnitude of the errors in the fWNIP derived values, the 

absolute values are reasonable when compared with other 

measurements. 

The FWNIP record is exceptionally consistent and Slable. 

However, on a few occasions in the 44-station-year record. as 

yet unexplained, step discontinuities have appeared in the raw 

data, which are most likely observational artifacts. For this 

reason and the fact that the derived values are wholly dependent 

on the absolute calibration of the instrument, model. and 

extraterrestrial solar spectrum, the results shown in Figures 3.3 

and 3.4 are best considered to be only model inputs that force 

the model to agree with FWNIP observations. Both the model 

and raw data need to be examined further to refine the results 

and defme error boWlds. 

Aerosol Optical Depth 

Other than the absolute levels and short term variability the 

most obvious feature in the aerosol optical depth data (Figure 

3.3) is Ihe peak starling in 1982 due to debris from El Chichon. 

The exact arrival time of the maximum in EI Chichon debris at 

BRW and SPO cannot be easily determined because of the 

seasonality of the measurements. However, the peak magnitude 

and multiyear decay time for the event is well depicted in the 

plots. 

Each station's aerosol record exhibits characteristics unique 

to that station's latitude and elevation. The annual cycles at 

BRW and MLO are due to the springtime Arctic haze and Asian 

desert dust respectively. The higher frequency variability at 

SMO is due to boundary layer sea salt. 
20 

0.>0 

0.20 

~ '" 

-' o 

Ul 

gO.IO 

~ 

,. 

0: 

CD 

~ 

IV 

'BRW 

~ 1\ V 

j l ~ 

~n n n _ " a U H U U a u 

YEAR 

0.>0 

0.20 

'" ~ 

-' o 

Ul 

00.10 

0: 

W 

< 

o 

'" Ul 0.00 

VJ I.JiI 

"1 

n 

1'1'1 ~ 

r~~~ ~r n -" " U 

YEAR 

S~10 

I 

~ ~ ~ ~ ,. U " a " 

0.>0 

~O lO .... 

-' o 

Ul 

o 

c: 

WO.IO 

< 

o 

-' 

'" 0.00 

0.>0 

0.20 

~ '" 

-' o 

Ul 

~o ,o 

w 

< 

o 

11. 

Ul 

0.00 

MI.O 

IA ~ VI ~ ~r V\ '\" ~,A ~ LVI\. 

77 71S 19 110 III 82 aJ 11!14 as 66 87 aa 

YEAR 

SPO 

, , 

\ j, \ \ , 1 I , 

» n n _ " " U H U " a " 

YEAR 

Fig. 3.3. Tw(}-week averages of aerosol optical depth values (averaged over the visible) that, when input to a solar transmission model, result in the 

model solar imdiances best agreeing with fWl',,']p observations at the GMCC observatories. 

,~oo 

.00 

'.00 

E 

~ '.00 0 

N 

I 

,. 2.00 

c: 

CD 

0.00 

10.00 

.00 

.00 

E 

~ 

0 ' .00 

N 

:x: 

0 .00 

::> 

Ul 

~oo 

Fig. 3.4. 

BRW 

l ~ 

,I ' ! r· I ~ \ ~~ ~ V " 

~ r-; » • n _ " a U H U " a " 

YEAR 

I SMC 

I 

~~ ~[ ~ l ' 

, 'I 

~ 

YEA! 

10.00 

'.00 

'.00 

E 

~ ' .00 

0 

N 

J: 

0 2.00 

-' 

'" 0 .00 

10.00 

.00 

_ 1.00 

E 

~ 

o 4 .00 

N 

J: 

o .00 11. 

Vl 

MI.O 

...." . , f" . 

n 18 H 110 81 12 ~ 84 ~ 85 87 N 

YEAR 

SPO 

• " - " " U .. U 

YEAR " " " 

Two-week averages of precipitable waler (an), as in Figure 3.3. Some aerosol contamination is evident in 1982 (see text). 
Precipilable lValer 

TIle precipitable water values in Figure 3.4 show a minor 

interference from the EI Chichon event. due to aerosol 

contamination of the water vapor retrieval algorithm. This 

interference is most evident in the last two-thirds of 1982 at 

MLO. The precipitable water values shown in Figure 3.4 cover 

4 orders of magnitude but in general agree to much better than a 

factor of 2 with other observations from radiosondes and a 

sunphotometer. 

Downward Solar Irradiance 

The downward solar component of the radiation budget has 

been most consistently measured and processed for all GMCC 

sites. Monthly averages of this component are shown in Figure 

3.5. These data were manually edited once and data gaps of up 

to several minutes were filled by interpolation. Only complete 

or nearly complete days were used to form the monthly 

averages. Missing days may adversely affect the monthly 

average if the missing days are concentrated at the beginning or 

the end of particular "transition" months, but this is not typically 

the case. Most months have just random missing days. 

Many interesting features are seen in the solar irradiance data 

in Figure 3.5. The most obvious are annual and station-tostation variations that are caused largely by sun-earth geometry. 

Year-to-year and seasonally dependent variations caused by the 

almosphere are seen best by comparing individual months of 

consecutive years. For example at BRW, April irradiances have 

varied less than ±1O% over the 11 years; however, July values 

decreased by 40% in the first 6 years, only to recover half that 

t 

I 

I 

-

-

BRW GLOBAL SOLAR (liON. AVG.) 

r d I. ! I. 

~ , 

IV .Mf ~ 

r IJill J\ I 

• 

SMO GLOBAL SOLAR (MO:';. AVG.) 

In , 

0 

I 

Ii 

21 

loss in 1 year and then steadily decrease again for the past 5 

years. The BRW July variability is of a magnitude that can only 

be caused by cloudiness changes associated with multiyeartime-scale climate fluctuations. 

The effect of the eruption of EI Chichon is not obvious in 

Figure 3·.5. This is because these data include all cloudy times 

as well as clear, and the effect is masked. The dip at MLO in 

1982 may be related to EI Chichon, but similar dips not evident 

at other stations are evident at MLO for different times. 

No sustained trends are discernible. There is an apparent 

slight decrease at SMO during the past 3 years, which is 

believed to be due to insttument detector deterioration common 

in the tropics and not fully corrected in this presentation. The 

SMO pyranometer is scheduled to be replaced in 1988, and the 

detector drift can then be corrected. 

Radiation Budget 

Nearly 3 years of complete radiation budget data have been 

acquired at three GMCC locations: SPO. BRW, and Erie, Colo. 

These records are considerably shorter than most GMCC data 

sets because of the relatively recent development of a suitable 

instrument for monitoring longwave radiation. The new 

instrument, an Eppley pyrgoometer with a silicon dome, has just 

enough increased complexity that it was incompatible with the 

data-logging capabilities at the observatories and with the data 

validation and processing procedures used in the project. These 

problems have since been solved, but the data are not ready for 

presentation at this time. 

i 

I 

, 

i 

1 

-

-

OM 

MLO GLOBAL SOLAR (liON. AVG.) 

\ 1 {\ ~ ~\ r~ ~ ~ ~: ~\ 1'~ , I 

. ~ • i;; 

spa GLOBAL SOL.\.R (MON. AVG.) 

j

l I 

~ ;1 

! I 

, 

I 

L [III! 

Fig. 3.5. Monthly average downward solar irradiance 0N m·2, averaged over 24 hours a day) observed at the four GMCC observatories. The slight 

downward trend at SMO is most likely a measurement artifact (see te,;t). 
22 

3.1.3. SOLAR RADIATlO",FAOlITY 

SRF activities during 1987 were devoted to the following 

areas: recalibration of a set of pyranomclers for resupply of the 

31 NOAA SOLRAD sites. other support of SOLRAD sites. 

completion of the new automated tracker purchase contract. 

installation of multiple automated tracker testing and operational 

capability in the SRF. development of data processing software 

for the SRF computer installation, coordination of and funding 

for a precision measurement of two view-limiting apertures for 

two ACRs designated to become the U.S. representative sensors 

in the World Standard Group of ACRs maintained in Davas, 

Switzerland, comparisons of NOAA reference ACRs with SERI 

ACRs as a check for consistent operation, and publication of a 

report summarizing the Seventh New River Intercomparison of 

ACRs. 

SOLRAD Network 

As pan of the preparations for resuming measurements of 

global and direct beam solar radiation at NOAA SOLRAD sites 

in the United States, a group of 30 rccalibrated pyranometers 

was prepared for exchange with sensors last calibrated in 1984 

(1982 for five of the sensors). Attempts were made to send the 

same sensor back to a given site if at all possible. Table 3.4 lists 

the sites and serial numbers of the sensors sent to them. 

Additionally, the calibration histories of each sensor are listed so 

that the long-term stability may be examined. It should be noted 

that rather-detailed histories of aU NOAA sensors have been 

developed during the past 12 years and that, overal1. the NOAA 

complement of thennopile sensors is quite well characterized. 

For this reason the reestablishment of the SOLRAD network 

with its new data acquisition capabilities and quality control 

should do well in collecting a high-qua1ity data set in the years 

ahead. 

Although the calibration values in Table 3.4 are not strictly 

comparable because not all are normalized to the same zenith 

angle, particularly for the earlier years, infonnation about the 

long-term stability of the NOAA group of thermopile-based 

pyranometers is present 

Each SOLRAD site also has a direct-beam sensor, an Eppley 

pyrheliometer (NIP), but an insufficient number of sensors 

prevents a complete exchange of field instruments. This is not a 

serious problem because of better long-term stability of the NIP 

compared with that of a global sensor. 

AutomaJedTracker Project 

Final production design of the new Eppley automated 

trackers was achieved during the summer of 1987. Design 

changes were incorporated that will ensure better long-tenn 

tracker performance and minimize maintenance requirements. 

Delivery of the first group of 15 production units was completed 

by the end of the year. The remainder of the units will be 

delivered in early 1988. Installation of the trackers at the 

SOLRAD sites should be accomplished during 1988. 

The SRF facility was fitted with pennanenuy installed 

control cabling sufficient to operate up to five of the new 

trackers simultaneously for monitoring and testing purposes in 

preparation for SOLRAD site installation activity. Each unit 

will be tested in Boulder prior to shipment to the field sites. 

SRF Standards Activity 

SRF primary and working standards were routinely checked 

during the year. Shade ca1ibrations of the SRF primary 

reference pyranometer. Eppley PSP 19917F3, were performed 

using the SRF ACR reference. TMl67502. Regular comparisons of reference NIPS were also performed. Historical scale 

factors were reproduced, and no significant departures from past 

performance were obseIVed. 

A comparison of SRF and SERI ACR reference instruments 

was also held on 4 days during August and Septcmber. The 

SRF reference ACRs, manufactured by Technical Measure· 

ments Inc. and by Eppley Laboratory, were compared with the 

SERI references. Significant departures from the historical 

record date back over 10 years. 

ACR Aperlure MeasuremenJs 

Two ACRs manufactured in the United States have been 

selected as representative sensors in the WMO World Standard 

Group of ACRs maintained in Davos, Switzerland. To fulfill 

requirements set forth by the WMO regarding the admission of 

these ACRs to the World Standard Group, the instruments' 

view-limiting aperture areas had to be measured. The NBS 

Dimensional Metrology Laboratory was contracted to perform 

high-precision diameter detenninations of the two apertures. 

These measurements were completed in late August and early 

September. and two U.S. ACRs were forwarded to the World 

Radiation Center in Davos. 

The two ACRs sent were manufactured by the Eppley 

Laboratory and by Technical Measurements Inc. They are 

essentially on permanent loan to the World Radiation Center by 

their respective owners, the Eppley Laboratory and SERI. 

Analysis of the data and discussion of fina1 results of the 

Seventh New River Intercomparison of ACRs (NRIP7) were 

published by Nelson et al. [1987J. 

3.1.4. TURBIDITY 

The number of monitoring siles in GMCC's U.S. Turbidity 

Network remained constant at 17 during 1987. Of these, 13 

continued to send data to GMCC in Boulder for reduction and 

processing. Sunphotometers at Sterling, Madison, Raleigh, and 

Lander, however, were used solely for quality control of 

pyrheliometric data. These locations are not yet reporting 

sunphotometer observations as part of the turbidity network. 

Turbidity measurements also continued at the four GMCC 

baseline stations during 1987. A five-channel Mainz n 

hand-held sunphotometer was put into service at MLO in July. 

This was the first of several Mainz n sun photometers scheduled 

to be sited at ADN stations. A Mainz J1 sWlphotometer was also 

shipped to the ADN station at Haute Provence in France during 

November. Table 3.5 lists the 22 stations and the wavelengths 

at which turbidity was measured during 1987. 

In 1987, 123 sunphotometcr calibrations were completed. Of 

these, 14 were not of sufficient quality to be recorded in the 

calibration history files for the respective instruments. Eightysix calibrations were completed in the mountains west of 
23 

TABLE 3.4. NOAA Calibration Histories (Scale Factors) of Pyranometers Currently in the SOLRAD Network 

Site Serial Number 

Lander, Wyo. 73-19 

Guam 73-23 

Salt Lake City. Utah 73-31 

El Paso, Tex. 73-38 

Omaha, Nebr. 73-4 1 

Dodge City. Kans. 73-40 

Fresno, Calif. 73-44 

Raleigh, N.C. 73-48 

Brownsville, Tex. 73-50 

Midland, Tex. 73-55 

Boise, Idaho 73-60 

Tallahassee, Aa. 73-62 

Montgomery I Ala. 73·63 

Phoenix, Ariz. 73-65 

Columbia, Mo. 73-66 

Greal Fa1ls. Mont. 73·82 

Nashville , Tenn. 73-83 

Coraopolis, Pa. 73-84 

Lake Charles, La. 73·89 

Albuquerque, N. Mex. 73-92 

Long Beach, Calif. 73-98 

Madison, Wis. 73-99 

A vg. Std. Dev. 

Grand Junction, Colo. 10095 

Ely, Nev. 11441 

Burlington, VL 11916 

Las Vegas, Nev. 11939 

Bismarck, N. Dak. 12258 

Seatlle, Wash. 12687 

Carioou, Maine 15130 

Sterling, W. Va. 15952 

Avg. Std. Dc .... 

Scale factors are in units of "V W-. m-2, 

·Rcbuilt sensor (nOf. used in computation). 

1976 1977 1978 

8.43 8.62 

9.47 9.58 

9.06 8.81 

9.91 10.09 

8.97 8.75 

8.84 8.74 

8.89 8.80 

10.63· 8.61 

9.72 9.35 

8.50' 8.26· 

8.67 

9.50 9.78 

8.3S· 8.40· 

10.07 10.07 

9.89 9.80 

8.78 

8.47 8.33 

8.24 8.16 

8.41 8.28 

9.49 9.35 

9.88 9.79 

6.92 

9.73 

9.15 

9.39 

9.05 9.01 

10.09 

Boulder. Colorado. and 37 were performed at MLO. Langley 

plot measurements were made at elevations of 2.7~3.5 km above 

sea level. This method of calibration was the only one used in 

1987 and has proved to be accurate and reliable for the majority 

of cases. 

Plots of typical calibration histories for NOAA ~series 

sunphotometcrs are presented in Fig. 3.6. The calibration 

constant for the 500~nm channel of sun photometer J202 shows 

litt1e variance and no significant drift. The 380~nm channels for 

1204 and 1203, however, show a more common pattern of 

downward drift with lime and more substantial variance. 

Calibration drift is generally linear for the J -series sun~ 

photometers. The estimated uncertainty in optical depth 

computations resulting from uncertainty in calibration trends is 

typically on the order of 0.005 to 0.04 optical deplh units at a 

relative air mass of 1.0. This uncerlainty is inversely propor~ 

tional to the relative air mass, and would be half the amount 

indicated, for example, if the relative air mass were 2.0. 

Software for acquisition of Mainz II sunphotometer data 

from the ADN sites was developed and tested in 1987. 

Logistical considerations and problems with the filter mecha~ 

1980 1982 1983 1984 1987 Average Std. Dey. 

8.50 8.72 8.67 8.59 0.11 ± 0.33% 

9.50 9.40 9.45 9.48 0.06±0.63% 

8.87 8.81 8.82 8.87 0.1O± 1.08% 

9.70 9.71 9.68 9.82 0.16± 1.62% 

8.57 8.58 8.71 8.72 0.15± 1.67% 

8.75 8.67 8.70 8.74 0.06± 0.66% 

8.74 8.70 8.71 8.77 0.07± 0.80% 

8.62 8.49 8.64 8.59 0.06± 0.68% 

9.22 9.04 9.04 9.27 0.25± 2.72% 

10.08 9.97 10.03 0.06± 0.55% 

8.79 8.60 8.57 8.66 0.08 ± 0.98% 

9.55 9.48 9.54 9.57 0.11 ± 1.13% 

7.54 7.47 7.50 7.50 0.03 ± 0.38% 

10.02 9.97 10.03 0.04±0.41% 

9.67 9.72 9.80 9.78 0.08 ± 0.77% 

8.54 8.44 8.50 8.57 0.13 ± 1.51% 

8.29 8.21 8.30 8.32 0.08 ± 1.02% 

8.06 7.98 8.04 8.10 0.09 ± 1.14% 

8.65 8.62 8.62 8.63 0.Ql ± 0.16% 

8.13 8.02 8.06 8. 18 0. 15± 1.77% 

9.03 9.03 9.23 O.20± 2.18% 

9.73 9.63 9.76 0.09± 0.93% 

0.1O± 1.09% 

6.90 6.82 6.83 6.87 0.04 ±0.63% 

9.33 9.26 9.26 9.40 0.20±2.08% 

8.67 8.74 8.79 8.79 8.83 0.17 ± 1.89% 

9.61 9.47 9.29 9.25 9.41 0.15 ± 1.55% 

8.80 8.78 8.66 8.91 0.28±3.19% 

9.02 8.90 8.57 8.91 0.18 ± 1.99% 

10.18 10.01 10.10 0.08 ± 0.84% 

9.67 9.52 9.50 9.70 0.24 ±2.45% 

0.17 ± 1.83% 

nisms on some of the Mainz II suphotometers contributed to 

delays in the deployment of these instruments at ADN Slations. 

Two of the nine Maim II sunphotometers were PUl into service 

in 1987. 

The rurbidity project staff began the design of a new 

five-wavelength sunphotometer to replace the aging ~scries 

sunphotometers at the baseline observatories. The new 

sunphotometers will use a detector~filter~amplifier (DFA) 

module developed by EG&G. Digilal panel meters, chips, and 

55 of these DF A modules were purchased. The new instruments 

will be more accurate and more rugged, and will have more 

features than the J-series sunphotometcrs. 

Data have been processed for 1982 through the end of 1987 

for Boulder (see Figure 3.7) and for 1983 through mid-1986 for 

Atlantic City, Bismarck, Caribou, Huron, Salem, Tallahassee, 

Alamosa, and Meridian. Data are complete for 1983 t1uough 

November of 1986 for Victoria. Data for 1986, the first year of 

operation for Ely, Las Vegas, and Salt Lake City, have also been 

processed. MLO and SPO data have been processed through 

1987. BRW and SMO data have been processed through 1987; 

however, priods of questionable data from these sites have not 

yet been corrected or deleted. 
24 

TABLE 3.5. GMCCTurbidity Monitoring Sites and Filter 

Wavelengths for Sunphotometers Used at Each Site 

Site 

BRW· 

MLO· 

SMO· 

SPO' 

Alamosa, Colo.· 

Atlantic City, N.J. 

Boulder, Colo. 

Bismarck, N. Oak. 

Caribou, MaineEly, Nev. 

Haute Provence, France 

Huron, S. Oak. 

Lander, Wyo.t 

Las Vegas, Nev. 

Madison, Wis.t 

Meridian, Miss.· 

Raleigh, N.C. t 

Salem, Ill,* 

Salt Lake City. Ulah 

Sterling, Va.t 

Tallahassee, Aa. 

Victoria. Tex,-

• BAPMaN station. 

Sunphotometer Wavelength (run) 

380,500,778,862 

380,412,500,675,778,862 

380,500,778,862 

380,500, 778,862 

380,500 

380,500 

380, 500,778,862 

380,500 

380,500 

380,500 

380,412,500,675,862 

380,500 

380,500 

380,500 

380,500 

380,500 

380,500 

380,500 

380,500 

380,500 

380,500 

380,500 

tNol yet reporting data as part of the Turbidity Network. 

Data for Boulder and other continental U.S. stations continue 

to show a clear annual cycle. having maxima in the spring or 

summer months and minima during November, December, or 

January. TIle impact of El Chichon is evident at many stations. 

The decay of the El nuchon signal appears as a slow downward 

Lrend in optical depths since the beginning of the record in early 

1983. 

SPO aerosol optical depths for a sample of wavelengths are 

shown in Figures 3.8 and 3.9. The ftrst graph in figure 3.8 

presents the 380-nm data record after it has been edited to 

remove observations made through clouds and thick ice fogs. 

This record has also been edited 10 remove negative aerosol 

optical depths, which arc generally artifacts caused by errors in 

the measurement process or errors in the calibration constants. 

A perturbation of 0.04 to 0.05 optical depth units is apparent in 

lale 1982 and early 1983. This marks the arrival of the El 

Chicon stratospheric aerosol cloud. 

The second graph in Figure 3.8 shows the 380-run data set 

prior Lo editing. Negative aerosol optical depths and the effects 

of clouds and ice fogs are evident. The magnitude of the 

negative aerosol optical depths is too great to be due to errors in 

the calibration constants alone. The instruments used at SPO 

are some of ilie most carefully and frequently calibrated of 

GMCC's sunphotometers. It is believed iliat the large negative 

values are caused in part by measurement techniques and in part 

by the peak-hold feature on the sunphotometers. 

The SPO staff have usually taken sunphotometer observations through an open window in the CAF. The readings are 

made fTom a table top within the facility. Cold air pouring into 

F 

~ 

x 

0 

~ ~ 

~ 

~ 

::; 

~ 

u 

> 

io 

z 

0 

<;; 

~ 

~ 

::; 

~ 

u 

;;-

io 

x 

0 

~ 

~ 

~ 

~ 

::; 

~ 

u 

J202 500 Hili CAUBRATION HISTORY 

3000 

2500 

2000 , . 

1500 

1000 

1981 1982 1983 198" 1985 1988 1987 1988 1989 

YEAR 

1203 380 NY CAI-JBRATION HISTORY 

3000 

2500 

2000 

1500 

1000 

500+-~.-~'----r~-r--~~-, __ -, __ -4 

198 1 1982 1983 198" 1985 1986 H18? 19B8 1989 

YEAR 

3000 

2500 

2000 

1500 

1000 

500 

1985 

no" 380 NW CALIBRA'l'tOH HISTORY 

1988 1987 

YEAR 

1988 1989 

Fig. 3.6. 

photometers. 

Typical calibration hislories for NOAA l-series sun-
AVBRACE DAILY 380 NY 1URBIDITY: BOULDER AVERACE DAILY 778 NY TURBIDITY: BOULDER 

+ 

0.75 0.75 

+ > + + !: .. Q + .. 0.' + + ~ + + ~ * ~ • + 0.25 

0 

YEAR YEAR 

Fig. 3.7. Daily average aerosol optica1 depths at Boulder at 380 nm and 718 nm. 

AVERAGE DAILY 380 NW 1URBIDITY: SOUTH POLt 

0.2,-----------------, 

0.15 

> +{ ~ 

Q 

.. 0. 1 ~ 

1 ~ 

~ 

+ .+ + 0 .05 t t + + 

+ 

,.+ 

0 

1982 1983 1984- 1985 1986 1987 1988 1989 

YEAR 

0.' 

0.4-5 

0.' 

0.35 

0.3 > 

~ 

Q 0.25 

.. 

~ 0.2 ~ 

~ 0.15 

0.1 

0 .05 

0 

-0.05 

UNEDITED SOUTH POLE TURBIDITY: 380 NlI 

____ • ________ ,.. ._ •••• 'i: •••••••••••••• ___ ._ ••••••• ••••• 

+ ....................... +: ••••••• ••••••••.....•.••••••••• 

+\ + ...... ., ................ _ .... __ ....................... _ .. \ + ••••..••...•..••••••• +: ••••••• •••••••.•• _ ....••••••••• 

;···fj····F:···S··············~················ 

f::::~.::::I:::~::::~::::\::::i~:::::: , 82 .3 , 

.. YEAR 

eo 87 

, 

•• .9 

Fig. 3.8. Aerosol optical depths al SPO: daily averages at 380 nm and unedited instantaneous 380·nm daLa. 

the heated room causes density discontinuity waves in the air 

around the window. Sunlight is apparently focused in some 

areas of the wave field, and the peak-hold feature stores the 

maximum signal received within the measurement period. An 

artificially high reading and correspondingly low computed 

optical depth result. This phenomenon has been duplicated at 

Boulder during observations made in subfreezing weather near a 

building air exit vent on the roof of the ERL building. 

> 

!: 

Q 

.. 

~ 

~ 

~ 

AVERAGE DAILY 862 NY TURBIDITY: SOUTH POLE 

0.2,-------------------, 

0.15 

0.1 

+ 

0. 05 i • 

+ 

+ 

+ + 

* 

25 

During the 1987-1988 austral summer, the SPO crew made 

sunphotometer observations outside the facility, and no negative 

optical depths were observed. The 1988·1989 crew will be 

asked to lake readings from inside the facility as well as outside 

in the hopes that this will provide some quantitative measure of 

the impact of past measurement practices on the South Pole 

record. 

1982 t983 1984- 1985 1988 1981 1988 1969 

YEAR 

Fig. 3.9. Daily average aerosol optical deplhs al spa at 862 nm. 
26 

3.2. SPECIAL i'ROJECfS 

3.2.1. ZEl\lT1I·SKY CLOUD DETEcnON FOR AurOl\.iATED 

DOBSON UMKEllR MEASUREMEl'orrs 

The seven automated Dobson instruments of the OMeC 

program operate in the Umkehr mode without the presence of an 

operator (Komhyr et al., 1984], In the absence of an ansile 

observer it is necessary to have an independent measure of 

lcnith.sky conditions, because the large-particle scattering 

condition (primarily clouds) of the zenith sky is manifested in 

the Umkchr measurement. which is accepted or rejected on the 

basis of the smoothness of the Umkehr curve. Erroneous 

Umkchr data could be due either to such cloud interference or to 

instrumentation malfunction. Large-particle scatterers such as 

cirrus c10uds present the most serious problem because of their 

optical thickness and variability over short periods of time. 

Atmospheric aerosols in the lroposphere are less serious because 

they are more homogeneously distributed in the lower aunos· 

phere where the Umkehr sensitivity is low and their optical 

thickness is considerably less than that of cirrus clouds. 

To monitor the zenith·sky brighlness as an indicator of cloud 

presence during an Umkehr measurement. GMCC consLructed a 

special photometer··a zentih·sky cloud detector (ZSCD)··to 

view essentially the same sky as the Dobson instrument does. 

Figure 3.10 is a drawing of the design of the ZSCD. The lens 

and aperture fix the field of view at 0.060 sr. The filter 

bandpass is 10 run centered at 862 run. The collimator tube is 

protected with a dust· and rl1in·resistant glass cover, lind the 

shade tube prevents the sun's direct rays from reaching the glass 

cover. Water drain holes are located in the block holding the 

shade tube. A stable EG & G silicon photodiode is used with an 

amplifier that is adjusted to give an output of 0·10 V. The 

SUl._ S"Io., Chu 

. rllhr 

fill" 

SI" .. 

, ... 

.w.,! .. 

0·11., . 

.. " ... 1''' ..... 

Fig. 3.10. A schematic of Ihe zenilh-sky cloud detector. 

system dark current is obtained each time the hatch cover of the 

Dobson housing dome is automatically closed between 

observation times. The output is adjusted 10 give a voltage 

reading of a few volts for a cloud-free zenith sky. An field 

insuuments were compared simultaneously, and amplifiers were 

adjusted to give the same readings. 

At the automated Dobson field sites the output of the ZSCD 

was fed to the data acquisition system. During the data 

processing procedure, which was carried out at Boulder, the 

digitized cloud detector signal and a plot of the signal strength 

versus time were automatically recorded. 

Figure 3.11 shows an example of zenith.sky signals at MLO 

received under conditions completely free of clouds on the 

morning of March 21. 1988. during the time thaI the Umkehr 

observation (solid line) was made. Note the low value of the 

ZSCD signal and the very smooth continuity in the fitted curve 

(dashed line). On March 19. 1988. during lbe aflCmoon 

Umkehr measurement, clouds interfered severely. The 

interference effects are shown in Figure 3.12. 

These examples serve to illustrate the sensitivity of the 

zenith-sky cloud observations and the ability to quantify the 

quality of the zenith-sky conditions during an Umkehr 

measurement. The Umkehr, being a ratio measurement. does 

not clearly display direct relationships between cloud presence 

and error, other than to produce a noisy observation. However, 

in general, thin cloud cover will cause the Umkehr observation 

N-values to become erroneously high at the smaller zenith 

angles. At the larger zenith angles, interference effects become 

less lhan a t the smaller zenith angles. 

3.2.2. AN OBJECTIVE METHOD OF CORRECTING UMXEHR 

M EASURE~ffi.''TS FOR VOLCAJl,1C AEROSOL ERROR 

An objective method of calculating errors to Umkehr 

measurements for slratospheric aerosol interference was 

developed and used on a selected set of Umkehr data. The 

INST. 76 AT MLO MAR 21. 1966 AM NC 

130 r--~-:t;>,","~~-~~=--~-~-"11O 

120 

110 

100 

90 

zao 

70 

60 

SO 

..................... ~ 

9 

a 

7 

6 

2 

Fig. 3.11. Umkehr observation N-values versus solar zenith angle 

(solid line), taken at MLO. The dashed line represents the zenith-sky 

signal observation from the ZSCD versus zenith angle at the same time 

as the Umkeh r observation. These results, obLained during the morning 

of March 21, 1988, are typical of completely cloud-free oondilions. 
INST. 76 AT MLO MAR 19, 1988 PM NC 

1<0 r-~--~--~----~~--~----~~IO 

130 9 

120 & 

110 7 

100 6 

9<l 

• SO 

• 

S~ 

70 

60 

SO 2 o 

'0 o 

30 o 100 9S 90 65 60 is 70 65 60 55 SO ztlm'H ANCLE, DEGREES 

Fig. 3.12. N-values and zenith-sky signals. both versus zenith angle, as 

in Figure 3.11 but for the afternoon of March 19. 1988, and under 

conditions of severe cloud interference for pan of the observation. 

method involves theoretical calculations that include observations of sll'alospheric ozone and aerosols. Stratospheric ozone 

and aerosol profile data used to calculate the errors to the 

Umkchr measurements are derived from ozonesonde observations and from observations provided by five lidar stations in the 

northern hemisphere middle latitudes. Optical properties of the 

stratospheric aerosol arc deduced from photometric observations 

and in silu observations of aerosol size distribution. The 

calculated errors are used to correct Umkehr data for several 

stations in Lhe northern middle-latitude region. The corrected 

data display noteworthy variations, one of which is an obvious 

decrease in ozone concentration in the upper stratosphere during 

the first half of the 1980 decade. However, the decrease does 

not appear to be out of the range of variations seen in the 

long-tenn data set. 

Calculalions of lhe SlraJospheric Aerosol Error 

A schematic diagram that gives the sequence of steps for 

correcting Umkehr ozone profiles is shown in Figure 3.13. The 

foUowing subsections contain a discussion of those steps. 

Dala sources. To calculate the error for a given month, it is 

necessary to acquire the following data: 

I), ~: I W.uI..)I-)I. ='UTI 

0, .~ u " 0 .o..I~!I:I:. l not; " • w ... , ,,: - J •.• ~ .... .. ! 

"WI, .,, I 

Fig. 3.13. Scheme of the steps to calculate the stratospheric aerosol 

error to the Umkehr ozone profile. 

27 

Stratospheric aerosol proftle infonnation from lidar sites 

and from satellites such as in the Stratospheric Aerosol 

and Gas Experimenl (SAGE). 

Optical thickness inIonnation from tidar and satellite 

measurement systems as well as ground-based turbidity 

measurements. 

Aerosol size distribution from in situ aircraft and 

dustsonde systems . 

Theorelical CompUlaJion. The procedure for calculating aerosol 

errors to the Umkehr profile is as follows: 

Use the Dave el al. [1979) multiple-scattering code with 

pseudo-spherical atmosphere approximation to calculate 

an Urnkehr profIle. 

Use monthly average lidar 

stratospheric aerosol profile for 

[DeLuisi el al., 1988]. 

observations of the 

input to Dave's code 

Use monthly average ozonesonde profile data [Tiao el al., 

1986) for input to Dave's code. 

Assume surface reflectance = 0 for the present study. 

The error is small. 

Calculate Umkehr N-values for atmospheres with and 

without aerosols separately. NA and Nc stand for 

N-values with and without aerosol effects, respectively. 

MI.= N. - NO' 

Invert the results of calculated Umkehr measurements 

following the procedure given next. 

The monthly averaged stratospheric optical thickness observed 

by tidar at five northern middle-latitude sites is shown in Fig. 

3.1 4 [DeLuisi et al., 1988], NOle the abrupt change caused by 

the eruption of El Chichon. The corresponding vertical profiles 

to the optical thickness results were used in !.he theoretical 

calculations for error. 

.11 

_ 10 

.09 

~ .06 ~ 

• c . 07 ~ 

~ . 06 

;:: 

~ . OS 

~ .Oq Q. 

0 . 03 

.02 

. 0 1 / '-.!' r, 

7 7 78 79 eo 01 82 63 Sq 65 et. 87 88 

Year 

Fig. 3.14. Monthly avel1lged (smoothed) stl1ltospheric aerosol optical 

thickness observed by lidar at five northern middle latitude siles vs. 

time. The sites were Langley, Virginia, U.S.A.; Aberystwyth, Wales; 

Haute Provence, France; Boulder, Colorado, U.S.A.; and GannischPanenkirchen, F.R.G. (figure from DeLuisi l!( al. 11988]). 
28 

fnversion of Umkehr. The procedure for estimating the ozone 

profile error due to aerosols is as follows: 

Use the WMO Uniform Evaluation System (conventional 

Umkehr) to invert the Umkehr measurement. 

Use a monthly average actually observed Umkehr profile 

acquired during conditions of stratospheric quiescence. 

Invert this Umkehr profile. Then, invert the same 

Umkehr proftle. but with .1N A added to it. 

Calculate the ozone error profIle by taking the difference 

between the two cases (with aerosol and without aerosol) 

and dividing by the without aerosol case. 

Results and Discussion 

Figure 3.15 shows the unweighted average ozone profiles for 

1970-1986, in Umkehr layers, for four of the five Umkehr 

stations: Belsk, Arosa, Lislxm, and Tateno. It is obvious that 

amounts for layers 5 through 9 were lower lhan normal during 

the passage of the major mass of the EI Chichon cloud. 

Year 

Fig. 3.15. Monthly average ozone partial pressure vs. time, in Umkehr 

layers 1-9 for Belsk, Arosa, Lisbon, and Tateno, for 1970-1986. Also 

shown (top) is a plot of total ozone (in Dobson units, DU) corresponding 

to the ozone proftle data. Data were supplied courtesy World Ozone 

Data Center at Toronto. These data have not been corrected for 

stratospheric aerosol error. Note the error effects of El Chichon during 

the winter of 1982-1983. 

Year 

Fig. 3.16. Monthly average ozone partial pressure vs. time as in Figure 

3.15, but including data from Boulder and beginning in 1979. Also, the 

data have been corrected for stratospheric aerosol errors throughout the 

entire length of record. The solid lines are the least-squares linear fits 

for slope. The dashed segments are the fit excluding the years 

1982-1984. 

The corrected profiles are shown in Figure 3.16. (The figure 

also includes data from Boulder station and is for 1979-1986.) 

We estimate an uncertainty of the calculated correction to be in 

the range of 10% to 20%. The maximum estimated error was 

38% ± 6% in layer 9 during the winter of 1982-1983. The lower 

values seen in layer 5 during years 1983 and 1985 and after 

correction are thought to be due to strong quasi biennial effects 

[see Bojkov, 1987]. In 1983 the increased error is due to the 

imperfect coincidence of the aerosol and Umkehr data. A 

12-mo running average was used to smooth the data of Figure 

3.16 and a least-squares linear fit was applied to estimate a 

linear change, excluding the years 1983-1985. The results are 

shown in Figure 3.17. This figure shows the 8-yr ozone change 

in percent for each Umkehr layer (dashed line with 20' confidence level). In addition, the change for the same time period 

given by the Lawrence Livennore two-dimensional model 

[DeLuisi et al., 1988] that includes photochemical depletion due 

to fluorocarbons and solar cycle variations is shown (solid line). 

The corrected Umkehr observations will be used to validate 

satellite SBUV measurements of ozone profile. 
10 50 

9 -'-, q5 '-, 

" 8 ~ qO 0 

" E 7 35 

" -, ", z 6 30 ~ " C- o 

~ 5 25 Q. 

< • -' 

--- " " q y<" 20 .c -- 3 0 

--- -" 3 15 - E , 

'" 2 ~ 10 

\ 

---+-- 5 

Q18 - 16 - 14 ,12 -1 0 -8 -5 , q -2 0 2 0 

"; ReductIOn 

Fig. 3.17. Plot of Umkehr ozone concentration reduction (dashed line) 

and modeled ozone concentration reduction (solid line) in Umkehr 

layers 1·9, during 1979-1986. The bars represent the 20' confidence 

level. 

3.3. REFERENCES 

Bird, R.E., and C. Riordan, Simple solar spectral model for direct and 

diffuse irradi ancc on horizontal and tilted planes at the earth's 

surface for cloudless atmospheres. J. Clim. Appl. Meteorol .. 25, 

87·97,1986. 

[]odhaine, B.A., and IJ. DcLui~ i. An aerosol climatology of Samoa, 1. 

Almos. Chern .• 3, 107-122, 1985. 

Bodhaine, B.A., J.1. DeLuisi, I.M. Harris, P. Houmere. and S. Bauman, 

Aerosol measurements at the South Pole. Tel/us, 38B, 223-235, 

1986. 

29 

Bodhaine. B.A., JJ. DeLuisi, I.M. Harris, P. Houmere, and S. Bauman, 

PIXE analysis of South Pole aerosol, Nucl.ll1Strum. Methods, B22, 

241-247,1987. 

Bodhaine, B.A., E.G. Dutton, IJ. DeLuisi, J.M. Harris, G.E. Shaw, and 

A.D.A. Hansen, South Pole aerosol measurements during 1987, 

Proceedings of the Twelfth International Conference on Atmospheric 

Aerosols and NucleatiOfl, August 22·27, 1988, Vienna, Austria , 

Springer.Verlag, 225·228, New York, 1988. 

Bojkov, R.D., The 1983 and 1985 anomalies in ozone distribution in 

perspective, Mon. Wea. Rey., 115,2187·2201,1987. 

Dave, J.V., J.1. DeLuisi, and c.L. Mateer, Resu lts of a comprehensive 

theoretical examination of the optical effects of aerosols on the 

Umkehrmeasurement, Spec. Envirofl. Rep. 14, World Metcorologi· 

cal Organization, Geneva, 15·22. 1979. 

DeLuisi, J.J., D.U. Longenecker, C.L Mateer. and D. J. Wucbbles, An 

analysis of northern middle latitude Umkehr measurements 

corrected for stratospheric aerosols for the years 1979·1986, J. 

Geophys. Res. submitted, 1988. 

Hansen, A.D.A .• B.A. Bodhaine, E.G. Dutton, and R.C. Schnell, Aerosol 

black carbon mea surements at the South Pole: Initial resuiLs, 

1986·1987, Geophys. Res. UII., 15, 1193·11 96, 1988. 

Komhyr. W.O., R.D. Grass, R.D. Evans. R.K. Leonard, and G.M. 

Seneniuk. Umkehr observations with automated Dobson 

spectrophotometers, Proceedings of thl! Quadrennial Ozone 

Symposium, September 3·7, 1984, Halkidiki, Greece, D. Reidel, 

Dordrecht, Holland, 316·320, 1985. 

Nelson, D .• R. Haas, J. DeLuisi, G. Zerlaut, Reswts of the NRIP 

intercomparison November 18·21. 1985, NOM Tech . Memo. ERL 

ARL·161, 108 pp., Air Resources Laboratory, Silver Spring, Md., 

1987. 

Tiao, G.c., G.c. Reinsel, J.H. Pedrick, G.M. AlIenby. C.L. Mateer, A.1. 

MiUer, and J.J. DeLuisi. A statistical trend analysis of ozonesonde 

data, 1 . Geophys. Ru., 91 . 13.121·13.136.1986. 

Quakenbush, T.K .• and B.A. Bodhaine, Surface aerosols at the Barrow 

GMCC Observatory: Data from 1976 through 1985, NOM Data 

Rep. ERL ARL.JO, 230 pp., NOAA Air Resources Laboratory, 

Boulder, Colo., 1987. 
30 

4. Carbon Cycle Group 

4.1. CONTINUING PROGRAMS 

4 .1 .1. CONTINUOUS IN·SITU CO, MEASUREMENTS 

The in situ NDIR CO2 analyzers at the four GMCC 

observatories continued to operate in 1987. The preliminary 

monthly and annual means for 1987 are shown in Table 4.1, 

expressed in the WMO 1985 mole fraction scale (X85). The 

complete record of the growth rate observed at each station is 

shown in Figure 4.1. Calibration and data acquisition 

procedures remained the same as in previous years. A 

digital-filtering technique [Thoning et ai., 1988] was used to 

separate the seasonal cycle and the long-term trend signals. The 

latter were plotted as the smooth curves in Figure 4.1. The 

differences between the annual means of 1987 and 1986 are 1.1 

ppm for HRW. 1.8 ppm for MLO. 1.7 ppm for SMO, and 1.6 

ppm for SPO. The complete record at MLO has recently been 

described by Komhyr et 01. [1988]. 

In August a new Siemens Ultramat 3 analyzer was installed 

at MLO parallel to the URAS analyzer that has been in use since 

the beginning of the program in 1974. To our surprise, the 

Siemens results were consistently 0.3 ppm lower than the URAS 

results when they were ooth analyzing the same air stream and 

using thc samc tanks of working standards. Further comparative 

tests showed that ooth analyzers gave identical and correct 

results when analyzing tank air of known concentration, using 

working standards that consisted of real air. Only when 

artificial air mixtures (specified concentrations of CO2, nitrogen. 

oxygen, and argon) were used as working standards, did the 

URAS results increase by 0.3 ppm for the tank: of known 

concentration. The Siemens analyzer officially replaced the 

URAS analyzer in September. Further tests are being carried 

out to detennine if, and for what period. corrections to the 

URAS record will be necessary. 

The calibrations of COz in air reference gas tanks continued 

in 1987; on 133 days, 266 tanks were calibrated. There was an 

Table 4.1. Provisional Monthly and Annual Mean COz Concentrations (ppm, Relative to Dry Air~X85 Mole 

Fraction Scale) From Lhe Continuous Analyzers in 1987 

BRW MLO SMO SPO 

Jan. 352.36 348.23 346.68 345.72 

Feb. 352.72 348.50 346.88 345.55 

March 353.90 349.58 346.84 345.54 

April 353.85 35 1.10 346.38 345.72 

May 354.44 35 1.87 347.92 345.95 

June 352.19 351.46 347.8 1 346.41 

luly 346.45 349.80 348.21 346.92 

Aug. 340.38 347.73 347.76 347.47 

Sept. 340.54 346.38 347.9 1 347.94 

Del. 348.38 346.49 348.03 348.02 

Nov. 349.50 347.7 1 348.23 348.17 

Dec. 352.57 348.93 348.79 348.10 

Annual 349.77 348.98 347.62 346.79 

:e 

< 

~ 

'" X 

o 

~ 0 ~ 

N 

o 

U . , 

~211.f11 ' ..,. ! ,iii ' "1'1 

--- ....... - ... 0 

--- --~ 

Fig.4.1. Long·term trends of CO2 concentration at the fou r GMCC 

observatories obtained by digital-fLltering of the daily data. The 

seasonal cycles have been removed by the filtering. 

accidcntal loss of one of the NOAA secondary reference gases 

during shipment to SIO for calibration. These gases define our 

link to the WMO calibration scale; therefore, this progranl is 

somewhat undercalibrated in this respect because of a lack of 

redundancy. Fifteen large (225 ft3 STP capacity) aluminum 

tanks have now been acquired for the backup and eventual 

replacement of our present set of secondary gases. The new 

tanks will be filled with dry air at Niwot Ridge, Colorado. 

4.1.2. FLASK SAMPLE CO, MEASUREMEl'-'TS 

Measurements of Lhe global distribution of atmospheric CO2 

continued during 1987 . Whole air samples were collected in 

glass flasks at the sites of the NOAN GMCC cooperative flask 

sampling network. The network consisted of the same 26 sites 

as in 1985-1986 [Schnell and Rosson, 19861. The provisional 

annual mean CO2 concentrations for 1985-1987 are given in 

Table 4.2. The annual mean concentrations for 1987 arc plotted 

in sine of latitude coordinates in Figure 4.2. ex tending a series 

of latitude plots given in Schnell and Rosson [1 986, 1987}. 

In a continuing effort to find a replacement for the greased 

ground-glass stopcocks currently in use on the O.S-L flasks, 

various O-ring stopcocks, with Vi1on, Buna. and Teflon O-rings 

were tested. Teflon was most promising, so several hundred 

Teflon O-ring stopcocks were purchased and installed on flasks. 

Larger scale laboratory and field tests are in progress to ensurc 

that changing stopcocks will not adversely affect the lime series 

for CO2 flask data. 

Analysis of thc statistical uncertainty and some of the 

systematic biases of fl ask sampling continued. Biases may arise 

from the time of day of sampling and from the data selection 

that results h om the rejection of outliers that have residual 

deviations from a smooth curve fit of more than 3 standard 

deviations. The biases depend on the method used to produce a 

smooth curve fit. A preferred method was selected that fiLS a 

sum of harmonics to represent the average seasonal cycle and 
Table 4.2. Provisional Annual Mean CO2 Concentrations 

From the Flask Network Sites 

Code Station 

ALT Alert, N.W.T., Canada 

AMS Amsterdam Is. 

ASC Ascencion Is. 

AV! St. Croix, Virgin Is. 

AZR Terceira Is., Azores 

BRW Pt. Barrow, Alaska 

CBA Cold Bay, Alaska 

CGO Cape Grim, Tasmania 

ClIR Christmas Is. 

CMO Cape Meares, Oreg. 

COS Cosmos, Peru 

GMi Guam, Mariana Is. 

lIBA Halley Bay, Antarctica 

KEY Key Biscayne, Aa. 

KUM Cape Kumukahi, Hawaii 

MBC Mould Bay, Canada 

MID Midway Is. 

MLO Mauna Loa, Hawaii 

NWR Niwot Ridge, Colo. 

PSA Palmer Station, Antarctica 

SEY Mahe Is., Seychelles 

SGI South Georgia Is. 

SHI Shemya Is. 

SMO American Samoa 

SPO South Pole, Antarctica 

STM StationM 

Square brackets indicate no flasks received. 

Dashes indicate no ongoing program. 

1985 1986 1987 

348.0 349.5 

344.1 345.0 I I 

345.0 345.8 348.1 

345.4 346.4 348.2 

346.0 348.7 348.7 

346.5 348.6 349.5 

347.2 348.1 349.7 

343.7 344.6 346.5 

345.9 346.3 348.5 

347.4 347.8 350.8 

I I I I I I 

346.2 347.4 349.4 

344.2 I I 347.2 

346.7 347.6 349.5 

345.6 346.5 348.5 

346.7 348.6 349.8 

347.6 349.7 

345.3 346.3 348.5 

346.1 346.4 348.6 

343.9 344.7 347.0 

344.8 346.0 349.0 

I I I I 

348.9 350.0 

344.7 345.2 347.1 

343.6 344.6 346.8 

346.0 347.2 348.8 

uses a digital filter to establish the trend and seasonal anomalies 

from the residuals. Our estimate of the depth of the summer 

photosynthetic drawdown of CO2 at high northern latitudes has 

increased somewhat compared with earlier work [Conway et ai., 

1988J. 

Regular flask samples are obtained from a commercial 

container ship sailing on a 6-wk round-trip schedule between the 

west coast of North America and New Zealand. The samples 

are obtained in pairs at approximately every 5" of latitude by 

exp:>sing evacuated 2.5-L flasks to ambient air. The sample 

collection is performed by the deck officers of the SOUlhiand 

Scar of the Blue Star Line. The project is intended to provide 

higher resolution data than is available from our network of 

land-based sampling sites, so that the spatial and temporal 

variations of CO2 and CH4 over the Pacific Ocean can be better 

detennined. 

Thus far, 11 round-trip voyages have been completed 

belween December 14, 1986, and May 20, 1988. Preliminary 

plots of concentrations vs. latitude show the ever-changing 

variations of atmospheric CO2 with both latitude and time. 

However, the seasonal variations at the 5" lattitude intervals are 

not as well defmcd as those from the GMCC Pacific Basin flask 

sampling network sites, as there is only one sample every 3 

weeks instead of one per week. Some samples must also be 

rejected because of poor pair agreement. How well this series 

of samples characterizes Pacific open-ocean background 

conditions should become apparent when a project to monitor 

31 

the CO2 continuously with an infrared analyzer is carried out on 

voyage 159 in July 1988. 

4.1.3. MODEL DEVELOP~fEl\~ 

A deeper understanding of the present global cartxm budget 

and its response to climatic changes is a necessary condition for 

any credible predictions of future levels of CO2, One of the 

original purposes of obtaining the GMCC flask data is to deduce 

the globally significant sources and sinks of atmospheric CO2 

from the observed spatial and temporal gradients. An 

atmospheric transport model is needed to interpret the 

observations in terms of sources and sinks. 

The Carbon Cycle Group has constructed and used for this 

purpose a two-dimensional (latitude and height) model that uses 

the advective and diffusive transport fields derived by Plumb 

and Mahlman [1987J from Ihe GFDL three-dimensional model. 

This model was used to deduce from the atmospheric 

measurements the existence of a seasonal cycle in the uptake of 

CO2 in the southern oceans and also in the tTopicai source of 

CO2, The model calculations illustrate that in the northern 

hemisphere the source deduction problem is very hard to solve 

without measurements over the great continental areas [TaIlS et 

al.,1989J. 

A global three-dimensional transport model is being 

constructed and Lested. It is a Lagrangian type model, in which 

parcels of air are followed around the globe. The transport is 

based on ECMWF-observcd and -interpolated wind fields. The 

model can either be stochastic, based on the statislical properties 

of the ECMWF fields, or il can use the ECMWF fields direclly. 

4.1.4. FLASK SAMPLE METIIANE MEASUREMENTS 

The measurement of methane in flask air samples returned 

from the NOANGMCC cooperative flask sampling network 

conlinued in 1987. Records of these data for SPO and MLO arc 

shown in Figure 4.3. The larger degree of scatter in the MLO 

data is typical of locations in the northern hemisphere [Sceele el 

al., 1987]. The average growth rale for 1983-1987 al SPO is 

352 

)S! 

350 

, 

• '" 

= 

N ,<, 0 

U 

347 

• ) .. 5 

345 

- I -.5 • 

SINCLATITUO£) 

.5 

~ I 

1987 

Fig. 4.2. Annual mean CO2 concentrations vs. sine of latitude for the 

GMCC flask sampling network. Data ploued with the symbol (+) were 

not included in the smoothed curve fit. 
~ 

~ 

l: 

U 

32 

""I Hlil" 

16~1I 

160B 

1559 

......... ~~ -~ 

• ...... :.:: ~r 

.,: 

P 

.I' 

. ~ -, 

I .. -. • 

...... ' ... 

l!eeL-____________ -" ______ ~ ______ '_ ____ _" ______ .J 

1993 L9a~ 1985 1986 19B7 \988 

Fig. 4.3. Rask methane data at SPQ (boxes) and MLO (pluses). In 

each case the saUd line results by joining adjacent values of the 12-ma 

running-mean methane concentrations, which are plotted 81 the midpoint 

of the appropri ate 12-ma interval. 

12.1 ± 0.1 ppb yr', while at MLO it is 12.2 ± 0.3 ppb yr'-

Growth rales were detcnnined by a linear fit to the 12-mo 

running-mean concentrations. The growth rales at both of these 

sites are now lower than they were just 1 year ago: for 

1983-1986 at SPO, the average growth rate was 12.5 ± 0.1 ppb 

yr' [Robinson el al., 19881, and for 1983-1986 at Mill it was 

12.6 ± 0.3 ppb yr'-

4.1.5. L'I SITU MEllMNE MEASUREMENTS AT BRW 

These measurements continued during 1987 with few 

interruptions. As in 1986 highly elevated methane concentrations were often observed when the winds had a westerly 

component. These elevated concentrations are clearly 

associated with local human activities to the west of the 

observatory site. 

More intriguing are the occurrences of elevated methane 

concentrations when the winds are from the cast, particularly 

a50r-----,------~----~r__r--~----'1 

. j' I 

• • • 

:t ! u i 

Il'32 ~ 

.1 . . I I 

.y. I .. ;;.< , 

I 

7e0<-----~3~5~'-----035~.c----c3~5~6-----=3~5'O-----~ 

C02 (ppm) 

during the Arctic spring. During 1986 these elevations in 

methane were correlated with elevations in carbon dioxide 

[Conway and Steele, 1988] and aerosol black carbon [Hansen et 

ai., 1988], suggesting a common source or source region for all 

three species. This finding was confirmed for methane and 

carbon dioxide during 1987 and is illustrated in Figure 4.4 

where scatterplots of hourly average me thane versus hourly 

average carbon dioxide are shown for March 1986 and March 

1987. The data shown in Figure 4.4 satisfy the restrictions that 

the corresponding hourly average wind speed was greater than 5 

m S·I , and that the hourly average wind direction was within the 

sector 20· -1 10·. Linear fi ts to the data give slopes of 21.1 ± 0.4 

ppb CH, per ppm CO2 for March 1986 and 18.1 ± 0.8 ppb CH, 

per ppm CO2 for March 1987. It appears that this correlation 

between CH4 and CO2 concentrations is a recurring 

phenomenon during the Arctic spring. 

4.1.6. L'I SlllJ METHANE MEASUREMENTS AT MLO 

During April 1987 an automated gas chromatographic system 

for the in situ measurement of atmospheric methane was 

installed at MLO. The chromatograph (Hach-Carle model 

04270-A) has a flame ionization detector, and the output is fed 

to a Hewlett-Packard 3393A integrator. Data are stored on 

3.5-in discs that are mailed to Boulder for processing. An 

ambient air sample is analyzed every 24 minutes, and samples 

of calibration gas are analyzed before and after every ambient 

sample. All air samples are dried before analysis. The ambient 

air is sampled from the top of the walk-Up tower. The methane 

concentrations for the ambient samples are printed out at the 

site. 

The Weiss-designed gas chromatograph was removed from 

the observatory in late April 1987 after a dcmonstration that 

over a period of 12 days the methane concentrations produced 

by this instrument were essentially identical to those generated 

by the Hach-Carle-based systcm. 

:>'. 

.1(. . 

··j-X ... r"~ ::- . '. :' '~ ." 

35'1 356 

C02 (ppm) 

358 

Fig. 4.4. ScatterplOls of hourly average methane concentrations versus the corresponding hourly average carbon dioxide concentration at BRW during 

March 1986 (left) and March 1987 (right). Data are shown only for those times when the hourly average wind speed was greater than 5 m s-I and the 

hourly average wind direction was within the sector20o-llDo. 
The in situ data show some interesting features. During 

upslope conditions the methane concentrations generally 

increase. This is opposite to the behavior seen for some other 

trace gases such as carbon dioxide and ozone. The increase in 

methane concentrations is consistent with the existence of a 

venical gradient in methane, in which lower concentrations are 

measured at higher altitudes most of the time. Comparison of 

the MLO in situ data with flask-sample data taken near sea level 

at Cape Kumukahi shows this venical gradient quite clearly. 

However, during October-November there were times when 

higher concentrations were measured at the observatory than at 

Cape Kumukahi. Perhaps the most intriguing feature of the in 

situ data is illustrated in Figure 4.5 which shows the daily 

average methane concentrations during 1987. The two gaps in 

lhe data were due to instrument malfunctions. These daily 

average concentrations are observed to change by as much as 50 

ppb over as little as a few days. A power spectrum of the daily 

data shows a prominent peak corresponding to a period of 12-14 

days. The origin of these fluctuations is still not known. 

4.2. SPECIAL i'ROlEcrs 

4.2.1. SAGA II ExpEomON 

The Carbon Cycle Group, in collaboration with the GMCC 

NOAH Group, participated in the SAGA II expedition aboard 

the Soviet research vessel Akademic Korolev. Data were 

obtained by gas chromatography on COl and CH4 in the 

atmospheric boundary layer and the sea surface waters between 

the Kamchatka Peninsula, U.S.S.R" and Wellington, New 

Zealand. 

4.2.2. EGYP"r PROJECT 

In October the Carbon Cycle Group participated in a project 

that was organized by the National Geographic Society [El·Baz, 

1988] in collaboration with the Egyptian Antiquities Organiza. 

tion. In 1954 two tombs were discovered adjacent to Cheops' 

16ee~"k"~C~'~'-C"~".,-,,~o"~"~'~'-"~"~-';~"--~"~'C-~s'~.~O~,~,-cH~O~'-'D~"~ 1967 

Fig. 4.5. Daily average methane ooncentrations at MLO during 1981. 

Data for January and February are from the Wciss-designed 

chromatograph. Data from April onward are from the Hach-Ca rle-based 

system. Gaps in the record are due to instrument malfunctioru. 

33 

pyramid in Giza. One of them was opened and found to contain 

all the parts of a remarkably well preserved boat. The ooat was 

reconstructed and is now on display at the site. It was reported 

that upon opening the first pit the researchers could smell cedar, 

which would suggest that there had been a very tight seal. It 

appeared therefore that the second tomb presented a chance to 

obtain large samples of "old" air. 

A special airlock assembly was designed by an engineer at 

Black and Decker, to allow drilling through the 6·ft-thick 

limestone roof of the chamber and extract air samples, without 

exchange of outside air with the air in the chamber. The hole 

was also used for the insertion of video and photography 

equipment to study the contents of the pit, as well as the 

insenion of a temperature and humidity monitor. Pieces of a 

ship similar to the first one were found, but no old air [Tans el 

al.,1988]. During the sampling of the air inside the chamber it 

became clear that there was communication between the inside 

and outside air. This was later confirmed by the measurements 

of the concentrations of modem industrial gases inside. such as 

the chlorofluorocarbons CFC-ll and CFC·12. The second boat 

appeared to be in much worse condition than the Hrst, but the 

reason for the difference is not understood. A complete and 

colorful description of the project was given by EI·Baz (1988] 

4.3. REFERENCES 

Conway, T.!. and LP. Steele, Carbon dioxide and methane in the Arctic 

atmosphere, J. Almo..r. Clum .• in press, 1988. 

Conway, T.J., P.P. Tans, LS. Waterman, K.W. Thoning. K.A. Masarie, 

and R.H. Gammon, Atmospheric carbon dioxide measurements in 

the remote global troposphere, 1981-1984, IIu.s, 408, 81-115, 

1988. 

EI-Baz, F., Finding an Ancient Pharaoh's Barque, National Geographic, 

173,5 13-533, 1988. 

Hansen, A.D.A., T.J. Conway, LP. Steele, B.A. Dodhaine, K.W. 

Thoning, P. Tans, and T. Novakov, Correlations among combustion 

effluent species at Barrow. Alaska: Aerosol black carbon, carbon 

dioxide, and methane, J. Atmos. Chern., in press, 1988. 

Komhyr, W.O., T.B. Harris, LS. Watennan. J.F.S. Chin, and K.W. 

Thoning, Atmospheric carbon dioxide at Mauna Loa Observatory: 

NOANGMCC measurements with a nondispersive infrared 

analyzer, 1974-1985,J. Geophys. R~s., in press,1988. 

Plumb, R.A., and J.D. Mahlman, The zonally averaged transport 

characteristics of the GFDL general cirrulation/lransport model, J. 

Almas. Sci., 44. 298-327, 1987. 

Robinson. E. , B.A. Bodhaine, W.O. Komhyr, SJ. Oltmans, LP. Steele, 

P. Tans, and T.M. Thompson, Long-term air quality monitoring at 

the South Pole by the NOAA program Geophysical Monitoring for 

Climatic Otange, Rev. G~ophys., 26. 63-80, 1988. 

Schnell, R.C., and R.M. Rosson, Geophysical Monitoring for Oimatic 

Change No 14: Summary Report 1985, NOAA Air Resou rces 

Laboratory, Boulder, Colo., 1986. 

Schnell, R.C., and R.M. Rosson, Geophysical Monitoring for Oimalic 

Change No 15: Summary Report 1986, NOAA Air Resources 

Laboratory, Boulder, Colo. , 1987. 

Steele, LP., PJ. Fraser, R.A. Rasmussen, M.A.K. Khalil, T.J. Conway, 

AJ. Crawford, R.H. Gammon, K.A. Masarie, and K.W. Thoning, 

The global distribution of methane in the troposphere, J. Almos. 

Chern" 5, 125·!71, 1987. 

Tans, P.P., J.W. Elkins, and D.R. Kitzis, Air sampling procedures and 

measurements of the air composition of the second boat pit of 

Khufu's pyramid, NOAA Tech. Memo. ERL ARL·J63, NOAA Air 

Resources Laboratory, Silver Spring, Maryland t 988. 
34 

Tans, P,P., T J. Cooway, and T. Nakajawa, Latitudinal distribution of 

the sources and sinks of atmospheric carbon dioxide derived from 

surface observations and an atmospheric transpon model, J. 

G~ophys. Ru., in p~ . 1988. 

Thoning, K.W., P,P. Tans, and w.n. Komhyr. Atmospheric carbon 

dioxide at Mauna Loa Observatory: n. Analysis of the NOAAI 

GMCC data, 1974-1985,1. Geophys. Res .. submitted, 1988. 
35 

5. Monitoring Trace Gases Group 

5.1. CONTINUING PROGRAMS 

5.1.1. TOTAL OZONE 

Routine Observations 

Routine total ozone observations were made with Dobson 

spectrophotomctcrs during 1987 at 16 stations that constitute the 

U.S. total ozone station network (Table 5.1). Of the 16 stations, 

5 are operated by GMCC personnel, 4 are foreign cooperative 

stations, 3 arc domestic cooperative stations, and 4 are operated 

by the NWS. 

Daily 1987 total ozone amounts applicable to local apparent 

noon for stations in the U.S. Dobson instrument network have 

been archived by the WMO, World Ozone Data Centre, 4905 

Dufferin SlIcet, Downsview, Ontario M3H5TH, Canada, in 

Ozone Data for the World. Table 5.2 lists provisional monthly 

mean total ozone amounts for 1987 for the NOAA observatories 

and the cooperative stations. 

1986 InlernaJional Dobson Spectrophotometer and Brewer 

Spectrometer Intercomparisons 

An international comparison of Dobson ozone 

spectrophotometers and Brewer spectrometers was conducted by 

NOANGMCC Ozone Project personnel in Arosa. Switzerland, 

in Augusl1986. A lotal of 16 Dobson and 3 Brewer irutrumenls 

participated. The reference standard irutrument for the 

TABLE 5.1. U.S. Dobson Ozone Spectrophotometer Station Network for 1987 

Station Period of Record Instrument No. Agency 

Bismarck. N. Oak. Jan. I, I 963-present 33 NOAA 

Caribou. Marne Jan. I. 1963-present 34 NOAA 

Wallops Is .. Va. July I. 1967-present 38 NOAA; NASA 

SMO Dec. 19. 1975-present 42 NOAA 

Tallahassee, Fla. May 2, 1964-present 58 NOAA; Fla. Slate Univ. 

Boulder, Colo. Sept. I, 1%6-present 61 NOAA 

Poker Flat, Alaska March 6. 1984-present 63 NOAA; Univ. of Alaska 

Lauder, New Zealand Jan. 29, 1987-prcsent 72 NOAA; DSIR 

MLO Jan. 2, 1964-present 76 NOAA 

Nashville, Tenn. Jan. 2, 1963-present 79 NOAA 

Perth, Australia July 30, I984-present 81 NOAA; Australian Bureau Meleorol. 

SPO Nov. 17, 1961-present 82 NOAA 

llaute Provence, France Sept. 2, 1983-present 85 NOAA;CNRS 

Huancayo. Peru Feb. 14, 1964-present 87 NOAA; IGP 

BRW June 6, 1986-present 91 NOAA 

Fresno, Calif. June 22, 1983-present 94 NOAA 

TABLE 5.2. Provisional 1987 Monthly Mean Total Ozone Amounts (m-aun-cm) 

Station Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. 

Bismarck, N. Dak. 370 358 373 350 334 335 313 314 297 295 307 325 

Caribou, Maine 377 427 380 375 399 369 347 335 333 328 335 340 

Wallops Is., Va. 328 335 374 397 384 344 336 327 322 312 289 301 

SMO 238 221 240 238 247 248 243 257 253 265 257 254 

Tallahassee, Fla. 302 283 342 365 360 314 320 315 323 288 280 263 

Boulder, Colo. 328 339 352 342 352 326 317 302 299 287 293 299 

Poker Flat, Alaska 406 424 405 360 326 303 309 311 

Lauder, New Zealand 289 287 274 286 301 325 314 329 368 365 335 306 

'-'ILO 249 239 263 278 294 292 280 267 262 248 249 237 

Kashville, Tenn. 329 320 363 387 352 338 329 326 325 314 291 285 

Perth, Australia 275 265 274 274 273 273 293 307 315 325 312 287 

SPO 287 278 246 243 241 253 257 141 184 312 

! laute Provence, France 329 366 398 385 411 372 346 333 308 298 308 298 

! luancayo, Peru 254 246 238 241 254 257 257 251 247 

BRW 443 410 400 360 335 305 333 321 

Fresno, Calif. 327 340 352 355 366 347 334 316 310 285 300 303 
36 

TABLE 5.3. Results of Calibrations of Foreign Dobson SpcctropholOmeters With U.S. Primary Standard Dobson 

Instrument No. 83, Expressed as Mean Total Ozone Differences (%) for Various Air Masses ().l) 

Dobson 

Inst. Calibration 1'= 1' = 1'= 1'= 1'= 1'= 

No. Country 0'1<,1986 1.15-1.5 1.5-2.0 2.0-2.5 25-3.2 3.2-4.0 1.15-3.2 

13 Portugal Aug. 15 -1.13 -2.36 -3.27 -5.80 16.34 -2.41 

15 Switzerland Aug. 15 -1.69 -2.06 -1.80 -2.94 -7.53 -1.99 

40 Belgium Aug. 15 2.39 1.49 0.95 1.16 0.65 1.84 

51 Switzerland Aug. 15 .{J.78 -1.62 -1.59 -1.69 -1.63 -1.22 

56 Norway Aug. 15 -1.02 .{J.91 .{J55 .{J.62 -1.01 .{J.89 

64 G.D.R. Aug. 21 .{J_16 051 0.27 .{J.06 .{J.21 0.11 

71 G.D.R. Aug. 15 1.69 1.78 2.73 2.49 0.98 1.94 

74 Czechoslavakia Aug. IS -1.73 -1.25 -1.11 -1.16 .{J.61 -1.46 

83 United States Reference Dobson Spectrophotometer 

84 Poland Aug. 15 3.22 1.70 0.9 1 0.58 .{J.IO 2.22 

85 France Aug. 21 .{J.17 .{J.33 .{J.43 .{J.05 0.13 -0.23 

92 Denmark Aug. 15 2_04 1.21 0.25 0.07 -1.28 1.34 

96 Egypt Aug. 15 1.69 0.61 0.33 .{J.93 -2.82 0.85 

101 Switzerland Aug. 15 -2.63 -2.62 -2.29 -3.42 -4.96 -2.73 

104 F.R.G. Aug. 6 3.78 1.36 0.34 0.34 .{J.34 2.41 

120 Spain Aug. 15 2.15 0.70 .{J.15 .{J.26 .{J.W 1.19 

Foreign minus Dobson instrument no. 83 percent orone differences are shown. The Dobson instrument values are derived from observations on AD 

wavelengths. 

comparisons was World Primary Standard Dobson instrument 

no. 83, maintained by NOANGMCC in Boulder, Colorado_ 

Table 5.3 lists results of preliminary calibrations of the 

various Dobson instruments relative to instrument no. 83, as a 

function of the air mass).1. Results of preliminary calibrations of 

the Brewer spectrometers are shown in Table 5.4. More 

detailed infonnation regarding the comparisons is available in 

Komhyr et aJ. [1988a]. 

Calibration of Portuguese Dobson InstrumenJ No. 13 in Boulder 

During 1987 GMCC continued the program that began in 

1977 to upgrade foreign Dobson spectrophotometers under the 

auspices of the WMO Global Ozone Research and Monitoring 

Project. At the Arosa Dobson instrument comparisons, 

Portuguese Dobson instrwnent no. 13 was found to be highly ~ 

dependent. Major repairs were made to the instrument in 

Bou1der in May 1987. The instrument was then optically 

aligned, calibrated relative to Dobson spectrophotometer no. 83, 

and returned to Portugal. 

Calibration Checks on Dobson Instrumenls in the Global 

Network 

Komhyr et aJ. (1981) devised a standard lamp method for 

identifying Dobson instrwnents that have gross cal ibration 

errors. In an ongoing program by NOANGMCC to upgrade the 

calibrations of Dobson spectrophotometers throughout the 

world, seven standard lamp units, each consisting of two 

calibrated lamps and a stable power supply, were fabricated in 

1981. The global Dobson instrument station network was then 

divided into seven areas, each containing 5 to 17 instrwnents, 

and a lamp unit was shipped to each area for checking the 

calibration of the Dobson instruments there. Results of the 

TABLE 5.4. Results of Calibrations of Brewer Spectrometers With U.S. Primary Standard Dobson Instrument No. 83, 

Expressed as Mean Total Ozone Differences (%) for Various Air Masses (J.l) 

Dobson 

Inst. Calibration 1'= 1' = 1'= 1'= 1'= I' c 

No. Country Date, 1986 1.15-1.5 1.5-2.0 2.0-25 2.5-3.2 3.2-4.0 1.15-3.2 

10 F.R.G. Aug. 15 0.0 .{J.5 -1.1 .{J.9 .{J.4 .{J.6 

5 Greece Aug. 21 0.0 .{J.I .{J.6 .{J.9 .{J.3 .{J.4 

10 F.R.G. Aug. 21 0.3 0.2 .{J.4 .{J.5 0.2 .{J.I 

17 Canada Aug. 21 1.1 0.8 0.3 0.4 0.2 0.7 

Brewer minus Dobson instrument no. 83 percent ozone differences are shown. The Dobson instrument values are derived from observations on AD 

wavelengths. 
37 

TABLE 5.5. Results of 1985·1987 Calibration Checks on Dobson Spectrophotometers Using Traveling Standard Lamps 

Imt Date of Inst. Calib. Inst Date of Inst. Calib. 

Station No. Calib. Check Error (%)' Station No. Calib. Check Error ('Yo). 

Area J-NOTlh America Haute Provence, France 85 June 21, 1985 -1.25 

Lisbon, Portugal 13 July 26.1 985 +0.66 

Toronto, Canada 77 May31,1985 -0.29 EI Arenosillo, Spain 120 Oct. 8, 1985 +0.66 

Resolute, Canada 59 Dec. 30, 1985 -0.81 Vigna DiVaUe, Italy 47 Nov. 27, 1985 +1.03 

Churchill, Canada 60 Feb. 12, 1986 +1.10 Brindisi, Italy 46 Nov. 23, 1985 +0.88 

Goose Bay. Canada 62 July 13, 1985 +0.08 Sestola, Italy 48 Dec. 6, 1985 +1.10 

Edmonton, Canada 102 Nov. 14, 1985 +0.15 Calgiari/Elmas, Italy 113 Nov. 16, 1985 -0.59 

Reykjavik, Iceland 50 June 10, 1986 +0.15 Casablanca, Morocco 106 

SPO 82 Fcb.2,1988 +0.15 Cairo, Egypt 69 Feb. 6, 1986 -1.25 

Bismarck, N. Dak. 33 July 28,1986 -2.35 Cairo, Egypt 96 Feb. II, 1986 +1.17 

Caribou, Maine 86 Oct.6,1986 -0.15 

Wallops Is., Va. 38 Oct. 10, 1986 -0.22 Area 5-Eastern. Europe U.S.S.R. 

Tallahassee, Fla. 58 Dec.3I,1986 -0.29 

Nashville. Tenn. 79 Jan. 9, 1987 +1.17 Leningrad, U.S.S.R. 108 April 2, 1985 +0.08 

Poker Flat, Alaska 63 Jan. 13, 1987 -1.10 Belsk. Poland 84 May 23, 1985 +1.24 

MLO 76 May 24,1987 +1.47 Hradec Kralove 74 June 26, 1985 -4.40 

SMO 42 July 15,1987 +1.61 Czechoslovakia 

BRW 91 Jan. 29, 1988 +0.30 Budapest-Lorini, Hungary 110 July31,1985 -1.54 

Fresno, Calif. 94 May 5, 1987 + 1.18 Bucharest, Romania 121 S,pt. 5, 1985 +2.72 

BooIder, Colo. 61 April II, 1985 -1.03 Potsdam, G.D.R. 64 Oct. 10,1985 -0.52 

Boolder, Colo. 65 April II, 1985 -1.25 Potsdam, G.O.R. 71 Oct. 10,1985 +0.66 

Boolder, Colo. 34 Jan.27,1988 +0.22 

Boolder. Colo. 80 Jan. 13, 1988 +1.40 Area 6-/ndia 

Arw 2-S0Ulh Amtrica, Africa New Delhi. India 36 Aug. 9, 1985 +0.73 

New Delhi. India 112 April 22, 1985 -0.52 

Mexico City, Mexico 98 May 22, 1985 +1.32 Srinagar. India 10 

Huancayo, Peru 87 April I, 1985 -0.37 Varanasi,lndia 55 Aug. 22, 1985 -1.76 

Cachoeira Paulista. Braz.il 114 June 6.1986 ±O.OO Mt Abu. India 54 

Natal, Braz.il 93 Poona. India 39 Jan. 23, 1986 +1.54 

Buenos Aires. Argentina 97 Nov. 4,1985 -0.52 Kodaikanal, India 45 July 5, 1985 +2.42 

Buenos Aires. Argentina 99 Nov. 6,1985 +0.15 Quetta, Pakistan 43 July 22,1986 +1.40 

Nairobi, Kenya 18 Quetta, Pakistan 100 July 19, 1986 +1.47 

Bangkok, Thailand 90 Oct. 9, 1986 -1.17 

Arw 3-Wutem Europ~ (1) Singapore 7 Dec. 18, 1986 +3.06 

Manila, Philippines 52 June 22, 1987 +1.18 

Bracknell, U.K. 41 

Brackne1l, U.K. 2 July 25,1985 -0.52 Area 7-Australia, Japan. 

Halley Bay, U.K. 123 Dec. 28, 1985 +3.67 

Argentine Is., U.K. 31 F,b. 19, 1986 +0.37 Sapporo, Japan 5704 July 15, 1985 -0.88 

Seychelles, U.K. 57 Aug. 26, 1985 -2.50 Kagoshima. Japan 5705 June 18, 1985 -0.22 

S1. Helena, U.K. 35 Sept. 25,1985 -0.59 Tateno, Japan 116 July 25,1985 -0.34 

King Edward Point, U.K. 103 Oct. 17,1985 -1.32 Naha/Kagamizu, Japan 5706 June 29, 1985 -0.44 

Lerwick, U.K. 32 July 31,1985 -2.28 Tateno, Japan 5703 Oct. 24,1985 -0.49 

Arosa, Switzerland 15 March 27, 1985 -2.57 Sapporo, Japan 5702 

Arosa, Switzerland 101 March 27, 1985 +4.55 Tateno, Japan 122 

Hohenpeissenberg, ER.G. 104 April 22, 1985 +2.42 Xianghe, China 75 F,b. 3, 1987 +0.66 

Cologne, ER.G. 44 Kunming,Olina 3 June 16, 1987 -0.74 

Oslo, Norway 56 July 12,1985 -0.66 Melbourne, Australia 105 July 9, 1986 +0.52 

Trams¢!, Norway 14 July 5, 1985 -1.03 Perth, Australia 81 June 16, 1986 +0.52 

Spitzbergen, Norway 8 July 3,1985 -0.22 Brisbane, Australia III Jan. 5, 1986 +0.22 

Cambridge, U.K. 73 Sept. 9, 1986 -2.79 Hobart, Australia 12 March 16, 1986 +0.73 

Macquarie Is., Austra1ia 6 

ArUl4-Wut~m Europt (2) Invercargill, New Zealand 17 Oct. 17,1986 -1.17 

Lauder, New Zealand 72 

Aarhus, Denmark 92 March 19,1985 +3.60 Seoul, Korea 124 Nov. 30, 1985 +1.I7 

Uccle , Belgium 40 April 5, 1985 +1.61 Melbourne, Australia 115 

Biscarrosse, France II Melbourne, Australia 78 

·See text for significance of indicated calibration error. Positive error means that instnnneni yields orone va1ues that are too large. 
38 

calibration checks were presented at the 1984 Quadrennial 

Ozone Symposium (Grass and Komhyr. 1985). 

We prescnt here the results of similar Dobson instrument 

calibration checks conducted in 1985-1987. Of 95 operational 

instruments, only 14 stations failed to report sufficient data. 

Results arc shown in Table 5.5. Deduced instrument calibration 

errors of absolute magnitude >2% were taken to signify that an 

instrument problem exists. According to this criterion, 13 of 81 

instruments were identified as needing recalibration. 

Calibration of Primary Standard Dobson InstrumenJ No. 83, 

1962-1987 

Dobson spectrophotometer no. 83 was established in 1962 as 

a standard for total ozone measurements in the United Stales. In 

1980. this instrument was designated by the WMO as the 

Primary Standard Dobson Spectrophotometer for the world. 

Since 1962. 15 domestic and 75 foreign instruments have been 

calibrated, many of them several times. either directly or 

indirectly relative to instrument no. 83. 

Absolute calibrations of instrument no. 83 (relative to 1953 

Vigioux. ozone absorption coefficients for Dobson instrument A 

and 0 wavelength pairs) were perfonned by the Langley slope 

method at Sterling, Virginia, in 1962, and at Mauna Loa, 

Hawaii. in 1972. 1976. 1978. 1979. 1980. 1981. 1984. 1986. and 

1987. Additionally, calibration checks on the instrument have 

been performed routinely since 1962 with a set of standard 

lamps. Analysis of results of the two types of calibrations has 

yielded data on the long-term ozone measurement precision of 

the instrument {Komhyr et aI., 1988b]. 

TIle most comprehensive calibration of instrument no. 83 was 

performed in 1976 at MLO when ozone observations were made 

during 90 one-half days. The standard error associated with the 

determination of the mean correction to the instrument values at 

that time was 0.0006, which corresponds to an Wlcertainty in the 

measurement of ozone of 0.07% for ozone values x = 300 DU 

and J.l = 2. This calibration of instrument no. 83 resulted in 

establishment of an August 26. 1976. Calibration Scale for the 

intrument that has been used through 1987 in calibrating all 

domestic and foreign Dobson spectrophotometers. 

The August 26, 1976, Calibration Scale was used to establish 

N values in 1976 for Dobson instrument no. 83 standard lamps 

83A. 83B. W. X. Y. Z. 83QI. and 83Q2. some of which had 

been run on the instrument since 1962. The lamp data were then 

used to establish a 1962-1987 Standard Lamp Calibration Scale 

for instrument no. 83. which. except for the 1976 tie in, is 

independent of the Langley slope calibrations of the instrument. 

Table 5.6 compares ozone values XI' determined with 

instrument no. 83 during 1962-1987 on the August 26. 1976. 

Calibration Scale. with similar values. x2 incorporating Langley 

slope calibration corrections; with X3 values measured on the 

1976 Standard Lamp Scale; and with x4 values detennined on 

the 1976 Standard Lamp Scale with Langley slope calibration 

corrections applied. We draw three conclusions from the 

results. First, the August 26, 1976, Calibration Scale has 

remained Wlchanged to within an uncertainty of ±O.5% during 

1972-1987. Second. because this scale has remained highly 

stable with time, additional calibration corrections are not 

needed for domestic and foreign Dobson instruments calibrated 

TABLE 5.6. Stability of the August 26. 1976. Calibration 

Scale for Dobson Instrument No. 83 

!()()(Xt - X2) !()()(Xt -X3) !()()(Xt -x.,) 

Xl X3 X4 

Year ('To) (%) ('To) 

1962 -0.7 -1.0 

1972 -0.1 -0.3 -0.1 

1976 0.1 0.0 0.1 

1978 0.0 0.0 0.0 

1979 -0.2 -0. 1 -0.2 

1980 0.2 0.0 -0.4 

1981 -0.3 -0.1 -0.7 

1984 0.5 -0.1 0.1 

1986 0.2 -0.5 -0.5 

1987 0.2 -0.2 -0.1 

XI ozone values: Based 011 the August 26. 1976, Calibration Scale and 

instnunent optical wedge calibration of August 26, 1976. X2 ozone 

values: As Xl values, but corrected by the Langley slope calibration 

method. X3 ozone values: Based 011 the Standard Lamp Calibration 

Scale established in 1976, and updated optical wedge calibrations. X4 ozone values: As ~ values, but correcled by the Langley slope 

calibration method. 

since 1976 with Dobson spectrophotometer no. 83. Finally, 

instrument no. 83 calibration observations made at MLO 

spanned a solar cycle sunspot maximum and two minima. 

Because the Langley slope and the standard lamp instrument 

calibrations gave essentially identical results, we conclude that 

if the extraterrestrial intensities of the Dobson instrument A and 

D wavelengths vary during the course of a solar cycle, the 

variations are not large enough to cause errors in ozone 

measurements greater than several tenths of a percent. 

Long-Term Changes in the SBUV/TOMS Reialille to the 

Primary Standard Dobson Instrwnenl No. 83 

The SBUV and TOMS instruments on Nimbus 7 measured a 

decrease in total ozone between 1979 and 1986 of 6%, while the 

Dobson network reported only a 3% decrease during the same 

period. bringing the long-tenn calibration of SBUVffOMS into 

question. SB UV and TOMS are independent instruments, 

except that they share the diffuser plate that is used for 

instrument calibration. The TOMS and SBUV ozone 

observations agree very well, except for a 3.0% bias. 

The time dependence of the calibration of the satellite 

instruments has been determined by comparing ozone measured 

by TOMS with that measured by instrument no. 83 [McPeters 

and Komhyr. 1988J at MLO during the summers of 1979.1980. 

1981. 1984, 1986, and 1987. As indicated earlier, instrument 

no. 83 observations were made for the pUT]X)se of monitoring 

the calibration of that instrument [Komhyr el al.. 1988b]. 

The percent differences between TOMS and instrwnent no. 

83 ozone values are plotted for each year in Figure 5.1. Two 

different results (data sets 2 and 3) are given for the Dobson 

inslrument; they represent two slightly different calibrations of 

the instrument. For set 2 the Dobson data were reduced using 

the 1976 instrument optical wedge calibralion for all years, 
whereas for set 3 the data were reduced using updated wedge 

calibrations. The two sets of results are shown to provide some 

indication of the level of uncertainty in instrument no. 83 

results. 

Figure 5.1 shows that the TOMS instrument was relatively 

constant with respect to instrument no. 83 in the period 

1979-1981, especially if the Dobson results for 1980 are 

down weighted because of known problems of observational 

technique that year. But by 1984 the difference in ozone 

measured by the two instruments was +0.5%, a 1.5% decline 

relative to the earlier period. and by 1987 the TOMS ozone 

values were 1.4% less than instrument no. 83 values, a decline 

of 3.4% from 1979-1981. The overall pattern is that the TOMS 

(and by implication SBUV) calibration was relatively constant 

relative to that of inslnunent no. 83 between 1979 and 1981, 

declined rapidly between 1981 and 1986, and appears to be 

declining less rapidly between 1986 and 1987. Our conclusion 

is that the diffuser plate used by both the SBUV and TOMS has 

suffered an uncorrected wavelength-dependent degradation, 

with most of the degradation occurring between 1983 and 1986. 

This change in the TOMS instrument calibration relative to 

the calibration level of instrument no. 83 confl1Jlls the change 

noted earlier relative to many individual stations. Also plotted 

in Figure 5.1 is the yearly average TOMS-Dobson trend relative 

to an ensemble of 41 Dobson stations for the period 1979-1985. 

These data were used by Fleig el al. [1986] to calculate the 

0.38% per year trend. but with data for 1985 comparisons 

added. 

Long-Term Ozone Trends al MW and SMO 

Total orone data obtained in the past at MLO and SMO, 

archived at the World Ozone Data Centre in Downsview, 

Canada, have been provisional. The MLO data record for 

1964-1987 and the SMO data reoord for 1976-1987 were 

reprocessed on the August 26, 1976, Calibration Scale of 

Primary Standard Dobson instrument no. 83 (Komhyr et al., 

1988c). Although some shortcuts were taken in reprocessing the 

data, it is unlikely that more detailed processing will give results 

over portions of the record mat differ on average from current 

values by more than 1 %. 

TOMS-DOBSON DIFFERENCE 

, 

3 a DATA SET 2 

o DATA SET 3 

LL 2 LL A is 

f0- G .••... " 

Z 

W 0 

U -' . 

..•. 'El a: -1 4' srATlo:ts 

W " "- " " -. -2 n 

- 3 

-, 7. ao 61 62 63 6' 65 66 67 66 

YEAR 

Fig.S.1. Average ozone differences in percent measured at MLO by 

TOMS and Dobson instrument no. 83 during 1979-1981. Differences 

for an ensemble of 41 Dobson stations are also shown. 

39 

Figure 5.2 is a plOl of ozone anomalies (i.e., deviations of 

ozone monthly means from monthly nonnals) at MLO for 

1964-1987. Quasi-biennial oscillations in ozonc are clearly 

evident in the record. Least-squares linear regression trend lines 

fitted to the data indicate that ozone at MLO increased on 

average at a rate of 0.37 ± 0.16% yr' during 1964-1974, but 

decreased at a rate of 0.35 ± 0.13% yrl during 1974·1987. 

(Indicated uncertainties are the 95% confidence intervals.) For 

the record as a whole, the mean ozone trend was -0.07 ± 0.06% 

yrl. Annual mean total ozone amounts at MLO were equivalent 

in 1964 and 1987, at 262 DU. 

The SMO Dobson instrument total ozone record was 

similarly reprocessed. Ozone anomalies for SMO for 1976-

1987 are shown in Figure 5.3. A least-squares linear trend line 

fitted lO the data shows that, on average, LOlaI ozone has been 

decreasing at SMO at 0.40 ± 0.11% yrl For 1976-1986, the 

downward trend in ozone was 0.35 ± 0.12% yrl. 

A record low mean monthly total ozone amount of 221 DU 

was measured at SMO in February 1987, at the time of a deep 

minimum in the 1986-1987 tropical quasi-biennial oscillation in 

ozone. This value was 13% lower than the average total ozone 

amount for February months of 1976-1987. Although the value 

is subject to revision, it is unlikely to be too low by more than 

several percent. 

TOlal Ozone at SPO 

Total ozone amounts measured at SPO during SeplemberNovember 1987 were the lowest on record. Figure 5.4 

compares spa total ozone data for 1986 and 1987. For the time 

interval January-May, the average total ozone amount in 1987 

was larger than in 1986 by about 8%. During the polar night of 

both years, total ozone increased from about 245 DU in early 

June to 280-290 DU in August. Total ozone began to decrease 

rapidly during September of both years, to a low of 158 DU in 

early October 1986 but to an unprecedented low of 127 DU in 

early October 1987. Thereafter, the total ozonc began to 

recover, but the recovery proceeded considerably more slowly 

(with a 3-wk delay) in 1987 than in 1986. Compared with the 

time of the springtime ozone increase at Soum Pole in 1978, as 

shown in Figure 5.4, the delay in the 1987 springtime ozone 

increase was 6 weeks. At year end for both 1986 and 1987, the 

total ozone amount at SPO was 315 DU. 

The 1987 October (October 15-31) mean total ozone amount 

at South Pole was 138 DU. The previous October mean low of 

161 DU occurred in 1985 [Komhyr el al., 1986]. The average 

total ozone amount for October months at spa during 

1962-1979 (i.e., before onset of the ozone hole fonnation 

phenomenon in about 1980) was 292 DU. 

The 1987 SPO November tota1 ozone mean of 184 DU was 

also illlUSUally low. The previous November mean low of 238 

DU occurred in 1985. The 1962-1979 average total Drone 

amount for November months at SPO was 351 DU. 

5.1.2. OZONE VERTICAL DISTRlBlJTION 

ECC Ozon.esonde Obsef1lations 

Weekly ECC oronesonde balloon flights sponsored by 

NESDIS continued in 1987 at Boulder, Colorado (51 flights), 
40 

s " 

e. MLO: 2O-N, 156·W 

~ 

" ~ 

0 

Z 

" w 

z 

2 

0 

~ 

g li6-4_1974: + 0.37 ::: O.16'1ttyr 1911-1981: -0.35::: O.13'1otyt ~ -" .. 56 " 10 72 ,. 76 78 80 82 .. .. 88 

YEAR 

Fig. 5.2. Deviations of monthly mean total ozone amounts from 

monthly nonns for the period of record at MLO (1964-1987). 

Least-squares regression trend lines are fitted to the data. 

5 

e. 

~ 

4: 

:2 

o 

Z 

4: 

w 

z 

8 

20 

o 

o -20 03 Trend 

0.40±0.11 %/yr 

....J 

f:! 

12 -4~L6~~78~L-8LO-L-8~2~~84--'L-8L6~~88 

YEAR 

Fig. 5.3. Deviations of monthly mean total ozone amounts from 

monthly noons for the penod of record at SMO (1976-1987). 

Least-square s regression trend lines are fined to the data. 

S" 

e. 

w 

z 

0 

N 

0 

--' 

" i2 

OJ 

« 

0 

200 

6 1978 ........ . 

+1986---

01987 --

100 '-;;-;:;-'-;:;;;-'~;;'-;-==:'-;;-:::-'"="'-::-:::-'-=-':::='":=-'::::::-' JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

Fig. 5.4. Daily 100al ozone amounts at SPO in 1986 and 1987, and a 

portion of the 1978 total ozone record, showing the springtime ozone 

increase that occurs each year in Antarctica. 

and Hilo, Hawaii (52 flights), extending the continuous record 

of weekly soundings to 3 y""" at these two sites (1985-1987). 

Mean Dobson nonnalization correction factors for these nights 

were 0.982 for Boulder and 0.984 for Hila with standard 

deviations of 0.044 and 0.043, respectively. The data were 

forwarded to NESDIS to assist in their efforts to validate ozone 

data from the SBUV instnunent on the NOAA F satellite. 

At BRW and SMO, approximately weekly ECC ozone 

soundings were made in 1987, except for an increased launch 

frequency at BRW during March. Regular ozone soundings at 

BRW date from February 1986, and at SMO from April 1986, 

both programs depending for future continuance on the 

availability of funding. 

Computer processing of ozonesonde data continued for the 

flight program operated by DSIR personnel at Lauder, New 

Zealand. Weeldy ozonesonde releases were made at Lauder 

throughout the year, except twice-weekly during AugustNovember months, for a total of 66 soundings [Malthews el al., 

1988]. This monitoring program provides an opportunity to 

assess the impact of ozone depletion in Antarctica on the ozone 

budget of the southern hemisphere at midlatitudes. 

With support from NOAA and the NSF Division of Polar 

Programs, a successful campaign of 76 ECC ozonesonde nights 

was conducted in 1987 at SPO. From August through 

November, twice-weekly flights were conducted; during the 

remainder of the year, weekly soundings were made. Results 

were published by Komhyr ., al., [1988d]. 

Laliludinal Dislribulion o[ Ozone From ECC Ozoneso"de 

ObservaJions 

ECC ozonesonde observations, made in recent years at nine 

U.S. and foreign stations whose locations range fTom the Arctic 

to Antarctica, have yielded a self-consistent data base from 

which the latitudinal distribution of ozone to 35 km altitude has 

been derived [Komhyr el al., 1988e]. The stations are Resolute, 

Canada (74'N, 95'W); Point Barrow, Alaska (71'N, l56'W); 

Edmonton, Canada (53'N, 114'W); Boulder, Colorado (40' N, 

lO5'W); Hila, Hawaii (19' S, 155'W); American Samoa (14'S, 

170'W); Lauder, New Zealand (45' S, l70' E); Syowa, 

Antarctica (69'S, 39'E); and South Pole, Antarctica (90' S, 

24.8-W). Average seasonal and annual ozone vertical 

distributions have also been derived for the sites. The data 

should be useful for comparison with model calculations of the 

global distribution of atmospheric ozone, for serving as a priori 

statistical information in deriving ozone vertical distributions 

from satellite and Umkchr observations, and for improving the 

satellite and Umkehr ozone inversion algorithms. 

Average December-January-February (DJF), March-AprilMay (MAM), June-July-August (HA), Seplember-OctoberNovember (SON), and arumal (ANN) ozone profiles for the nine 

stations are plotted in Figure 5.5. Avcrage seasonal and annual 

isopleths of ozone partial pressure to 35-krn altitude, as a 

function of latitude, are presented in Figures 5.6 and 5.7, 

respectively. For 75 " _90oN latitude, the isoplcths were 

extrapolated, since the northcrnmost ozone data in the Arctic 

were obtained at Resolute at latitude 74"N. 
2 

\ _.w. ~ '-" ---~ 

'\ ._- ~ :-~:: ::=. 

~, "4, 

5 

10 

~ 

""c----I ::::: 

_._-::,.. - ............ \ 

~~" " . ',., 

JJA ... w._ --- ..... CIII~ ._- --- -.,,-, 

& 

\ SON 

.=:::--;;;--

--- tou..DI.O \ 

~. ._- ~ --- --............ ~ , 

~~, 

ANN 

-_.- --- ..,.".,.. ._- ~ ---

_.,"""""", 

\~ I 

40 

35 

30 

41 

'7' t\ 

20 

50 

"~: r>; : ~ 25 

20 ~ ~ 

100 / /-;:j --- / , .( / -' V) / '" ..-.' VA / " ';;p UJ 

15 0 

::J 

... ~"",;:::." "-

200 ({If i I [' If"'" i )1 t°W ' I 

ro 500 

e 

UJ 1000 

f:',,/ I 

/ I 

}- ! 

"071 \ \ .. . 

i i 

) I 

tI- I 

I \ , \0 ~ I )y 

v.:;, . 10 5 

5 

<C 

UJ 

a: 

a: 0 50 100 150 200 0 50 100 150 200 0 50 100 150 200 0 50 100 150 200 0 50 100 150 200 

UJ 

I 

0.. 

::J (/) 

(/) 

ill 

a: 

0.. 5 h-, -'<---+-+-4 

\ " 

10 I--'""",",,,---r-l '. 

'\" 

20 1- ~&-I+-4 

50 1--;>.L-7"-'+--- 1 

/ .... ,,'" " ~- ( /~.;; 

200 Ih/ '-+r--D::-J7::F""'" n 

100 

, --::.: =-

500 ir ::-~'::J

1000 LL...L.---'_..L...--' 

I I I 

\ \>. .... , "~ I 

" " ..... "'" \ 

' . I • 'X'/ ' I 

/ " / .) " ""-

I ~ 

'/1 MAM iv" , --- -.-

:.:..: . 

, - -,-""" , I 

I I I ~ ..... I \\~"~ ! I ' ', " 

! J I 

1/ .. J.- it 

/{ /."/ b¥' 1 

; ~: t j /.-

i'< ., /- --- ! =:. ~ -:00..11_ 1\ 

• I I 

I 

o 

40 ::;: 

!;;: 

35 0 

a: 

30 C§ 

z 

25 ~ 

(/) 

15 

10 

5 

o 50 100 150 200 0 50 100 150 200 0 50 100 150 200 0 50 100 150 200 0 50 100 150 200 

OZONE PARTIAL PRESSURE (NB) 

Fig. 5.5. Average seasonal and aMual ozone profiles derived at nine stations from observations made in recent years with Eee ozonesondes. 

Antarctica Springtime Ozone Depletion 

Compared with the ozone depletion in lhe spring of 1986, the 

ozone hole at the south pole in 1987 formed more rapidly, was 

deeper in vertical extent, and lasted longer into the summer 

season [Komhyr et al,. 1988f], A 4-km-thick atmospheric layer. 

centered on 17 km, was nearly completely depleted of ozone in 

early October. Select ECC ozonesonde data, comparing ozone 

hole formation at the south pole in 1986 and 1987, are shown in 

Figure 5.8. 

In further contrast to the spring of 1986, colder stratospheric 

and warmer tropospheric temperatures in 1987 accompanied the 

deeper losses in ozone. The polar vortex broke down during 

late November.early December, 3 weeks later than it did in 

1986. The enhanced ozone decrease at the south pole in the 

spring of 1987. compared with 1986. probably resulted largely 

from atmospheric circulation changes associated with the 1987 

ENS a event. These changes augmented environmental 

conditions that promoted photochemical ozone destruction on 

polar stratospheric clouds and increased polar vortex stability, 

causing the springtime transport of ozone to Antarctica to be 

delayed, 

Changes in Soulh Pole Ozone Verlical Djstrjbwjons Sjnce lhe 

Early 1960' s 

A comparison of ozone vertical profile data obtained at SPO 

with Regener chemiluminescent ozonesondes in 1962·1965, and 

ECC ozenesondes in 1967-1971 and 1986-1987. has revealed a 

progressive ozone decrease with time for a11 seasons in the 

region of the ozone maximum centered at about 17 km (Figure 

5.9), with the decrease rate accelerating in recent years during 

October months [Komhyr el al .. 1988g). The altitudes of the 

ozone maxima, furthermore, exhibit an increase with time for all 

seasons. During swnmer months, a reduction in ozone with 

time has occurred in the stratosphere below 20 krn, but an 

increase in ozone appears to have occurred above 20 km. 

Umke.hr Observaljons 

In 1987, Umkehr observations were made with automated 

Dobson spectrophotometers (Komhyr et al,. 1985] at six 

stations: Boulder. Colorado (BDR. 4O·N. 105'W); Mauna Loa 

Observatory. Hawaii (MLO. 20'N. 156'W); l'Observatoire de 

Haute Provence. France (OHP. 44'N. 6'E); Poker Flat Research 

Range. Alaska (POK. 65'N. 148'W); Perth Airpor~ Australia 
42 

DEC-JAN-FEB MAR-APR-MAY 

30 

- 20 

15 15 

10 10 

JUN-JUL-AUG SEP-OCT-NOV 

35~~ 30bi~ 

25 

20 

15 

10 

5 5 

O~~~~~~~~~~ o~~~~~~~~~~ 

-90 -60 -30 0 30 60 90 -90 -60 -30 30 60 

LATITUDE (DEG) 

o 90 

LATITUDE (DEG) 

Fig. 5.6. Average seasonal isoplcths of ozone partial pressure (nb) to 35 km altitude as a nmclion of latitude, from ECC ownesonde observations 

made in recent years at nine stations between 74°N and 90·5 latitude. 

(PTH, 32' S, 116' E); and Lauder, New Zealand (LDR, 45'S, 

169'E). LDR became operational in February 1987. No serious 

instrument problems occurred at any of these stations. In 1987, 

1298 usable ozone profiles were obtained. The Umkehr data are 

archived at the World Ozone Data Centre, Atmospheric 

Environment Service, Dowl1Sview, Ontario, Canada. 

The Dobson instrument at Huancayo was operated manually 

throughout 1987 for total ozone observations only. Umkehr 

observations were not made, owing to malfunction of the 

automated instnunent's computer system. A trip to the station 

was made in August to attempt to repair the system. A number 

of components were brought back to the United States for 

repair, and returned to the station, but the system remained 

down because of poor-quality main power. An isolation 

transformer was ordered for the system, but was not received by 

year's end. 

A study was made [Evans et al., 1988] of Umkehr profiles 

deduced by the conventional method [Mareer and Dutsch 1964] 

from data obtained at BDR, MLO, OHP, POK, and PTH during 

1986 and 1987. By this time, stratospheric aerosols from the 

1982 EI Cluchon eruption no longer affected the Umkehr 

observations adversely. Seasonal and annual Umkehr profiles 

for the five stations are shown for 1986 and 1987 in Figure 5.lD. 

Differences in the proftles at each station for the 2 years are 

small. For annual means, no station shows a difference in any 

layer larger than the standard deviations associated with the 

means. This is generally repeated for the seasonal differences, 

except for the October-December MLO averages where 
35 ANNUAL 

~~~ '" 30 oj) ~~'Oo!b 

:x:: 

~ - 25 ~~. ~,~ 

w - 20 ' 

C~ ~'~ ~~ ~ 0 

~[)\~ ::::l 15 It:J 10 « ~~ ~ ,,/ ~ )~~ 5 ~ ~ / ~ 

) <!' ~ 

0 ! 

-90 -60 -30 0 30 60 90 

LATITUDE (DEG) 

Fig. 5.7. Average annual isopleths of ozone pan.ial pressure (ob) to 35 

km altitude as a funaion oflatitude, from Eee ozonesonde observations 

made in recent years at nine stations betwccn 74"N and 90·S latitude. 

significant differences have resulted from quasi-biennial 

oscillation effects. Classical features of the atmospheric ozone 

vertical distribution are exhibited by the profiles. The altitudes 

of the primary ozone maxima decrease as station latitude 

increases, and the maxima at higher latitude stations are broader 

than those at lower latitude. This broadening is greatest during 

winter seasons. 

ECC Ozonesonde and Umkehr Profiles Compared 

Ozone profiles obtained quasi-simultaneously from ECe 

ozoncsonde and Dobson Umkehr observations at Boulder and at 

Hilo/MLO during 1985-1987 are given in Figures 5.11 and 5.12 

respectively. The proftles show agreement [Franchois el al., 

1988] to within ±10% in Umkehr layers 4-6 (19-35 km). In 

layer 7 (35-40 km) the differences range from 15 to 25%, 

depending on season and station. Use of inadequate ECe 

ozonesonde pwnp efficiency corrections in Umkehr layer 7 most 

likely contributes to the observed differences in measured 

ozone. However, because the differences vary with station and 

season. it is most likely, also, that inadequacies in the inversion 

algorithm used in processing the Umkehr data contribute to the 

observed differences. The problem probably lies with the a 

priori infonnation (ftrst-guess profiles) used in the inversion 

algorilhms. 

5.1.3. TROPOSPHERIC OZOl'o.'E 

Prior to this report, GMCC tropospheric ozone research has 

concentrated on the four-station surface-based in situ ozone 

measurements. In 1985 ozone vertical profile measurements 

using ECC ozonesondes were begun on a weekly schedule at 

Boulder and Hilo. In 1986 ozonesonde programs were 

inaugurated at BRW, SMO, Lauder, (in cooperation with 

43 

DSIR), and SPO. Although these soundings were begun 

primarily for stratospheric research, they provide a wealth of 

tropospheric data as well. Included here are results from the 

surface measurements as well as from the lropospheric portion 

of the ozonesonde proHles. 

Although ozone amounts at the surface at MLO have been 

near the long-tenn mean in recent years, the overall 15.yr record 

shows a significant increase (Figure 5.13). This has been 

primarily a result of increases during the winter months. At 

BRW (Figure 5.13), on the other hand, which also shows a 

significant increase for the 15-yr period of observations, the 

largest increase is during the sununer months. 

In the southern hemisphere (Figure 5.14), the trend at SMO 

for all months is not significant, but during the seasonal 

minimum, which occurs during the austral summer, a large, 

significant decrease (1.9% yr1) has taken place. This is similar 

to the decrease seen a1 SPO during the same time of year 

(Figure 5.14). This is also the seasonal minimum in surface 

ozone at SPO. The low value for the seasonal minimum 

reported at SPO in 1987 [Komhy' et al., 1988h] continued the 

downward trend reported last year [Schnell and Rosson, 1987]. 

The seasonal maximum was also much lower in 1987, reversing 

what appeared to be a nwnber of years of increasing values. 

On the basis of oronesonde data from nine locations (the six 

GMCC sites described above as well as two Canadian sites and 

a Japanese station in Antarctica) stretching from 75°N to 9WS 

there is strong evidence that there is more tropospheric ozone in 

the northern hemisphere than in the southern hemisphere (Figure 

5.15). On an average annual basis for all altitudes below 400 

rnb there is more ozone at all locations in the northern hemisphere than at any site in the southern hemisphere. 'nlis is nol.., 

however, always true on a seasonal or monthly basis. The 

reason for larger values in the northern hemisphere is probably 

both greater cross-tropopause fluxes of ozone from the 

stratosphere into the troposphere as well as possible production 

of ozone in the northern hemisphere troposphere there as a result 

of the emission of anthropogenic ozone precursors. 

5.1.4. STRATOSPHERIC WATER VAPOR 

Approximately monthly soundings of the water vapor content 

of the upper troposphere and stratosphere to about 25 km were 

continued in Boulder. In addition three soundings were 

anempted at McMurdo Station. Antarctica. during the austral 

spring. Because of problems with the balloon valving system, 

good descent data were not obtained on any of the nights. 

Several pieces of useful infonnation were obtained from the 

ascent portion of the profiles, however. The McMurdo results 

[Rosen el al., 1988] indicate that water vapor mixing ratios in 

the region between 15 and 20 kIn were approximately 2 ppmv. 

Because of the possibility of contamination from the balloon 

and instnunent on balloon ascent, these data can only be 

construed as upper limits. To altitudes of about 70-80 mb 

(17-18 km), there is usually good agreement between ascent and 

descent data for flights made in Boulder. Above this altitude the 

amounts diverge, with the ascent data always higher. 

Several instrument-related developments to the frost-point 

hygrometer are of note. Persistent noise problems that have 
44 

~ 

~ r 

, 

, ' .. ' 

ffIf 

.\ 

"'" , 

, ",\ 

fI( 

II 

"'" 

" 

"-

-\ I-l! ru; ti l U12 

7 k. 

" 

~ , , \ 

I~- ----t- , 

sru!" t).[ 

)5CI'86t2H " - ) ~I' 8 1 12H f" 

...... p 

100 '!IeI 100 ~ go 70 so -)0 - 10 

- I\,.. 

). _ 2l I\JG til tl12 l 

ps" r - .i 

'""' . -

,f 

SOJIH ro..( 

I' SCI' Il(, 11 10 

- 19 SC:I' 81 " 90 

/ " 

i 

tee'; (,.,.j- -f--l----j" 

t '---t--- f--j --t 20 ~ 

H---t--+-t--f" ~ .1 ~ ~If--+-+-{" 

t- I-·· ·· ···-"···f' ~-+ 

~ 

, '" 100 ISO 200 lSO -90 -10 -5(1 .)1) '\0 

\. If) " " 1\ ,r"" 

" " 1--'" l-- 11 t\G " 1212 (. 

~ ,- ; 20~ '" ) (, ~ IS ~ 

1= ,.. 1 ~ tt 

" 

50JIII rue >.'1 5(1' fl& 111' " - 13 '!O 81 IIU ~ "" !\ 

"'" , '" ' 00 '''' "" "'" 

10 .... \ 

I-I--" , 

'" ." . ", .,. ." 

t-j ~H " 

f-+HI(c.."·-""f--i " l(-i 

--j'1-+ +-~ 20 ~ (/ -

-t--t-~---l " ~ 

~ r-'II--j---l--1 " 

, 

, " .. " 

~ 

, 

I: " ~ 1-21 iI\.G 11 1212 

.t. '--

) 

{ 

) -

) ~, 

~ 1\ 5Wlllf'O..[ 

····12 SCI' i!I6 UIO " -'!O"1221 f'-, 

-p , .. , 100 ISO 200 2'SO . eo 70 -!IO .31) -10 

, 

, ,. " 

~. / (' " .' 1/ 

", C,21 ('JQ 87 1212 ( .... . , 

[', 

(( , ..... '. i 

" .. -

\\ ..... . '

J , t "\-'" 

50Jrn FU.( 

···· 22 SCI' 116 120! 

- 21 50' 11 1181 

" .. - p 1000 0 SO 100 ISO 200 250 90 10 50 JO " 

., " ~t, I), 

/ I{ 

~ " " 1->.". f ~ lr ....... $- 21 IU 81 1m ), ...... 20~ 

~ '" !>~~ ) 

~IOO ,,~ 

i~ ". j ~ f 

, \ 50JTH PO.C 

~ " ~ , 

\ lDtTi!I6ILS8 

, OCT '" 1128 "" I -.::.> 

'000 , " '00 ,so "" >SO .", ." ." . ., ." , 

, \ , 

i. 

/: 

1)\ 

...... ' 

. 

/ 

" 

" 

,. 

:,. 

"'" 

i , 

!f SWIH PCLt ···. 21 OCT es flU 

-19 OCT " ~ '" " 

II - 1--" , .. , 50 100 I SO 200 2SO 90 70 so XI to -II,.., 1'IIt.S!oI.IIt 11111 T'O'F'O'tI'Itu!c 11:1 

Fig. 5.8. Select ECC ozonesonde data showing ozone hole formation at the south pole in September and October 1986 

and 1987. Values in parentheses in the legend boxes, and in the labels for the August 24, 1987, ozone profale shown for 

comparison, are total ozone amOlmls in Dobson units. 
iii 

~ 

w 

a: 

:> 

en 

en 

w 

a: 

a. 

() 

10 

20 

50 

100 -

>. /...:.r67 - 71 

,,,/<>/ 

200 

,;;.:( ::<62-65 

500 DJF ( . ) 

1000 0 50 100 150 200 250 

OZONE PARTIAL 

PRESSURE INS) 

- 86-87 

10 

20 

50 

}\ /) 

.. : ....... .. 

/ ; ..... \. ... , .... 62-65 

MAM 

o 50 100 150 200 250 

OZONE PARTIAL 

PRESSURE (NS) 

~86-87 

' . _67-71 

'-"" , \ 

" ) ,,," .... r .. ·· ..... 

""" 62-65 

(<1 

JJA 

30 

25 

20 

15 

10 

5 

o 50 100 150 200 250 

OZONE PARTIAL 

PRESSURE INS) 

rr-,-,---,-..-...., 35 ~ 

_ 86-87 ~ 

\ \ __ 67-71 

\ , " .... -

w 

30 0 

E 

25 t; 

< 

w 

a: 

20 ~ 

a: 100 w 

; ~ .. ' ...... ~\ 

/'/" O

fu 

15 .r 

a. 

en 

o 

::;; 

~ 

200 

500 SON ('I 

1000 OL-:'50:---100'--'1~50::-2:-'0"'0--'-'250 

10 

20 

200 

500 -

OZONE PARTIAL 

PRESSURE (NB) 

___ 86-87 

(,) OCT 

1000 0 50 100 150 200 250 

OZONE PART(AL 

PRESSURE IN S) 

o 

I. ) ANN 

50 100 150 200 250 

OZONE PARTIAL 

PRESSURE (NB) 

-86-87 

Ih) SEPT 

-90 -70 -50 -30 -10 10 

TEMPERATURE (C) 

o 

,.:......... 62-65 ... , .... 

(f) SEPT 

50 100 150 200 

OZON E PARTIAL 

PRESSURE (NB) 

II) OCT 

::;; 

~ 10 0 

5 ~ z 

250 

~ (/) 

5 

-90 -70 - 50 -30 -10 10 

TEMPERATURE (C) 

Fig. 5.9. (a)-(g) Comparison of average seasonal, annual, and September- and October-month ozone proftle.s for 

1962·1965, 1967-1971, and 1986-1987. (h)-(i) Average temperature profLIes, from September and October ozone 

soundings made in 1967-1971 and 1986·1987. 

45 
46 

• : . 

; . 

e • 

e . ~ , 

• 

• 

1" 

~ , 

• 

• 

• 

• 

, 

I: 

II • ~ . 

• 

• 

, 

• • • 

, 

. - , 

e , 

~ . -

1081( .. , >0, " 1 0,.,( '" I V'''C '" '" " 00 00. ... ... • 00 00. ' 00 ... ... . .. POK H'W POK AUJ 

• • 

• 

, 

I: I: 

II ' II ' ~ . " . • • , ... ( .. , ,.,de 00' '" 111,.( .. , I ••• C 10 .. \ 10'''1( '" 1017( .. , 7>, '0'''( , .. U87( 31 1111 00. ,10 3100 • 00. ... ... t 0 ;aoo • ... ... ... ... 160 .10 • .. , "' • N • 

! : I: I: I: 

I' ' I' ' II ' I! ' ~ . ~ . ~ . ~ . • 10.,( .,' 10.,( ." loa.( ... 10"( .. , I •• 'C ' II) t •• ,,{ >0, ,0,,,( . .,1"'( .. ,1""( . ., " ." 31, .. \ •• ... ... ... • >0' ... ... 00 >0. .. . ... >0. .., .. , 00 >0 • 160 ao lOft , ,. .. 110111 AWl 80l1li 'AS 80" ONO ••• 

• 

• • , 

I: I: 

II ' ~ . 

• • , • " "C 110) " "( ", 18.'( . ., 1 ••• ( ." 1 0.S( 301\ t017( 1 11'1 loa,( u, I 057( 101) ",."( I a,,) ,11.1' 1 .. 111 

.W 00 -, .. ... • o aoo • .. >0. .. . .00 • .. >0' .. , .. , , • >0' ' 60 31 0 wt..o AWl WLO U .• • ' ND ." • • • • 

• 

, 

I: I: I: 

I! • e' I! ' ~ ~. ~ . 

• • \Olll( '" IIIIUI( .. , lilalle ." IOllae 00' 108.( 2 .. 0) u".,( 1 06) I IIII?( ", I IIII?( >0, 1 0'''( ", IUI?( .1.,,1 

.. >0. .. . ... >0. .. . ... >0. .., ... • .. >0. .., ... • .. ... I~O :010 PTH Jr'W PTH .'.1.1 PTH ' AS PTH ONO H 

Fig. 5.10. Seasonal (columns 1-4) and annual (column 5) Umkehr layer average ozone partial pressures (nanobars) at five 

Umkehr observatories during 1986 and 1987. Solid-line profiles are from 1986; dashed~line profLIes are from 1981. The 

values in parentheses after the dates indicate the number of profLIes in the average. 
BOR I19BO 20 

• 

• 

• 

-, I II 0 

• OO-(UIoI'" _aONOE)/ U ... O< 

DOR Oe. - 07 OJF" 

• 

• 

7 

• 

.. , 

. . ,

L---7-----'; ,0 ., : ,._.( .. 0, , 

, "o.oC , . " 

- 0_ _ , I 0 30 

. 00·(UIoI0<_1I0NOE)/U ... 0< 

DOR 11961'1 20 

• 

6 

2 .11 0, 

~~ 

_30_ _ ,0 ° ,0 20 30 

,OO-CU .. K_SONOE)/ U ... K 

BOR e~ - 67 ).( ... hoI 

• 

• 

7 

• 

_30_20 _ 1 0 0 o ,. ,00- (U'I":-SONOE)/ U'" 0< 

SOH IOU7 

o 

u 

, .,j 

F 

p, 

, ., 

... 

2 

-a~o" 10:10 ao • OO-(U"'O<_>OOOlOE ) . u ... ..: 

ROR 8=> - 67 JJ ... 

o 

o 

• 

' 7_11, II II, 

.. ..,( "., 1).1 .. It' I~ .... , ... , .. 0, ~ '" :1 • . ,,( I. 01 

... :u ''':1) 

_30_:10 -'0" , 0 ,,0 30 

100'(U"'0< -1I0HOE" U"O< 

OLlR 01 1'> _ ~7 ., 

u 

: '. ~~.J 

: J'" ,., :f I., "j 

[-- -; '"'' ... , 

: ~_~I .. II , 

:".~ 

, I, ....... 

-30 - 0--=-100-'0-:1--0--30 

1 00',V""'_&ONUI.:, Viol", 

DOH d~ - fj-' ::iON 

" 

• 

7 . " 

... 

. " 

n, 

.. , 2 ~, :>1 ..... , . ., 

- 30-=---i"'-.:, o- o--,""----Z-O-:io 

10U',U""':- so .. """ U"'''' 

Fig. 5.1 I. Annual, long-Ienn, and seasonal percentage ozone differences (detennined by 100 [Umkehr-sonde]/Umkehr), by Umkehr layer for 

Boulder, 1985-1987. Values in parentheses are 95% confidence intervals. 

MLO 11960 

• 

• 

, 

-30-.0_. 0 •• :so ,00·(VIoIK-aONOE)/ U ... K 

""LO 00 - 67 OJ,.. •• 

• 

• 

7 

... 

, .. 3, , '1-___ ---;' -.... a, .... 7' 

-3 _:10_ , 0'0 .. 0 

• OO-'V"K _SO .. OE) /U"'K 

NLO 11900 

• 

• 

7 

• 

3 

2 

_30_20_100 , 0 "0 30 

, OO-(U"'K_SONOIf)/ U,-,'" 

.. fLO 80 - 07 ~",).I 

o 

• 

7 

• 

: _ .... ,« t. '" 

_3 _20_ 10 0 ,0 :10::10 

• 00- (U ... K_50 .... 0E)/ UUK 

MLO 19U7 3. 

u 

" 

7 2::1 . 6! II I 

• ; '," , ., 

-03! 

:L'" 

... 

'" 

>0, 

.. , 

2 :II '" . 0 .. , 

.. , 

_ 30 "0-.0 ° .0 ao 30 

. OO-,U"'I(-»O"O':' .· \10"; 

t-.tLO e~ - e ·, JJ ... 20 

o 

6 

7 

" 

2 

80 III ~ II, 

F'" 

]::11 .. 3' 

: _a .. '" 1 1 . 1) 

_:10_:10 _.0 ° .0 20 ::10 • 00-, UUK _ SONOE)/ u .. ..: 

)'fLU I:S~ - 67 00 

o 

u 

7 

• .. , 

:["61 I I' 

: L-" '" ~.( 7., 

I :_.0 -.' 611 

2 

- :J (j--:'""io-::"io-o· - '0- -~...,__:JO 

l oo-,"""'_SONUO:) U"'O< 

....1.0 U!'I 

u 

" 

? 

" 

3 

_3o=-TO _ . 0 0 ,0 ~O ,,0 

1 00·(U .. K_,"0"UIC) U",K 

Fig. 5.12. Annual, long-tenn, and seasonal percentage ozone differences, as in Figure 5.11 bul for MLO/Hilo, 1985-1987. 

47 
48 

: ~~J1t~\rI'1:;.\1rtNlJT.nl~ 

-~ ~ 

~ 

" I'll ". ("> '" 

([ 

:"5 ~. 

'" 

"' -, ,,, 

, '" .. 

~ 

~ '" 

O.19'O.44Uyr 

- - - -. - -HH-+hHt-t+l1H 

'--=-=======--1 

O.7810.42't./yr 

;+ ~ . l " 'I 1'. n 11 111 n m 61 112 03 D! 115 06 01 

nrm: 

Fig. 5.13. Surface ozone monthly mean partial pressures (bouan plou) 

and anomalies (lOp plots) at BRW and MLO. The trends are linearleast-squares regressions of the monthly anomalies with 95% confidence 

interval. 

periodically plagued the operation of the instrument over the 

years were identified as coming from the phototransistors that 

are part of the optics portion of the servo-control system 

[Mendonca, 1979], In the pasliliis problem was partially solved 

by selecting components with inherently low noise characteristics. This was very time consuming, and adequate performance 

could not always be attained. Modifications were made in the 

circuitry to electronically reduce the noise; recent tests indicate 

that these changes have improved the performance of the 

hygromeler. 

As part of the recent tests to improve the perfonnance of the 

instrument, it was discovered that a flaw existed in the 

calibration procedures. For calibration temperatures at O'C the 

resistances measured were too low; because of the curve·fitting 

process used to detennine frosH>aint temperatmes colder than 

the lowest calibration value of -79·C. the frost-JX>int 

temperatures colder than ·79"C were too high. The enor in 

resistance determination at O'C leads to frost-point temperatures 

~.."m .O.26!O.65Vyr 

lli: ;;~ -----M-- -MJ- - H-+'1-tI'I-t--H-'+H 

:: :: ,,' ", 

," '" 11-=====================1 ,,' ," ~ 

"-

.. 

" ... ". ':( 

-Mf'\t~"f'vr:::I\r. ~~~=,I ~.ooTIi rn,.c -O.46!.O.37t/yr 

0, 

~~-H-::; 

February 

-2 .001 1.1cYf,/yr 

n 71 ~ ~ " ~ n 00 01 ~ ro anTe 1)1 05 OG 01 

Fig. 5.14. Surface ozone monthly mean partial pressure anomalies, as 

in Figure S,13 but fo.-SMO and SPQ, 

100 

150 

200 

250 

300 

400 

500 

600 

700 

850 

1000 

Annual Average , •• 0 

," .. ,.,. 

,.

?' •...•.• ,. • ............. .. 

,,' f: ...•.......•.. 

d···· :' (' ~ j ~.~_::,:::.v>'. 

1 • N~ .. .... .. ::.::.::.:·-·--

o ~: r 

(/.' I 

f!t

:, ~u· I /.-.. ~ .. ~ .. ~ .. 

' . :: 'I' ........ Hllo 

? 1 ! .----.. Boulder 

~ 6 J 1 1 l--l Edmonton 1r/i I l ) .-.-. Resolule 

j

.pi ... if, 0, .. , .... 0 Somoa 

"'~. {.~/ .o.-~.-.o. Louder 

J' /' X--X Syowa 

8 : 0-'-0 Soulh Pal 

125 

Volume Mixing Ratio (ppb) 

Fig. 5.15. Annual mean tropospheric ozone mixing ratio profiles from 

ozonesonde soundings. 
thai are too low by approximately 0.40'. 0.30'. 0.17'. and 

0.06'C aI 10. 20. 50. and 100 mb respectively. This leads to 

mixing ratios that are too low by about 7, 5, 3 and 1 % at each of 

the pressures. The actual corrections for each sounding are 

slightly different because the correction depends on the 

magnitude of the thermistor resistance at O·C. This correction 

applies to soundings made between August 1982 and December 

1986. 

5.2. REFERENCES 

Evans, R.D., G.L. Koenig, W.O. Komhyr, 1. Eauon, and P. March~ 

Umkehr observations at five automated Dobson spectrophotometer 

!lations in 1986 and 1987, Proceedings of the 1988 Quadrennial 

Ozone Symposium, GOltingen, F.R.G., submitted, 1988. 

Fleig, AJ., P,K. Bharun, C.G. Wellemeyer. and D.S. Silberstein, An 

assessment of the long-tenn drift in SBUV total ozone based on 

compriSOOl with the Dobson network, Geophys. Res, utt., 13, 

1359·1362. 1986-

Franchoil. P., G. Koenig. R.D. Evans, and W.O. Komhyr, Ccmparison 

of Eee ozonesonde and Umkehr profUes at Boulder, Colorado, 

1985·1981. and Mauna Loa. Hawaii. 1985·1981. Proceedin8' of the 

1988 Quadrennial Ozone Symposium. Gettin8en. F.R.G .• submitted. 

1988. 

Grall, R.O .• and W.O. Komhyr. Traveling standard lamp calibntion 

checkl on Dobson ozone spectrophotometen during 1981·1983, in 

Atl1'lO$pMric OtOllt, Proceedings of the Quadrermial Ozone 

Sympo.ium held in Hallidiki. G=oe. September 3·1. 1984. Reidel. 

Donl=h~ Holland, 316·380. 1985. 

Kattthyr. W.O .• R.O. Gran. and R.K. Leonard. WMO 1911 international 

compariloo. of Doblon ozone spectrophotometers, Proceedings of the 

Quadrennial International Ozone Symposium, August 4·9, 1980, 

Vol. L edited by 1. London, National Center for Atmospheric 

R .... n:h. Battlder. Colo .• 25·32.1981. 

Kattthyr. W.O .• R.O. Gru •• R.O. Evan •• R.K. Leonanl. and G.M. 

Scmenink, Umkehr observations with aulOOlated Dobson 

lpectrophotometen:, in Almosphtric OZOfIt, Proceeding I of the 

Quadrennial Ozone Sympolium held in Halkidiki, Greece, 

September 3·1. 1984. O. Reidel. Oord=ht. HolllJld. 316·320.1985. 

Komhyr, W.O., R.O. Gran, and R.K. Leonard, Total ozone inaule at 

South Pole. Anwtlica. 1964·1985. Geoph'l". R ... ull .. 13. 

1248· 1251.1986. 

Kattthyr. W.O .• R.O. Gran. R.O. Evans. and R.K. Leon.nI. Re.u1l& of 

international Dobson spectrophotometer and Brewer spectrometer 

intercompariSonl, Aro .. , Switzerland, 1986, Proceedings of the 1988 

Quadrennial Ozone Symposium, GOttingert F.R.G., submiued, 

1988 •. 

49 

Komhyr, W.O., R.O. Grass, and R.K. Leonard, Dobson 

spectrophotometer no. 83: A standard for total ozone measurements, 

1962·1981,J. Geoph'j$. Res .• submitted. 1988b. 

Komhyr, W.O., R.O. Gran, and R.K. Leonard, Calibration of primary 

standard Dobson spectrophotometer no. 83 and total ozone ltends at 

MatUla Loa Observatory, Hawaii, and American Samoa, South 

Pacific, Proceedings of the 1988 Quadrennial Ozone Symposium, 

Gottingen F.RG. , submitted, 1988c. 

Komhyr, W.O., P.R. Franchois, S.E. Kuester, P.I. Reitelbach, and M.L 

Fanning, ECC ozoocsonde observations at South Pole, Antarctica, 

durin8 1981. NOAA Dota Repo" ERL ARL·J5. 319 pp .• NOAA A~ 

Re.sources Lab., Boulder, Colo., 1988d. 

Komhyr, W.D., SJ. Ohmaru, P.R. Franchois, W. F. Evans, and W. A. 

Matthews, The latitudinal dislribution of ozone to 35 km altitude 

frOOl ECC ozonesonde observations, Proceedings of the 1988 

Quadrennial Oz.one Symposiwn, GOttingen F.R.G. , submiued, 

1988e. 

Komhyr, W.O., R.D. Grass, P.I. Reitelbach, P.R. Franchois, M.L 

Fanning, and S.E. Kuester, Total oz.one, ozone vertical distributions, 

and stratospheric temperatures at South Pole, Antaraica, in 1986 and 

1987, J. G~oph~. Res., submitted, 1988f. 

Komhyr, W.D. , SJ. Ohman!, RD. Grass, P.R. Franchois, and R.K. 

Leonard, Changes in total ozone and ozone vertical dislribl.lIions at 

South Pole. Antarctica. 1962·1981. Proceedings of the 1988 

Quadrennial Ozone Symposium, GOttingen F.R.G., submiued, 

19888. 

Komhyr, W.O., SJ. Oltmans, and R.D. Grau, Atmospheric ozone at 

South Pole, Antarctica, in 1986, J. G~Ophy3. Res., 93, 5167·5184, 

1988h. 

Mateer, C.L. and H.U. DUtsch, Unifonn evaluation of Umkehr 

observatioru from the World Ozone Network: Part I, Proposed 

standard evaluation technique, lOS pp., National Center for 

Atmospheric Reseacb, Boulder, Colo., 1964. 

Matthew., W.A., W.O. Komhyr. and P.R. Franchois, Vertical 

distribution and variation in atmospheric ozone over Lauder, New 

Zealand, Proceedings of the 1988 QuadrelUlial Ozone Symposium, 

Gottingen F.RG., submitted, 1988. 

McPeten, R.D., and W.O. Komhyr, Long-tenn changes in 

SBUV/fOMS relative to the world primary standard Dobson 

instnmlent, Proceedings of the 1988 QuadrelUlial Ozone Symposium, 

Gettingen F.R.G .• submitted. 1988. 

Mendonca, B.G., Geophysical Monitoring for Oimatic Clange, No.7: 

Sununary Report 1978, 131 pp., NOAA Enviraunental Research 

Laboratories. Boulder, Colo. 1979. 

Rosen, I.M., DJ. Hofmann, lR. Carpenter, 1.W. Harder, and SJ. 

Oltmans, Balloon borne Antarctic frost point measurements and their 

impact on polar stratospheric cloud theories, G~ophys. R~s. uu., 15, 

859·862. 1988. 

Schnell, R.C., and R.M. Rosson, Geophysical Monitoring for Climatic 

Change. No. 14: SummaI)' Report 1981. 155 pp .• NOAA 

Environmental Research Laboratories, Boulder. Colo., 1987. 
50 

6. Acquisition and Data Management Group 

6.1. CONTINUING PROGRAMS 

6.1.1. STATIONCUMATOLOGY 

The interpretaLion of measured values of aerosols, trace 

gases, and turbidity requires the measurement of meteorological 

variables to adjust gas measurements to standard conditions and 

to assess the influence of local pollution sources. Surface 

weather includes the measurements of wind direction. wind 

speed, station pressure, air and dewpoint temperature, 

precipitation amount and a determination of boundary layer 

stability. The current sensors used at GMCC stations were 

selected to withstand the extreme conditions of the environment 

at the two polar stations. The same sensors are used at all four 

stations. except the sensors measuring temperature at the South 

Pole. Wherever }Xlssible, WMO-recommended standards for 

exposure are used. A complete list of the sensors, model 

numbers. and heights appears in Nicurson [1986J. 

In 1984 the CAMS units were installed at all the stations; 

they increased the reliability of the data acquisition hardware 

and significantly reduced the quantity of missing data, The 

daily routine of printing hourly averages and comparing them 

wiLh observed conditions improved the quality of the data as 

well. The DWR, which contains hourly average values for the 

individual meteorological variables for a 24-h period. seJVed 

this purpose, The DWRs are sent to Boulder, checked, and 

stored on microfiche for future reference, Herbert el ai, (1986a, 

b1 presented a detailed discussion of the individual elements in 

the DWR and other CAMS printouts. 

The global climatic trend for 1987 has been largely affected 

by the ENSO event. Many records and extremes were recorded 

at all four stations while the event was in the mature stage. 

BARROW 

t 987 

w 

" , =:::J' ... ;; < 10 

c::=:::J w:; ~ 10 

N. WIND ROSE 

s "!ND fREQ 

Barrow 

A description of the BRW site, its surroundings, and climate 

can be found in previous GMCC Summary Reports [e.g., 

DeLuisi, 1981], Wind roses of the hourly average resultant 

wind direction and speed are presented in 16 direction classes 

and 4 speed classes. The distribution of the wind by direction 

for 1987 (Figure 6.1) is consistent in general distribution wilh 

lhe average for the 1977-1986 period, The predominant wind 

direction is again from the "representative sampling sector" 

NE-SE (65%), and all other directions except westerly are less 

than 5%. Winds with a speed equal to or greater than 10 m S· 1 

were obseJVed 16% of the time in 1987 as contrasted to 9% for 

the long-term average. The prevailing wind direction for 

January was from the WSW quadrant (Table 6.1), in contrast 

with the nonnal direction from ENE. The W direction logged 

the year's maximum wind speed of 19 m sol on February 25_ 

The most significant event of the year was the passage of a 

low-pressure system on July 22, which yielded 35.6 mm of 

rainfall in a 24-h period, and broke the 24-h precipitation record 

(25.4 mm, October 1926) that stood for nearly 61 years at 

Barrow village. Another record was broken on September 14 

when 132.1 m.m of mowfaU accumulation was recorded in 24 h; 

this contributed to a new September record of 411 .5 mm total 

snowfall accwnulation. This unusually high amount of 

precipitation for BRW resulted in a 1987 total water equivalent 

of 130.6 mm, which is 10.2 mm above the nonnal. 

The temperatures and pressures in 1987 were close to the 

long-tenn averages; the temperature was O.4"C colder than 

nonnal and the pressure was 0_6 mb higher than nonnal. The 

minimum temperature for 1987 of -48.3"C occurred on February 

17, breaking the lO-yr record of -47·C at BRW. The maximum 

pressures reported for June and August also broke the 10-yr 

BARROW 

71-86 

IV 

j 1l"ISD SPE:E:D(WI'S) 

N 

s 

-. 

WI ND ROSE 

WISD FREQ 

, 

E 

Figure 6.1 . Wind rose of surface winds for BRW for 1987 Oefl) and 1977·1986 (right). The distributions of the resuhant wind direction and speed are 

in units of pcrCetil occurrence for the year and IO-yr period, respectively. Wind speed is displayed as a function of direction in three speed classes. 
51 

TABLE 6.1. BRW 1987 Monthly Climate Summary" 

Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. 1987 

Prevailing wind WSW ENE ESE ENE E E E E ENE E ENE ENE ENE 

direction 

Average wind 6.5 6.4 5.7 6.3 6.8 7. 1 6.3 7.4 7.3 6.6 9.0 6.2 6.8 

speed (m s .1) 

Maximum wind 18 19 13 13 13 13 13 15 17 17 19 17 19 

speedt (m s·l) 

Direction of max. 262 266 57 59 75 59 260 250 272 98 76 110 266 

windt (deg.) 

Average station 1006.8 1019.1 1022.1 1016.7 1014.3 1011.3 1015.7 1017.3 1007.2 1008.8 1019.0 1008.4 1013.8 

pressure (mb) 

Muimwn pressuret 1033 104Q 1037 1033 1029 1031 1029 1030 1022 1022 1032 1034 1040 

(mb) 

Minimum pressuret 978 998 1007 993 1002 996 1001 1007 993 977 1000 989 977 

(mb) 

Average air -26.0 -30.3 -25.2 -21.6 -7.1 0.3 2.8 3.0 -2.0 -4.8 -20.7 -23.0 -12.6 

temperature ("C) 

Maximum temperaturet -6 -9 -4 -9 5 15 II 7 0 -10 -6 15 

('C) 

Minimum temperaturet -43 -48 -38 -33 -20 -5 -I -2 -13 -14 -32 -36 -48 

('C) 

Average dewpoinl -26.8 -31.2 -26.2 -23.0 -8.9 -2.0 0.8 I.l -5.0 -6.4 -21.8 -23.7 -14.2 

temperature ("C) 

Maximum dcwpointt -7 -10 -6 -II -I 10 9 3 -I -12 -7 10 

temperature ("C) 

Minimum dewpointt -44 ·49 -39 -33 -20 -9 -3 -6 -17 -15 -33 -36 -49 

temperature ("C) 

Precipitation (mm) 0 0 0 4 2 45 24 15 0 92 

·Inslrument heights: wind, 17 m; pressure, 9.5 m (MSL); air and dewpoint temperature, 3 m. Wind and temperature inst ruments are on a tower 25 m 

northeast of lhe main building. 

tMaximum and minimum values are hourly averages. 

record. Lower pressures and colder temperatures characterized 

the BRW winter in 1987. 

MaunaLoa 

A description of the MLO site and its general climatology 

can be found in previous GMCC Summary Reports. The MLO 

1987 monthly climate summary is shown in Table 6.2. Note 

that, for most variables, the average values are not 

representative of median values because of the bimodal 

distribution of the wind direction based on the time of day. The 

effect of Mauna Loa is to redirect stronger, predominantly 

easterly or westerly winds aloft down the slope with a more 

southerly component. The winds were again predominantly 

from the SSE (34%) in 1987, southerly wind speeds of less than 

S m s" occurring 8% of the time (Figure 6.2). Many spring 

stonns, causing some flash floods at lower altitudes, were 

reported in 1987. On May 10 a storm passed MLO and caused 

the pressure to fall to 672 mb breaking the IO-yr record for May. 

The average temperature in May was also I·C colder than 

normal for that month. 

The ENSO event index reached its peak during April and 

May [Wagner, 1987) and can be associated with the change in 

MLO's climatic pattern for 1987. The equatorial central pacific, 

from the date line to 150'W, and from IS'N to 15' 5, displayed 

positve sea surface temperature anomalies, which caused 

enhanced atmospheric convection in that area, which includes 

MLO. Associated with this convective area, an upper 

atmosphere anticyclone was centered with observations of 

negative outgoing longwave radiation anomalies (Freitag, 1987]. 

MLO's prevailing wind direction for JWle was from the NW 

direction. The normal SE wind direction for MLO was affected 

by strong equatorial westerly anomalies. Another interesting 

feature that was pointed out in the GMCC Summary Report for 

1986, is the large number of storms and high wind speeds in 

December. More than half of the year's total precipitation 

occurred during December, and the year's maximum wind speed 

of21 m S·l was reported on December 18. 

The average presswe [or 1987 was 1.2 mb below the IO-yr 

average for the period 1977-1986. The average air temperature 

stayed the same as the long-term average, at 7.0·C. The 

precipitation amount of 557 mm was down 116 nun from the 

1986 total, but was still 28% more than the 13-yr average 

reported by Chin eJ al. [1971]. 
52 

MAUNA LOA 

1987 

w 

WI/;O ~H D (W/ S) 

-- ~ .·""5< 5 

= 5 ~ "5 < 10 

ws ~ 10 

N WIND ROSE 

E 

WIND ... FR[Q 

MAUNA LOA 

77-86 

w 

"I~ D SPt£D(W!S) 

- ~'''S<~ 

~ S5 "'5<10 

c:::::J WS I 10 

N 

s 

WIN D ROSE 

WISD FRrQ 

, 

E 

Figure 6.2. Wind rose of the surface winds for MLO for 1987 (left) and 1977-1986 (right). The distributions of the resultant wind direction and speed 

are unilS of percent occurrmce for the year and 100yr period, respectively. Wind speed is displayed as a function of direction in three speed classes. 

TABLE 6.2. MLO 1987 Monthly Climate Summary. 

Jan. Feb. March April May June July Aug. Sept. Oel. Nov. Dec. 1987 

Prevailing wind SE SW SE SE SW /o.'W SE SE SE SE SE SSE SE 

direction 

A ... erage wind 4.4 5.3 6.1 4.5 5.3 3.6 3.7 3.8 3.7 3.6 5.3 4.4 4.5 

speed (m s·l) 

Maximum wind 12 13 17 13 14 13 19 13 10 13 15 21 21 

speedt (m s·l) 

Direction of mu. 256 159 270 232 218 147 37 154 213 90 139 139 

windt (deg.) 

A "crage station 679.4 677.2 679.0 679.5 678.4 681.0 680.7 680.6 680.8 680.6 680.8 679.8 679.8 

pressure (mb) 

Maximum pressurct 683 681 683 683 685 684 683 684 684 683 685 684 685 

(mb) 

Minimum pressuret 672 670 673 674 672 677 678 677 678 678 676 673 670 

(mb) 

Average air 5.5 5.0 5.2 7.3 6.9 7.6 8.3 9.5 7.6 8.3 6.7 6.2 7.0 

temperature rC) 

Maximum temperaturet 15 16 14 17 18 17 17 17 16 17 15 14 18 

('C) 

Minimum temperalUret -2 -3 -2 -1 0 0 3 3 3 -3 

('C) 

Average dewpoint -13.9 -13.4 -9.8 -9.2 -4.3 -7.6 -1.0 -5.9 -10.8 -6.5 -8.4 

temperature rC) 

Maximum dewpoint 4 5 6 6 19 14 8 8 6 22 22 

temperaturet ("c) 

Minimum dewpoinl -32 -38 -31 -23 -24 -24 -23 -23 -35 -32 -38 

temperaturet ("C) 

Precipitation (nun) 2 29 8 6 60 18 32 34 63 0 305 557 

·lnst.rument heights: wind, 17 m; pressure, 3399 m (MSL); air and dewpoint temperature, 3 m. Wind and temperature instruments are on a towe r 

located 2S m northeast of the main building. 

tMaximum and minimum values are hourly averages. 
Samoa 

A comparison of the wind rose for 1987 with that for the 

preceding 10 years shows a very similar distribution except for 

the shift in the predominant wind direction to a more southerly 

component (Figure 6.3). A higher precentage (10%) of wind 

speeds equal to or greater than 10 m S·l was also observed. This 

shifted distribution is abnost identical to the 1986 wind rose, 

with the exception of higher velocity southerly winds in 1987. 

The SSE quadrant accounted for the highest percentage (37%) 

of the observed wind directions. The average wind speed for the 

year was 5.9 m s" (Table 6.3) , which was 1.5 m s" above the 

long.tenn average. New maximum wind speeds were observed 

for the months of February and April. The maximum wind 

speed recorded on February 3 of 18 m 5.1 is the highest value for 

!.he year. The precipitation recorded in February was 600 mm, 

the highest monthly total for 1987. The winds from the NNW 

quadrant early in the year were associated with stormy periods 

accompanied by precipitation. 

The main event for SMO in 1987 was the passage of tropical 

cyclone Tusi on January 17-18. This storm dropped the 

pressure to 987 mb and established a new record for minimum 

pressure in January. The stann's main swath passed 70 mi east 

of GMCC's site on Tutuila Island and hit Manu'a Island, 

causing enough destruction that President Reagan declared it a 

disaster area. The other extreme feature for SMO in 1987 was 

the effect the ENSO event had on the faU precipitation. An 

extreme drought for 6 months, from July to December 

devastated the island's lush vegetation. Precipitation amounts 

for September and November were 2 nun and .54 mm 

respectively, new minimum precipitation records for both 

months. The average monthly precipitation for the year of 143 

mm was 70 mm below nonnal. 

SAM OA 

1987 

-w 

__ ~. lfS ~ 

c::::::::J5. 11"5 < 10 

_5 ~ 10 

.---.--. 

-- ----"1"----. 

---------0. ___ _ 

WI ND ROSE 

\ 

WiNO rREQ , 

53 

The average station pressure for the year was 1.4 mb higher 

than the long-tenn average, and the average temperature was 

0.5"C lower than nonnal. The ENSO event that caused the 

drought in the fall may also be responsible for the high-pressure 

records during the fall drought. The maximum pressure record 

for September was broken on September 29 and 30 with 

measurements of 1008 mb. 

SOUlhPo/e 

The most distiguishing feature of the distribution in the 

surface wind direction at SPO is that the predominant wind 

direction was grid ENE (20%) as compared with the long-term 

prevailing NNE direction (Figure 6.4). A very small percentage 

of these winds have speeds greater than 10 m 5.1• The prevailing 

wind direction was easterly in July-October in contrast to the 

nonnal, which has an associated northly component (fable 6.4). 

Another feature of the 1987' wind rose is the relatively large 

number of occurrences of wind speeds less than 5 m S·1 (50%). 

The average wind speed for the year of 5.3 m S·1 is identical to 

the long-teon average. New maximum wind speeds were 

observed for the months of April and June (16 m S-I). 

The most significant weather event for the SPO station in 

1987 was the colder-than-normal average air temperature for the 

year of -Sl.O·C. August was the coldest month ever on record 

(since 1957), having an average monthly temperature of -66.8' 

C. The recorded minimum hourly average temperature for this 

month was -80.4"C. It is interesting to note the change in the 

wind direction between May and Augwil. Ouring May and June 

the wind direction was predominantly from the north with 

associated high pressure and warm temperatures. The 

circulation pattern changed in July and August to a 

predominantly easterly flow. This triggered the colder air and 

lower pressures for the month of August. 

SAIIOA 

77-86 

w 

mD """""'" _ .. ,"'<0 

I11III 0''''<11) 

00110 

N 

s 

WIND ROSE 

WIHD FR!Q. 

• 

E 

Figure 6.3. Wind roses of the surface wind for SMO for 1987 (left) and 1977·1986 (right). The distributions of the resultant wind direction and speed 

are in units of percent occurrence for the year and to-yr period, respectively. Wind speed is displayed as a function of direction in three speed classes. 
54 

TABLE 6.3. SMO 1986 Monthly Climate Summary" 

Jan. Feb. March April M.y June July Aug. Sept. Oce Nov. Dec. 1987 

Prevailing wind NNW SSE SSE SSE S SSE SSE SSE SSE SSE SSE SE SSE 

direction 

Average wind 3.7 4.0 3.8 6.S S.9 S.5 7.3 8.6 6.2 8.0 5.4 S.S S.9 

speed (m 5. 1) 

Maximum wind IS 18 13 17 IS IS 13 14 II 13 II 14 18 

speedt (m S·I) 

Direction of max. IS7 329 IS8 163 162 IS9 163 134 16S IS9 161 341 329 

windt (deg.) 

Average station 997.3 996.8 1000.1 1000.0 1001.6 1002.2 1003.5 1003.1 1004.3 1003.1 1001.3 998.6 1001.0 

pressure (mb) 

Maxirnwn pressuret 1003 1002 1004 1007 lOOS 1007 1008 1007 1008 1008 1004 lOOS 1008 

(mb) 

Minimum pressuret 987 990 988 992 998 998 997 999 1000 999 998 992 987 

(mb) 

Average air 27.4 27.7 27.5 27.3 26.3 2S.7 2S.2 24.8 25.4 26.0 27.1 27.7 26.S 

temperature ("C) 

Maximum temperaturet 31 32 32 31 31 29 29 28 30 30 33 33 33 

(0C) 

Minimum ternperaturet 24 24 23 24 23 23 22 21 23 23 23 24 21 

("C) 

Average dewpoint 

temperature ("C) 

Maximum dcwpoint 

temperaturet ("C) 

Minimum dewpoint 

tempcraturet ("C) 

Precipitation (nun) 242 600 184 136 IS 13S 44 S2 2 S4 S4 200 l718 

*Instrument heights: wind, 14 m; pressure, 30 m (MSL); air and dewpoinl temperature, 9 m. Wind and temperature instruments are on Lauagae 

Ridge, 110 m northeast of the main building. Pressure sensors are located in the main building. 

tMaxUnum and minimum values are hourly averages, 

SOUTH POLE 

1987 

w 

, WINO SP([O [W S) I __ ~,wS !I 

=~:;; liS < lo t 

1C""J1fS ~ 10 

WIND ROSE 

WI:<D -;FR[Q 

SOUTH POLE 

77-86 

w 

lq:-;n 5P[[~'" '5) 

- ~,.-s<~ 

c;:;::::::; ~5"SclO 

' =lfSilIO 

N WIND ROSE 

,.. I-----c""'~ E 

.. s ll"l~n fR[Q 

• 

Figure 6.4. Wind roses of the surface wind for SPO for 1987 (left) and 1977·1986 (right). The disributions of the resuhant wind direction and speed 

are in units of percent occurrence for the year and 10-yr period, respectively. Wind speed is displayed as a function of direction in three speed classes. 
55 

TABLE 6.4. SPO 1987 Monthly Climate Summary' 

Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. 1987 

Prevailing wind N NE EJ'lE fu"'E N ENE E E E E E.t,,{E NNE ENE 

direction 

Average wind 4.1 4.6 6.4 5.6 5.6 6.2 6.6 5.1 6.2 5.4 4.6 3.1 5.3 

speed (m 5. 1) 

Maximum wind 8 9 13 16 14 16 13 11 15 13 8 8 16 

speedt (m 5.1) 

Direction of max. 19 336 31 37 359 13 8 352 358 20 29 31 37 

windt (deg.) 

Average station 695.7 683.4 681.8 680.1 679.9 683.0 681.1 665.6 680.2 675.0 677.8 686.3 680.7 

pressure (rob) 

Maximum pressuret 707 699 705 692 693 702 699 674 700 693 688 693 707 

(mb) 

Minimum pressuret 678 667 664 669 669 658 667 655 657 661 666 677 655 

(mb) 

Average air -25.7 -40.1 -49.8 -57.6 -58.0 -55.6 -59.9 -66.8 -60.4 -51.4 -39.3 -28.9 -51.0 

tcmperalure ("C) 

Maximum temperaturet -20 -27 -35 -38 -42 -33 -39 -52 -43 -34 -29 -23 -20 rC) 

Minimum temperaturet -31 -51 -68 -72 -73 -71 -74 -SO -72 -63 -52 -47 -SO rC) 

Average dewpoint 

temperature rC) 

Maximum dewpoint 

temperature ("C) 

Minimum dewpoint 

temperature ("C) 

Precipit.ation (mm) 

·Instrument heights: wind, 12 rn; pressure, 2841 m (MSL); air temperature, 2 m. The anemometer and thennometer arc on a tower 100m grid 

east-southeast of CAF. Pressure measurements are made inside CAF. 

tMaximlUn and minimum values are hourly averages. 

6.1.2. DATA MANAGEMTh"f 

The automated data aquisition system (CAMS) continued 

operation tJuough 1987 with no major problems. Table 6.5 

shows the operations record for CAMS at the four observatories 

in terms of the number of blocks (data records) recorded for 

each possible block type. SPO and SMO had no unintentional 

down time for CAMS this year. BRW had 21 autorestarts and 1 

BRAM loss, while MLO had 40 autorestarts and 3 BRAM 

losses. These down times reflect mostly power outages and 

some bad battery backed up memory boards (ZRAMs), which 

were replaced. In addition. a 12-V power supply failed and was 

replaced in BRW, a tape drive and an A-D board were replaced 

at SMO, and a tape drive and a ZRAM board were replaced at 

SPO. At every station. new clock boards and clock batteries 

were installed this year. Improvements were made in the 

software for the M03 CAMS, among them a modification that 

fixed a bug in the Dasibi weekly calibration and that saves the 

results on tape. 

In the summer of 1987, software (called the CAMS-VAX 

Data Management System) was developed and installed on the 

V AX computer that processes incoming CAMS cassettes and 

allows users to manipulate and display the data in various ways. 

OMCC users were lraincd on this software and have been 

accessing the CAMS data with tlus system. Because of this 

system, CAMS data arriving from the observatories can be made 

available to OMCC users within a week. 

6.2. SPECIAL PROJECTS 

6.2.1. ATMOSPHERIC TRAJECTORIES 

Computer models that calculate atmospheric trajectories on 

isobaric and isenlropic surfaces have been developed within 

OMCC and have been available for use by OMCC and 

cooperative scientists for a number of years. Descriptions of 

lrajectory model development and studies appear in the five 

previous GMCC Swnmary Reports. Methodology for the 

isobaric model is documented in Harris [1982) and for the 

isentropic model in Harris tmd Bodhaine [1983]. 

Table 6.6 lists most of the trajectories computed during 1987. 

These were provided for atmospheric researchers within OMeC 

and ARL as well as scientists at universities or research 

institutes of foreign governments affiliated with GMCC. In all, 

more than 45 station-years of trajectories were computed. Table 

6.7 lists experiments supported in 1987. 
56 

TABLE 6.5. GMCC CAMS Operations Summary, 1987 

Blocks Recorded and [Blocks Missing) 

Block Expected No. of 

Type Description Blocks yr'"h BRW MLO SMO SI'O 

A Hourly aerosol data 2190 2162 (28) 2185(5) 2191(0) 2190 (I) 

H Daily aerosol data 365 364 (I) 365(0) 367(0) 366(0) 

S Hourly solar radiation data 8760 8252 (108) 8745 (IS) 8761(0) 8758 (2) 

C Hourly CO2 data Variable 8127(221) 8310 (45) 8392(1) 8247 (7) 

D Daily CO2 data 365 361(6) 365(0) 368 (10) 365(0) 

E Hourly CO2 calibration data Variable 404 403 367 480 

F CO2 calibration report 52 55 55 55 67 

M Hourly meteorological data 4380 4305 (74) 4361 (22) 4362(19) 4328 (52) 

0 Daily ozone data 365 368 (0) 366(0) 354 (II) 365(0) 

W Daily meteorological data 365 362(3) 366(2) 367(0) 359(6) 

I Meteorological caibration 365 361(0) 368(0) 364 [0) 364 [5) 

N Ozooe calibralioo t 365 7 14 7 \3 

-Discrepancies between the expected number of blocks and blocks recorded + blocks missing are due to clock problems or autoreSlaru. 

tNew data block started when new M03 PROMS were inst.alled. 

TABLE 6.6. GMCCTrajeclOries Calculated in 1987 

Location 

Norfolk, Va. 

Torres de Paine, Chile 

BRW 

MLO 

SMO 

SI'O 

Liule Rock, Ark. 

Arctic (flight locations) 

Bermuda (climalOl.ogy) 

Ester Dome, Alaska 

Augustine Island 

Kalherinc, Australia 

Mount Lemmon, Ariz. 

Amsterdam Island 

Crozet Island 

SL Francis, Soulh Africa 

Niigala, Japan 

Yucatan, Mexico 

Cape Haneras, N.C. 

(climatology) 

Charleston, S.c. 

(climatology) 

Alert, Canada 

Buffalo, N. Y. 

State College, Pa. 

Saranac Lake, N.Y. 

Key Biscayne, Aa. 

Adrigole, Ireland 

China 

Station M (climatology) 

Glasgow, Mont 

St Ooud, Minn. 

Dates 

Feb., April 1985 

1986 

1986 

1986 

1986 

Selected date, 1986, 1987 

Feb., April, July, Oct. 1987 

April 1983 

1983-1984 

March-April 1986 

March-April 1986 

Sep<.1986-AprilI987 

AprilI5-M.y 27 

1985-1986 

1985-1986 

1985 

May 1986 

June-Sept 1986 

1982-1986 

1982-1986 

March-April 1986 

June 1987 

June-July 1987 

June-July 1987 

1985-1987 

1986 

May-June 1987 

Nov.-April 1982-1987 

Jan.-March 1987 

Jan.-March 1987 

TABLE 6.7. Experiments Supported During 1987 

Experiment Dates Organization 

TOGA cruise Dec. 1985-Feb. 1986 WPL 

EMEX flight Jan. 1987 AOML 

Arctic flight March-April 1983 Fraunhofter Inn. 

AGASP-I,II March-April 1983, GMCC 

1986 

RtsearCMr Cruise, June 1987 AOML 

RITS-1987 

ANATEX Jan .. Feb. 1987 GMCC 

CURTAIN Feb.-April, GMCC 

July-Oct. 1987 

PRECPY June 1987 GMCC 

The two data sets available fOT trajectory calculations consist 

of analyzed grids of meteorological data from the National 

Meteorological Center. Data on the northern hemisphere 65 x 

65 grid cover the period 1975 to the present. Data on the global 

2.5- latitude, longitude grids extend from 1977 to the present. 

Data are delivered from NCAR on a monthly basis and are 

available in house within 2 months of analysis lime. 

Improvements were made to the isentropic model this year to 

allow it to run on the 2.5- latitude, longitude data set. As a 

result, both isobaric and isentropic models now have global 

coverage. The isentropic programs were generalized to make 

changing of subgrids easier. Another improvement allows for 

the creation of up to five isenlropic surfaces at a time. A new 

feature of the isentropic trajectory plots is shown in Figure 6.5. 

The lower plot shows the vertical path of the trajectory, and 

days from the destination along the x axis. 
TRAJI:CTORIES TO ,36{ 7I.32N.l56.62W) 63073 - 3/14/63 

A: OOZ 8 . 122 

THETA· rn K 

100' W 

160· W • 140'· W 

SOUD - ox DASH -122 it:::;- c_· __ · __ · _____ , , i , 

• i , 

o I 2 3 4 ~ e 7 

DAYS FROM #36 

• 10 

Fig. 6.5. BRW back trajectories arriving on March 14, 1983, on the 

27S-K isentropic surface. The lower plot shows the vertical paths of the 

trajectories. 

Atmospheric trajectories were provided in support of the 

1987 spa aerosol study. The first part of this investigation 

produced a monthwise trajectory climatology of SOO-mb 

trajectories to SPO. This mandatory level was chosen since SOO 

140' W 

~ WB TRAJECTORIES TO SPO (8999S. 24.BOW) 

fRON 8730~ - I V 1/87 TO 87334 - 11/30/81 

oz AND 122 

20·.W " 

70'S - . 

60· S -

160' 'If 

. 40· E 

60' £ 

Fig. 6.6. SPO 2.5-day back trajectories arriving during November 

1987 at the SOO-mb level. 

60' W 

60· w 

120· W 

~ WB TRAJECJ'ORIES TO SPO (69.995. 24.80'1") 

fRON 81335 - 12/ 1/81 TO 87365 - 12/31/81 

OZ AND IZZ 

20' W " 

10'S -

60· S -

160' W 

140~ E 

160~ E 

57 

60' £ 

60' E 

100· £ 

Fig. 6.7. SPO 2.S·day back trajectories arriving during December 1987 

at the SOO-mb level. 

rob is the first such level aoove the surface at SPO. To 

distinguish months in which long-range transport was possible 

from months in which winds were light and variable, the tracks 

were plotted for only 2.S days back. This representation of the 

climatology pointed out a seasonal difference in the flow pattern 

to SPO. Figures 6.6 and 6.7 show trajectories for November 

and December. These plots can be contrasted to Figures 6.8 and 

6.9, showing trajectories for July and August. During the 

austral summer months trajectories meander slowly and are 

confined to the continent. During the austtal winter months of 

July and August trajectories indicate much higher wind speeds 

and more direct pathways for transport from lower latitudes . 

The faster trajectories result from well-organized storms off the 

coast that have been linked with episodic sea salt events in 

aerosol scattering extinction measured by the nephelometer at 

SPO [Bodhaille et al., 1986]. Events associated with air flow 

from the north during July and from the south during August 

were studied in detail, but for expediency only the July case is 

discussed here. 

Nephelometer data collected at SPO for July 1987 (Figure 

6.10) show a deftnite shift at the middle of the month that raises 

the level of the aerosol scattering extinction coefficients (alP) an 

order of magnitude to about 10.6 m-I. Individual 500-mb 

isobaric trajectories ploued daily for July likewise show a 

change in character at the middle of the month. Figure 6.11 

shows 500-mb trajectories computed for July 10, 1987, 

characteristic of the first half of the month when winds were 

light to moderate, meandering around the continent. In contrasL, 

Figure 6.12 shows a pattern typical of the latter half of July. 

Wind speeds at 500 mb during this time varied from 10 to 25 m 
58 

]20' .. 

500 we TRAJ£CTORI£S TO SPO (89 995. 24 BOW) 

FRO", 87182 - 7/ 1j'lr7 TO 872IZ - ?j31j87 

OZ AND 122 

16~'W 60'S _ 

180· 'III' 

140' E 

60' E 

100' E 

120· E 

Fig. 6.8. SPO 2.S-day back trajectories arriving during July 1987 at the 

5OO-mb level. 

5.1, Trajectories show travel from 70'S to SPO in 1-2 days. To 

investigate further the ]Xlssibility that marine aerosol was 

transported to spa during July and August 1987, isentropic 

trajec tories were computed for the periods of interest. An 

example for July 20 is shown in Figure 6.13. The isentropic 

trajectories are similar in the horizontal to the isobaric ones; 

however they differ in the vertical in that the isentropic 

trajectories rise from near lhe ocean surface off the coast to 

approximately 550 mb above SPO. The slope of the isenttopic 

60' .. 

100' .. 

120' .. 

500 WB TRAJECTORIES TO SPO (69.995, 24.BOW) 

~ow 87213 - 8/ 1/87 TO 872·41 - 8/2'i1/87 

OZ AND IZZ 

20' E 

60' £ 

80' £ 

120· £ 

Fig. 6.9. SPO 2.5-day back trajectories arriving during August 1987 at 

the 500-mb level. 

surface could provide the mechanism for raising the marine 

aerosol from close to the surface to a level above the inversion 

at SPO. Transport to the surface at SPO is thought to occur 

during periods of warming. strong winds. or wind shear. which 

weaken the inversion. 

The 500-mb heights [or July 1987 (Figure 6.14) show a large 

storm that persisted to the grid northwest of SPO. High wind 

speeds developed in the area between the low and the ridge to 

the grid northeast that presumably provided the transport of 

marine aerosol to spo. 

SOUTH POLE AEROSOL DATA 

~ 

~ 

I 

e 

~ 

~ 

Il. 

• 

~ ~ 

.. 

0 

~ 

- 5 

-6 

-7 

-8 

182 18{ 188 188 190 192 19~ 195 198 200 202 204 206 208 210 212 

JULY 1987 (Day of Year) 

Fig. 6.1 0. Hourly geometric means of asp at SPO for July 1987. a lp values are shown for 450 (Nt), 550 (N2), 700 (N3), and 850 (N4) nm. Arrows 

indicate aerosol events studied. 
TRAJECTORIES TO 5PO( 89.995.24 80W) 87191 - 7/ 10/ff7 

80' • 

60' W 

120' W 

14~' • 

A: OZ 600 we e In flOowe 

, '. o· 

80'5 -

180' • 180" E 

60' E 

100' [: 

120' E 

Fig. 6.11. SPO trajectories arriving on July 10, 1987, at the 500-mb 

level. 

TRAJECrORIES TO 5PO( 69.995. 24 80W) 87201 - 7/20/ 87 

(10' " 

140' 'If 

A;OZ ~WB 6 . 122 MO W6 

o· 

80'S -

180' W 

20' (; 

160" [: 

120' (; 

140" E 

80' (; 

Fig. 6.12. SPO trajectories arriving on July 20, 1987. at the 500-mb 

level. 

TRAJ[:Cl"OR1ES TO SPO( 69.995. 24_BOW) 87201 - 7/'lO/87 

A: DOZ B 12Z 

THEiA .. 280 K 

60' 

120' • 

16~' '160' 5 - '. 180' 11" 160 E 

~ 5 ~ DAYS FROM SPO 

140' E 

, 

7 

, 

, 

80' [: 

100' E 

, 

• 

SOUD - OZ DASH - 122 

, 

'0 

59 

Fig. 6.13. SPO trajectories arriving on July 20, 1987,00 the 280-K 

isentropic surface. The lower plot shows the vertical paths of the 

trajectories. 

Fig. 6.14. Height in meters of the 500-mb pressure surface over 

Antarctica on July 19. 1987. 
60 

6.3. REFERENCES 

Bodhaine, B.A., JJ. DeLuisi, I.M. Harris, P. Houmere, and S. Bauman, 

Aerosol measurements at the South Pole, T~lIu.r. 38B, 223·235, 

1986. 

Chm. I.F.S., H.T. Ellis, B.G. Mendoca, R.F. Pue.che1, and HJ. 

Simpson, Geophysical monitoring at Mauna Loa Observatory. 

NOAA Tech. Memo. ERL APeL·J3, 34 pp.o NOAA Environmental 

Research Laboratories, Boulder, Colo., 1971. 

DeLuisi.l.1. (ed.), Geophysical Monitoring for Climate Olange, No.9: 

Summary report 1980, 163 PP, NOAA Environmental Research 

Laboratories, Boulder, Colo., 1981. 

FricUlg. P., Equatorial wind, temperature and preuure observations, 

Climate Diagnostics BuJ/diM 1987, 12 pp., NOAA/NWS/NMC 

Climate Analysis Center, Washington, D.C., 1987. 

Harris, I.M., The GMCC atmospheric trajectory program. NOAA Tuh. 

Memo. ERL ARL·} 16, 30 pp .• NOAA Environmental Research 

Laboratories. Boolder, Colo., 1982. 

Harris, I.M" and B.A. Bodhaine (edl.), Geophysical Monitoring for 

Climatic Change, No. 11: Swnmary Report 1982, pp. 67·75, NOAA 

Environmental Research Laboratories, Boulder, Colo., 1983. 

Herbert, G.A., E.R. Green, 1M. Harris, G.I- Koenig, and K.W. Thaul, 

Control and monitoring instrumentation for the continuous 

measurement of atmospheric COl and meteorological variables, J. 

Almos. Ocean. Tuh. 3, 414-421,19800. 

Herbert. G.A., E.R. Green, G.L. Koenig, and K.W. Thaut, Monitoring 

instrumentation for the continuous measurement and quality 

assurance of meteorological observations, NOAA Tech. Memo. ERL 

ARL·148, NOAA Environmental Research Laboratories, 44 pp .• 

Boulder, Colo., 1986b. 

Nickenon. E.C. (ed.). Geophysical Monitoring for Climate Change. No. 

13: Summary Report 1984, 111 pp., NOAA Environmental Research 

Laboratories. Boulder. Colo .• 1986. 

Wagner, I.A., The global climate of March·May 1987: Moderately 

stroog mature phase of ENSO with highly persistent monthly and 

seasonal temperature anomalies over the United States. Mon. WlD. 

Rev.,lJ5, 3166-3187,1987. 
61 

7. Air Quality Group 

7 .1. CONlTh'UING PROGRAMS 

7.1.1. I~"fRODUcnON 

AQG research during 1987 had three objectives: (I) to 

improve understanding of the mechanisms responsible for the 

formation of acidic aerosols; (2) to explain the effects of these 

aerosols and of trace gases on the formation, colloidal stability, 

optical properties, and chemical composition of clouds; (3) to 

supply observational data to validate and improve the acid 

dCjX)sition models now under development. AQG acquired data 

to satisfy these objectives using the NOAA King Air C-90 

aircraft (Figure 7.1). Table 7.1 summarizes the research flights 

made by the King Air in support of our activities during 1987. 

7.1.2. NATIONAL ACID PRECIPITATION ASSESSMEl>T PROGRAM 

The Interagency Task Force on Acid Precipitation. created by 

Congress, sponsors NAPAP. This program consists of task 

groups entitled (A) Natural Sources. (B) Manmade Sources. (C) 

Atmospheric Processes. and (D) Deposition Monitoring. AQG 

continued its participation in NAPAP during 1986 by 

contributing to Task Groups A and C. 

"'''-' L. 1 .. . 

Seitnlilt mln"'\0!\1 Aad. or TeclYician '. or TIKtri:iItI " '. / , 0,1. 

-~ ; . f . At 1oI\.cn 

r-~~--1 [ - (\ ( '[- 'Ii" . . / \ Co·""" Plot ~ .. 

Fig. 7.1. The NOAA King Air C·90, configured for research. 

7.1.3. WESTERN ATI.ANIlC OCEAN EXPERIMENT 

WATOX data analysis continued during 1987. The purpose 

of the project was to quantify the flux of various trace species, 

notably sulfur and nilrogen, away from the United States. 

7.1.4. PROCESSING OF EMISSIONS BY CLOUDS AND 

PRECIPITATION 

The PRECP experiment made it possible for AQG to 

investigate the complex chemical transformations occurring in 

and near clouds. The NOAA King Air flew near to many active 

thunderstonns at selected altitudes during the 1987 period. 

Other flights were made to characterize the chemical state of the 

troposphere before the initiation of convection. A pe~istent 

"nose" profile of H20 2 with altitude was produced during the 

June flights. H101 concentrations were about 2 ppbv at the 

surface. increased to about 5 ppbv at the top of the planetary 

boundary layer, and decreased slowly above. SO, 

concentrations were at or near the instrument detection limits (1 

ppbv) except during occasional anthroJX)genic plume 

encounters. OlOne concentrations were between 80 and 100 

ppbv. Columbus. Ohio. was the site for a PRECP field effort 

during June 1987. 

7.1.5. CENTRAL U.S. RADM TEST AND ASSESSMENT 

INTENSIVES 

CURTAIN was begun with two purposes in mind. One was 

to compare the observed concentrations of trace species along 

the western boundary of the RADM (a three-dimensional 

numerical model) with those predicted by the RADM. A second 

was to establish an observational data base along the western 

boundary of the RADM as an aid to model irtitia1ization in the 

future. 

The field site for CURTAIN was Little Rock. Arkansas . 

Research aircraft flights were made north and south along the 

91'30'W meridian. The plans for CURTAIN included field 

periods in February. April. July. and October 1987. 

Each field period had two series, each consisting of a night 

flight and two day flights. One day flight was north to the Iowa 

border and the other south to the Gulf of Mexico. Each night 

flight was within 250 kIn of Little Rock. 

Hydrogen Peroxide in Air During Winler Over the SouthCenlral United Stales 

H101 is important in atmospheric chemistry, both because it 

is an indicator of the recent concentrations of free radicals that 

were involved in photochemical reactions and because it plays 

an important role in the direct oxidation of sulfur species and 

other acid precursors. Several researchen have reported on 

H101 and organic peroxides in clouds and precipitation [Zika et 

al .• 1982; Kelly el al., 1985; McElroy. 1986] and in polluted 

atmospheres [Bu/alini el al., 1972; Kok el al .• 1978]. 
62 

TABLE 7. 1. NOAA King Air Research FlighlS During 1987 

Time (LSn 

Date 1987- Stan End 

ANATEX 

Jan. 13·1 1342 1803 

Jan. 13·2 2018 2346 

Jan. 15-1 1420 1822 

Jan. 15-2 2043 2333 

Jan. 18-1 0909 1347 

Jan. 18-2 1543 1758 

Jan. 20 1519 1922 

Jan. 23 0303 0709 

Jan. 26 1004 1334 

Jan. 28 0244 0625 

Jan. 30 1430 1832 

Feb. 17 1133 1559 

Feb. 18 08 16 1226 

Feb. 19 1601 1949 

Feb. 20 0830 1210 

Feb. 22 1136 1506 

Feb. 24 1427 19 12 

Feb. 27 0820 0929 

March 19 0220 0614 

March 21-1 1315 1411 

March 21-2 1447 1838 

March 24-1 0839 1018 

March 24-2 11 22 1319 

March 26-1 1455 1842 

March 26-2 2032 0031 

CURTAIN 

Feb. 5 1141 1612 

Feb. 6-1 1351 175 1 

Feb. 6-2 2050 0044 

Feb. 9 11 27 1601 

Feb. 10-1 1022 1501 

Feb. 10-2 2017 0056 

April 21 0931 1048 

April 22 1148 1620 

April 23-1 1315 Inl 

April 23-2 2226 0246 

April 25 1042 1516 

April 26-1 1021 1447 

April 26-2 2147 0227 

My 22 1104 1509 

July 23-1 0930 1340 

July 23-2 2310 0301 

·Oates marked with an asterisk are 1986. 

Only Heikes el aJ. [1 987] reported on airborne measurements 

of H20 2. 03' and 502' over an appreciable latitude range. They 

conducted a series of research nights during fall 1984 in which 

they made vertical profile measurements at selected locations 

from southern Alabama to upstate New York. They found H10l 

concentrations ranging from <0.2 to 4.1 ppbv, and an increase in 

concentrations from north to south at altitudes below 3000 m 

msl. They also reported an inverse relationship between H10z 

Time(LSn 

Date 1987- Stan End 

July 25 0928 1406 

July 26- 1 0917 1348 

July 26-2 2229 2701 

Oct. 22 1138 1620 

Oct. 23 1440 1752 

Oct. 25 1313 1833 

Ocl.26 2257 0404 

Oct. 27 2113 0 124 

Oct. 28 1022 1501 

RADM Model Evaluation ExperimenJ 

June 14 1420 2028 

June 17 1722 2 121 

June 24 1202 1622 

June 28 1951 2302 

June 30-1 11 31 1510 

lune 30-2 1630 2044 

PRECP-5 

June 3 1041 1421 

June 4 1734 2 151 

June 6 1732 2 154 

June 8-1 1748 2010 

June 8·2 2250 0 147 

June 9 1611 2031 

June 12 1417 1619 

June 16 1640 2050 

June 18 1700 1949 

June 19 1906 2055 

June 20 2008 2318 

June 21 1821 2204 

RITS 

July t- 085 1 1255 

July 16- 0906 1217 

Jan. 8 1050 1437 

Feb. 3 1057 15 16 

Marth 3 1008 1500 

April 7 09 18 1338 

May 28 0943 1448 

July 2 0940 1350 

Aug. 4 0914 1345 

Sept. IS 0938 1341 

and SOl' but found no relationship between H20 1 and 0). The 

NOAA King Air made similar measurements during CURTAIN. 

The instrumentation aboard the aircraft measured 0) and S02 

concentrations, wind speed and direction, temperature, pressure, 

dewpoint, solar radiation, position, and heading. H10l was 

measured continuously using the method described by Lazrus et 

at. [1986] and an instrument built by K & K Enterprises, 

Boulder, Colorado. 
Five.minute·average concentrations of HlOz during the 

daytime nights of February 5, 6, and 10 (flights I, 2, and 5) are 

shown in Figure 7.2, plotted versus latitude. The figure suggests 

(rl = 0.7) that the HzOz concentration was increasing toward the 

south at about 0.046 ppbv per degree of latitude. 

Heikes er aI. [1987J reported a dependence of H,o, 

concentration on altitude. Their measmements, designed to 

provide vertical profiles of the atmosphere at mu1tiple locations, 

generally showed a positive correlation between altitude and 

HlOl concentration, although with much variation, depending 

upon meteorological and pollution conditions. Since om flights 

consisted of long horizontal transects, direct comparison with 

the vertical profiling results of Heikes et al. is limited to the 

locations where we made altitude changes. These were usually 

at the ends of the transects. In order to provide the greatest 

validity to such a comparison, we used the average HzOz 

concenlrations within the 10 minutes of level flight irrunediately 

preceding and following an altitude change to show changes of 

concenlration with respect to altitude. Figure 7.3 shows these 

concentration pairs. 

In five of the seven examples, the change in concentration 

was positive (j.e., increasing upward); in the other two it was 

negative. Although the average profUe derived from these 

examples is weakly positive, the confidence level is low. The 

establishment of a valid altitude profile awaits more data 

Research flights were made from Little Rock, to southern 

Iowa. and to the Gulf of Mexico during February 5·10,1987. In 

five of the six flights, the H20 1 concentration range was <0.1 to 

1.0 ppbv, and concentrations increased from north to south at 

0.04·0.05 ppbv per degree latitude. Measurements made during 

the day and at night were not demonstrably different. The 

remaining flight was in an air mass that was transported from 

the vicinity of the U.S.-Canada border within the preceding 24 

hOUIS. The HlOl concentrations within this air mass were about 

0.1 ppbv. 

The data suggest that latitude is a primary detenninant of the 

HZOl concentration, and meteorological transport is one of the 

most important features affecting variability in HzOz concentrations at given altitudes. An increase in HlOz concentration with 

00 

tl Flight I, Feb. 5 0 .' 

0.' 

.. Fl ight 2, Feb. 6 

0 0 ~ Flight 5, Feb. 10 

0.7 0 

0 0 

.. 0 0 

00 "" D 0 .• 0 Cc- OO ~ 

~ 0 .5 0 '. N , 0 ....... ... 0 , 0 """,, .. N 0 .' 0, 0 '." 

J: "'" " .. +. " 

0. ' 0 ' . . 

J "" 0. 2 " 

I ~ 

0.' 0 I 0 .. " 0 i 

" " " " " ,. '0 

Lolilude (deg) 

Fig. 7.2. Five·minute averages and linear regression (r2 = 0.7) of H101 

concentrations during flights I, 2, and 5, venus latitude during 

CURTAIN. 

63 

, 

2.' ) 121 16b} '''' lib) 

E 

2.' 

2.' 

2 .2 ~ /1 / ~ '" L ' ,I; j v; 

E L. 

~ L ' {lol 29.0" N 

L 2 ((Il) 3 1.6° N 

] (2) 39.4° N 

<[ I {~ 39.5" N 0.' 

~ ~ 40.5· N 0.' '" (6a} 37.6° N 0.' J (6b)32.2" N 0 .2 

0 , 0 .2 0 .' 0 .• 0 .• 

H20 2 (ppbv) 

Fig. 7.3. Average H20 1 concentrations for the IO·min periods 

immediatcly preceding and following altitude changes during the 

CURTAIN flighlS indicated in parentheses. The latitudes where the 

altitude changes were made are listed. There were two altitude changes 

during flights 1 and 6. 

altitude prevailed in five of seven cases investigated. However, 

the small number of examples and the weakness of the 

relationship requires further research. Van Valin er al. (I987b) 

gave a more complete description of these results. 

7.1.6. ACROSS NORTI! AMERICA TRACER EXPERIMENT 

ANATEX was conducloo during January·March 1987. The 

purpose of the experiment was to observe a plume of tracer 

material (perfluorocarbon) after release from Glasgow, 

Montana, and St. Cloud, Minnesota. Two research aircraft and 

a worldwide surface network accomplished this task. AQG used 

the NOAA King Air, based at Eden Prairie, Minnesota, to 

follow tracer plumes after their release from St. Cloud. 

Analysis is continuing, but two preliminary results are available: 

1. The aircraft detected and characterized the tracer plume 

during nearly every flight. The plume was detected as far as 

500 km from the release point. 

2. Stable atmospheric conditions trapped the tracer plume at 

altitudes below 200 m above grolUld on several occasions . 

Numerical prediction models did not forecast the plwne position 

welllUlder these conditions. 

7.1.7. RADM EVALUATION ExpERIMEKr 

EPA contracted AQG and the NOAA King Air to provide 

further verification data for the RADM. Several research flights 

took place during late June 1987 from Columbus, Ohio to 

Saranac Lake, New York. These flights were coordinated with 

the Battelle Pacific Northwest Laboratory DC-3 research 

aircraft. The purpose of these flights was to document the 

chemistry of the lower troposphere in the Northeastern U.S. 

These data will be analyzed similarly to those of CURTAIN, as 

verification to the RADM. Some preliminary data analysis has 

occurred; results are not yet available. 
64 

7.1.8. RAnIA TIVEL Y IZ-UORT ANT TRACE SP£aES 

The RITS project ma rutars trace species that are important to 

the Earth·s radiation budget Certain atmospheric trace gases, 

notably CO2, are know ... to absorb long-wave radiation from the 

Earth, thus preventing escape of the radiation to outer space. 

The capacity of these gases to trap long-wave radiation in the 

atmosphere plays an important role in the radiation balance of 

the Earth-atmosphere system. CO, is increasing in the 

atmosphere. Knowledg e of this has led to speculation that the 

Earth-atmosphere system will experience a warming (the 

Greenhouse Effect) with. serious environmental consequences. 

Other trace gases such as CO and CH. are also known to be 

effective absorbers of lamg-wave radiation. However, they were 

considered much less:, imponant in the Earth-atmosphere 

radiation ba1ance beca'alSe of their low concentrations in the 

atmosphere. GMCC r ound that the concentrations of these 

gases were increasing at their observatories. This spawned 

concern that these gasfi (notably CO and CH.) would soon 

beoome important conbributors to the Greenhouse Effect along 

with COl' In order to s'alpplement their surface measurements of 

these radiatively impoItant trace species, GMCC deemed it 

important to obtain climatologically representative vertical 

profiles of them. The NOAA King Air made 10 research flights 

near Miami, Florida, to gather these data. 

Preliminary analyses. of the data suggest the following: 

1. Measurement of CH~ and CO from an aiIcraft is possible. 

2. CH. and CO are altitude dependenl Surface concentrations 

do not characterize !be tronosphere. 

3. CH. and CO are seasonally dependenl 

4. CH. and CO are variable over short time and space 

intervals. 

7.1.9. USE OF AN AIIuJORNE AIR SAMPllNO PLATFORM FOR 

REGIONAL AIR QUAUIY STUDIES 

The need to investig ate regional air quality issues motivated 

AQG to develop an airborne platform capable of providing 

complete air quality information using limited resources, on the 

one hand, but retaining the flexibility to operate anywhere 

within the North American continent, on the other hand. Since 

our objectives called for operation over areas affected by 

anthropogenic pollutiom, the analytical instrument package on 

board used commercially available units. These units may be 

less sensitive than. experimental or developmental 

instrumentation but provide a higher degree of reliability. In 

early 1984, the AQG kased a Beechcraft King Air C-90 from 

the Department of Interior (001) and modified it for use as a 

regional air quality UIl1lpling platform. Ownership of the 

aircraft was later transferred from 001 to DAD, NOAA. 

The Beechcraft Kimg Air C-90 is a twin-en8ine aircraft 

equipped with 550 hp Fran-Whitney PT-6A-20 turbine en8ines. 

The aircraft has a uselUlload of 1600 kg, a gross wei8ht of 4380 

kg, and was originally designed to carry a crew of two and up to 

seven passengers. 1:15 fuel capacity is 1400 L and the 

consumption rate is 25() L h·l . The ran8e of the aircraft, fully 

fueled, is 2100 kin at ... average speed of 420 kin h·1 and cruise 

altitude of 6400 m. The service ceiling of the aiIcraft is 7600 m. 

The outside dimensions are 10.8 m (length) by 15.3 m (wing 

span) by 4.3 m (vertical stabilizer height). The available cabin 

volume is 8.2 m3 (excluding pilot compartment) with an 

additional 1.5 m' available in the baggage compartment at the 

rear of the cabin. The aircraft is fully equipped for operation 

under instrument flight rules (IFR), can be pressurized, and has 

complete deicing capability. When equipped as described 

below and with a crew of three (pilot, copilot, and scientist 

flight director) the aircraft weighs 3560 kg. This allows 820 kg 

of fuel and provides for a flight duration of about 4 hours. 

The change from a passenger aircraft to an airborne 

laboratory required several major modifications to the aircraft. 

Alwninum research instrument racks were mounted, using the 

original floor track hardware [Wellman, 1982]. Power to the 

instruments (most of which require 1l0-VAC), is supplied by 

lightweight DC to AC inverters connected to the aircraft 

28-VDC electrical system. The power pack consists of three 

1l0-VAC (750 VA) 400-Hz inverters made by FliteTronics Co. 

Inc, two llO-VAC (1000 VA) 60-Hz units built by Avionics 

Instruments Inc., and an additional 28-VDC, 70-A power 

supply. 

Spar doublers and torque boxes reinforced the end sections of 

the wings. This enabled the mounting of scientific instruments 

weighing up to 20 kg on each wing; wiring in the wings carried 

the power and signals for these instrwnents. To aid in sampling 

outside air, a stainless steel air intake system was installed in a 

reinforced portion of the fuselage above the right-hand side of 

the forward cabin. Three shutter assemblies were also installed, 

one on the top center and two on the right rear of the fuselage. 

They allow in situ or remote sensing, as needed. 

A LORAN system determines the aircraft position 

accurately. This system (Advanced Navi8ation Inc. model 

7(00) enables determination of position to 0.5 kin. A radar 

altimeter (King, KRA10) aids in maintaining constant altitude at 

low elevations (fewer than 7(IJ m) and enhances flight safety at 

low-altitude. 

The air intake system aboard the aircraft has different intakes 

for different applications. The WATOX, PRECP, RITS, and 

SAFE studies, used a five-tube stainless steel configuration. 

Three tubes pointed forward and two pointed vertically. One 

inlet tube, used for total aerosol sampling, was isokinetic at any 

flight sampling speed. Another inlet tube had an inner Teflon 

tube and supplied air for the gas monitors. A third tube supplied 

air to a cyclone particle separator described by Boa/man and 

Wellman [1988]. Additional air samples, for intermittent 

sampling devices, are drawn from the vertical tubes and the 

,extant port at the top center of the fuselage. 

A fully computerized data acquisition system digitizes the 

data from all continuous monitors, aerosol probes, mass flow 

meters, and navigation system (Algo, Inc.) and records it to 

magnetic tape. The onboard computer system displays the data 

during flight. Magnetic tape also records the data from the 

navigation system (Algo, Inc.). All magnetic tape data are later 

merged into one file for analysis using an HP 1000 computer 

system (Hewlen-Packard, Inc.). 

The DAD operates the aiIcraft with an OAO pilot and 

copilot. The scientific personnel aboard include a mission 

scientist and, if required by the program, an instrument 
operator-technician. An illustration of the aircraft as configured 

for scientific research is given in Fig. 7.1. Refer to Boatman e/ 

al. [1988] and Wellman el al. [1988] for a more detailed 

discussion of the aircraft platfonn. 

7.2. SPEOAL PROJEcrs 

7.2.1. NATURAL SULFUR FLUX FROM TIlE GULF OF MEXICO, 

DIMEJ1{Yl. SULFIDE. CARBONYL SULFIDE. AND SULFUR DIOXIDE 

The emission of reduced sulfur compounds into the 

aunosphere through natural processes is well established In 

recent years. however. a growing interest in the magnitude and 

composition has evolved. mainly because these compounds may 

make a significant contribution to the abnospheric loading of 

SOt aerosols. It is difficult to accurately assess the exact 

emission rate of S-containing compounds into the atmosphere; 

therefore, variations of 2 orders of magnitude between some 

estimates are not surprising [Milller, I 984b)]. 

It is widely believed that the primary atmospheric source of 

natural atmospheric S is dimethyl sulfide (DMS). Andreae and 

Raemdonck [1983] estimated that the global biogenic emission 

of S is abeut 10' Tg yr', about half as DMS. Marine sources 

emit the most DMS (-75%), but continental areas alao have a 

role [Adams et al .. 1981]. Other sources of biogenic S include 

hydrogen sulfide from biological deeay 3245 Tg (S) yr' 

[Adams et al .. 1981]. Khalil and Rasmussen [19g4] put the 

biogenic emission of carbonyl sulfide (COS) and carbon 

disulfide (CS,) at about I and 1.3 Tg (S) yrt. Other biogenic S 

compounds, such as methyl mercaptan, dimethyl sulfoxide, and 

dimethyl disulfide, contribute to the global S cycle in only a 

minor way [e.g., Milller, 1984b; Adams et al .. 1981; Aneja el 

al., 1982; Steudler and Peterson, 1984]. An additional natural 

source of atmospheric S is sulfur dioxide (SO,) from volcanic 

activity. Cullis and Hirschler [19g0] estimated that SO, from 

volcanos is unlikely to contribute much more than -5 Tg (S) 

yr'; Cadle [19g0] estimated as much as 30 Tg (S) yrt, but other 

authors [e.g .. Mililer, 1984b] have placed the value at abeut 2 

Tg (S) yrt. 

Because the global natural emission of S is on the same order 

of magnitude as [Cullis and Hirsehler, 1980] or somewhat 

larger than [Milller, 1984a] the anthropogenic emission, a 

program to investigate the contribution of natural S to the total S 

budget over North America was included in NAPAP. This 

appeared to be particularly advisable after Reisinger and 

Crawford [19g0] reported sal' fluxes from areas southwest of 

central Tennessee that were as much as 2.3 times the fluxes of 

all the other sectors. As a part of this program, AQO conducted 

a series of research aircraft flights in IWle 1985 to detennine the 

flux of S compounds into the North American continent from 

the marine atmosphere and from the zone extending inland as 

much as a few hundred kilometers. 

Although there may be a large experimental uncertainty in 

the DMS measurements, the results of this study suggest that 

atmospheric DMS is surface derived, has a half-life 

commensurate with the boundary layer mixing time, and is very 

sensitive to the presence of trace atmospheric pollutants. Under 

65 

clean atmospheric conditions in marine air masses, DMS 

concentrations over the Gulf of Mexico approached those 

typical of remote oceanic areas. A reduction in DMS by a factor 

of 4 occurred when the Gulf air was displaced by continental 

air. 

There was no demonstrable diurnal cycle for DMS during the 

study; any possible diurnal cycle was within the noise level of 

the data. The very low concentrations at night, when admixture 

of continental air is suggested, support the importance of the 

recently proposed dark reaction between DMS and NO,. COS 

concentrations were slightly higher in the boundary layer than 

above the boundary layer. The ratios between the 

concentrations of DMS and SOl' and their reaction rates with 

HO, suggest that the oxidation of DMS is the principal source of 

SO, in the marine atmosphere. Van Valin el al. [1987a] gave a 

complete account of this work. 

7.3. REFERENCES 

Adams. D. F .. S. O. Farwell. E. Robinson. M. R. Pack, and W. L 

Bamesbelief, Biogenic sulfur source strengths, Environ. Sci. 

TeeMol.i5, 1493·1498, 1981. 

Andreae, M. 0 ., and H. Raemdondc. Dimethyl sulfide in the surface 

ocean and the marine atmosphere: A global view. SCUtICt. 221. 

744-747,1983. 

Aneja. V. P .• A. P. Aneja. and D. F. Adams. Biogenic sulfur compounds 

and the global lulfur cycle. 1. Air PolluJ. Control Assoc., 32, 

803·807, 1982. 

Boabnan, 1. P., and D. L Wellman, An aerolol leparator for Ule in 

aircraft, Atmo.r. Environ., in preu.1988. 

Boatman. J. P .. D. L. Wellman, R. C. Schnell, K. M. Busnen. M. Luria. 

and C. Van Valin, In-flight intercomparisons of some aircraft 

meteorological and chemical measurement techniques, Global 

Biogtocn"m. Cyclu, 2, 1-11. 1988. 

Bufalini, 1. 1.. B. W. OIY, Jr., and K. L. Brubaker, Hydrogen peroxide 

formation from fonnaldehyde photooxidation and its presence in 

urban atmospheres. Environ. Sci. Techno/., 6, 816-821. 1972. 

Cadle. R. D .. A comparison of volcanic and other fluxes of atmospheric 

trice gls constituenu:, Rev. Gtophys. Spau Phys .. 18, 746-752. 

1980. 

Cullis, C. P .. and M. M. Hirschler. Atmospheric sulphur: Natural and 

man-made sources. Almo.r. Environ. 14, 1263-11:18. 1980. 

Heike., B. G., G. I. Kok, J. G. Wales" and A. I. Lamll. H,O" 0" 

and S02 measurements in the lower troposphere over the eastern 

United S ..... durinS fall, J. G.ophys. Res., 92, 915·931, 1987. 

Kelly, T. 1.. P. H. Daum, and S. E. Schwartz. Measurements of 

peroxides in cloudwater and rain. J. Gtophys. Ru., 90, 7861-7871, 

1985. 

Khalil, M. A. K .. and R. A. Rasmullen, Global SOUrcel, lifetimes and 

rna .. balances of carbonyl sulfide (OCS) and carbon disulfide (CSi) 

in the earth 'J atmosphere, Almo..r. Environ.lB, 1805-1813, 1984. 

Kok, G. 1.... K. R. Darnall, A. M. Winer. J. N. Pitts. Jr., and B. W. Gay. 

Ambient air mcalUlemenU of hydrogen peroxide in the California 

South COlit air basin. Environ. Sci. TtcJtn.oI., 12, lrJT7-1080. 1978. 

lazru., A. I., G. L. Kok, J. A. Lind, S. N. Gitlin, B. G. Heikes, and R. 

E. Shetter, Automated fluorometric method for hydrogen peroxide in 

air, Altai. Glum., 58, 594-597, 1986. 

McElroy, W. 1.. Sources of hydrogen peroxide in cloudwaler, Almos. 

Environ., 20, 427438, 1986. 

MbUer, D., Estimation of the global man-made sulphur emission. Atmru. 

Environ., 18.19-27,1984 •. 

Moller, D .. On the global natural sulphur emission, Atmru. Environ., 18, 

29-39, 1984b. 

Reisinger, 1.. M .• and T. L Crawford, Sulfate flux through the 
66 

Tennessee Valley region, J. Air Pollia. COl'llr. Assoc., 30, 1230-1231, 

1980. 

Stcudler. P. A" and B. 1. Peterson, Contribution of gaseous sulphur from 

salt marshes to the global sulphur cycle, NaJure. 311, 455-457. 1984. 

Van Valin. C. c., M. Luria, D. L. Wellman, R. L. Gunter, and R. F. 

Pueschel. Natural suUur flux fran the Gulf of Mexico: Dimethyl 

sulfide, carbonyl sulfide, and sulfur dioxide., NOAA Tech. Rep. ERL 

432-ARL 9, Air Resources Lab., Boulder, CO, 14 pp.o 1987a. 

Van Valin C. C., 1. D. Ray, 1. F. Boatman, and R. L. Gunter, Hydrogen 

peroxide during winter in air over the South·Cenlral. United States, 

Geophys. Res. ull., 14, 1146·1149,1987b. 

Wellman D. L.. M. Luria, C. C. Van Valin, and J. F. Boatman, The use 

of an airborne air sampling pladonn for regional air quality studies, 

NOAA Tech. Memo., in press, 1988. 

Zilca, R.o E. Saltzman, W. L Chameides, and D. D. Davis, H20 1 1evels 

in rainwater collected in south Florida and the Bahama Islands, J. 

Geophy,. Res., 87, 5015·5017, 1982. 
67 

8. Nitrous Oxide and Halocarbons Group 

8.1. CONTINUING PROGRAJ,fS 

8.1.1. SAMPLES 

GMCC scientists have been analyzing flask samples for 

nitrous oxide (N,o), and halocarbons CFC-12 (CClzF,) and 

CFC-11 (CC1,F) since 1977 at the GMCC baseline observatories 

and NWR. During 1987, air samples pressurized to about 8 psig 

were collected in a pair of O.3·L Summa treated stainless steel 

cylinders each week at BRW. NWR. MLO. and SMO. Station 

personnel at spa collected a pair of flask samples each week 

only during the Antarctic summer (November·lanuary). These 

air samples were shipped back to Boulder for analysis by 

EC·GC. 

Figure 8.1 shows plots of the average concentration from a 

flask pair versus time for N,O, CFC-12, and CFC-ll at BRW. 

NWR, MLO, SMO. and SPO. Table 8.1 lists monthly concentration means for NOAA/GMCC flask pairs as mole fraction 

in dry air for N,O, CFC-12. and CFC-11 collecled from NOAN 

GMCC baseline stations and NWR. Estimated secular trends 

and ±2 standard deviations at the 95% confidence level are also 

presented. Flask data are not included for May 1984 to 

February 1985, because the ECD response during this time was 

not linear. Figure 8.2 shows the strong latitudinal dependence, 

higher in the northern hemisphere than the southern hemisphere, 

and the accummulation rates of CFC·12 and CFC-11 from plots 

of the yearly mean concentration versus latitude since 1977. 

More infonnat.ion on experimental design and techniques used 

in data selection are described in Thompson et al. [1985]. 

Since 1983, a manually operated Shimadzu Mini-2 GC at 

spa measured N20, CFC·12, and CFC·ll in situ twice a week. 

The monthly mean concentrations of N20, CFC-12, and CFC·l1 

from the in situ GC were compared. with month1y means from 

500 

flask samples and are shown in the bottom panel of Figure 8.1. 

The ECD on this GC became contaminated by February 1987. 

and analyses were slOpped until a new detector arrived during 

the midwinter air drop in June 1987. The results from the flasks 

and in situ GC at SPO were so sporadic that it was decided to 

upgrade the existing in situ GC in early 1988. The upgraded OC 

system will include unattended, automated analyses, increased 

frequency of atmospheric sampling to once every 3 hours, and 

the additional sampling of new compounds, methyl chloroform 

(CH,CC1,) and carbon tetrachloride (CC1,). An IDM PC clone 

computer will be used to store chromatographic information 

from two HP integrators. and to send Lhis information back to 

Boulder via satellite each week for rapid analysis of data and for 

diagnosis of potential problems. These improvements may help 

resolve the question concerning the effects of vertical transport 

on the ozone hole. More technical infonnalion on GMCC's 

SPO N20 and halocarbon measurements can be found in 

Robinson er al. [1988J and Elkins er al. [1988J. 

The calibration scales for GMCC's atmospheric 

measurements of CFC·12 and CFC-ll have been based since 

1977 on the OOC scale of R. Rasmussen [Rasmussen and 

Lovelock, 1983J. NOAA primary calibration tank no. TI072, 

which was used exclusively from 1977 until 1985 when it was 

expended, was calibrated last in 1983. The current primary 

calibration tank no. TI088 was compared almost every 6 months 

between 1977 and 1985 with tank no. TI072 and replaced it in 

1985. Because of concerns about the stability of CFC·12 and 

CFC·11 in the new tank, it was calibrated at OGC in December 

1987. Drift was found to be about 4.5 ppt yr1 for CFC-12 and 

negligible for CFC·l1 during its 2 years of use. It was assumed 

that, before 1987. the drift of TI088 was identical to the drift of 

tank no. TI072, having drift rates of about -1.5 ppt yr1 for 

CFC·ll and +5 ppt yrl for CFC-12. The new drift corrections 

, 20 300 

, I 0 

3 0 0 

BRW 4 0 0 

30 0 

063 : 0.04 ppb yr o

, 

250 

200 

~ 150 ~ 9 7 ! 0 I ppt yr" 

. -.' b 

, 167:0.2pptyr·' 

-= 

3 I 0 

, 00 

NWR 

.~ ~. let. . r'i~"~"'''::;'' 

.' if , 0 67 : 0 0 4 ppb y r ' 

g: 310 

MLO 

S 

= 

300 

3 I 0 

300 

-.5- ....... .. 075.004ppbyr-' 

SMO 

SPO 

3 I 0 

300 ·0 ••• ::;.,·:.~t ,. .9:ri;:g-! 

068 t IJ 07 ppb yr-' 

29077798183858789 

TIME (YEAR) 

, 00 

30 0 

~ 

=-

CL.~O O 

C'.2 30 0 

""--

, 00 

30 0 

, 00 

30 0 

2 00 

2 5 0 

20 0 

I 5 0 

.N ~~ ~1 9.1 : 0 I pp t yr .' 

. ., 

159 t 03 ppt yr-' ~ 

::: 250 

-=::: 2 0 0 

I 5 0 ~ 16 c.... 

~ . 9 6 , 0 I ppt yr" ! 02 ppt yc' 

2 5 0 

200 

I 5 0 ~ 

St-.·10 

9.7,02 ppt yr -' ~ 

S MO 

SPO 250 SPO 

.. 200 , 

I 5 0 

100 ~t05 ppl yr-' 93 : 05 ppl yr·' 

7 83 " 9 8 87 8 9 77798183 8J 87 89 7 7 I 

TIME (YEAR) TI ME (YEAR) 

Fig. 8.1. Average concentration of (a) N20, (b) CFC·l2, and (c) CFC-ll from measurements of paired fla sk samples versus time at BRW, J\TWR, 

MLO, SMO, and SPO, The trends and ± 2 s.d. errors are shown. The bottom panel (SPO) in each plOl also shows the monthly means (0) from a 

manually operated GC. -
68 

TABLE 8,1. Monthly Concenlration Means for NOANGMCC Flask Pair.; for N,O (ppb by mole fraclion in dry air), 

CFC-12 (ppl), and CFC-ll (Ppl) Collected From BRW, NWR, MLO, SMO, and SPO 

',' crCll crCll 

... """ • co '"' '" ... ... 'L' 'K' '" .. . """ l'tLO '"' '" 

n, " 151.1 137.4 

'" " 2)0 . 2 153. a IU. , 

"'" " 141.6 

'" " 150. a 

"'" " lOLl I H. ~ 

'" " 227. a 144.1 

m " 160.2 141.2 

'"' " ]01 . 1 16&.3 lll.l IH .5 151. , IH.1 137. J 

'" " 191.2 199 . 1 )02.1 101.1 lSt .J 15& . 1 255 .• llL 5 152.6 IH.2 149.' 1l1.2 

'" " 10S . 1 191 . • 299 .• 297.4 161.1 lJ9.4 IU.l 156. J 14L6 119 . 1 

'" " )01.' ]00 .• 199.2 296. , lH,l H2.' 240.0 160.4 151. 2 149 .J 131. , 

'" " 105 . I ) OLO '" , , 1I~. 2 186. , 11l . ., lU.S 241.2 162.., 159.9 149 •• 117 • ., 

'" ,. 304 . 1 lot.5 )01.5 29& . J '" " 2U.9 21$. ) lsO. , 160.' 154.6 US .• 14LJ 

'" ,. 30).1 ]01 . ., lO l. , 298 .2 '" , , 2U. , 257.6 m , . IU.' lS9.4 152. • 141 .• "". ,. ]0 l. I ]01.1 '" · . 199.5 '" ., '" , , 179. , 215 .1 245. , 162.4 lS6.6 149.0 143 . , 

'" ,. )0 l.' )01. 1 199. , 299.1 '" ., 260. 217.9 '" , , 164.J 154.1 1" .) "'" ,. )01. 0 ]01 . ., '" · . 300. a '" ., U7. US. , 161 .9 166.6 1 Sf. 5 141i. I 

'" ,. ]01. , ]01.1 '" ., ]00.1 '" " 191.6 '" . , l55 , , 162.4 151.1 154. a 14 S. I ,"L " 100. t )00.1 '" , , 299.1 '" " lH.7 ]01.5 210.6 lSl . , 161.6 161.5 1St. a 1H.6 156.6 

'"' " lOa .J )00.1 '" · , 198.5 101. a 219.3 254. , 164.a 165. a 15a .1 141 . 0 

'" " )02. a 50, " 100. , 298 .• 2U.2 285.1 211.7 '" " 16a .4 110. I 160.4 141.9 

'" " 101.6 SOl " 100. l 2,. . 4 190.6 196.5 211.5 '" " 2U .1 169.0 115.4 151.4 lU . 5 

'" " 101 . 7 101. l laO. , 299.4 100.l liL. 19).' lIl.5 '" " 251. 4 174.0 167.6 159. a 152.5 U5.4 

'" " )01.7 102.' 10 0. , 2,. .• 100.7 li2.4 291. a '" , , 251.5 111.1 164.1 159. a IH .4 154 .• 

"" " )01.2 )02. 4 ]0 1. 0 100 .• )00 •• 211.1 183. , 190.4 269 .1 25a. , ua.1 164.5 161. • IH .4 151.1 

'" " )01.7 2U.7 )0 1. 9 299.4 laO.' 290.0 192. S U).J HI.S 25).4 111.3 161.1 164. ) 151.1 151.' "". " )02.4 30) . 4 )01.0 298 .• 296 .2 2U.5 2" .1 114 .1 113.1 164. ) IH .5 ". " )02.1 ]01. 9 30 1. 5 298 .1 219.2 316.4 21).2 269.0 17 l.2 1". , 16l. • 156.4 

"'" " )0), 0 ]02. 0 301 .• )00.0 2U.l 191.1 11'.3 261. S 112.6 1". ) 162. a 155.4 JUM " )02. , 102. 0 '" " 299 . 5 291. 0 191.1 293.9 2" .1 112.2 1".2 161.1 lSS .1 

'" " )02.5 102. • )01. 100.4 194.4 19 5.1 19].3 211.2 In .0 161. , 165.1 lS6.9 

'"' " 102.4 102. 1 300. )01.1 Ul.l 100.1 215.1 112 .2 172. a 158 .9 ... " 102.7 100.0 ]0 1. 102. ) laO .1 311. 1 291. a 215.2 115.' 1n.5 169 .• lS6.0 

'" " )01.1 101 .• 'Ol , . ]0] . a 199.1 191.1 a6.' no .1 215.1 291 .1 1" .1 114. ) 115.5 162.2 ." " 101.2 ]04.4 '" , , 199 ., )01.2 296.0 101 .• 298.1 269.' 2l~L 1 177. , 1".4 111.1 151.2 154.1 

'" " 30]. , 10' .1 301. , )01.2 101.5 104.1 106.5 299 . S 215.1 214 .5 112.0 114. , 111.1 151.1 169 •• 

'" " lOl.l 106 .• )02 .• ]01 . a 102.2 306.2 114.2 109.1 279 •• 215.0 111.1 115.4 Ill.1 U4.0 162.1 ,.. " 101 .• 30), t )0 2.2 301.9 102.5 101.7 105.5 310 . • 219.1 211 •• 111 ,1 11Ll Ill. ) 1" .9 161.1 "". " loa.2 102. 9 )0 1.2 )00.1 )01.' 10), 5 100. 0 191 .• 219.) III .• 114.9 115.1 lU .• ". " 100.1 30l. 4 30 1.1 291 . 0 )01 .• 10t.0 )04.1 104.2 2Il. S 216.9 112.1 1". a 117.9 155.9 161.5 

"'" " 302.2 302. • 301.' 299 .2 103.1 lot. a 110 .• 191 . ' 211.1 211 .1 111.9 Ill. 4 IH.S US.9 114.9 

'"' .. )0 2.1 304.1 301. a ]00.' 299.9 10'.9 )01. 1 109 . 1 211.1 211 •• Ill.. 110.1 117.1 I" . 1 161.' 

"L .. 30 1.7 10 1. 4 101. a ]00.0 299 .1 103.2 101.) 116.1 1I4.S 219.6 Ill.' 111.1 1".4 1".1 ... .. 304. ) 303. , 301. 9 299 .5 )04.2 101.1 101.' 100. , 211. , 1 .... U5.2 1" .1 1".' 

. ".. 30 2.1 JO).l 301.1 100 •• 11l. ) 10'.7 101.2 21 •. 1 100.6 115.4 114.1 116.1 170.' OC, .. 100. S 30J. a 301. S lOa.' )00.1 1l1.1 104.1 110.9 U7.4 216 .1 114. S Ill. ) 111.1 1".4 117.1 

"'V " '" " 10], 4 )01. ) al.o 101.1 3ti.' lOS .0 309.) 2".1 214.1 ti2.' lIS.4 113.1 161.' U5.S 

'" .. 'Ol " )02.2 100 .• a1.1 100.1 327.9 30 •. ' 106.0 nO.5 216 .9 119 •• In,] 111 . S U9.5 161 .1 

''''' " ) 01.1 )03.3 101. ) ]00 . , 299 •• 115.1 109.5 10), • 2fl. S 216 .2 11 •.• 11 •.• 1" .1 111.1 110.J ,.. " )02 .• 30]. a )01 .1 103.1 )01.3 315.' 101 . , 310.6 291 .J 2U.' ti3.' 114.1 1Il.. 111.1 "". " )03.1 )0' .2 101. 0 ]00 .5 101 .4 3U.0 llS . 5 310. ) 29 •• J 1".0 115.1 113.. IH .l 

'"~ " )04.1 104. , 101. • 291 •• 104. 6 ))1.3 316.6 120. , 100. S ULO 114.0 114 •• 175.1 

"'" " 101.7 )03.1 )03.2 ]02.0 102.3 121.' 111.4 124. ) 10], • a4.9 190 •• 1 .... 114.4 115 .• 115. S >0. " ]01. , 10).' )04.1 301. • )0). 6 lU.O 120. a 132 .1 101 •• 192.2 11 •.• 1" •• 115.5 >OL " )0).1 102.3 )02. , 302. , )03. , 32'.1 3ll.1 )19.5 105.1 It 2.3 11'. 4 111.1 116 .• .. , " lOS.4 )03.' 10J. 0 lOa.' lOl. 9 )]1.5 324 •• U) .• 107.0 101- 9 190 .2 111.5 1". ) ... " 30) . 1 102.' )02. 5 )02.1 lOJ.5 327.4 325.9 1l0.4 305 . 5 314.0 111 .• 191.4 190. , 111.1 

'" " 102.5 102.' 10J. 1 )01.' lOS .1 )n.' lll.2 ))).4 301 •• U9.S 116.1 11 J. 4 190. , 110.4 194.9 

"'V " 102 . S )02. • )01. , 102.' 10) .1 ))2.1 H2.) 111.1 lll.) Itt .1 190 . 9 190. a 112.4 171.9 

'" " )0) .• 103.1 )01. 7 101 . 5 J02. • ))S .• US., llt. , 112. , Hl . 2 20 1 .5 111. , 192.2 112 •• 1".5 ". " 102.4 104.1 103.4 laO .1 10) .• ll9. , 329 .1 3ll.6 111. • )0'.4 199. , 191.1 119. , 114 .• ... " 104.4 103.1 101. S 101. a 143.0 n6.S ) lI. 6 112. a 20 2.) 191. , 190 .1 liS .2 "". " ]0' •• 103.' 304. a 100.5 3l1.6 ]]0. , 119.9 111.1 )0) .1 191.1 191. • 111.6 , .. " )05.5 )05.9 304.7 301.1 3lt .• ))9 .• llO .1 nO.4 20 1.4 ti1.9 192.2 1".1 

"'" " l05.1 10S.0 104. , 103.6 340.0 ll1. a ll2. 5 120 .2 199 ., 191 .2 194. S 1". , 

'" " 104.9 105.2 304 •• 104.4 ]]4.1 111.1 llO.9 31 •• , 1t'.4 ti7.1 ti1.9 111.1 

'" " 104.4 lOS .1 104.2 )02.6 340.1 145 . 1 llO •• 321. 0 20 1.' 201.1 192.2 111.3 ... " J04.1 )01. S 305 .• 102 . , 341. , lH .• 114 .1 122. 5 20 1.' U'.l 195 .• 119 .1 

'" " 10'.1 10S . 0 304. a 10' .2 341.2 ll9.1 ll1. , U3.3 20). • Ut.S Ul.S 119 .1 

'" " ]01.9 104.5 104. , )01. , H •. 1 H) .1 llt . ] US .1 20' . 1 U9.7 191.5 UO.l ." " 10 •. , )05 .• 104. S 10) .0 103.1 3S1.2 H3.S 1l9.7 US. a ll1. 1 20' .• 204.1 191.7 UO . ' 102.2 

'" " 10~ .9 )05.4 10' .1 102.5 303 .• 350. t 14l.1 14 2. 5 US.2 201.0 204.1 191.2 119 .• 201 .• 

n. " )05.2 306.0 10 •. , 104.1 303.1 Ul.. 144 .1 In. 1 no .1 340. a 209.' 202.3 19'.9 194.9 20 ],1 

'" " )05. , 10'.5 30S.J 101.1 151. , 341.1 In.l 310. , 209.1 205 . 7 200. a 191. • "". " 105 . 1 106 . 2 30S .• 10) . 0 lSl. • 149.1 Hl.l 314.5 ~09. , 20' .• 201.5 191 .1 ". " 10 •.• 105.1 305. a 101.4 lSJ. 2 149.S 343.6 1l1.7 211.1 209.' 202.S 19 S. 4 

"'" " 10'.5 106.' 305.3 101.J 296.9 35S .1 153.2 In.) lll. , 210.4 204.1 19 5 . 1 

'UN " )04.9 105.5 104 .• 103.0 104. a 152.3 Hl. , 141.1 1l1.1 14 5.6 U2.l 20'.5 209 .1 191 .• IH .• 

'UL " 10' .• 306.' 101.5 lOS .1 151.1 lIS.9 157. , II '- 5 UC' 20'.4 20a .1 191.0 

'U' " 304.4 107. ) 104. , 104.9 155.4 lU.2 14 5.4 llS .• UO.' 20'.4 201.' 19 5.' SIP " 301.7 10'.' 104.4 102. a 361.0 157.2 15S.6 341 .• 211.1 209. a 204.7 19 7 . 4 OC, " 304. 9 10'.2 104.1 104.5 Ul.l 112.2 156. , 145.9 215.5 U2.4 109.1 200 .• ." " )04.4 lOS. a 304.5 lO) .4 ]10.0 363.2 351.1 141 . 0 U' ., 212. 4 20a.' 191 .1 

'" " )04.' 106. S 104. t )0 •. 2 )0). , lst.l 316. , 357. a 14'. , lH.) 2U ., H' .1 20).7 20 4.1 196.2 ". .. la' .1 10S.5 105.3 )0' .6 )04.0 Ul.2 liS .0 3S1 .• 3U.S 220.9 214.3 20'.' 205. S 

'" .. 105.2 105.5 105. a 104.4 304.J In.' 361 .• 361.0 15'. a 141 •• 221.1 211. 0 212.6 20 1.1 199.5 "". .. )04.9 304.1 304.1 107.0 U4.l 110 .1 15) .• 15l.2 220.4 211.9 111.1 20 2.1 ". .. 105. , 305 .• 105.5 30' .2 315.1 31t.' 1 .... 360 .• 211.4 215 •• 212.7 20 1.1 
TABLE 8.1. Continued 

-,' erel2 ere1! 

OR' "'" "" '"' '" ... "'" "CO '"' '" ... ... "CO '"' 

'" .. )05.4 306. , 303.0 lit.) 371. ) lU.' 225 .J no. , 211 ... ,." IS )06.1 105. " 105 ... 104 ... 317.' HO.O 379.5 )61.0 114.5 ,.. .. 219.1 109 ... 

'" .. '" .. 106.0 )1)5. '7 105.5 319. '7 119.9 175 . .. 369 ... 227 •• Ut. , 11".1 HO.7 

"'" .. '" .. 101.2 105 ... 304,7 39].5 1 .... 312.4 37) .0 2B.5 Hl.O HO .J HO. , 

'"" .. " . ., 105.0 )06.0 106.' lH.6 lI5.0 no.s )11.5 22 2. .. 219.5 ] 20.' 201.' 

'" .. 30] . 1 106.5 104. , 10 .. , 318.1 116.1 312.7 ) 75. '7 22 2.0 UI." 217. " 110. " ." .. '" . . 105.7 304 ... 305. " 393.4 Blot 314.5 )13.7 22"1.5 221. 0 219.0 H1. a 

'" IS lOS . 0 )06.0 lOS. , 304 ... 400 •• 406 . , 396.0 319. • H,., 230. , 2H." '" .. '" .. 105 ... 306,0 106 . .. 105.' 404.0 401. 6 391.6 '" .. 13].4 la.' 226. '7 115 .1 

"" .. 105. '7 106.1 106. '7 lO4.1 104 ... 406 •• 40J • ., )92.1 '" .. 315.1 B5. '7 no .J U4. , llLl 

'" .. 105.J lO5. • )06. '7 305.9 105.1 401.J )91.1 391 .J '" .. n'.6 2]6.1 2H.O 231.1 HI.O 

"'" .. 105.5 10/i.I 106.5 301 .• 106 .• 401.0 391.1 395.1 '" .. lI1. 0 H '". 2a.l 211.5 21 7.2 

... .. 105 .• 106.2 )05.8 306 .• 40'.4 191.1 400.0 1 .... 2U.6 ~a.l 217.2 216.2 "". .. 105 _9 106.1 107.2 105.5 409.6 391.4 ltl.4 H6.6 213.9 227.2 22'.4 211.6 

An .. 306.1 106.6 106.4 106.0 410.7 U7.2 400.2 H7.1 24 •. , H1.9 214.0 225.7 

"'" .. 307.5 )06.4 106 .• 105.' 407.7 404 .2 399.5 347.1 2l1.5 2]4.2 2ll.6 234.0 , .. .. 107 .1 )06.1 106.7 101.1 '07 .• 404 .5 401.1 Ul. 5 H' . 4 214 •• 2]5.4 216 .1 

m .. 10 •. 1 107.5 307.9 106.5 '06.7 400.1 191 .2 311.9 H 7.9 211.7 214.1 225.6 

'" .. 101.6 )06.6 301. , 107.9 404.J 405.5 402.1 391.7 240.4 217.0 2ll .• 216. , 

... .. )06. ) 106 .• 301.4 )06.9 406.4 U9.2 401.1 192.6 240.5 21l. 9 2lt .• 211.9 

'" .. 106.4 106.9 loa.6 306.3 413.1 406.1 4U.l UL' 241.' 240.7 240.' 227 .• 

"'V .. 106 .1 106. a )0 7.7 101.9 105.9 415.5 405.2 409. , 190 .• U5.1 246.5 143.1 240.2 225.7 

'" .. 105. , 106.9 107.1 106.3 304. 9 419.4 406. I 409.' U4.1 317.1 250.5 1)9.9 239. , 229.9 

"'" " 107.1 107.7 307.2 105.7 107.1 417. ° 409. 0 410.5 lt6 .0 390.5 241.9 HO .1 H' .• 229.6 

... " 107 .• 106.1 ]06.6 30'.7 411.5 406.1 401. , lta. , 24'.1 243.5 2".4 ..... " 101.0 101.0 107.6 10S.3 41 .. ' 41'. , 421. 5 40t. 5 250.2 243.9 241.3 

An " 301.2 )07.1 105.2 303.' 421-6 411.3 412.6 40 •. 1 2S1.3 242. I 235.0 

"'" " 309.1 107.5 )07.5 430 . , 253.9 241_ 4 

'UK " 10'.1 )07.5 101.0 101. 5 429.1 ULO 423.1 400.5 253.1 241_1 2".9 Ul.O 

'UC " 307.) 105.5 )05.6 10'.2 '14.4 U1.3 412. :2 40 •. 0 255.1 241 .• 142.2 132.' 

AU' " 307.7 )07.0 107.2 411.1 429.2 416.5 2".5 151.1 246.2 

... " 301.] )05.1 105.5 30 •. ' 439.5 41' . 4 US •• lS9.0 254.5 24' .• 211.2 

'" " 101. , 307.9 107.2 30'.1 '43.5 441.3 435. , 409.1 262.1 liD.' 154.5 2".5 "'V " 101.1 301.4 loa. , 30'.1 107 . , 444.1 4]9.0 4". a 411.0 '01.' 16 5.5 2".3 152.1 2H.' 

'" " 109.' lt~ .1 101.7 305.2 301.2 .... J 43 • • J 42J .0 411. 5 410. , 16 5.' 260 .0 14'.5 241.1 

Data presented for 1986- 1987 are subject to change, pending final calibrations. See text for discussion of calibrations and gaps in data. 

-t so 

cl . .. • 

• ' 00 4 • .-.--- " j • ~ 

86 · -.----. .. 85 • - - - ... . --_ . -

~ :}')O 81 • -e - • ____ • 

~ e ---e -- . ---- .. 83 , .; e -------- - - ... - e __ ._ • . _._-· -e 82 

G JOO ~ 81 e -----·-------- -----e .-.--, ~ • 80 - . -- -. • ,. e --- . ----- .. 79 . -------- - - ... , , -, . .-

2Su " 78 .. ------

77 • ....- SPO SMO MlO \'; R BRW 

200 

-90 -60 - 30 a 30 60 

l a t it ud e 

275 

250 

225 

~ 

~ 

200 

"' U 

" 1 i5 

150 • 

125 

90 

b __ .e -- .•. --

87 . -----·---·----------· ... ----. 

:: . - --- - - - - - - -. -----~- ~-~-. ~ 

:~ : --~-: 8 2 . -------- - - -. --- _ . ---. -----

81 .--------------------. -- .... _-- -e 

8 0 -- . • -----.- • 79 • - - - - ______ .-. - - _ . . • 

78 . ----- __ __ . ______ . __ _ . ----- .-00--- 77 __________ ~.__ 

SPO 

i 

- 90 -60 

SMa Ml O NWR 

- 30 a 30 

l a tItud e 

BRW 

60 

69 

'" 

H,"' 

120.9 

221_1 

121.2 

HI.1 

217 . , 

90 

Fig. 8.2. Latitudinal dependence of yearly means for (a) CFC-12 and (b) CFC-ll concentrations at DRW, NWR, MLO, SMO, and SPO for 

1977-1987. Yearly means for years 1977, 1984, and 1985 were ca.1culated from the coefficients of the linear least-squares fit in Figure 8.1. 
70 

5 0 0 

400 

BRW ADR 

-------- ~ ".+'~ •• -

3 0 0 - ........ ~..e t ; ; 

. ALE 1 6.9 ± 0.4 ppt yr-' 

~ 

4 o 0 ........, 3 0 0 s::::::>-

s::::::>-

NWR CMO ~.."... 

,.....- -

; , , ............. .,.. - .... ,.t-._ .. ~ ..... .:i - .>. 

~ 

ALE 14.1 ± 0.7 pp t yr-' 

~ 

C=- 4 o 0 

MLO RPB ---.,.To-~ - .. ~ 

c.:> 3 0 0 

c.:> 

LnM ext .... ~~ ALE 1 6 .6 ± 0.2 ppt yr-' 

C'-2 

~ 4 0 0 

C=-

3 0 0 

S MO SMO 

te1!~ 

......,...,.... .. - .. -

.--"'-- ALE 1 6. 1 ± 0.5 pp t yr-' 

S PO CGO 

4 0 0 

300 

2 0 0 

~ 

___ ~o;d. .. t! .J -~~ a . . . .,. ALE 1 6. 5 ± 0.2 pp t yr-' 

777879808 182838485868788 

TIME (YEAR) 

3 0 0 

250 

200 

BRW ADR -.. -~ -

....... , ; III!' -- 1 50 -- ALE 8.6 ± 0.2 ppt yr- 1 

250 

200 ........, 

s::::::>- 150 

s::::::>-

- NWR CMO 

------- - -~ 

.,.~.+01-1""'; ! .. j' -

j"I:,..+............ ....,.. 

ALE 8. 1 0.3 ppt yr- 1 - ± 

~ 

C=- 2 5 0 MLO RPB _"~ ~ 

2 0 0 

c.:> 

c.:> 150 ....,....,..,. ; 'w 

ALE 9.2 ± 0.1 ppt yr-I 

~ 

~ 2 5 0 

C=- 2 0 0 

SMO SMO -

- ................. ............,. ............ -

1 50 

lo>MtwUL 

~ ALE 9. 4 0.2 pp t yr-I - ± 

2 5 0 

2 0 0 

5 0 

1 00 

SPO CGO ~ 

- CDJlID++ - 1M-:.4S m ! .-= b -

Wu·t . - • • . ALE 9. 4 ± o. 2 ppt yr- 1 -

777879808182838485868788 

TIME (YEAR) 

Fig. 8.3. Monthly mean concentrations for (a) CFC· 12 and (b) CFC· ll from the NOANGMCC flask (+) and the ALE/GAGE (6) networks. The 

SPO plots also show monlhly means (0) from the GMCC in situ OC. The ALE/GAGE data were from Cwuwld et al. [1986], and some additional 

preliminary data for RPB were provided by P. Simmonds. The trends and ±2 s.d. errors are shown for the ALE/GAGE data. 
to tank no. TI088 had the effect of reducing the concentration 

values of CFC-12 and CFC-ll in the last 3 years, yielding for 

CFC-12 and CFC-ll about a I and a 0.6 ppt yr' lower growth 

rate, respectively, than reported in Schnell and Rosson [1987]. 

Figure 8.3 shows monthly mean concentrations of CFC-I2 

and CFC-II from the in situ GCs of the ALE/GAGE network, 

[Cunnold et al., 1986] and the monthly means from GMCC's 

halocarbon flask network. Stations of comparable latitude from 

each network are plotted together. For example, CFC-II and 

CFC-12 data from the RPB Slation of the ALE/GAGE network, 

which is partly supponed by NOAA, at 13'N, 59'W in the North 

Atlantic Ocean is plotted with data from MLO. P. Simmonds 

from RPB has graciously provided further data, which are 

currently provisional and subject to change from mid-1985 to 

mid-1987. The comparison in growth rates for CFC-12 and 

CFC-II between the two networks is very good at most 

locations, and excellent where the two networks share the same 

site at SMO. 

The calibration scale used for GMCC's atmospheric N20 

measurements is the NBS SRM scale, prepared using 

gravimetric techniques [Zielinski el 01., 1986]. On average, this 

scale is I ppb lower than the gravimetric and dynamic dilution 

scale of Komhyr et al. [1988] and I ppb higher than the 

manometric scale of Weiss et al. [1981], and is acceptably 

within the experimental uncertainties of other techniques. The 

NBS N20 scale is about 3 ppb lower than the Rasmussen scale 

currently used by the ALE/GAGE network. 

8.1.2. RITS COl".rrTh'UOU5 GAS CHROMATOGRAPH SYSTEMS AT 

GMCC BASEW.'E STATIONS 

The new RITS automated ac and data processing system 

was instaUed at MLO in June. This system joined others that 

were installed at SMO in June 1986 and at BRW in October 

1986. Additions in 1987 to the systems included a separate 

backflush EC-GC for measuring N20 without any interference 

from CO" a Supeloo S1'2100 column to separate CFC-113 from 

CFC-II, two calibration standards instead of one, and specially 

treated aluminum cylinders to enhance the stability of 

halocarbons in standards. The system consists of an HP model 

no. 5890 GC, a Shimadzu model no. GC-8AIE GC, two Nelson 

Analytical interfaces, an HP9816 computer, an HP9133 15-

megabyte hard disk drive, and a printer. The system measures 

air ooncenlIations of N,O, CFC-12, CFC-II, CH,CCI" and 

CCl4 every 3 hours. Figure 8.4 shows a comparsion of flask 

samples with daily means from the in siN RITS GC for CFC-12 

at BRW and SMO. The growth rate of CFC-12 in 1987 from 

BRW flask pairs appears to have increased from ilS average rale 

by aboUl 8 ppt yrl, and this increase is also apparent from the in 

situ GC results at BRW. The reason for the increase is unknown 

and is being investigated for both real and experimental causes. 

Figure 8.5 shows results from the new back-flush N20 GC at 

BRW and SMO. The N20 concentration values from the flask 

pairs thal include a correction for CO2 and H20 interference 

appear to be 1 to 2 ppb higher than those measurements from 

the in situ back flush GC's at the stations. This implies that our 

correction for the N20 values from the flask pairs may need 

further refinement. Owing to regulator contamination problems, 

-l75 

' ?-

~-" 

::;-375 

0.. 

0.. 

-

375 

71 

BRW ~~ ~js 0 

o:x%Ot9~o 0 -:.c. o~o~fi, .. .. • ....,,,. 

~ OO$-~ OJ 

1':> Ave Flask Pai:1 .... Ave III sHu GC a , 

, 

SMO 

~o~oo~Q:)dJo ~~ 00 

0 ~ 

b 

325 J~ MAIIJJA:sONUJrllA!iJJASOI D 

1986 1 987 

Fig. 8.4. CFC·12 concentrations from flask pair samples (0) and daily 

means from the in situ RITS GCs (+) versus time at (a) BRW and (b) 

SMO. 

315 

BRW 

310 0 0 0 

0 %> 090 Q. 0' + 

o 0 

305 o 0 0 + 

---- ...0 300 o Ave Fla sk Pair 0.. + Ave In sitll GC a 

0.. 

-----

0 SMO 

C\l 310 

Z 0 

90 

0 '" 0 

305 0 + cP 

0 

0 ~ 

0 

300 b 

295 J F M A MJJA SON D 

1987 

Fig. 8.5. N20 concentnnions from nask pair samples (0) and daily 

means from the in situ RITS GCs (+) (using Porapak Q in backnush 

mode) versus lime at (a) BRW and (b) SMO. 

the data for CH)CCl) and CCI4 are very noisy. Changes win be 

made in 1988 to correct the conla.rTlination problems. 
72 

8.1.3. Low ELECfRON AITACHMENl' POTENTIAL SPECIES 

Considerable progress was made towards our goal in 

measuring the low electron attachment potential species 

(LEAPS). LEAPS are atmospheric gases which have a low 

response on an ECD either due to their low atmospheric 

concentration levels or their lack of sensitivity on the ECD. A 

literature review was completed on possible approaches for 

measuring the four gases: halons 1211 (CBrClF) and 1301 

(CBrF,). and halocarbons CFC-22 (CHClF,) and CFC-1l3 

(CCl,F-CClF,). Decisions were made by GMCC scientists 

concerning sample collection. concentration, and analysis, and 

the gas chromatograph and columns were chosen. The initial 

approach will involve preconcentrating samples onto tubes 

packed with adsorbent. The ultimate choice of collection 

temperature and adsorbent will depend on the results of ensuing 

tests. The tubes can then be brought to Boulder for analysis. 

The gases adsorbed to the tube packing will be thermally 

transferred to a cryogenic focusing trap. injected onto a 

wide-oore capillary column, and measured by temperatureprogrammed EC-GC. Pressurized Summa-treated stainless steel 

flasks also will be collected at baseline observatories and NWR, 

and shipped to Boulder for analysis by cryogenic focusing and 

capillary EC-GC. 

It is plarmed to compare a nwnber of columns, including the 

new PLOT columns, for their ability to separate these gases. 

These columns should be able to separate all of the gases 

without interference from oxygen. However, CFC-22 may 

require carrier-gas doping. If two columns are needed, dIe 

LEAPS GC is equipped with two independent channels for 

separate analyses. It also is apparent that it will be possible to 

obtain measurements of CFC-l13 from the packed SP2l00 

columns on RITS station GCs. The problems that have been 

identified with the current CFC-I13 analyses are contamination 

by the gas regulators and preparation of a long-lived standard. 

An investigation of possible solutions to these and other 

problems has begun, and it is anticipated that the first 

measurements of LEAPS gases will occur in 1988. 

8.1.4. GRAVIMIITRIC STANDARDS 

A gravimetric standards laooratory was completed at Boulder 

in 1987, and a CIRES research assistant was hired to prepare 

gravimetric standards. A custom Voland double-pan analytical 

balance. which is capable of weighing 10 kg cylinders (0.9 m 

tall by OJ m wide) to ±l mg. was installed. For liquid phase 

halocarbons. like CFC-ll. CFC-1l3. CH,CCl,. and CCl •. a 

microbalance capable of weighing 4 g of a liquid in a glass tube 

to precisions of ±O.l Ilg was also set up. Gravimetric standards 

of NzO were compared against the OGC scale and the SIO 

scale, and the results were discussed at the end of section 8.1.1. 

Gravimetric standards of CFC-12 and CFC-ll were compared 

against the OGC scale. The results were in good agreement 

with the NOAA scales for CFC-12 and CFC-ll from 

gravimetric standards, and were fOlUld to be about 1 and 4% 

lower than the OGC scale. respectively. NOANGMCC will 

continue to report CFC-12 and CFC-II values on the OOC scale 

until these small disagreements are resolved. Gravimetric 

standards for CH,CCl,. and CCI. were prepared, and the NOAA 

scale for these gases will be compared in the future to other 

international stoindards. 

8.2. SPECIAl,. PROJECJ'S 

8.2.1. SOVIET-AMERICAN GAS AND AEROSOL EXPERIMENl' 

Objectives 

The N,O and Halocarbons group took the lead for GMCC's 

effort in SAGA n. a joint US/USSR research cruise that 

occurred from April to August 1987. This expedition involved 

the measurement of atmospheric and dissolved trace gases in 

and over the west Pacific and east Indian Oceans, and was 

conducted in conjunction with the Carbon Cycle group of 

GMCC. NOAA/PMEL. OGC. SIO. University of Washington. 

Washington State University, and University of Hawaii. The 

gases measured by GMCC were NzO in the atmosphere, surface 

waters. and at depth. and CFC-ll. CFC-12. CO,. and CH, in the 

atmosphere and surface waters. Flask samples were also 

collected for subsequent analysis of CCl •• CH,CCl,. CO,. CH •• 

and perhaps the LEAPS gases as well. 

The cruise track is shown in Figure 8.6. GMCC scientists 

began the cruise at Hilo, Hawaii, sailed up to the Kamchatka 

Peninsula, down to Wellington, New Zealand, around Australia 

into the Indian Ocean. up to Singapore, and back to Hilo. 

The objectives were (1) to test a highly precise technique for 

measuring NzO WIder rigorous operating conditions. (2) to test a 

new, automated, headspace sampler for measuring dissolved 

NzO. (3) to compare the latitudinal, atmospheric gradients with 

those indicated from our station sampling network, (4) to detect 

any sharp interhemispheric gradients of N,O. CFC-ll. CFC-12. 

COz' or CH4 near the equator, (5) to evaluate the fluxes of these 

gases from the sea surface to the atmosphere along this transect, 

50 

40 

,. 

". 

" 

E. INDIAN 

TRANSECT 

LEG II 

eo 

VLADIVOSTOK. 1·· 

, 

D. 

. ."t9 

,-

W. PACIFIC TRANSECT 

,';:N. EQUATORIAL TRANSECT 

~S~ NGA -I" ORE~ ~ ~ ....... '" . 

LEG J 

'" '" '" ,so ,eo 

LEG III 

,so 

Fig. 8.6. Cruise track of the SAGA II experiment during April-July 

1987 aboard the Soviet research vessel AkLJdemik Korolev. The dashed 

line shows the shake-down leg. 
(6) to observe any signals that may be associated with the recent 

ENSO event, Wld (7) to compare our atmospheric measurements 

with those from other shipboard investigators and from some of 

the ALE/GAGE network stations. 

Results 

More than 2000 measurements were made each for NaO, 

CFC-lI, and CFC-12 in the air and surface water and more than 

600 measurements of NaO at depth. The precision of the NaO 

backflush technique, discussed by Zielinski et al. [1 986], 

remained at less than ±O.2% for air samples; atmospheric 

CFC-12 and CFC-ll were measured with precisions of ±O.3% 

and ±O.5%. Relative error was less than ±1% for the 

equilibrated surface water and less than 2% for the automated 

headspace sampler. Substantial CO2 and CH4 data were 

obtained for most of the ftrst leg, but the Weiss dual-catalyst 

FID GC never fully recovered from a breakdown near the 

equator. 

Figure 8.7 shows the atmospheric, the surface water, and the 

difference between air and surface water concentrations for 

N,D, CFC-12, and CFC-ll versus distance traveled. The 

average atmospheric NaO concentration in the northern 

hemisphere was about 0.97 ppb higher than that for the southern 

hemisphere. This is essentially equivalent to results from our 

station network and very close to results reported by Weiss 

[1981]. Except for some apparently seasonal cooling effects in 

110 

108 . a N,O 

160 

110 b F' 12 

73 

the middle-Southern latitudes, the surface waters were 

supersaturated with NaO. with an overall mean of 2.5%. This is 

consistent with the concept of the ocean as a source of NaO, but 

it is the lowest value reported to date. Although the area of 

coverage may have contributed in part to this lower value, the 

suppression of equatorial upwelling in the west Pacific in 

association with the 1987 ENSO event may have played a part 

as well. There may have been other ENSO effects, but they are 

more difficult to ascertain. The overall effect may have been 

significant, in that the mean surface concentration of N20 did 

not differ significantly from that reported by lVeiss [1978J, in 

spite of an atmospheric increase of nearly 5 ppb during the past 

decade. 

Although the equilibrator measurements of surface CFC-12 

and CFC-11 required some filtering, owing to contamination by 

the ship. it is clear that seasonal warming and cooling 

predominated in detennining surface saturations. The atmospheric profiles of CFC-12 and CFC-ll were virtually identical, 

underscoring their value as inert tracers. Small supersaturations 

(averaging between 4 and 6% above atmospheric levels) of 

CFC-12 and CFC-ll were found in the surface waters of the 

north Paciftc ocean. On average, the oceans represent a small 

sink for the atmospheric CFCs; however, small supersaturations 

and undersaturations of dissolved CFCs can result due to the 

fact that the rate of thermal warming between the surface waters 

and the atmosphere is faster than the rate of gas exchange 

c F' I 1 

"i: 106 

~IO I ~ ~~ .... , ... 

" 110 

~ 100 ~ .~w-~Wl 

100 

110 

com 

" 110 

110 

~ -"'i"" ~~Vl ,... _"- 101 

m , i 110 I' " 

1m 

110 

:~ ~l . 

~W~ ...... "'" 0 

I~ , , 

108 

II 

! 10 LJ II 

I 

-II 0 10100 11000 

DI STANC E (km ) 

" " 

110 

11 0 

0 

0 

0 

0 

0 

I 

I 

·1 

0 

0 

0 

0 

0 

o Or . ' .. "1 ~ : (J iii: ! • 

"0 ~ ... • ~J-~ tt ._:t i i ,..\'tr~f/. , 

~'I'~~~ ~ 10m 11000 10000 10000 

DI STANC E (km ) 

10010 

11 

~H 

1>11 

11 

" " 

-I 

0 

0 

0 

0 

0 

0 

0 

0 

0 

-I 0 

·1 0 

.\ 

o \ ~~ ii • • 

·lJ . • 

~~ ~I ~'lI",.. ~ 10100 11100 10111 10101 

DI STAN CE (km) 

11000 

Fig. 8.7. Aunospheric concentrations (top panel), surface water concentrations (middle panel), and the saturation anomaly (bottom panel) for (a) N20, 

(b) CFC-12, and (c) CFC-ll versus distance traveled. The distance ranges for various sections were the following: Hila ta Kamchatka «()'4921 km), 

Leg I (4921-14770 km), Leg II (14785-33172 km), and Leg ill (35706-45471 km). 
74 

between the atmosphere and surface waters. Along the west 

Pacific meridian, both gases decreased at a rale of 0.35 ppt deg-I 

latitude in the northern hemisphere and remained virtually 

constant in the southern hemisphere. These gradients, as well as 

the absolute values shown in Figure 8.8, also corresponded well 

with results from the GMCC station network and measurements 

from other investigators. The CGO CFC-12 and CFC-ll 

provisional data were provided by P. Fraser of CSIRO, and the 

Khalil and Rasmussen CFC-12 and CFC-11 data were from the 

cooperative programs section 10.2 of this report. 

As shown by others (Yoshinari, 1976; Elkins e/ al., 1978], 

N20 at depth from the SAGA IT cruise correlated negatively 

with dissolved 02 and positively with NO;. Figure 8.9 shows 

435 

dissolved NzO and O2, and NO; concentrations over the Kun! 

Trench. The data from the headspace sampler were very 

consistent. giving us the most widespread data set of subsurface 

NzO to date. The highest NzO concentrations were in the 

intermediate waters of tlJ,e northern hemisphere in both the west 

Pacific and east Indian Oceans. Waters bearing higher NzO 

were found in the high northern latitudes. near the equator. and 

near other regions where surface currents diverge. including the 

ocean boundaries. Dissolved NzO in waters of the southern 

hemisphere was much lower than that in the north, giving 

generally uneventful profiles. A strong temperature relation. 

similar to that discovered by Elkins et al. [1 978], was found 

between the amount of dissolved NzO produced (6NzO) and the 

WEST PACIFIC-SAGA II 

425 

415 

405 

395 

250 

240 

230 

220 

50S 

• • ~ 6 

6. In Situ 

o F l ask * GMCC Station • Rasmussen • Cape Grim 

o 

• 

o 0 

• 

· ~.. ,;~~irlf. 0 

SMO 

30S lOS 10N 

Latitude 

• 

a 

b 

30N 50N 

Fig. 8.8. Latitudinal dependence of (a) CFC-!2 and (b) CFC-II during Leg I of SAGA II from in situ GMCC GC (triangles) and GMCC flask 

analysis in Boulder (circles). Measurements are compared with SAGA II averages from the data presented in section 10.2 of this reJXlrt (squares). 

GMCC stations (stars), and preliminary data from the CGO (diamonds) (p. Fraser, private communication). 
0 ., 

a ~ .. b c ~ . • • • \ . . • I 

• ; 

2000 I \ r 

-" • • ~ ( ~ r v ! = ·.\000 

• 60 0 of-.--r--.- -r-,--j 

o 10 20 30 .;0 50 0 100 200 300 400 0 10 20 30 40 50 

N,O (nM ) 0, ~M ) NO; (~ ) 

Fig. 8.9. Dissolved (a) NzO and (b) Oz. and (e) NO;- concentrations 

versus depth over the Kuril Trench during the SAGA II experiment. 

amount of dissolved oxygen consumed (AOU). It is apparent 

from these data that warmer water promotes a more rapid, 

subsurface production, which is consistent with laboratory 

studies of N10 microbial production (Figure 8.10). 

8~2.2. IT IR SPECTROMETER ARCHIVE PROJECf 

A Nicolet Ff·IR spectrometer was moved from NBS in 

Gaithersburg, Md~, and installed in Boulder in RL~2. This 

instrument will be used to archive IR solar spectra for future 

analysis of compounds not currently analyzed by GMCC. 

Methods of analysis will be checked by comparing column 

densities dctcnnined by the FT -IR spectrometer against Dobson 

ozone measurements and oilier trace species measured by 

GMCC. The instrument was put to its ftrst test on analyzing a 

flask sample for high levels of COl from inside the second boat 

pit of Khufu's pyramid in Egypt (see section 4.2). Figure 8.11 

",--------------- --------------------~ 

" ~ S" 

I 

c 

z 

~ 

:c -! 

, J 50 

... au < ..... ·.1 

Fig. 8.10. .1.Nl

O versus AOU (or dissolved oxygen conswned) as a 

function of temperature t for aU SAGA Il data for AOU > 35~. The 

equation, .1.Nl O = ·13.3 + (0.124+0.00941) AOU, was determined by a 

nonlinear,leasHquares fit. 

75 

06 

Q 0'1 

0 

~ 

0 o , ~ 

0 

< j 

= 0 

~ 03 

~ ~ 

< 

02 

o 1 

2200 2250 

Wavenumber (em") 

Fig. 8.11. Fr·IR spectrum of the v) band of CO2 from a sample , SIS, 

thai was laken in a tomb from Khufu's pyramid. The resolulion of the 

Fr·IR spectrometer was 0.06 em· 1 and the CO2 concentration was 

measured at 745 ppm. 

shows a spectrum of the v) band of COl in a lO-cm-long cell 

with KBr windows at 500-mm-Hg pressure. The measured 

concentration was 745 ppm compared with the Weiss 

dUal-catalyst FlD GC analysis of 750 ± 7 ppm (95% confidence 

level). 

8.3. REFERENCES 

Cwmold, D.M., RG. Prion, R.A. Rasmussen, P.G. Simmonds, F.N. 

Alyea, C.A. Cardelino, AJ. Crawford. PJ. Fraser, and R.D. Rosen, 

Almospheric lifetime and annual release estimates for CFa) and 

CFl01 from 5 years of ALE data, J. Geophys. Res., 91(D10), 

10797 ~ 10817, 1986. 

Elkins, I.W., S.C. Wofsy, M.B. McElroy, C.E. Kolb. and W.A. Kaplan, 

Aquatic sources and sinks for nilrous oxide, Nature, 275, 602-606, 

1978. 

Elkins, J.W., T.M. Thompson, B.D. HaIl, K.B. Egan, and I.H. Butler, 

NOANGMCC halocarbons and nitrou s oxide measurements at the 

South Pole, Ani. J. U.s .• submined,1988. 

Komhyr, W.O., E.G, Dutton, and T.M. Thompson, A general 

gravimetric dilution technique for preparing trace calibration gases: 

N10 calibration gas preparation, Environ. Sci. T~chfWl , 22, 

845~8488, 1988. 

Rasmussen, R.A., and I.E. Lovelock, The Atmospheric Lifetime 

Experiment: 2, Calibration, J. Geophys. Res., 88(CJ3), 8369·8378, 

1983. 

Robinson, E., B.A. Bodhaine, W.O. Komhyr, SJ. Oltmans, LP. Steele, 

P. Tans, and T.M. Thompson, Long'lerm air quality monitoring at 

lhe south pole by the NOAA program Geophysical Monitoring for 

Climatic Cllange, R~v. Geophys., 26, 63·80, 1988. 

Schnell, R.C. and R.M. Rosson (Eds.), Geophysical Moniloring for 

Climatic Change, No. 15: Summary Report 1986, 155 pp., NOAA 

Air Resources Laboratory, Boulder, Colo., 1987. 

Thompson, T.M., W.O. Komhyr, and E.G. Dutton, Chloronuorocarbon1 I, ·12, and nitrous oxide measurements at the NOAA/GMCC 

baseline stations (16 September 1973 to 31 December 1979), NOAA 

T~ch. Rep. ERL 428·ARL 8, 124 pp., NOAA Air Resources 

Laboratory. Bouldcr, Colo., 1985 . 

Weiss, R.F., Nitrous oxide in the surface water and marine atmosphere 

of the North Atlantic and Indian Oceans, £OS. 59, 1101, 1978. 

Weiss, RF., Surface water and atmospheric trace gas measurements 

during the NORPAX Hawaii-Tahiti shuttle experiment, £OS, 62. 

894.1981. 
76 

Weiss, R.F., C.O. Keeling, and H. Craig, The detennination of 

tropospheric nitrous oxide, J. Geophys. Res., 86(C8), 7197·7202, 

1981. 

Yoshinari, T.. Nitrous oxide in the sea, Marine Chern., 4, 189·202, 1976. 

Zielinski, W.L, E.E. Hughes, I.L Bames, J.W. Elkins, and H.L Rook, 

High accuracy standards and reference methodology for carbon 

dioxide in air, DOE Tech. Rep .• TROl3, 74 pp., Department of 

Energy. Washington, D.C., 1986. 
77 

9. Director's Office 

9.1. ALKALINE AEROSOLS PROGRAM: 

DUST EMISSIONS MODELING 

9.1.1. INfRODUcnON 

A model for the estimation of total dust production for the 

United States was discussed by Gillette and Passi [1988). Its 

primary use was in constructing an inventory of alkaline 

elements for acid/base balance studies of atmospheric 

precipitation by the NAPAP. It has also been used for present 

estimates of soil aerosol generated by the wind and having lhe 

possibility of interacting with adds in the atmosphere. 

9.1.2. BASIS OF TIlE OUST PRODUcnON MODEL 

The model is a summation of the expected dust production 

caused by wind erosion for individual sampling units of the soil 

and land use inventory of the NRI compiled by the USDA. The 

model is based on a dust emission function derived theoretically 

and verified by experiment Its form is 

where E is the mass of dust emitted in the time period tJ'; C is a 

constant to be dctcnnincd by calibration; i is the index of 

summation over N different erodible areas within the region of 

interest; Rj is effect of soil roughness; geL) is the effect of field 

length, LI~ Ai is the area of the land being considered; G(V) is 

the vertical mass flux of dust (mass per unit area per time) as a 

function of wind speed, U; plU) is the probability density 

function of the wind speed during the time period of interest; 

and Vii is the ith threshold wind speed for dust emission. 

Owen's theory of suspension of dust that predicted that flux 

of dust should follow the fourth power of friction velocity was 

used (p.R. Owen. personal communication. 1987). G(U) is 

integrated for all wind speeds above threshold, V,. for each 

subarea of the region of interest; N such subareas are added 

together to obtain the total dust flux. The effects of live and 

dead vegetative protection of the surface. roughness of the soil, 

and soil moisture are largely built into the threshold wind speed. 

Experimentation has supplied values of this parameter for the 

calculation [Gillette e/ al .• 1980. 1982; Gil/elle. 1988). The 

integral is multiplied by a function of field length. giL,). that 

was set to unity in this evaluation; by a ftmction of the 

roughness of an individual soil. RI~ by time duration l1T; and by 

area of a given soil, Ai' The time l1T for each integration for 

which the soil parameters are assumed to remain constant is I 

month. 

Wind data used in the model were obtained from the WERIS 

for the y""" 1948·1978 [Barchell. 1982). WERlS provided 

information on hourly mean winds by the month for 1432 

locations in the United States. Precipitation data were obtained 

from the National Climatic Data Center. We used the USDA 

1982 NRI [Commiltee on ComervaJicn Needs and 

Opportunilies, 1986] for soil infonnation, land use. and wind 

erosion parameters including the roughness function, Ri

. We 

organized our assignment of threshold parameters to the 

ShUcture of the NRI data set. This data set contained over 

350.000 individual point sampling units containing 841.860 

records La give a detailed inventory of the land of the United 

States. Wind erosion data were obtained for point sampling 

units judged to have wind erosion potentia1. These 

supplementary wind erosion data consisted of 259.628 records. 

Equation (1) was integrated using the method described by 

Gillette and Pass; [1988]. Dust emission estimates were made 

for each MLRA, for each month of the 31-yr data set for winds. 

9.1.3. CAUBRA1l0NOFTHEMoDEL 

To evaluate C of Equation (1) for a scale appropriate to a 

national inventory, a large-scale area was chosen that could be 

effectively isolated and that had wind erosion data sufficient for 

our needs. This area is 1.25 x 10' Jan' (1.56% the area of the 48 

contiguous United States). It constitutes MLRA 77 and 78 in 

the 1982 NRI data set and roughly includes the "panhandles" of 

Texas and Oklahoma and some bordering areas. The dust 

emission data used to calibrate the model were obtained from 

Gillette e1 al. [1978J. The data were total dust production 

estimates derived from dust concentrations measured in each 

dust cloud at several altitudt:s and locations multiplied by the 

volume of the dust cloud estimated from aircraft observations, 

meteorological charts. and ground-based observations. All of 

the major dust-producing events in the month of April for 1972, 

1973, and 1975 were used for the calibration. Areas from which 

the dust originated were derived from data obtained from the 

USDA which compiled infonnation on the dates of individual 

dust storms, area of erosion. and duration of erosion for eroding 

soils in a study area including Texas, New Mexico. and the 

Great Plains states. 

9 .1.4. RESULTSOFTIlEMoDEL 

Plots of median dust flux values, 90th percentile flux, and 

10th percentile flux are shown in Figures 9.1-9.3. The median 

flux in Figure 9.1 shows maxima in the dust bowl region, in the 

Red River Valley of North Dakota, and along the 

Montana-Canadian border. Maxima are much larger on the 90th 

percentile map in Figure 9.2, and the area of dust production is 

also larger although centered at about the same areas as on the 

median map. The features of the 10th percentile dust flux map 

in Figure 9.3 show much reduced dust fluxes; only small 

amounts of the most productive areas are still active, and much 

of the country has zero dust flux. Total dust fluxes for the 

median, 90th percentile, and 10th percentile maps are 3.8 

million, 628 million, and 0.6 million t )1"1 . 

The patterns of number of days for observed blowing dust 

shown in Figure 9.4 [after Orgill and Sehmel. 1972) shows 

agreement with the broad features of Figure 9.3 in the Great 

Plains, and Southern Plains area and the Red River Valley. 
78 

, " " " " " " " .. .. Ii " " " , , , .. ,, ' " 

" " 

" " U " 

" 0 " 

" " 

" _ > 1'-' V ... ' " -""_1'-'" .. , 

0""'-1'-'1"'" o (L'-',,_' 

• • " U 

Fig. 9.1. Median flux of dust emission (g cm-2 y("l) for model runs. 

• " " " " " " " " " .. .. , , " , , , , , , , , , , , , " 

" " 

" " 

" " 

" " 

" " 

" " 

" - > ,,-' &I'''' " - 1,".1."" ... ' B 10"-,1"1/ ... ' 

04 •• "&1"" 

• • • " " " u " " " " " .. " 

Fig. 9.2. The 90th percentile flux of dust emission (g an-2 yrl) for 

model runs. 

• " " " " " " .. " " .. .. .. .. .. " 3S t: i: " " 

"E " f-

,,~ tr~ ~ " 

"E C " 

" " UUST 'IInUUCTiO'" 

" _ > "",, ... ' " Iii! It"-I'" v-' 

G 1""1'-: v-' 

0·"-"'" , • • ." " " u " " " " " " .. Fig. 9.3. The 10th percentile flux of dust emission (g an-2 y,.-I) for 

model runs. 

; 

/ 

o 

,,,0 

--. -'-. \Y'-~ /\ 

t5 Y'''' 

o 

~ 

600 Om 

Fig. 9.4. Annual frequency of dust hours with visibility less than 11 km 

in the United States (from Orgill and Sehmt/, 1976]. 

9.1.5. CONCLUSIONS 

Areas of maximum dust production are in the panhandles of 

Texas and Oklahoma, and Nebraska. western Kansas, eastern 

Colorado, the Red River Valley of North Dakota, and northern 

Montana. Areas of minimal dust production are the southeastern United States, New England. and forested and 

mountainous areas. 

9.2. ARCTIC GAS AND AEROSOL SA.,\oIPllNG PROGRAM: 

SPRINGTIlvlE TROPOSPHERIC OZONE DESlRUCTION 

IN THE HIGH ARCTIC 

9.2.1. IImIODUcnoN 

In the AGASP·I and AGASP·ll flights in 1983 and 1986, 

ozone concentrations often showed a steep decline with 

decreasing altitude, beginning immediately beneath the top of 

the surface temperature inversion, to essentially zero values near 

the surface [Raalz el al .. 1985b; Herberl el al., 1988; Bridgman 

eI al., 1988). DlImans [1981) noted that in the surface ozone 

record at BRW, ozone concentrations near zero may persist for 

periods of days during the spring in contrast to the remainder of 

the year when low ozone values are not observed. 

Barrie el al. [1988a) presented strong evidence, based upon 

ozone and other chemical species measurements at Alert. NWf 

(82·N), that the springtime depletion of ozone is the result of 

photolytic reaction between ozone and gaseous bromine to form 

filterable bromine. Filterable bromine was defined by Barrie et 

al. [1988a) as the sum of particulate Br and gaseous HBr 

collected on filters. This sequence begins at polar sunrise and 

diminishes as summer approaches. At the end of the spring, 

both the precursor gaseous bromine reactants are depleted and 

the capping temperature inversion decreases in slrength 

allowing enhanced downward mixing of ozone from above 

Barrie eI al. [1988a). 
9 .2 .2. VERTICAL EXTIJ"T OF TIlE OZO?\"E DEPLETION 

The Arctic is often under the influence of strong temperature 

inversions that create stable conditions near the surface with 

little mixing of this layer with air from above the boundary layer 

[Raalz el a/., 1985a]. NOAA WP-3D aircraft profiles of 

springtime ozone concentrations above and upwind of BRW, 

over the deep Arctic ice pack, and over the ice upwind of the 

Alert Baseline Station [Bridgman et ai., 1988; Herbert et ai., 

1988], show that the greatest ozone depletion is restricted to the 

atmosphere beneath the top of the surface temperature inversion. 

An ozone and temperature profile for a flight north of Alert at 

82.5'N on April 14, 1986, is shown in Figure 9.5. In this figure, 

the gradient of ozone (l-min running mean) across the 

temperature inversion is essentially a step function. On 15 of 16 

AGASP flights over ice in the Arctic in 1983 and 1986, ozone 

depletion was observed beneath the top of the surface temperature inversion. On the one remaining flight, strong southerly 

downslope flow from the Brooks Range, past BRW, out over 

the ice is thought to have mixed air of higher ozone content 

down to the surface. 

9.2.3. SEASONAL PATIERN OF SOlAR INSOlATION AND OZONE 

CONCENTRATIONS ATBRW 

During spring. solar insolation reaching the surface in the 

Arctic increases dramatically. This increase is shown in Figure 

9.6B where the daily sum of the total global flux at BRW is 

plolted in relation to the BRW ozone record (Figure 9.6A). 

Beginning early in March, the solar flux begins a rapid rise, 

March and April being months with a high number of days with 

700 3 

TA tOZ 

, 

-, 750 , 

, 

WP-3D PROFILE , 

APRIL 14, 1986 i 2 , ~ 

800 E NEAR ALERT, NWT .' :,< 

, ~ 

. ~ ( Q) 

.0 850 - -C 

E -, :J ~ 

, :=: 

Q) ,- :!:! 

~ 900 .' 1 « 

:J , If) --- If) -, Q) 950 Inversion Top , ~ 

, a. --, 

1000 

-30 -28 -26 -24 -22 -20 

TA (DC) 

a 10 20 30 40 50 

OZ (ppb) 

Fig. 9.5. An ozone (OZ) and air temperature (TA) profile showing 

ozone depletion below the top of the temperature inversion observed by 

the NOAA WP·3D aircraft north of Alert, r-..rwr, April 14, 1986. 

,---------------------------~ 

aRO~orOR:1 

2/8'\ - 9/87 

(Bl .• 

(XCESS B'lO:1!~.[ 

9176 - 8/BO 

leI 

2 I 6 8 10 ," II 1'6 Ie <'!I II "t 26 28 JIl 1" Jt J6 16 tJ "" tt \ 6 \ 8 ">C ..,., 

W[Eo< 

JR.~ r(8 r-.AA fli'R l"ilY ..lJ.'1 ..u. /lUG. 5EP QCi NOV OCC 

N)NTH 

79 

> 

°t 

z ."'~ 

Fig. 9.6. (A) The seasonal ozone variation at BRW for 1976-1986. The 

medians (dots), the upper and lower quartiles (ends of me boxes), and 

upper and lower ftfth perccmiles (ends of lines) are shown. (8) Total 

global flux of solar radiation at BRW for 1976·1983 (as in A) and mean 

monthly bromoform mole fraction for 1984-1987 (squares) [Cicerone el 

a/., 1988]. (C) Weekly means and standard deviations of me excess 

fLlterable bromine at BRW for 1976-1980 [Berg et at .• 19831. 

relatively clear skies. Although the radiative input continues to 

climb through May, there is a significant increase in cloudiness. 

This is indicated by the median falling well below the upper 

envelope that could be drawn through the 95 percentile values. 

As the period of 24-h daylight approaches (mid-May), 

cloudiness increascs. The end of the period of near-zero surface 

ozone concentrations (Figure 9.6A) also coincides with the 

beginning of total daylight. By late May, the ground is no 

longer continuously covered with snow at BRW and the thermal 

stability in the near-surface air layer is much reduced. 
80 

9.2.4. OZ0r'm DESTRUCTION A1'-'D FILTERABLE BRO}'ffi..'E 

FOR:-'lATION 

Barrie et al. [1988b] showed tha~ al Alert during April, 

ozone concentrations were anticorrelated at 0.95 confidence 

level (p < 0.05) with the concentration of bromine sampled daily 

by filters. They attributed the ozone concentration minima to 

destruction by photochemical reactions of ozone with brominerich gases (mainly bromoform) to produce aerosol bromine 

collected on the filter. These reactions began at, and immediately following, polar sunrise at Alert and continued until about 

the beginning of the 24-h-daylighl period_ 

Extensive filterable bromine measurements by Berg et al. 

[1983] al BRW during 1976-1980 (summarized in Figure 9.6C) 

indicate that during springtime, there also are extremely high 

values of filterable bromine relative to other times of the year, 

Since the sampling periods were 3-7 days, they do not facilitate 

correlation with the sharp day-to-day fluctuations observed in 

the surface ozone data. The filterable bromine record (Figure 

9.6C) exhibits a gradual increase in February, but dramatic 

increases do not take place until March. This is consistent with 

the surface ozone data that also begin seasonal plunges to nearly 

zero concentrations in March. By mid-May filterable bromine 

has declined to lower values, and the sharp drops in ozone have 

essentially ended. The transport of ozone from above down 

into the boundary layer proceeds more freely by mid-Mayas the 

frequency and strength of the inversions are reduced. Any 

bromine (being converted le filterable fonn) would probably be 

more thoroughly mixed into the lower troposphere at this time. 

A marine source of bromine gases in the aunosphere might also 

be weaker in this season, although this has not been proved. 

That the appearance of sunlight in the spring is an important 

faCler in the large seasonal plateau in filterable bromine 

concentrations is suggested by the data of Berg et al. [1983]. 

and Sturges and Barrie [1988]. These data, obtained al four 

localions in the Arclic (Igloolik al 69.5"N, BRW al 70.5"N, 

Mould Bay al 76'N, and Alert at 82'N), cover about a 12' range 

in latitude. It should thus be possible to distinguish a difference 

in the seasonal cycle of filterable bromine, particularly an earlier 

appearance in the springtime rise in concentrations at the lower 

latitudes. That this is indeed the case can be seen from Figure 

9.7, which shows the monLhly variation of the mean concentration of excess bromine at Igloolik and Alert, the two stations 

most widely separated in latitude. This average is based on 4-6 

years of data depending on the location. Individual samples 

were collected weekly. It is clear that at the more southerly site 

(lgloolik) the seasonal increase begins sooner than at the more 

northerly site (Alert). The other two sites (BRW and Mould 

Bay) fall between these two in time of spring rise. The rate of 

falloff from the peak does nol display this same latitudinal 

dependence. 

9.2.5. VERTICAL AND AREAL DISTRlBtmON OF FILTERABLE 

BROI\.III\'E IN TIlE ARcnc 

Figure 9.8 shows the amount of excess filterable bromine 

(Br ) in the aerosol for all nonstratospheric filter samples 

coli:cted during AGASP-! and AGASP-II aircrafl flights 

3,------------------------, 

IGLCO_IK 169',1) 

o 2 ~ 68 IOI21~1618mn2~~~~lZl~35~\l12~~Gt~!~5Z 

\.;[[K 

JFI:, fi:a ~~R ~?R r'.fI't JU:.' JIJL ALiG S[P OCi hOY O:::C 

Fig. 9.7. WeekJy means of the excess ft.herable bromine at Igloolik and 

Alert, 1979-1984 [Slurges and Barrie, 1988]. 

covering the Arctic from Alaska to Greenland to Norway. 

Elemental analyses of the 1983 AGASP filter data are published 

ele,where [Sheridan, 1986; Sheridan and Zoller, 1988]. 

Samples were classified as containing significant marine aerosol 

contributions (M), when collected at low altitude over open 

ocean, or as having been collected over the pack ice in 

tropospheric air (1) at least 200 kIn from open ocean. Samples 

were plotted according to the weighted mean ambient pressure 

during sample collection as an approximate measure of altitude. 

Since we wanted to emphasize fmdings from aerosol collected 

within the surface inversion over the ice, we included pressure 

ranges for the T samples to show the vertical extent of sampling. 

For T samples where no pressure range is shown, the limits lie 

within the sample symbol. Pressure ranges for M samples were 

not included, since none of these samples contained appreciable 

Br,u. 

lrP-:) P HROSOL fILTER DHA fR O}! 1963.\."0 1966 AG.~SP MI SS IOIiS 

300 c 9 

- 8 m - T - 7 

500 ~ 

, 600 - " " 700 - z 

~ 

" 800 - ~ " 

900 -

1000 -

110 0 

P " ~ 

T I 4 ~ 

I - 3 0 

=> 

f 2 

;.. 

':; 

I 0 

< 

, 

, -, 2 3 ~ 5 6 6 

EXCES S DR ( NG j M3) 

Fig. 9.8. Excess fllterable bromine in the Arctic from AGASP aircraft 

samples. M = over ocean, marine sample ; T = over ice, tropospheric 

sample. The M and T symbols are plotted at the weighted mean ambient 

pressure of the sample, and the vertical bars indicate th~. sampling 

altitude range. The shaded section indicates the mean position of the 

temperature inversion over ice, observed in Arctic springs 1983 and 

1986. 
T samples collected wholly in the fTee troposphere genera1ly 

show intermediate Bru concentrations (-0.5.2 ng m"). The 

remaining T samples in Figure 9.8 had significant aerosol 

contributions from below the temperature inversion layer. Most 

had sampling time ncar the surface at pressures >1000 mb. 

These samples contained elevated Bru concentrations. Three of 

the four largest Br.u T samples were coHecled over pack ice 

north of Alert. 

9.2.6. DISCUSSION AND CONCLUDING REMARKS 

The work of Barrie et 01. [1988a] suggests that bromine is 

important in the distribution of ozone near the surface at Alert in 

April. Our examination of the seasonal variation in ozone near 

the surface at severa1 high Arctic stations suggests that both 

meteorology and photochemistry have significant roles in 

explaining the Arctic ozone·bromine cycle. The average 

behavior of atmospheric bromoform along with the ozone, solar 

radiation. and filterable bromine from BRW are shown together 

in Figure 9.6 to emphaze the regular timing of the seasonal 

patterns in these quantities. 

To date, there has been little published concerning the causes 

of the high concentrations of filterable excess bromine. The 

excess bromine observed is much higher than can be explained 

by contributions from bulk seawater and leaded gasoline, 

although other air pollution sources cannot be ruled out. It is 

widely known though that many marine organisms, among them 

red benthic algae, contain high levels of brominated compounds, 

including bromoform [Faulkner, 1980J. A red algae source of 

bromoform in the Arctic was suggesled by Dyrssen and 

FogeIqvist [1981], who measured bromoform levels in surface 

seawater north of Svalbard. This source has been endorsed by 

other researchers as a major contributor of atmospheric gaseous 

bromine 10 the Arctic [e.g., Berg el 01.,1983, 1984J. 

The character of the seasona1 cycle in both ozone and 

filterable bromine at a number of locations in the Arctic 

suggests an important role for the appearance of sunlight in 

initiating the chain of events that leads to a drastic depletion of 

ozone in the boundary layer during the spring. The fact that the 

ozone loss is a springtime rather than an equinoctial event is 

compatible with the proposed interaction with bromofonn and 

the consequent appearance of filterable bromine. In the autumn 

as the sunlight declines there is little bromoform present 

[Cicerone et al., 1988] and the concentrations do not begin to 

build up again until after the autumnal equinox when there is a 

rapid rise to the wintertime va1ues. 

The role of nitrogen oxides and other forms of nitrogen in the 

determination of the seasonal variations in the surface ozone in 

the high Arctic has not been included here. Limiled measure· 

ments of these species are available for some Arctic locations 

[Barrie el 01., 1988b; Logan, 1983, 1985J. Seasonal measurements of the nitrogen compounds are not available at Barrow. 

Because of the generally low levels of the nitrogen oxides as 

well as the lack of wintertime sunlight, Levy el 01. [1985J found 

a tendency for only limiled ozone production at high latitudes. 

A fmal detennination of the role of photochemically produced 

ozone in the high Arctic, however, awaits the routine knowledge 

81 

of the behavior of these nitrogen compounds as well as an 

understanding of the details of bromine chemistry. A much 

better knowledge of the possible ocean sources and the 

processes iliat produce the organic bromine gases is a1so 

required. 

9.3. REFERENCES 

Barchett, W.R., Wind energy resource infonnation system: system 

operation, Technical Memorandum prepared for the U.S. Department of Energy under Contract DE-AC06-76RLO 1830, Banelle 

Pacific Northwest Laboratory, Richland, Wash., 1982. 

Barne, LA., J.W. Bottenheim, R.c. Schenll, PJ. Crutzen, and R.A. 

Rasmussen, Ozone destruction and photochemical reactions at polar 

sunrise in the lower Arctic atmosphere, NaJure, 334, 137·141, 

1988a. 

Barne, LA., G. den Hortog, 1.W. BottenheUn, and S. Lansberger, 

Anthropogenic aerosols and gases in the lower troposphere at Alert, 

Canada in April,J. Atmas. Chem., in press, 1988b. 

Berg, W.W., P.O. Sperry, K.A. Rahn, and E.S. Gladney, Atmospheric 

bromine in the Arctic, J. Geophys. Res., 88, 6719-6736, 1983. 

Berg, W.W., L.E. Heidt, W. Pollock, P.O. Sperry, and R.1. Cicerone, 

Brominated organic species in the Arctic atmosphere, Geophys. Res. 

Ull., 11,429-432, 1984. 

Bridgman, H.A., R.c. Schnell, G.A. Herbert, B.A. Bodhaine, and S.l. 

Oltmans, Meteorology and haze during AGASP·ll, Part 2: Canadian 

Arctic flights 13-16 April 1986, J. Atmas. Chern., in press, 1988. 

Cicerone, R.l., LE. Heidt, and W.H. Pollack, Measurements of 

abnospheric methyl bromide and bromofonn, J. Geophys. Res .. 93, 

3745·3749,1988. 

Committee on Conservation Needs IUld Opportunities (M. Gordon 

Wolman, Dlainnan), Soil Conservation: Assessing the NalioMI 

ResolU'ces Inventory, Vol I . 112 pp., National Academy Press, 

Wa shington, DC, 1986. 

Dyrssen, D., and E. Fogelqvist, Bromoform concentrations of the Arctic 

ocean in the Svalbard area, Oceanol. Ac/a,4, 313-317,1981. 

Faulkner, 0.1., Handbook 0/ EnvironmenJai Chemistry, Vol. I, 

Springer-Verlag, Berlin, 1980. 

Gillette, D., Threshold friction velocities for dust production for 

agricultural soils, J. Geophys. Res., 93, 12,645· 12,662, 1988. 

Gillette, D. and R. Passi, 1988, Modeling dust emission caused by wind 

erosion,J. Geophys. Res., 93, 14,233·14,242, 1988. 

Gil1eue, D., ClaytOn, R.N., Mayeda, T.K., Jackson, M.L., and K. 

Sridhar, Tropospheric aerosols from some major dust storms of the 

southwestern United States, J. Geophys. Res. 87, 9003-9015,1978. 

Gillette, D.A., 1. Adams, A. Endo, and D. Smith, Threshold velocities 

for input of soil particles into the air by desert soils, J. Geophys. 

Res., 85(CJO), 5621·5630,1980. 

Gillette, D.A., 1. Adams, D. Muhs, and R. Kihl, Threshold friction 

velocities and rupture moduli for crusted desert soils for the input of 

soil partic1es into the air, J. Geophys. Res. 87, 9003·9015, 1982 

Herbert, G.A., R.c. Schnell, H.A. Bridgman, B.A. Bodhaine, and S.1. 

Oltmans, Meteorology and haze slructure during AGASp·ll, Part I: 

Alaskan Arctic flights, 2-10 April 1986, J. Almas. CMrn. in press, 

1988. 

Levy H., 1.0. Mahlman, W.l. Moxim, and S.c. Lim, Tropospheric 

ozone: The role of transport, J. Geophys. Res., 90, 3753-3772, 1985. 

Logan, 1.A., Nitrogen oxides in the troposphere: Global and regional 

budgets,J. Geophys. Res .. 88,10,785-10,807,1983. 

Logan, J.A., Tropospheric ozone: Seasonal behavior, trends and 

anthropogenic influence, J. Geophys. Res., 90, 10,463-10,482, 1985. 

Oltmans, SJ., Surface ozone measuremenU in c1ean air, J. Geophys. 

R"., 86, 1174·1180, 1981. 

Orgill, M., and G. Sehmel, Frequency and diurnal variation of dust 

stonns in the continental United States, Almos. Environ., 10, 

813·8252, 1976. 
82 

Raatz., W.E., R.C Schnell, B.A. Bodhainc, SJ. Ohmans, and R.H. 

Gammon, Air mass characteristics in the vicinity of Barrow, Alaska, 

9-19 March 1983, Almas. Environ., 19, 2127-2134, 1985a. 

Raatz, W.E., R.C. Schnell, M.A. Shapiro, S,!. Oltmans, and B.A. 

Bodhaine, Intrusions of stratospheric air into Alaska's troposphere, 

March 1983, Almas. En.yiron.., 19, 2153-2158, 1985b. 

Sheridan, PJ., The use of analytical electron microscopy for the 

individual particle analysis of the Arctic haze aerosol, Ph.D. 

dissertation, 281 pp., University of Maryland, College Park, 19&6. 

Sheridan, PJ., and W. H. Zoller, Elemental composition of particulate 

material sampled from the Arctic haze aerosol, J. Almos. Ch£m., in 

press, 1988, 

Sturges, W.T., and LA. Barrie, Chlorine, bromine and iodine in Arctic 

aerosols, Almas. Environ., 22. 1179·1194, 1988. 
83 

10. Cooperative Programs 

Aerosol Black Carbon Measurements at the South Pole: Initial Results, 1986-1987 

A.D.A. HANSEN 

UJWTtnCt BerbJy LaboraJory. Berb/y, California 94720 

B.A. BODHAlNE AND E.G. DurrON 

NOANGMCC, 325 Broadway, Boul"'r, Colorado 8()302 

R.C. SCHNELL 

Universily o/Colorodo, CIRES, Bowder, Colorado 80306 

1. IN1RODUcnON 

The combustion of carbonaceous fuels results in the 

discharge to the atmosphere of both the major species. carbon 

dioxide and water vapor, and of minor or trace effluents. One of 

these trace effluents is graphitic or ''black'' carbon emitted as 

submicromcter aerosol particles. This material is a good tracer 

for combustion emissions, and may have a long lifetime in the 

atmosphere. It has been found in all studies in urban and 

regional locations as well as in the Arctic haze and in remote 

oceanic locations. Its detection in the Arctic implies transport 

paths exceeding 8000 Ion [Bridgman et al .. 1988J. 

Aerosol black carbon is a tracer for combustion emissions as 

well as a species of chemical and physical oonsequence in its 

own righL It has a large optical absorption cross section, it may 

act as a condensation nucleus, and its surface may act as a site 

for the destruction of ozone [Stephens et al., 1986J. Its 

widespread distribution in the troposphere may lead to its 

eventual presence in the stratosphere [Chuan and Woods, 19841. 

Graphitic carbon has been measured in the Antarctic 

snowpack in the vicinity of SPO [Warren, 1988J, clearly 

indicating the effects of local sources on the areas downwind of 

the station. In December 1986 an aethalometer was installed at 

spa to measure concenlrations of aerosol black carbon with a 

time resolution of 1 hour. We present data covering a l.yr 

period from December 1986 through November 1987 [Hansen 

et al., 1988J. 

2. EXPERIMENTAL DETAll.S AND RESULTS 

The aethalometer draws the sampled airslream at a flow rate 

of approximately 20 SLPM through a 1.1·cm2 active area of a 

quartz fiber filter while monitoring the transmission of light 

through the filter. The accumulation of aerosol black carbon on 

the filter causes this transmission to slowly diminish relative to a 

reference beam intensity. At the low concentrations 

encountered at the South Pole, the filter was changed 

approximately every 2 weeks. Data were recorded during the 

last 20 minutes of each hour and stored on magnetic tape. 

We flIst scanned the hourly data to identify abnonnal events, 

which were clearly evident above a threshold set at 25 ng m·3• 

Thirteen such local contamination events were identified in the 

data during 1987 and were extracted for separate examination; 

lhese events were not included in the subsequent analysis of 

background data. We separated the periods when measurements 

were contaminated by local combustion sources (0.4% of the 

time) from periods when measurements represented large·scale 

background conditions (99.6% of the time). We calculated I-d 

averages for the backgroWld data and used an exponentially 

declining weighted nmning mean on the hourly data to calculate 

a smoothed value for the concentration. Figure I shows these 

results. The points indicate the daily averages and the line shows 

the running mean calculated with a weighting function of 80·h 

half-width. 

Figure 2 shows the hourly measurements during a local 

contamination event in which the black carbon concentration 

increased greatly above its background mean value (1.6 ng m·3 

at that time), accompanied by a similar great increase of eN 

M 

~ c 

'0 ,------------------------------------, 

0.' 

'. , .... .. . . . ,'" . ••••• ~'f 

..... i .. 

. -. 

,', ' .. : 

0.01 I-:c::cTCCC:-r:::lccc::-r=T-:::-rc::-r=:-r=r::::-r=:T.:::::1 OEC JAN Fl:a MAR APR MAY JUN JUL AUG SEP OCT NO" 

1988 1987 

Fig. I. Aerosol black carbon concentrations (ng m·3) measured at SPO 

from December 1986 to November 1987. Data were recorded every 

hour; events of local contamination were removed. The solid points 

represent 24·h means; the solid curve was generated by a smoothing 

function of 8o...h width. The open points represent data calculated from 

the operator's daily logsheets when hourly data were unavailable; the 

dashed curve shows a running average of 4-d width for these points. 
84 

c~ 

.8.§. 

-en rl c 

D§ 

~ '';:: 

.D!" 

" C ~ " ~ U 

C 

0 .. U 

NOAAjGMCC South Pate Observatory 

Hourly mean data 

1000 tOOOO 

tOO r- - 1000 $7 a UE i! U 

a cc 

to- o 0 - 100 ~g ~ !" c- o 0 " c 00 " C " U o c 1-, - 10 u8 

0.1 I 1 

18 21 3 6 9 12 

19Jan 87 20 Jan 87 

Fig. 2. Aerosol black carbon (vertical lines) and condensation nucleus 

data (circles) for a local contamination event occurring January 19·20, 

1987, at SPO. Note the logarithmic scales. The mean smOOlhed value 

of backgrolUld black carbon concentration at this lime was 1.6 ng m ol. 

concentration. For 6 hours, carbon concentrations eltceeded 160 

ng mol (i.e. a greater than lOO-fold increase over background), 

Other observations suggested that this event was due to 

contamination by local activities. The amOlUlt of carbon 

collected during these 6 hours was 50% greater than the total 

amount collected during the following 10 months of the study 

period. excluding other contamination events. It is imp:lItant to 

note that such events are infrequent and can easily be detected 

by examining continuous hourly data. 

3. DISCUSSION 

The results show that background aerosol black carbon 

concentrations general1y ranged from 50 pg m·l to 5 ng m·l 

during the 1986·1987 sampling period at Spo, and that a 

pronounced minimum occurred in the early austral winter. This 

seasonal cycle is approximately in phase with that of the aerosol 

scattering extinction and the CN concentration [Bodhaine el al., 

1986]. We may compare the black carbon concentrations with 

the following ranges measured at other locations: 10-100 ~g m·l , 

winter coal heating season in European cities; l-lD Jlg m·l , 

annual averages for U.S. urban areas; 0.1-1 J-lg m·l , annual 

averages for U.S. regional areas, and concentrations found in 

Arctic haze layers; and 10-100 ng m·l , remote middle-latitude 

ocean area [Goldberg, 1985). The concentrations at SPO are 

therefore much smaller than concentrations measured at any 

other location, but are nonetheless detectable. The material 

reaching the South Pole is the most long-lived fraction of the 

global background aerosol, and we may estimate a lower limit 

for lhe concentration of its black carbon component of about 10 

pgm·'. 

We also note the essential attribute of real-time data in 

distinguishing local influences at a remote sampling location. 

The example illustrated in Figure 2 shows that the amount of 

carbon collected during only a few hours of local contamination 

could exceed that collected during an entire year of background 

sampling at such a remote location. Consequently, results 

derived from the analysis of filter samples operated for long 

periods of time may be seriously misleading if contaminating 

events are sampled. When sufficierH data are available from 

several years of continuous sampling, it will be possible to study 

the statistics of local aerosol black carbon contamination events 

superimposed on background measurements at the South Pole. 

The real-time nature of aethalometer data allows for this 

examination in a manner that filter sample analyses do not. 

4. SUMMARY 

Measurements of aerosol black carbon in background air at 

the South Pole for December 1986 to November 1987 show 

daily concentrations of this combustion-derived pollutant 

ranging generally from 50 pg m·l to 5 ng m·l , and having a 

minimum in the early austral winter. These concentrations are 

many orders of magnitude lower than those measured at lcss 

remote locations, and imply extremely long-range transport of 

energy-related anthropogenic emissions. The l·h time 

resolution of the measurements allows for the identification of 

local source contamination events. 

Acknowledgments. This work was supported by the Director, 

Office of Energy Research, Office of Health and Environmental 

Research of the U.S. Department of Energy under contract 

DE·AC03·76SF00098, and by the National Oceanic and 

Atmospheric Administration under contracts 40RANR730071 

and 40RANR705255. The South Pole Observatory is funded 

and operated by the National Science Foundation. 

REFERENCES 

Bodhaine, B. A" J. 1. DeLuisi, J. M. Harris, P. Houmere, and S. 

Bauman, Aerosol measurements at the South Pole, TeJlus, 388, 

223·235, 1986. 

Bridgman, H. A" R. C. Schnell, 1. D. KahI, G. A. Herbert, and E. 

loranger, A major haze event near Point Barrow, Alaska, during 

AGASp·n, 2-3 April 1986: Meteorological analysis of probable 

source regions and transport pathways, Atmos. Envjron.., submiued, 

1988. 

Chuan, R. L, and D. C. Woods, The appearance of carbon aerosol 

particles in the lower stratosphere, Geoplrys. Res. Ult .• 1 J. 553-556, 

1984. 

Goldberg, E. D., BlacJcCOTbon in EM Envirol1mLn.I, 196 pp., Wiley, New 

York,1985. 

Hansen, A.D.A, B.A. Bodhaine, E.G. Dulton, and R.C. Schnell, Aerosol 

black carbon measurements at the South Pole: Initial resuls, 

1986·1987, Geophys. Res. Ull .. /5, 1193· t 196, 1988. 

Stephens, S., M. 1. Rossi, and D. M. Golden, The heterogenesis reaction 

of ozone on carbonaceous surfaces, Int. J. Chem. Kin2tics, 18, 

1133·1149, 1986. 

Warren, S. G., Optical propenies of Antarctic snow, Ani. J. U.S., in 

press, 1988. 
85 

Global Distributions of Anthropogenic Chlorocarbons: 

A Comparison of CFC-ll, CFC-12, CFC-22, CFC-1l3, CC4, and CH3CCl3 

From an Ocean Cruise and From Land-Based Sampling Sites 

M.A.K. KHAUL M'm R.A. RASMUSSEN 

fnsti/ule of Atmospheric Sciences, Oregon Graduate Center. Beaverton. Oregon 97006 

1. INTRODUCTION 

Between May and July 1987 aGe participated in a joint 

Soviet-American research program dealing with the effects 

of human activities on the global climate (SAGA II). Our 

experiments were conducted on the Soviet ship Akademik 

Korole\!. The ship sailed from Hila, Hawaii, to high 

northern latitudes to the Kamchatka peninsula, and then 

sailed south to New Zealand, westward to Tasmania, north to 

Singapore, and finally returned to Hila. From this long trek 

we obtained flask samples from latitudes between about 

50'N and about 45·S. 

2. SAMPLING 

Here, we report on the concentrations of six anthropogenic 

chlorine-containing trace gases including CFC-ll (CCI)F) 

and CFC-12 (CClzFz}, two of the main chlorofluorocarbons 

implicated in the depletion of the stratospheric ozone layer. 

Of the six , CFC-l13 (CzCI3F3) has been increasing most 

rapidly in the atmosphere in recent years, reflecting its 

growing use as a degreasing solvent in the high-technology 

electronics industry [Khalil and Rasmussen, 1986]. 

Methylchloroform (CH)CCl)) is also a degreasing solvent, 

but its uses are not growing as fast, so the rates of increase 

now are much less than in previous years [Rasmussen and 

Khalil, 1986]. All these chlorocarbons are much more 

concentrated in the northern hemisphere than in the southern 

hemisphere because most of their sources are in the 

industrialized middle northern latitudes. 

In addition to taking measurements on ocean cruises such 

as SAGA II, we have obtained air samples, for nearly a 

decade, from sites distributed in latitudes from the Arctic 

Circle to the South Pole. The sites are located at Barrow, 

Alaska, inside the Arctic Circle; Cape Meares, Oregon, near 

our laboratory; Mauna Loa Observatory and Cape 

Kumukahi, Hawaii; American Samoa; Cape Grim, Tasmania; 

and the South Pole. At all the sites. except Cape Meares and 

Cape Grim, samples are collected for us by NOAA/GMCC. 

The weekly samples from these sites obtained at the same 

time as samples from the cruise of the Akademik Korolev can 

be compared wilh each other. Such a comparison shows 

very good agreement, demonstrating that the flask-sampling 

sites accurately reflect the concentrations of these trace 

gases, and many others not discussed here, for the entire 

range of latitudes represented by the sites. 

3. RESULTS 

The main results are summarized in Figure 1 and Table 1. 

Figure 1 shows the concentrations of the chlorocarbons 

obtained on the Akademik Korolev and the concentrations 

during the same time at Lhe flask sampling sites. The 

shipboard measurements were averaged over latitudinal 

bands of 0.2 in the sine of latitude. So, for example, the 

point plotted at 0.5 in the sine of latitude is the average 

concentration in the latitude band spanning 0.4 and 0.6 in 

sine latitude or between 23 ~ and 37°. We use sine of latitude 

as a standard unit of horizontal extent since equal divisions 

of sine latitude represent equal amounts of surface area on 

the earth. The verti cal bars represent the 90% con ridence 

limits of the mean concentrations. The solid line is an 

empirical fit to the average concentrations rrom the ship 

measurements. The empirical relation is expressed as 

dC a; ~ bra-C) (C-d) (I) 

where C is the concentration (pptv),).l is the sine of latitude, 

and a, b, and d are constan ts. The constant a represents the 

upper limit of concentrations at high northern latitudes, d is 

the lower limit in the southern hemisphere, and b is a 

parameter that expresses the rapidity and the magnitude by 

which concentrations fall as one moves from the northern 

hemisphere to the southern hemisphere. This is a logistic 

equation that has been applied to many natural processes in 

which limited changes are expected. The solution of this 

equation is given by 

d+aKe'~ 

c= I +KeX~ (2) 

where K is the constant of integration and A = bfa-d). The 

parameters to be fitted are a, b, d, and K, which we list in 

Table 2. Table 1 also contains the data on the average 

concentrations measured in each latitudinal band . The 

empirical function for the latitudinal distribution can be used 

to detennine the average concentrations in any latitudinal 

band. 

4 . CONCLUSIONS 

The current latitudinal distributions are shown of six 

anthropogenic chlorine-containing trace gases in the 

atmosphere that are implicated in the destruction of the 

stratospheric ozone layer. At present the most effective in 

this role are CFC-ll and CFC-12 . The primary data are from 

the cruise of the Soviet ship Akademik Korofev. Simultaneous measurements taken at the sites of our global 

network are shown to agree with the results from the cruise 
86 

260 

F - 11 ,. 2 50 0. • -"'- T 

• 0. 

240 

, 

"- 230 

220 

{ 

r T ~ ~ 

L ., , ~ j 

I • 1 1 

440 

,. 425 c; 

0. 

" 410 

, 

"- 3 95 

F - 12 

y~ _2 .1 

T • T 2 T ; ~ • • 

! 1 

380 I 

120 

F-22 ,. 1 10 c; 

0. 

" 100 

T 

T ________ - -

Q ~ 

~ 2 

• ~O 

" , 

"- 90 • Q ~ 

0 

80 

45 

,. F- 11 3 0 

1 

c; 40 0. 

M 35 

T 0 

• f~ , 

L 

L 0 ;; y , 30 "- • j 

25 

145 

CCI4 

.:: 140 ~ 

0. 

0. 

.,. 135 

0 

() 1 30 

125 

: ~ Q 

T ~ 

j " 

I 

200 ,. 

c; 180 0. 

M 160 

0 

() 140 M 

I 1 20 () 

100 

CH3CCI3 /' T ~ , , 

, 0 ~~ L T 

" 

f 

-1.0 -0.6 -0.2 0.2 0.6 1.0 

Sine of Latitude 

Fig. 1. The latitudinal distributions of six anthropogen ic chlorocar· 

bons obtained from a ship cruise (SAGA II - filled diamonds) and 

from systematic flask sampling sites (open diamonds). The vertical 

bars are the 90% confidence limits of the mean values. The solid 

line is an empirica l fit of the data to a logistic model described in 

the text. 

TABLE 1. The Latitudinal Distribution (pptv) of Six 

Anthropogenic Chlorocarbons Obtained Onboard 

the Cruise of the Akademik Korolev (SAGA II)' 

sin ~ CFC-12 CFC-II CFC-I13 CH,CCI, CO, CFC-22 

0.7 426 251 37 186 138 110 

0.5 417 247 39 173 137 106 

0.3 410 241 36 155 135 102 

0.1 403 234 34 136 133 99 

-0.1 399 235 32 130 132 98 

-0.3 401 229 32 125 131 

-0.5 392 226 31 122 131 93 

-0.7 395 229 31 {25 131 

·The concentrations are averaged over latitudinal bands of ± 0.1 

in sine of latitude surrounding the average location in the sin)1 

column. 

TABLE 2. Values of Variables for the Empirical Logistic 

Model Fitted to the Latitudinal Data in Table 1 

Variable CFC-12 CFC-II CFC-113 CH,CCI, CC1, CFC-22 

d 

• 

K 

b 

395 

429 

0.10 

0.18 

228 

253 

0.25 

0.18 

31 

38 

0.40 

1.10 

122 

192 

0.20 

0.06 

131 

138 

0.15 

1.00 

96 

112 

0.10 

0.35 

data. These results validate the shipboard measurements and 

show that measurements taken at the land-based sites 

represent the latitudes in which the sites are located. The 

data are fitted to an empirical logistic fonnula to represent 

the global latitudinal data by four parameters (a, b, d, and K) 

listed in Table 2. OGC is continuing the research based on 

the samples from the SAGA II program to analyze data on 

these and many other trace gases, both in the almosphere and 

in the sea water, to detennine the global mass balances of 

some 20-30 almospheric trace gases. 

Acknowledgments. We thank John A. Rau, a Senior Research 

Associate at the Institute of Atmospheric Sciences of the Oregon 

Graduate Center, who collected gas and aerosol samples on board 

the Akademik Korolev, including the samples on which the results of 

this paper are based. Financial support was provided by National 

Science Foundation Grant # ATM-8414020. We thank NOAAI 

GMCC for collecting the samples for our land-based, long-term 

flask sampling program. Additional support for this program was 

obtained from the resources of the Biospherics Research Corporation and the Andarz Company. 

REFERENCES 

Rasmussen, R.A., and M.A.K. Khalil, Atmospheric trace gases: 

Trends and distributions over the la st decade, Science, 232, 

1623-1624,1986. 

Khalil, M.A.K., and R.A. Rasmussen, Trichlorotrifluoroethane 

(F-1l3): Trends at Pt. Barrow, Alaska, in Geophysical 

Monitoring For C/imotic Chal1ge, No. 13.' Summary Report 

1984, E.C. Nickerson (ed.), NOAA Environmental Research 

Laboratories, Boulder, CO, 91-93,1986. 
87 

Some Characteristics of Aerosol Size Distributions at MLO 

ANTONYD. CLARKE 

Hawaij Insritule of Geophysics, University of Hawaii, Honolulu, /-Iawaii 96822 

1. INTRODUCTION 

In-situ measurement of the aerosol size distribution was 

initiated at MLO in 1986 and was resumed in late 1987 through 

March 1988 as part of NASNGWBE in order to characterize 

aerosol properties of importance to the LAWS program. 

Previous experiments have demonslralcd that aerosols measured 

under clean downslope flow at MLO undergo an annual cycle 

dominated by the springtime (February·lune) transport of Asian 

dust and continental aerosol in the free troposphere [Bodhaine el 

ai. , 1981; ParTington et al., 1983]. The rest-of-the-year average 

mass concentration is an order of magnitude lowCT. However. 

previous data were often averages over a week or so; therefore, 

shorHenn variability in aerosol concentrations or properties was 

obscured. The poor size descrimination also limited infonnation 

on particle munber and mass distributions. This infonnation is 

necessary to NASA/LAWS in order to relate aerosol microphysics to the existing MLO aerosol scattering extinction data 

so that aerosol backscatter at the 10.6 }JJ11 CO2 wavelength can 

be beuer modeled, based on the nature and variability of low 

aerosol concentration!' in the marine free troIX>sphere. 

t .... o c 

,.cr------

I1I'SLOP[ 

i 

I / , 

~/ 

~ V 

DUSt DOolI!SLOPE 

! 

2. MEASUREMENTS AND RESULTS 

A measurement program was initiated at MLO using a 

modified LOPC with 254 size channels between O.IS and 7.0 

J.UT1 . The LOPC operated under microcomputer control and 

accumulated data continuously over 3-h intervals. Aerosols 

entering the LOpe first passed through a thennal conditioning 

systcm that heated thcm to 4WC, ISO·C, and 340·C in separate 

charutels. At IS0·C sulfuric acid was driven off, and at 34WC 

all sulfates were volatilized to leave refractory components (e.g., 

soot, salt, dust). as shown in Figure 1 [Clarke €I al .• 1987). 

Sulfates have been identified as the major noncrustal downslope 

aerosol at MLO [Bjgg, 1977], and this interpretation also 

appears appropriate here. 

The 2.S-cm-ID sample inlet line was situated at about the 

24-m level of a tower that was about 13 m from the enclosed 

sampling building. Calculated particle losses for the turbulent 

flow become significant at about 4 ~m. Since other investigators [ShUll. 1980J and our own data from 198 1 and 1982 

(unpublished) find a mass mean diameter during dust events of 

between 3.0 and 4.0 }JJ11 after about 6000 km of transport, we 

~lS0 C 

i 

! 

/ 

':'. 

t-)40 C 

.---' ------·1 

! 

I 

,I . , 

1 

1 

lr~'·l-"i--.-:·j -----1 

1 

I / I 

'1 

i 1 

... , ... u .t .4 .' I l ,~ Lrr-~~--,·J 0.' 

0.1 

CLEAI. OOIIHSLOPI 

, 

! 

, . /\ .' 

J '-\/),\_ 

.1r-:r--:"r:r-li....i:..:., 

./ 

/ \..J".._/';\ 

. rr-;-;-:r-rT":--rr 

DTUiITEJI (11,,\ 

Fig. 1. Three volume size distributions of aerosols with diameters between 0.15 and 7.0 Il1Tl measured at MLO with the LOPC at 4O"C, 150·C, and 

340·C. The top row shows upslope air from the boundary layer, the middle row shows an A~ian dust event (March II, 1988); and the bottom row 

shows clean downslope air. 
88 

estimate that our coarse particle mass data may be 30% low but 

coarse number count will be at most a few percent low. 

Several examples of the LOpe size distributions are shown 

in Figure 1 for each temperature. The top row is an example of 

a daytime upslope aerosol mass distribution fyom the marine 

boundary layer and illustrates the typical volatile component 

below 0.5.,un diameter (fme particles. sulfate) and refractory sea 

salt or dust at larger diameters (coarse particles) [Clarke, el al.. 

1987]. The second row shows the character of the aerosol under 

downslope flow for March 11. 1988, when Asian dust was 

u ,. , 0" a 0" 

.. ,

0 . 10 . 

0'" 

0« ." , .. ,, 0 0 

0.011 , 0 .00 , "' , 0 .0. 

, " 0 001 • 

0 

" " " ,. Lope NUWKR " > 01 IN " '" " •.. , o .Ot b • 

t; 0 .0' 

u , § 0 .07 

5 

0 0.0' • • 0 • 

:0 O.O~ 

0 , • 0 0' 0.0" g, 

] .Q~ • • 

e 0 .02 

0 

Z 0.01 

• 

" " " ,. " .. '" " 0.' 

0 ." c 

0.01 , 0.07 

0 .0' 

O.OS 

0 .04 

0.0) • • , 

• 0 .01 

i ! 0.01 • • • , • • : • • • 0 

" " n " .. .. ,. " 

• ... . 041' 0#' nN'l ."'" • -

present in the troposphere above MLO. The 15% decrease in 

mass at 150·C and 25% decrease at 340·C for this case are 

attributed largely to higher coarse particle losses in the heated 

channels. Corrections for these decreases are applied to all of 

the data that follow. The bollom row of data is a charactcristic 

distribution during downslope flow for the "clean" periods at 

MLO (note scale change) and shows the much reduced coarseparticle fraction and refractory fine fraction. Although 

concentrations are very low in comparison with the mixed laycr, 

the presence of a significant fine mode «0.4 ~ diameter) 

•.. d 

O • 

.. ,

•.. 

" 

" 0 

. 0 

.. ,

" •.. i , I i • i 

" , • , 

'" " " " .. " '" " .., 

e 

0 . " 

"e , • 

.:; " •.. . . 

n 

e • 

• • 0 .0) • • 

i • 

• 

, 0 • .. " n " " .. ,. " 0 .' 

f 

0." 

0.' 0 

• , 

0.0) • , • • • 

& • , , : 0 

.. ,. n " " .. ,. Qll.1'01' ...... " 

• 'DC . ... .... Fig. 2. Time series of coarse aerosol mass and number concentrations, measured with the LOPC at 40·C, ISO·C, and 340·C. for downslope periods 

discussed in the text. Shown are (a) the number of particles greater than O.S }UTl diameter; (b) the same as (a), but rescaled 10 show lower values; (c) the 

number of panicles greater than 1.0 ~ diameter; (d) the mass (118 m·l) of particles greater than 0.5 )U1l diameter; (e) the same as (d), but rescaled to 

show lower values; (f) the mass at particles greater than 1.0 }UTl diameter. 
refractory component at 340·C is characteristic of a continental 

combustion source. A similar component has not been found in 

association with either high sea salt or high dust concentrations, 

but it has been observed when high soot concentrations were 

measured in remote polluted air [see Clarke, 1987]. A 

rccalibration of the LOPC for soot instead of sulfate would 

reduce this refractory component by about a factor of 3 in 

apparent concentration, down to about 10 ng m-J, similar to soot 

concentration values estimated from light absorption 

measurements at MLO in 1981-1982 [Clarke and Charlson, 

1985]. 

Thirteen rughts, in the period January 18 to February 1, 1988, 

were chosen for clean conditions based upon low CN counts and 

wind directions that did not favor transport of aerosol from the 

Mauna Loa ca1dera south of MLO. These data were then 

selected for the lowest aerosol concentrations observed, 

occurring generally between 0100 and 0400 LST. Figure 2 

presents time series of integrated mass and nwnber 

concentrations for particles greater than 0.5 and 1.0 ~ 

diameter. Minimum and maximum concentrations in mass or 

number range over 2 orders of magnitude even though the 

highest dust concentration (January 30) is an order of magnitude 

lower than that illustrated for the large dust event shown in 

Figure 1 (March 11). The data points at 4O'C, 150'C, and 

340·C reveal the decrease of volatile particles and mass upon 

heating and were corrected for losses mentioned earlier. This 

response suggests that the sulfuric acid and ammonium 

NASA-MLO 1988 PERCENT CON11'tI8lIT10N TO 8002 

70 

.. S .0 

~ 

t 

e .. ~ 

8 30 

u 

6 20 

• 

'0 

2 :3 4 5 11 12 13 

_ OUST GA."!' or 'I"E'.FI ~ COAAS£ SULF. r2'Z2J FlN£ SUL.f'. 

Fig. 3. Histogram of estimated percent BC02 backscatter attributed to 

coarse (d > 0.5 ~) refractory aerosol (dust), coarse sulfate aerosol, 

and fine @p<0.5 J.lffl) sulfate aerosol for each sample interval. 

89 

sulfate/bisulfate [Clarke et al.,1987] present in these coarse 

particles can account for more than 80% of their mass at times 

of low concentrations of coarse aerosol but drop to a negligible 

fraction during the dustiest of these nights (e.g. January 30). 

The lowest concentrations obtained during this period, show that 

the number (mass) of coarse particles with diameters greater 

than 1.0 fUll were usually less than om cm-' (0.03 ~g m·'). 

The interpretation of the above data in terms of backscatter at 

10.6 fUll CO, laser wavelength (BC02), is of interest to the 

NASA GLOBF/LAWS programs. Here we estimate the various 

contributions to BC02 from each component as a lognormal 

distribution in number centered at a particular diameter. These 

contributions are based upon the BC02 per particle per cubic 

centimeter calculated for lognonnal distributions of various 

components, a dust aerosol lognormal number peak at 1.0 ~m, 

an ammonium sulfate coarse aerosol number peak at 0.6 ~m, 

and an ammoniwn sulfate fine-particle number peak: at 0.16 Jim. 

These relative contributions to BC02 are shown in Figure 3 as a 

histogram for each of the 13 sequential periods. A clear change 

can be seen in the relative contributions to BC02 as the 

transition to a higher dust concentration takes place. The 

low-dust periods show contributions to BC02 from dust of 

about 15-25% compared with 50-70% for minor dust incursions 

(periods 11, 12, 13). With one exception, the fine-particle 

sulfate contribution decreases from about 40% to 15% of the 

total. Coarse volatile sulfate tends to dominate the contribution 

to BC02 during low-dust periods and remains significant even 

for the increasing dust concentrations seen in periods 11, 12, 13. 

REFERENCES 

Bigg, E.K., Some properties of me aerosol at Mauna Loa Observatory, 

J. Appl. Meleorol.16, 262·267,1977. 

Bodhaine, B.A., B.G. Mendonca, 1.M. Harris, and 1.M. Miller, Seasonal 

variations in aerosols and aunospheric transmission at Mauna Loa 

Obse.val0'l'. J. G,ophys. R.,., 86, 7395-7398,1981. 

Clarke, A.D., Size distributions of volatiJe and refractory Arctic haze 

aerosol compnents measured at Barrow during AGASP·ll 1986, in 

Geophysical Monitoring for Climatic Change, No. 15: Swnmary 

Report 1986, edited by R.C. Schnell and R.M. Rosson, pp. 115·119, 

NOAA Envirorunental Research Laboratories, Boulder, Colo., 1987 . 

Clarke, A.D., and R.I. Charlson, Radiative properties of me background 

aerosol: Absorption oomponent of e~tindion, Science, 229, 263-265, 

1985. 

Clarke, A.D., N.C. Ahlquist, and D.S. Covert, The Pacific marine 

aerosol: Evidence for natural acid sulfates, J. Geophys. Res., 92, 

4179-4190.1987. 

Parrington, 1.R., W.H. Zoller, and N.K. Aras, Asian dust: Seasonal 

transport to the Hawaiian Islands, Science, 220, 195-197, 1983. 

Shut2, L, Long range transport of desert dust with special emphasis on 

the Sahara, Ann. N.Y. Acad. Sci., 338, 515·532, 1980. 
90 

Snowfall Measurements in the Arctic 

GEORGE CLAGETI 

Soil COIIStrWJtion Service. Anchorage, AloslaJ 99501 

1. INlRODUCTION 

Arctic winters are characterized by months of very low 

temperatures. infrequent and light-density snowfall, and 

incessant wind, the sum of which precludes much hope of 

accurate snowfall measurements using traditional methods. A 

precipitation gauge without artificial windshielding has little 

chance of catching a correct amount of new moisture falling out 

of a wind-driven Arctic snowstonn. In the mid-1970's, the 

University of Wyoming produced a windshield after 7 years of 

research that included tests in a wind tunnel [Rechard, 1975]. It 

provided snowfall catch in an exposed. windy area that was 

within 7% of the catch in a forest-protected area. This report 

compares snowfall catches using Wyoming windshielded 

gauges with catches using NWS nonshielded gauges at Barrow 

and Barter Island on Alaska's Arctic Coast for the last 12 years. 

These measurements are also compared with nearby 

measurements of the tundra snow-water equivalent (SWE). 

2. METHODS 

The Wyoming windshield consists of two concentric rings of 

snowfences surrounding the precipitation storage can orifice. A 

solid framework elevates the 1.2-m tall snow fence mesh. The 

outer circle is 3 m off the ground and 5.1 m in diameter; the 

inner circle is 2.4 m off the ground and 3 m in diameter. The 

rings of fencing are canted inward at the bottom, 30· from the 

vertical for the outer ring and 45" for the inner ring, to fonn a 

cup or funnel effect. The level of the storage can orifice is 2.4 

m above the ground surface (i.e., level with the top of the inner 

ring of fencing). 

The f'wutel shape is a critical part of the design, since wind 

hitting the leading edge of the fencing is forced downward and 

underneath the gauge rather than over the top. This causes air 

speed below the gauge to increase slightly in order for the larger 

air volume to pass. With the increased air speed below the 

fencing, a downward pressure gradient is created within the 

fencing, causing snow particles clearing the top of the gauge to 

settle out within the fencing and to fall into the can. Research 

suggests that the snow passing under the gauge is primarily drift 

material and snow at the 3-m elevation is primarily new 

snowfall. 

The precipitation cans mounted within the Wyoming 

windshields are storage devices with an antifreeze solution and 

an evaporation-inhibiting oil layer. The storage-type gauge is a 

basic requirement of remote. seldom-visited locations, which 

constitute the bulk of the network of 23 active Wyoming 

windshields in Alaska monitored by the SCS. Frequency of 

readings generally ranges from twice monthly at Barrow to nine 

times annually at Barter Island. Contents of the 20.3-cmdiameter by 0.9-m-tall storage cans are weighed with an 

open-face dairy scale read to the nearest 0.25 cm. In 1984, a 

larger 30.5-cm-diameter by 2.4-m-ta11 can was installed at 

Barter Island, along with the attachment of a float-driven fluidlevel recording system, whose accuracy is also to the nearest 

0.25 cm. This level of resolution makes accurate evaluation of 

small increments over shon time periods impossible, especially 

in the Arctic where many small events are often required to 

meet the smallest recordable increment. Therefore, monthly 

totals are used for the evaluation period of this report 

The Barrow gauges are separated by 7 km: the NWS gauge is 

near town center, which affords some disruption of air flow past 

the gauge; the Wyoming gauge is northeast of town near the 

NOAA-GMCC facility. GMCC services the Wyoming gauge. 

At Barter Island, the Wyoming gauge was originally 1.6 km 

south of town; however, it was difficult to get consistent 

readings by local observers, so the gauge was moved closer to 

town in J\D1e 1983. The new location is only 230 m from the 

NWS gauge which is about 60 m beyond the Barter Island DEW 

Line barracks. Readings are currently being made by the U.S. 

Fish and Wildlife Service. 

3. COMPARISON OF DATA 

NWS has staffed a first-order weather station for 67 years at 

Barrow and for 40 year.; at Barter Island. Published 

precipitation averages (30-yr peri<Xi) for the two sites are 12.06 

em annually and 6.45 em during the September.May winter 

months for Barrow, and 16.48 and 9.70, respectively. for Barter 

Island. Scientists have recognized that these averages are not 

accurate winter precipitation levels [Black, 1954; Benson, 1982]. 

Benson constructed two of the first three Wyoming gauge 

installations in Alaska at these two villages in the fall of 1975. 

By the end of the 1987 watcryear, 11 years of matching records 

were collected at Barrow and 8 years at Barter Island. Table 1 

lists the average monthly catches over the last 12 years for both 

the NWS WlShielded and Wyoming shielded gauges. NWS 

figures in the table correspond to the same periods that are 

available for the Wyoming gauge. For Barrow, the 1982 

wateryear is missing because the Wyoming gauge was damaged; 

for Barter Island 1978. 1980. 1982. and portions of 1976 and 

1981 wateryears are missing. 

In Table 2 we combined the monthly totals by periods of the 

year for matching periods during 1976-1987. The shielded 

gauges yielded an overall catch 2 times that of unshielded 

gauges during the 9-mo winter season. However, the factor is 3 

times during the November-April coldest months. Although the 

windshield is the probable reason for these discrepancies during 

the winter months, a windshield does not seem to provide any 

significant additional benefit during the three summer months. 
TABLE 1. Average Monthly Precipitation (cm) at Barrow 

and Barter Island 

Barrow 

NWS NWS Wycming 

1976-1987 30-,.,. 1976-1987 

Month Avenge· Avcnget Avenge· 

Scp<. 1.96 1.50 1.73 

Oct. 1.02 1.40 1.55 

Nov. 0.43 0.76 1.34 

Dec. 0.28 0.46 1.14 

Jan. 0.30 0.53 1.19 

Feb. 0.36 0.43 0.96 

March 0.23 0.43 0.96 

April 0.33 0.53 0.64 

May 0.28 0.41 0.53 

June 0.66 0.94 1.14 

July 2.03 2.18 2.08 

Aug. 2.11 2.49 2.13 

*Does nof. include 1982 wateryear. 

tFor the period 1951·1980. 

Barter Island 

NWS r-,'WS Wyoming 

1976-1987 30-,.,. 1976-1987 

Avenge; Avenget Avenge; 

1.40 2.03 2.13 

1.40 2.06 2.36 

0.56 1.02 1.37 

0.64 0.58 1.57 

0.56 1.27 1.52 

0.25 0.68 1.35 

0.48 0.61 1.52 

0.30 0.56 1.32 

0.43 0.89 0.84 

0.81 1.42 1.37 

1.90 2.62 2.26 

2.41 2.74 3.05 

tDoes not include 1978, 1980,1982, and portions of 1976 and 1981 

watel)'ears. 

Table I points out another peculiar discrepancy. The NWS 

monthly average data over the last 12 years are consistently far 

below published 30-yr long-term averages (for the period 

1951-1980). Benson [1982) noted that the Barrow station was 

moved in 1955 and again in 1966 and that these moves or 

possibly the addition of an Alter shield to the gauge had a 

profound effect on the recorded precipitation. After 1955 the 

gauge caught 1.4 times as much as before the move, but after 

1966 it caught only 0.63 as much. The result is that most years 

since 1966 have precipitation data far below the inflated 

average. Barter Island also recorded a higher rate of 

precipitation during the period 1956-1967 than afterward. A 

sharp break OCClUTed in 1967 on the double mass plot to 0.67 as 

much precipitation, even though the gauge was not moved, 

leading one to suspect that the Alter windshield was removed 

from both Barrow and Barter Island gauges at that time . Benson 

states that the site histories for both sites mention the use of 

91 

TABLE 2. Monthly Snow Catch Total (cm), Combined Into 

Period of the Year, for Matching Periods During 1976-1987 

Barrow Barter Island 

NWS Wyoming Factor NWS Wyoming Factor 

Wateryear 

OcL I-Sept. 30 9.98 15.42 1.54 1l.l5 20.67 1.85 

W inter Season 

Scp<o I-May 31 5.18 10.06 1.94 6.02 14.00 2.32 

Mid·Winter 

Nov. 1·April30 1.93 6.25 3.24 2.79 8.66 3.10 

Alter shields, but do not give details. It is known, however, that 

gauges have been unshielded since 1966 at Barrow and 1967 at 

Barter Island. 

The NWS measurement technique creates another problem. 

Precipitation increment is measured four times per day by 

exchanging the can each 6 hours with another one. The catch 

for the previous 6 hours is thawed, then measured to detennine 

the new increment If the catch is less than 0.13 nun, it is 

recorded as a trace. The can is then dried to be ready for its next 

6·h shUt. Since Arctic snowfall generally comes in small 

amounts, is of light density, and is wind driven, this technique 

of discounting even 0.13 mm four times a day becomes 

significant, as the wlShielucd gauge appears to be catching only 

a fraction of the small natural snowfall increments. This results 

in an extraordinary number of trace readings in the record. 

Benson [1982] reported that traces in the winter record go as 

high as 80% of all precipitation entries. Accumulation of 

precipitation over time in a storage gauge eliminates this 

problem. 

Tundra snow measurements provide more data for compari. 

sons (Table 3). The USGS team made reconnaissance snow 

measurements on the Arctic Slope during the spring of the year, 

just prior to the breakup season, in five different years (1977, 

1978, 1979, 1982, and 1983). In 1979, however, they were 

late, as spring thaw was well Wldcr way in much of the region. 

TABLE 3. USGS Tundra Snow-Water-Equivalent (SWE) Measurements Compared With Wyoming 

Sruelded Gauges and NWS Unsruelded Gauges 

Tundra 

Tundra Wyoming NWS SWE NWS NWS 

SWE Gauge Gauge as %of as %of as % of 

Year Location D". (em) <em) <em) Wyoming Wyoming Tundra 

1977 Barrow April 22 7.9 9.6 4.3 82% 45% 55% 

1978 Barrow April 17 7.4 9.1 4.1 80% 44% 55% 

1982 Barter [so April 24 11.9 5.3 58% 

1983 Barrow April 25 6.1 8.6 3.6 70% 41% 58% 

1983 Barter Is. April 22 7.9 11.7 0.8 67% 6% 10% 

Average (Barrow only) 7.11 9.14 4.06 73% 43% 56% 
92 

They landed a ski plane on the tundra at 24-40 sites over alx>ut a 

1 ~wk period each year. Their transects avoided obvious 

deposition areas. Their reported figures represent an average of 

40 individual random samples per site [Sloan eJ al., 1979J. 

These surveys provide valuable insight into the variability of the 

snowpack across the slope. 

Tundra snow measurements do not provide a precise 

comparison because of too many remaining unknowns, such as 

amount of wind exJX>sure, representativeness of sample, or 

sublimation loss. But they do provide a starting point from 

which to make comparisons. For Barrow, the NWS gauge 

caught 56% of the precipitation remaining in the tundra 

snowpack. This is less than what fell. since a significant amount 

is blown away, according to the downwind drifts, and another 

portion is sublimated. The NWS gauge caught 43% of that 

caught by the Wyoming gauge, which is also probably less than 

what fell. (The values for Barter Island are much lower.) 

Theoretically, the measurements from the two gauges and the 

tundra snow would be the same if snow always fell during calm 

air. However, wind is a dominant feature of the Arctic Coast 

Long-term mean wind speed is 5.8 m S·l at Barter Island and 5.4 

m S·l at Barrow [Searby, 19681 and calm air occurs only 2-3% 

of the time [Wendler, 1978J. It is probable that the principal 

difference in the two catches is attributable to wind-speed effect. 

The U.S. Forest Service's Rocky Mountain Forest and Range 

Experiment Station at Laramie. Wyoming, studied the Wyoming 

shield catch efficiency for 7 years and concluded that the catch 

efficiency drops off with increasing wind speed when the 

temperature is below -2'C [Sturges, 1984J. If the catch does 

drop off with increasing wind speed for a shielded gauge, it is 

probable that it drops much further with an unshielded gauge. 

The undercatch of a nonshielded gauge may be exemplified by 

comparison of a shielded catch with an unshielded catch at 

Barter Island in 1983 (fable 3): the unshielded gauge caught 

only 6% of that of the shielded gauge. At the same time, 

snow-on-the-ground water equivalent measurements by the 

USGS were 10 times greater than the unshielded gauge 

measurements. 

Still another problem affects the comparison of shielded 

versus unshielded catches at Barrow and Barter Island: the 

Arctic Coast has a significant incidence of riming events in 

which supercooled fog coats everything, including the inside of 

the orifice of a precipitation can. NWS does not consider rime 

as ll1.le precipitation and effectively eliminates it from the 

record. since rime and precipitation events do not overlap and 

the gauge is serviced every 6 hours. Because the Wyoming 

shielded gauges are unstaffed and visited only once or twice a 

month, rime builds up from time to time, sometimes capping the 

orifice. This reduces or precludes further precIpitation 

accumulation until the rime melts or is removed during 

maintenance visits. Therefore, the error is magnified, resulting 

in either a net loss due to the covered or reduced orifice or a net 

gain due to the rime melting into the can. Wyoming gauge 

observers are instructed to carefully remove rime from the can 

whenever it is found. in an attempt to be as similar as possible to 

NWS procedures. The field observers have frequently stated 

their belief that the riming error leans heavily to the net loss 

side. Some scientists argue that eliminating rime from the 

precipitation total is a mistake. 

4 . CONCLUSION 

The accuracy of the data from the Wyoming windshielded 

gauge compared with true or total snowfall-water-equivalent is 

still somewhat unknown. The small amount of data presented 

here only indicate that the shield allows 2 to 3 times greater 

catch during the winter months compared with unshielded 

gauges along Alaska's Arctic coast. Unshielded gauges, in fact, 

catch only slightly more than half the snow-water equivalent of 

snow remaining on the tundra. Since accurate data is needed 

from locations offering no natural wind protection, there appears 

to be no viable alternative other than the use of a windshielded 

measuring device. 

REFERENCES 

Benson, C.S., Reassessment of winter precipitation on Alaska's Arctic 

slope and measurements on the flux of wind-blown snow, Report 

VAG R-288, 26 pp., Geophysical Institute, Vn iv. of Alaska, 

Fairbanks, Alaska, 1982. 

Black, R.F., Precipitation at Barrow, Alaska, greater than recorded, 

Trans. Am. Geophys. Union. 35, 203-206, 1954. 

Rechard, P.A., Measurement of winter precipitation in wind-swept 

areas, Proc. of Snow Management on the Great Plains, Bismark, 

North DakOla, July 29, 1975, Great Plains Agriculture Council, Pub. 

73, pp. 13-30, Agriculture Experiment Station, Vniv. of Nebr., 

Lincoln, Nebr., 1975. 

Searhy, H.W., Climatology of the states, ESSA c[ifNJtology of the United 

Stales, No. 6049, V.S. Weather Bureau, 1968. 

Sloan, C, D. Trabant. and W. Glude, Reconnaissance Snow Survey of 

the National Pelroleum Reserve in Alaska, Apri11977 and April-May 

1978, Water Resources Investigations Open·File Report, 79, V.s. 

Geological Survey, Anchorage, Alaska, 1342. 1979. 

Sturges, D.L., Comparison of precipitation as measured in gauges 

protected by an alter shield, Wyoming shield, and stand of trees. 

52nd Proc., Weslern Snow Conference, Sun Valley, Idaho, April 

1984, pp. 57-67, 1984. 

Wendler, G., Snow blowing and snowfall on the North Slope, Alaska, 

Report UAG R·259, 22 pp., Geophysical Institute, Vniv. of Alaska, 

Fairbanks, Alaska, 1978. 
93 

Resolution and Geochemistry of Ionic Components 

in the Late Winter Aerosol at Barrow Station 

During AGASP-II 

SHAO·MENG LI AND JOHN W. WINCHESTER 

FloridtJ Slale University, Tallahassee, Florida 32306.3048 

Sixty-nine size-fractionated aerosol samples were taken day 

and night, March 16 to May 6, 1986, at BRW, during the 

AGASP-I1 project in order to identify components of the Arctic 

haze and their likely sources. In the experimental design. 12-hr 

samples were taken sequentially by two-stage stacked 

Nuclepore filters; 12 ionic species in the samples were measured 

by ion chromatography, and multivariate absolute principal 

component analysis (APCA) was used to resolve different 

components, each consisting of the ions sulfate SO:. chloride 

cr, bromide Br", nitrate NO; I methanesulfonate MSA, fonnate 

Fo·, acetate Ac', propionate PP", pyruvate Py", potassium K+, 

sodium Na", and ammonium NH; in different proponions. In 

applying APCA, linear physical mixing of components of fued 

composition is asswned to cause the temporal variability in 

measured ionic concentrations, and goodness of fit is indicated 

by ihe fraction of data variance R2 explained by the mixing 

model. The ovcrage absolute concentrations in air of the 

components and their ionic constituents, and standard deviations 

(s.d.), were then calculated by multiple linear regression. The 

results are summarized in Table 1. 

Coarse and fme aerosol components exhibited both 

similarities and differences. Three components (CI, C2, and 

C3) explain more than 80% of the coarse concentration 

variance: sea-salt-contaminated CI, containing non-sea-salt 

(nss) SO~ and nss K·; a carboxylic acid anion component C2; 

and C3, containing most of the Bi, NO, and MSA. Ion 

balances between cations and anions in all three components are 

close to unity, consistent with these components being internally 

mixed aerosols. The large amount of nss K· in Cl suggests 

aerosol from lower latitude combustion sources. C2, mainly 

carboxylic acid anions and some sea salt, may represent uptake 

of the acids by salt particles. C3 could be the product of gas 

phase reactions of marine organic compounds; its MSA/nss SO; 

ratio supports such an origin. A non-APCA component, found 

in seven coarse samples with the highest concentrations of Ac' 

and sea salt, is identified by the combination of linear regression 

and APCA and does not belong to the communality of the rest 

of the data. 

In the fme fraction four components (FI, F2, F3, and F4) 

explain 86% of the variance, with the compositions of FI, F2, 

and F3 resembling their coarse fraction counterparts. Fl is 

mainly a mixture of organic anions with additional N~ and 

Na" resembling C2 in composition. F2 is a contaminated 

sea-salt component similar in composition to the contaminated 

sea salt in Cl; however, F2 contains smaller amounts ofnss SO; 

and is not as deficient in Cr. F3, which exhibits a charge 

imbalance with an anion excess, has a composition similar to 

C3 . Like C3, this component also contains the largest amount 

of MSA, with an MSA/nss SO~ ratio similar to those reported 

for remote marine atmospheres. F4, apparently acidic, as 

indicated by an ion imbalance, is mainly nss SO~ plus most of 

the NO; and significant amounts of NH;, and may be classified 

as ammoniwn bisulfate. F4 is uniquely a fine component and 

has no coarse-fraction counterpart. 

These four aerosol types, consisting of the seven APCA 

components in the coarse and fine aerosol fractions, are 

attributed to different sources. The most prominent type is the 

contaminated sea salt coming from sea-salt scavenging of 

combustion products, as shown by the high content of nss K·, 

and is considered to be transported to the Arctic as primary 

pollutants. The second contains the carboxylic acid anions, its 

internal relationships among the carboxylic acid ions suggesting 

natural vegetation emission sources. Lacking local winter 

Arctic sources, the carboi\ylic acid aniuns may have originated 

at lower latitudes as acid vapors and then been transported to the 

Arctic and condensed into aerosols al cold temperatures. The 

third, with the MSA/nss SO~ ratios and the collection of Br", 

NO;, sma11 amounts of carboxylic acid anions, and sea salt, is 

demonstrated to be natural marine aerosols, and may be a 

collection of products from gas phase oxidation of precursors. 

Finally, a fine NH4HSO, component is a likely product of 502 

conversion in air and therefore a pollutant component. Most 

components have good charge balance, as indicated by their 

anion/cation ratios, reflecting extensive acid-base reaction in the 

components in aged aerosol systems with long atmospheric 

residence times. 

We have attempted to partition by multiple linear regressions 

the total ionic concentrations as contributions from the stated 

natural and anthropogenic aerosol sources. Total inorganic ion 

concentrations are similar to previous data rep:med from the 

Arctic. The total coarse.plus·fme MSA average is 0.12 ± 0.02 

nmol m·l . High levels of Fo"and Ac· and traces of Pp' and Py' 

were found, which altogether account for 20% of the total 

aerosol mass: Fo' 5.3 ± 0.7; Ac' 12.4 ± 2.2; pp', 0.3 ± 0.1; and Py 

0.1 ± 0.04 nmol m·l . With partitioning, about 10% of the 

carboxylic acid anions are associated with pollutants in the first 

aerosol type. The second type accounts for 80% of Fo' and 60% 

of Ac· in the Arctic aerosols. The third type in the marine 

aerosols, accounts for 18% of Fo' and 10% of Ac·. Thus, the 

carboxylic acid anions appear to be mostly natural; more than 

909"0 of Fo· and 70% of Ac' from natural sources. In coarse 

aerosols, 67% of nss SO: is in the contaminated sea salt. In 

fme, 52% of nss SO: is connected to N11. and must be due to a 

secondary pollution source. Natural marine nss SO: is indicated 
94 

TABLE I. Ionic Concentrations in Components of Both Fine and Coarse Aerosol Fractions, Based on 68 and 62 

Samples, Respectively 

100 Ionic Concentn.tion (runol mol), ± s.d. R' 

Fine Const. s.d. FI s.d. Fl s.d. F3 s.d, F4 s.d. Total 

Fo' -0.19 0.14 2.01 0.05 0.20 0.03 0.27 0.09 0.11 0.03 2.40 0.96 

Ac' 0.82 0.29 2.26 0.11 0.25 0.06 0.23 0.18 -om om 3.49 0.86 

Pp' -0.06 0.02 0.09 om 0.02 0.00 0.()4 om 0.01 0.00 0.19 0.77 

Py' -0.03 0.06 0.11 0.02 0.04 0.01 0.03 0.04 0.00 0.02 om 0.28 

MSA- 0.00 0.02 0.00 0.01 0.01 0.00 0.06 0.01 om 0.00 O.OS 0.27 

o· 1.84 0.66 0.84 0.26 3.48 0.15 4.25 0.43 ·1.02 0.16 9.39 0.91 

Br' 0.03 0.02 0.02 0.01 0.03 0.01 0.23 0.02 -0.00 0.01 0.31 0.81 

NO; -0.22 O.OS O.OS 0.03 0.01 0.02 0.64 0.05 0.11 0.02 0.62 0.74 

n55 so; 0.66 0.30 0.22 0.12 0.28 om 1.04 0.19 2.41 om 4.61 0.94 

Na' · 1.01 0.55 2.04 0.21 3.37 0.12 1.31 0.35 1.18 0.13 6.89 0.94 

NH: 5.18 1.13 3.90 0.45 1.45 0.25 3.47 0.73 1.6 0.28 15.67 0.71 

nss K-t ·1.08 0.23 0.93 0.09 1.17 0.05 0.25 0.15 0.45 0.06 1.72 0.92 

Anion 3.43 0.96 6.12 0.38 4.91 0.22 7.93 0.61 4.OS 0.23 26.47 

Cation 3.OS 1.28 6.91 0.50 6m 0.28 5.05 0.82 3.32 0.31 24.43 

NC 1.12 0.56 0.89 O.OS 0.81 0.05 1.57 0.28 1.23 0.13 I.OS 

Mass 171.60 678.50 908.00 408.54 666.30 1727.57 

Coone ConsL s.d. CI s.d. C2 s.d. C3 s.d. To<a1 

Fo' -0.35 0.19 0.40 0.06 1.97 O.OS 0.69 0.11 2.71 0.92 

Ac' 0.76 0.28 0.45 O.OS 2.02 0. 12 0.40 0.17 3.63 0.84 

Pp' -0.11 0.04 0.11 0.01 0.17 0.02 -0.02 0.02 0.15 0.74 

Py om 0.02 -0.00 om -0.01 .01 0.05 0.01 0.03 0.27 

MSA' om 0.Q2 ·0.01 om 0.01 O.Ot 0.03 0,01 0.04 0.14 

o· 3.28 1.71 7.15 0.52 1.97 0.76 3m 1.04 15.47 0.77 

B~ -0.02 0.02 0.03 0.01 -0.00 om 0.18 0.02 0.19 0.73 

NO) -0.03 0.13 0.01 0.04 0.25 0.06 1.01 O.OS 1.24 0.77 

nS5S04' -O.OS 0.54 2.23 0.16 0.78 0.24 0.41 0.33 3.34 0.76 

Na' 0.20 1.60 8.78 0.49 3.46 0.71 3.15 0.98 15.59 0.86 

NH: 2.72 0.93 3.47 0.28 3.55 0.41 2.36 0.57 12.10 0.80 

nss K-t -0.91 0.44 1.53 0.13 0.89 0.19 0. 16 0.27 1.67 0.72 

Anion 3.40 2.06 13.64 0.62 8.34 0.91 6.60 1.25 31.98 

Cation 2.01 1.90 13.97 0.58 7.97 0.84 5.74 1.17 29.69 

A/C 1.69 1.90 0.98 0.06 1.05 0.16 1.15 0.32 I.OS 

Mass 126.60 1756.60 773.68 411.95 2039.47 

s.d., standard deviation; R2, squared adjusted conelatioo coefficient; conSL, conSlarlt lenn; n55, non-sea-salt; A/C, anion-to-cation ratio. 

by its association with MSA in both fractions. This marinerelaLed nss SO; is about 20% of the total nss SO; measured. 

These results show that natural compounds are important 

constituents in Arctic aerosols. Since cr and Na· are naurral sea 

salt., the proportion of products from natural sources may exceed 

the pollutant proportion. Hence, natural products cannot be 

ignored in future Arctic haze studies. 

Ackriow/tdgmen,. Support for this research was supplied in part by 

NSF gran. A TM ·86-01967. 
95 

The Global Precipitation Chemistry Project 

WILUAMC. KEENE AND JAMES N. GALLOWAY 

DefXJT~fII of Environnvnud Sciences. Uflivusity of Virginia. CMrlotttsville. Virginia 22903 

GENE E. LIKENS 

lnsliluu of Ecosysltm Slwtiit$, Cory Arboretum. Millbrook, New York 12545 

JOHN M. MiLLER 

NOAA, Air Ruolll'cu Laboratory, SiJ'IIU Spring. Maryland 20910 

1. INIRODUCI10N 

Anthropogenic emissions of S02 and NO:.: have resulted in 

widespread acidification of precipitation and subsequent 

environmental damage in eastern North America and northern 

Europe. Of numerous research questions posed by this 

phenomenon, two are of special interest: (1) What was the 

composition of precipitation prior to the use of fossil-fuels? (2) 

To what degree does the long-distance transport of sulfur and 

nitrogen species influence the coffiJX>sition of precipitation in 

remole regions of the world? The GPCP was initiated in 1979 

to address these questions. Principal objectives of the project 

are to measure the chemical composition of precipitation in 

remote areas of the world and to detennine major processes 

controlling measured composition. Earlier reports of the GPCP 

compare the composition of precipitation in remote and 

impacted regions [Galloway et al., 1982; 1984]; quantify the 

importance of, evaluate sources of, and intercompare 

measurement techniques for carboxylic acids in the atmosphere 

[Keene eI al .. 1983. 1988; Kane and Galloway. 1984a,b, 1985, 

1986]; assess factors controlling the chemical comJXlsition of 

precipitation at remote locations [Jjckells et al., 1982; Church et 

al .• 1982; Galloway and Gaudry. 1984; Dayan el al .• 1985; 

Likens el aI .• 1987]; and present objective methods for 

differentiating sea-salt and non-sea-salt (nss) constituents in 

marine precipitation and aerosols [Keene et aI., 1986]. This 

report summarizes current research and reviews more recent 

contributions of the project 

2. MATERIALS AND ME1lIODS 

Samples of precipitation are collected, by event, in 

scrupulously washed polyethylene containers. Immediately 

after collection, pH is measured, samples are treated with CHCI) 

to prevent biological activity, and aliquots are subsequently sent 

to the UniversilY of Virginia for analyses for major organic and 

inorganic chemical constituents. To date we have analyzed 

samples of precipitation collected at 14 land·based sites and 

during nine oceanic cruises. 

3. RESULTS AND DISCUSSION 

3.1. THE CHEMISTRY OF PRECIPITATION ON AMSTERDAM 

ISLAND. INDIAN OCEAN 

Between May 1980 and August 1985, 190 prec'p,tation 

events were sampled on Amsterdam Island (37' 50'S, 77' 35'E) 

in the central Indian Ocean and samples were subsequently 

analyzed for major chemical constituents. Isobaric back 

trajectories were calculated for each event, and cluster analysis 

techniques were used to identify structure in the multivariate 

data sets for both chemistry and transport. Two chemical 

clusters (Nit = 141, Ns = 21) were identified. Stonns in the 

smaller cluster occurred mainly in the spring and were 

associated with significantly greater depositions of W, ~. 

NO;, and nss SO:. Four distinct transport clusters revealed no 

significant differences for either concentrations or per-event 

depositions of any of the major chemical constituents. 

suggesting that transport is not an important factor in controlling 

the chemical composition of precipitation on the island. 

Although a continental influence on some air masses was 

suggested from both back trajectories and data for 222Rn and 

CO2, a signal in tenns of major ions in associated precipitation 

events was not discernible from the marine background after the 

mean 3.S·day transport over !he ocean. A significant seasonal 

signal in nss SO:. ~ and W is consistent with stronger source 

strengths of marine emissions and enhanced photochemistry 

during wanner months. 

3.2. THE BrOOEOCHEMICAL CYa.JNG OF FORMIC AND ACETIC 

ACIDS THROUGH 11IE TROPOSPHERE 

Despite remaining uncertainties, a general picture of the 

biogeochemical cycling of HCOOH and CH,COOH is 

beginning to emerge [Keene and Galloway, 1988]. These acids 

are ubiquitous vapor- and aqueous-phase constituents of the 

global troposphere. contributing significant fractions of the 

natural acidity in precipitation and c1oudwater, particularly in 

continental regions of the tropics and subtropics. The similarity 
96 

of concentrations in remote and impacted regions indicates that 

anthropogenic emissions of carboxylic acids or precursors are 

probably not important sources over broad geographical areas. 

In continental regions. seasonally varying emissions of acids 

and hydrocarbon precursors from vegetation are thought to 

represent major sources for both acids. In marine areas, the 

seasonality of wet deposition and apparent lack of transport 

from continents support the hypothesis of a marine biogenic 

source. Ratios of total (aqueous + vapor) concentrations of 

HCOOH versus CH,COOH in clouds vary as a function of It. 

This observation is consistent with the hypothesis of a 

pH-dependent aqueous-phase source and sink for HCOOH in 

clouds, which may act to stabilize aqueous-phase ratios against 

shifts in solution H". Large diel periodicities in the 

concentrations of v8.JXlr-phase species over continents. together 

with a lack of evidence for long-distance transport, suggest that 

HCOOH and CH,COOH have short atmospheric lifetimes, of 

several hour.; to a few (at most) days. Because they are 

important controllers of free acidity and represent a potentially 

large sink for aqueous-phase OH radicals, the cycling of 

carboxylic acids is expected to interact directly and indirectly in 

the chemical cycling of other abnospheric constituents. 

3.3. STANDARD ERROR CALCUlATIONS FOR NON-SEA-SALT 

CONSITtJENfS IN MARINE PRECIPITATION 

Studies of pollutant transport and investigations of 

geochemical cycling often involve calculation of nss 

concentrations for various ionic constituents of precipitation and 

atmospheric aerosols. The nss concentrations are calculated 

from measurements of the concentrations of a reference species 

and the species of interest. Formulas for determining the 

accuracy of calculated nss concentrations are necessary because 

this accuracy can vary significantly from sample to sample 

within the same data set, as well as from one study to another. 

Formulas were derived demonstrating that the standard error of 

calculated nss concentrations is dependent on the nature and 

magnitude of the analytical errors made in measuring total 

concenlralions. Application to a real data set indicates that this 

standard error is often greater than the calculated nss 

concentration. and that the standard error may vary by orders of 

magnitude for various samples in the same data set. The 

magnitude of the potential errors has important implications for 

the reliability of conclusions based on calculated nss concentrations, and the sample-to-sample variation of these errors 

complicates the process of determining the accuracy of 

5wnmary statistics such as the volume-weighted concentration. 

In addition, these variations in accuracy can obscure the 

relationships between n55 concentrations and other variables, 

both chemical and meteorological. This complicates 

investigations of source-receptor relationships and geochemical 

cycling, and may lead to faulty conclusions. 

4. ONGOING RESEARCH 

Research efforts currently under way within the GPCP 

include the following: 

Evaluation of shipboard data to determine factors controlling 

the atmospheric chemistry of the equatorial Atlantic Ocean 

during August and September 1986. 

Analysis of a 15-yr data record for precipitation chemistry at 

MLO. 

Determination of the speciation and overall importance of 

organic nitrogen in precipitation. 

REFERENCES 

Church, T. M., I. N. Galloway, T. D. Iickells, and A. H. Knap, The 

chemistry of western Atlantic precipitation at the mid-Atlantic coast 

and on Bennuda, J. Geophys. Res., 87, 11,013-11,018, 1982. 

Dayan, V., 1. M. Miller, W. C. Keene, and I. N. Galloway, A 

meteorological analysis of precipitation chemistry from Alaska, 

Almas. Environ., 19, 651-651, 1985. 

Galloway, 1. N., and A. Gaudry, The chemistry of precipitation on 

Amsterdam Island, Indian Ocean, Atmos. Environ., 18, 2649-2656, 

1984. 

Galloway, 1. N., G. E. Likens, W. C. Keene, and I . M. Miller, The 

composition of precipitation in remote areas of the world, J. 

G,ophys. Res., 87, 8771-8786, 1982. 

Galloway,1. N., G. E. likens, and M. E. Hawley, Acid precipitation: 

Natural versus anthropogenic components, Science, 226, 829-830, 

1984. 

Iickells, T. C., A. H. Knap, T. M. ClUTCh, 1. N. Galloway, and 1. M. 

Miller, Acid precipitation on Bennuda, Nature, 297, 55-56, 1982. 

Keene, W. c., and 1. N. Galloway, A note on acid rain in an Amazon 

rainforest, Tel/us, 36,137-138,1984a. 

Keene, W. c., and I. N. Galloway, Organic acidity in precipitation of 

North America, Almos. Environ., 18, 2491-1497, 1984b. 

Keene, W. c., and I. N. Galloway, Gran's titrations: Inherent errors in 

measuring the acidity of precipitation, Atmos. En'IJiron., 19, 199-202, 

1985. 

Keene, W. C., and 1. N. Galloway, Considerations regarding sources for 

fonnic and acetic acids in the troposphere, J. Geophys. Res., 91, 

14,466-14,474,1986. 

Keene, W. C., and 1. N. Galloway, The biogeochemical cycling of 

fonnic and acetic acids through the troposphere, Tellw, in press, 

1988. 

Keene, W. C., 1. N. Galloway, and D. H. Holden, Jr., Measurement of 

weak organic acidity in precipitation from remote areas of the world, 

J. G,ophys. Res., 88, 5122-5130, 1983. 

Keene, W. C., A. A. P. Pszenny, 1. N. Galloway, and M. E. Hawley, 

Sea-salt corrections and interpretation of constituent ratios in marine 

precipitation,J. Geophys. Ru., 91,6641-6658,1986. 

Keene, W. c., R. W. Talbot, M. O. Andreae, K. Beecher, H. 

Berresheim,1. C. Fanner, J. N. Galloway, M. R. Hoffman, S.-M. Li, 

1. R. Maben, 1. W. Munger, R. B. Norton, A. A. P. Pszenny, H. 

Puxbaum, H. Westberg, and W. Winiwarter, An intercomparison of 

measurement systems for vapor- and particwate-phase 

concentrations of fonnic and acetic acids, J. Geophys. Res., 

submiued,1988. 

Likens, G. E., W. C. Keene, 1. M. Miller, and I. N. Galloway, The 

chemistry of precipitation from a remote terrestrial site in Australia, 

J. G,ophys. Res., 92, 13,299-13,314, 1987. 
97 

Radioactivity in the Surface Air at BRW, MLO, SMO, and SPO 

RICHARD LARSEN AND COUN SANDERSON 

U. S. Department a/Energy, EnYiro~nt41 Measuremenls Laboratory. New York, New York 10014.3261 

1. INTRODUCTION 

Air filter samples are routinely collected by GMCC 

personnel at BRW, MLO, SMO, and SPO for the SASP. The 

primary objective of this program is to study the temporal and 

spatial distribution of specific natural and anthropogenic 

radionuc1ides in the surface air. 

2. MATERIALS AND METHODS 

High.volume air filter samples are continually collected on 

a weekly basis using Microsorban filter material. The air 

samplers move -1500 m] of air per day through a 20-cmdiameter filler. The weekly filter samples collected at BRW 

and MLO are analyzed by compressing a section of the filter 

into a 1-2 em3 cylinder. which is analyzed by ganuna-ray 

spectrometry using a high-purity germanium (HPGe) detector 

with a 1.5-crn-diameter well. For each site, sections of the 

weekly filter samples are added together to fonn a monthly 

composite sample. These composite samples are compressed 

into a 45 ·cm3 plastic planchet, and are analyzed for gammaray·emitting nuclides using either HPGe n-type low-energy 

coaxial, or Ge(Li) or HPGe p-type coaxial high-resolution 

gennanium detectors. The activities from specific gammaray.emitting radionuclides are determined by computerized 

analyses of the spectral data. Detailed information on SASP is 

periodicaUy published [Feely el al., 1985]. 

3. RESULTS 

Table I presents the weekly surface air concentrations 

of 'Be and "oPb at BRW and MLO during 1987. Table 2 

presents the surface air concentrations of 'Be and 210Pb during 

1987 in monthly composite filter samples from SPO and 'Be 

monthly concentrations from SMO. The "less than" values 

for 'Be at SPO result from its radioactive decay in the sample 

prior to analysis. These values are excluded from sununary data 

tables. There were no announced atmospheric nuclear weapons 

tests or other significant releases of radioactive materials into 

the atmosphere during 1987, and the concentrations of the 

fission products 95Zr, 137CS, and 144Ce were below our lower 

limit for data reporting (0.5 rei m·l). The long. term mean 

monthly surface air concentrations of 'Be and 210Pb at BRW, 

MLO, SMO, and SPO are presented in Table 3. The mean 

values are reported along with the standard deviation at the 10 

level; the number of data points used to calculate each value is 

presented in parentheses. 

4. DISCUSSION 

The weekly concentrations of 'Be and 210Pb at BRW and 

MLO show a pronounced episodic behavior throughout 

1987. 'Be (half-life 53.2 days) is produced by cosmic-ray 

interactions in the upper troposphere and !.he stratosphere. 210Pb (half-life 21 years) is a decay product of 222Rn, 

which is a natural radionuclide emitted from soils. Because of 

their distinctly different source regions, these nuclides serve as 

excellent tracers for upper and lower tropsopheric sources and 

transport processes. We believe the three episodes of 

TABLE 1. Surface Air Concentrations (fCi mol) of 'Be 

and lloPb in Weekly Filter Samples CoUected at 

BRW and MLO During 1987 

1/ 1/87- 2/ 1/87 

2/ 1/87- 2/1~/81 

'/14/97_ 2/'4/87 2/14/87- 2/28/87 2/n/81- 3/ 7/B7 3/ 7/81- 3/14./87 3/14/81- 3/21/87 

3/21/87- 3/28/87 

3/21/81· 4/ 4/81 4/ 4/87- 4/11 /87 

4/11/81- 4/21/87 

4/21 /87 - 4/26/81 

4/26/87- 4/28/81 4/28/87- 51 2/87 

6, 2/87- 6/ 8/87 

'I 8/87- '/16/87 6,16/n· ti/28/87 6/2&/81- 6/28/87 6/28/87- 8/ 3/81 

8/ 1/87· 8/18/81 

8/18/87- 8/22/87 

8/22/87- 7/ 8/81 

11 8/81- l1U/81 

1113181- 1111/81 

1/ 2/81- 1/ 8/81 1/ 1/81- 1/18/81 

1/18/81- 1/22/81 

1/22/81- 2/ 2/81 2/ 2/81- 2/ 8/81 2/ &/81- 2/11/81 

2/17/81- 2/23/81 2/23/81- 3/ 2/81 3/ 2/81- 3/ ./81 

3/ 8/81- 3/18/81 3/18/81- 3/23/81 3/23/81- 4/ 1/81 4/ 1/81- ~/ 1/81 ~/ 1/81- ~/16/81 

4/16/8" ~/22/87 

4/22/87- 6/ 1/87 6/ 1/87- 6/ 8/87 

6/ 1/81· "H,/Sl 6/16/81- 6/22/87 6/22/87· 8/ 1/81 8/ 1/81- 8/ 1/87 

8/ 8/87- 8/16/87 8/15/87- 8/22/87 8/22/81- 1/ 1/81 

? doublful values 

, 

,. 

.. " 

, " .. 

" 

.. " 

.. 

.. 

'" '" 

'" " .. 

.. " 

" " " 

.. " 

" 

m 

'" '" '" '" '" '" '" '" '" '" '" '" '" ". '" '" '" '" '" m 

'" '" '" 

" " " " " " " " " " " 

" • 

, • 

, 

, 

, 

, 

, 

, 

" 

, • 

, 

, 

, 

" " , , 

( " , 

U 

U 

" " , 

• " U 

" • " " " 

S l oop 1lna Int.r~.1 ,~ 

'". 7/11/81· 1/2~/87 

1/14/81· 8/ 4/87 " 8/ 4/91· 8 /16/87 " , 8/18/81- 8 / 14 /87 

8/14/81- 8/11 /81 '" 8/21/87- 8/28/81 " 8/21/81- 'il 8/81 " ,. '1/ 8,81- 9/14 /&1 

e/l4j81- SI/IB/ll " 9/11/81- 'i/28/87 " 'in8/87-lflJ/ 3/87 " 181 3 /81-18/ 1,87 " 181 ./87-10/U/87 " 18/17/81·10/13/81 " 18/23/87-10/38/87 .. " IB/10/I7-I1/ 11181 

11 /0/87' 11 / 18/87 " 11/18/87-11/23/17 " 11/23/81-12/ 4/87 " 12/ 4 /8 7-12/ 8/87 " 1"1/ 8/81-12/14/87 " 12 / 14 /81- 12 1'12 181 .. " 12/22/1'-12/2'l/81 " 

... 7/ 1/81- 1 I 18/81 

1/18/81- 1/22/81 no 1 /22/81- 1/ 1/11 B/ 1/81- B/ 1/81 '" B/ 1/81- 1/14/81 '" 8/14/B1. 1/21 /81 '" 8/21/81- 8/ I/Bl '" 8/ 1/81- 8/ 8/81 " &/ 1/81- ./16/81 '" 

g/l6/81- g/22/Bl '" 8/22/81-U/ I/Bl '" 10/ 1/81·10/ 8/81 '" '" 18/ 8/81·18/15/81 18/15/87-18/22/81 '" 18/22/81- U'/38/81 '" 18/l8/81·11/ 8/81 '" 11/ 8/87-it/H/Il '" II/H/I1-11/21/87 '" 11/21 /87·12/ 1/81 '" 12/ 1/11-12/ 8/87 '" 12/ 8/81·12/18/87 '" 41 1 

12/18/81- 12/22/87 8l? 12/22/87· 12/31/87 '" 

, , 

" , 

, 

, 

" 

, 

, 

, 

, 

" " " " " " " 

, • , 

, 

" , 

• 

" 

" 

, • 

, 

" " , 

Counting errors at 20 are less than 20%, except A counting errors are 

between 20% and 100%. 
98 

TABLE 2. Monthly Surface Air Concentrations (fCi m") of'Be at SMO and SPO, and 210Pb at SPO During 1987 

Month SMO SPO SPO ~onth SMO SPO SPO 

Jan 68 130 2" Jul 73 64 < 1 

Feb 68 94 < 1 "ug 139 64 < 1 

Mar 66 174" 2" Sep 110 < 4 1" 

"pr 68 69 < 1 Oct 114 103 < 3 

May 82 77 < 1 Nov 72 190 < 1 

Jun 112 < 8 1" Oec 48 140 < 1 

Counting errors at 2a are less than 20%, except A counting error are between 20% and 100%. 

TABLE 3. Long.Term Monthly Mean Concentrations (fCi m·l ± Icr) of 'Be and '''Pb at BRW, MW, SMO, and SPO, 

7 

Be 

210pb 

Month BRW MLO SMO SPO BRW MLO SPO 

Jan 66*19 (12) 226*60 (16) 61*24 (11) 176*38 (17) 24* 7 ( 7) 8* 6 (10) 1* 1 ( 9) 

Feb 64*20 (13) 198*62 (18) 67*16 (11) 167*62 (11) 23*10 ( 7) 9* 3 (11) 1* 1 ( 7) 

Mar 74*20 (11) 224*43 (16) 64*13 (11) 147*68 (14) 22*10 ( 6) 12* 3 ( 9) 1* 1 ( 7) 

"pr 76*20 (10) 209*48 (14) 60*10 (11) 111*36 (13) 19* 7 ( 6) 16* 6 ( 8) 1* 1 ( 6) 

May 66*11 (12) 209*41 (18) 87*17 (12) 117*70 (14) 9* 4 ( 6) 16* 7 ( 8) 1* 1 ( 7) 

Jun 26* 8 . (12) 223*38 (18) 80*26 (12) 83*29 (16) 3* 1 ( 7) 14* 4 ( 9) 1* 1 ( 7) 

Ju I 26* 7 (11) 211*39 (16) 90*17 (12) 99*36 (16) 3* 1 ( 7) 10* 3 ( 9) 1* 1 ( 6) 

"ug 19* 7 (11) 196'"49 (16) 88'"23 (11) 87'"26 (17) 2* 1 ( 7) 9* 2 (10) 1'" 1 ( 7) 

Sep 27* 4 (13) 186*60 (16) 90*16 (11) 94*23 (16) 6* 2 (7) 8* 2 (10) 1* 1 ( 8) 

Oct 42*12 (13) 182*31 (17) 79*21 (11) 101*17 (18) 9* 3 ( 8) 9'" 4 (11) 1'" 1 ( 8) 

Nov 69*11 (12) 167*63 (17) 80*30 (12) 143*41 (16) 16* 8 (7) 7* 3 (12) 2* 2 ( 7) 

Oec 63*20 (11) 214*62 (16) 69*16 (11) 176*47 (18) 21*10 ( 6) 8* 3 ( 9) 2* 1 ( 8) 

~e.n 48*24 (141) 202*49 (193) 72*24 (136) 123*62 (181) 13*10 ( 79) 10* 6 (116) 1* 1 ( 87) 

elevated 7Be with undetectable llOPb at MLO reported in 1987 

(March 2·9, March 16·23, August 1·7) indicate periods when a 

significant descent of air masses from the upper troJX)sphere or 

stratosphere may have occurred. 

The monthly 210 Pb concentrations al SPO are low with no 

delectable seasonal variation, reflecting the distance of SPO 

from 210Pb source regions. A seasonal cycle in the surface air 

concentrations of 1Bc occurs at BRW. SMO, and SPOt and a 

seasonal cycle in 210Ph occurs at BRW and MLO. Larsen and 

Feely [19861 have related the seasonal variations of 'Be and 

1lOPb at BRW to the transport of air masses poleward during the 

winter, and the seasonal variations of llOPb at MLO to the 

transport of continental air masses to MLO during the spring. 

Feely et al. [19881 describe four factors that affect the surface 

air concentration of 'Be at a nwnber of the SASP sites. 

Acknowledgmenl. We wish to thank the NOANGMCC staff at 

BRW, MW, SMO, and SPO for the collection of air filter 

samples for the SASP. 

REFERENCES 

Feely, H.W., RJ. Larsen, and C.G. Sanderson, Annual report of the 

surface air sampling program, EML·440, U.S. OOE Environmental 

Measuremenu Laboratory, 82 pp., New York, 1985. 

Feely, H.W., R.I. Larsen, and C.G. Sanderson, Factors that cause 

seasonal variations in Beryllium·7 concentrations in surface air, J. 

Environ. Radioactivity, submitted, 1988. 

Larsen R.I. and RW. Feely, Seasonal variation of ltOpt, and 'Be at 

Mauna Loa and Barrow, in Geophysicol Monitoring for Climatic 

Change, No 14: Summary Report 1985, edited by R.C. Schnell and 

R.M. Rosson, pp. 127·129, NOAA Environmental Research 

Laboratories, Boulder, Colo., 1986. 
99 

Precipitation Chemistry 

R.S. ARTZ 

Air Resources LtJboralory. NOAA. Si/vu Spring. Maryland 20910 

l. L"'1RODUCTION 

Routine precipitation chemistry measurements continued at 

the 14 regional sites and at the four OMeC baseline stations. 

New daily monitoring protocol was instituted at three locations 

on the island of Hawaii and on the observatory roof in Samoa. 

A cooperative project, instituted through the University of 

Virginia and designed to measure organic acids in precipitation, 

continued with little change. 

2. BASELINE MEASUREMENTS 

Along with the initiation of the new collection protocol for 

the sites on Hawaii and Samoa, several other new projects were 

pursued at the background stations, Important events include 

the following: 

To reduce equipment washing requirements at SMO, an 

automatic wet-dry Acrochem Metrics sampler was shipped and 

insta1led. Because of the drought and associated water problems 

HAL/II ~ilLL '98 ~1 

C:2l .. 1S:5l..,... 

:1'--~---l , I .. , 

D ~] 

rr ~ k ~ fL ~ ! e21.. CS3!""'-

at the laboratory, no samples were collected using that sampler 

until December 1987. 

Several samples were collected by roth the funnel and bottle 

collector, and the new Aerochem Metrics collector, during 

December at SMO. Preliminary indications from these samples 

and from paired samples similarly collected at MLO are that 

considerable dry deposition may be elevating precipitation ion 

concentrations, even with daily collection. To quantify such 

differences, a short-term intercomparison will be designed for 

studying the MLO samples. 

Although the new Dionex QIC and the aging Dionex Model 

10 are both currently operationa1. chloride data for SPO are not 

reported due to suspected column problems, and cations are not 

available (except for MLO) due to the current shortage of 

laboratory time. MLO monovalent cation values should be 

available in the next report after reanalysis. 

Figures 1-5 swnmarize the precipitation chemistty data for 

1987. 

Mf.urM LOA OBSE.I?y,\lQRY 14)8 1 

'~ r--------------------------------

.• 

j ." 

.~ 

~ 

" 

" 

" 

Fig. 1. Monthly precipitation weighted means for three sites on the 

island of Hawaii, 1987: Halai Hill, 22 Mile, MLO. 

HAWAIIAN MONTHlf DQ(C'PIT ATiOr. O/.T;. 

.. r------------- ~~~~~~, 

" 

I 

I 

• 

.. 

~ 'JWU "" .. Fig. 2. Monthly precipitation at Hawaiian sites, 1987. 
100 

HAWAIIAN MONTHLY S:Jt Ff.1E. 0/,1,\. 

" , 

I 

I 

~ ~ , 

:' 

m ! 

I~ In- t~ ~h [ 

" 

" 

CS3J 11 .... 1 

Fig.3a. Monthly precipitation weighted sulfate means for the Hawaiian 

network, 1987. 

" " 

HAWAIIAN MONTHl'( HYDROGEN lOt . [)M'" 

" " ~~~~~~~~~~ 

Fig. 3b. Monthly precipitation weighted hydrogen ion means for the 

Hawaiian network, 1987. 

HAWAII,',N MONTHL '( C ..... LORIDE D/. -: /. 

.: 1 I 

i " 

~ '" 

::H I i 

J LI3 I 

" ~ ~ " ~ ~ 

"'" C':'9 u "'-, f¥.J ""-'- ....... 

Fig. 3c. Monthly precipitation weighted chloride means for the 

Hawaiian network, 1987. 

CAPE 1.4ATATU lP 1987 

Fig. 4. Monthly precipitation weighted hydrogen ion, su1fatc, and 

nitrate ion means for SMO, 1987. 

BARROW 198--: 

"I 

" 

" 

= ISS \.c •• 

SOUTH POL[ j 987 

-- - ---- -- --l 

i 

I 

, 

, 

, 

, , I 

. 

"" 'L~ Jl 

Fig. 5. Monthly average hydrogen ion, sulfate, and nitrate concentrations for snow samples collected at BRW and SPO, 1987 . 
3. REGIONAL MEASUREMENTS 

A statistical comparison of precipitation data collected at the 

paired regional stations of Beeville and Victoria, Texas, and of 

Caribou and Presque lsle, Maine, was conducted for lhe purpose 

of detennining whether stations violating siting protocols had 

101 

different precipitation chemistry results than stations sited 

according to network rules. Small differences were found 

between both Maine and Texas pairs, although differences were 

seldom statistically significant. As a result of this study, two 

regional stations, Victoria and one of the Maine stations. will be 

closed at the end of fiscal year 1988. 
102 

UVB Monitoring Data From Mauna Loa, Boulder, and Rockville 

DAVID L. CORRELL 

Smithsonian &vvonmental Research CenleT, Box 28, Edgewater, Maryland 21017 

OUT laboratory has been continuously monitoring smface 

irradiance in a series of eight 5-nm band passes in the UVB at 

these three locations wilh high-precision. accurately calibrated. 

interference filteT radiometers. Long-tenn data sets are now 

being screened and analyzed before publication and archiving. 

The data include 1976 to the present at Rockville, Maryland 

(39'N, 77'W); from July 1987 10 lhe presenl .1 Boulder, 

Colorado (40'N, lO5'W); and Augusl 1984 10 lhe presenl .1 

MLO (I6"N, 156"W). 

Data file screening and editing include routine concerns, such 

as file fannat consistency; screening for data processing and flle 

maintenance errors by testing for unreasonable ratios between 

channels. time of sunrise and sunset. and effects of cloud cover; 

corrections for calibration changes and equipment malfunction· 

ing; and altered equipment design. 

Until this process is completed, no data will be available. 

Requests for data or further infonnation should be directed to 

David L. Correll, Acting Director, at the address above. 

A new·generalion 20·channel interference filter radiometer is 

under development and nearing completion. This new 

instrument features not only more optical channels and modem 

electronics, but improved PC·based data acquisition and 

PC·controlled choices of set gains over 3 orders of magnitude 

for different channels in the same operational instrumenl. Both 

present radiometers and radiometers under development operate 

as cosine collectors. 
103 

Nitric Acid and Aerosol Nitrate Variations at Mauna Loa 

BJ. HUEBERT AND W.M. WARREN 

Graduate School of OaaflOgraphy. University of Rhode Island, Narragansett, Rhode Island 02882-1197 

1. INlRODUCI10N 

Much of the NO and NOz that is emitted into the atmosphere 

is converted to nitric acid vapor or aerosol nitrate before it is 

removed by dry or wet deposition. This conversion to nitrate is 

largely complete within a few days of lhe odd-nitrogen's 

emission; therefore, in remote areas such as at MLO, the total 

nitrate concentration (vapor plus aerosol) represents a fair 

estimate of the total odd.nitrogen concentration. It is possible 

thal there may be similar amounts of PAN at high altitudes in 

clean air, but at this writing measurements are still too few to 

test this hypothesis. 

With support from NSF, we measured nitrate concenlrations 

at MLO for several years to help identify the imJXlrtant sources 

of odd-nitrogen compounds in remote parts of the globe 

[Galasyn et al .. 19870, 1987b; Robinson and Harris. 1987]. In 

1987 we initiated a program of sampling from the new walkup 

tower to minimize the effects of dry surface deposition of nitric 

acid on our nitric acid measurements. 

2. MATERIALS MID MElli ODS 

We use a teflon/nylon filter pack method for collecting 

atmospheric nitrate. The fllter packs are exposed by a 

sequential sampler during 8-day visits to the site approximately 

every 2 months. Filters are returned to the laboratory for 

extraction and analysis by ion chromatography. OUf final data 

are sorted using three criteria (wind direction, humidity, and eN 

count) to eliminate those samples that have been influenced by 

local sources on the island, 

Our tower sampling was sporadic during 1987 because it had 

to be perfonned manually, The difficulties associated with 

nighttime filter changes limited our ability to observe diurnal 

changes from the tower. However, we have just finished 

fabricating and installing an automated sampler on the tower to 

facilitate such measurements in the future, 

3. RESULTS AND DISCUSSION 

3.1. DruRNAL VARIATION 

At our earlier sampling site (about 1.5 m above the surface), 

we found a distinct diurnal cycle in nitric acid concentration, 

even when we removed the island-influenced samples. 

Nighttime concentrations were sometimes only half the daytime 

values. We believe this was the result of the rapid dry 

deposition of nitric acid vapor, which is resupplied fTom the free 

troposphere more rapidly in the daytime than at night. 

Our preliminary tower sampling supports this idea. since the 

few day/night sampling data sets we collected at about 26 m 

show no apparent diurnal variation. We also found that nitric 

acid vapor concentrations decreased ncar the surface, while 

aerosol nitrate did not appear to have an altitude gradient. The 

nitric acid gradient was steepest during the stable nighttime 

hours, These observations arc understandable in view of the 

rapid dry deposition of nitric acid vapor. 

3.2. AN?\'UAL VARIATION 

We have observed a sharp maximum in mtnc acid and 

aerosol nitrate concentrations in the late summer. Possible 

reasons for this peak include reduced loss rates during this time 

period (which seems unlikely), increased natural sources (such 

as lightning in the ITCZ, which is closer in summer), and 

increased transport of anthropogenic material to M LO. One 

possible anthropogenic source is the North American continent, 

which is in the general direction of the origin of MLO back 

trajectories, We still have too little tower data to say what effect 

seasonal variations in surface deposition may have had in 

generating the annual variability we noted ncar the surface, 

We hope that the study of the late-summer nitric acid 

maximrnn will lead to improvements in our ability to describe 

those coastal eddies and diurnal flows that arc missed by 

trajectories using input winds from GCMs. The search for an 

explanation of the maximrnn continues to !'timulate our 

research. 

4. O NGOING RESEARCH 

We are now making our routine measurements from the 

tower in an attempt to clarify the role of dry deposition and 

assess the actual variability of nitric acid in the free troposphere. 

We are planning to panicipate in a joint program with numerous 

other investigators during the spring of 1988 to study the clean 

troposphere's nitrogen cycle at MLO in much greater detail. 

We arc also trying to arrange for daily sampling throughout 

the year to see if the relatively high concentrations we observed 

in August were simply an infrequent "event" that may not be 

representative of the norm at MLO. To address this possibility 

we clearly must change to an inclusive sampling strategy, even 

though it will require some local assistance for wcckly sample 

changes. 
104 

REFERENCES 

Galasyn, I.F., K.L Tschudy, and B.1. Hucben. Seasonal and diurnal 

variability of nitric acid vapor and ionic aerosol species in the remote 

free troposphere at Mauna Loa, Hawaii, J. Geophys. Res., 92, 

3105·3113,1987 •. 

Galasyn. J.F., K.L Tschudy. and B.1. Huebert, Authors' Reply 10 the 

Comment of Robinson and Harris, 1. Geophys. Res., 92, 14868. 

1987b. 

Robinson, E. , and 1. Harris, Comment on "Seasonal and diurnal 

variability of nitric acid vaJXlf and ionic aerosol species in the remote 

free troposphere at Mauna Loa, Hawaii," by I.F. Galas)'n, K.L 

Tschudy, and BJ. Huebert, J. Geophys. Res., 92, 14865-14867, 

1987. 
105 

11. International Activities, 1987 

During September 21·25. B. Bodhaine and R. Schnell 

traveled to Leningrad, U.S.S.R., to attend the Arctic Aerosol 

Symposiwn under the U.S.-U.S.S.R. bilateral agreement. 

Working Group Vill. This was the first opportunity for U.S . 

and U.S.S.R. scientists to work together on the Arctic haze 

problem. The symposium was held at the Arctic and Antarctic 

Research Institute in Leningrad, and was attended by eight 

members of the U.S. delegation and many Soviet scientists from 

Leningrad and Moscow. 

B. Bodhaine. R. Schnell, and G. Herbert attended the Fourth 

IIIJernalional Symposium on Arctic Air Chemistry during 

September 29-0ctobcr 2 at Hurdal, Norway. This meeting was 

hosted by the Norwegian Institute for Air Research and was 

devoted to the Arctic haze problem, particularly the question of 

long-range transport. Many of the results of the AGASP 

experiments were rqx>rted by scientists from many nations at 

this meeting. 

On February 7-11. J. DeLuisi and three other U.S. representatives participated in a Working Group vm meeting in the 

Soviet Union. The meeting was hosted by the Aerological 

Observatory at Moscow. The purpose was to provide a briefing 

by each side on the research being conducted on the 

stratospheric ozone depletion problem, and to suggest cooperative research projects that would involve combining scientific 

eXJX!rtise and resources for solving experimental and theoretical 

research problems. 

A cooperative SouLh Pole Observatory lidar project was 

organized between the University of Rome, Italy, and GMCC. 

The University of Rome effon, headed by G. Fiacco, supplied a 

complete lidar system and trained the GMCC observers. The 

GMCC effort, coordinated by J. DeLuisi, provided the 

winter·over observers, modifications to the NSF Clean Air 

Facility roof (partly supplied by NSF), and a frost-proof window 

in the roof. The lidar measurement project will provide valuable 

data on cloud structure, aerosol structure, and polar stratospheric 

clouds. 

In November, P. Franchois traveled to SPO to assist with 

ozonesonde flights and to install software for processing the 

sonde data on site. Upon his return trip, P. Franchois visited the 

DSIR Observatory in Lauder, New Zealand, where the use of 

similar software for processing ozonesonde data was 

implemented. 

During the summer, optical adjustments were made in 

Boulder by R.D. Grass to Ponuguese Dobson spectrophotometer 

no. 13, new electronics were installed into the instrument, and 

the inslrUment was recalibrated relative to World Primary 

Standard Dobson instrument no. 83. 

During January and February, R. Evans installed automated 

Dobson spectrophotometer no. 72 at Lauder, New Zealand. The 

site is one of six NOAA and NOAA· foreign cooperative 

observatories where Umkehr observations are made routinely. 

R. Evans traveled to Huancayo Observatory, Peru, in August to 

repair automated Dobson spectrophotometer no. 87 located 

there, and to train observers in operation of the instrument. 

P. Steele was appointed to the Source Gases Working Group 

of the Ozone Trends Panel. He wrote the section on 

atmospheric methane for the report of this panel. The report is 

due to appear in 1988 and updates WMO Report No. 16: 

Atmospheric Ozone 1985. 

J. Butler and K. Egan participated in the SAGA-II 

experiment aboard the Soviet research vessel Akademik Koro/ey 

from May 30 to August 10. J. Elkins, T. Thompson. and T. 

Conway assisted 1. Butler in setting up OC's on April 26 to May 

2 before the Koroley left Hilo, Hawaii. J. Elkins discussed the 

cruise results with V. Koropolov and A. Shashkov in Hilo, 

Hawaii, near the end of SAGA-II from July 28 to August 1. The 

results of the cruise are discussed in section 8.2 of this report. 

J. Elkins was a cochairman of the lnJernatiorral Workshop on 

Nitrous Oxide, held September 15·16 in Boulder. T. Thompson 

and K. Egan attended the workshop and its special sessions. 

The purpose of the workshop, which was cosponsored by EPA, 

NOAA, USDA, and NASA, was to evaluate our current 

understanding of N10 in the atmosphere and sources of N10 

from combustion. 

J. Elkins, R. Schnell, M. Luria, and H. Sievcring attended the 

Sixth lnJernational Symposium on Global Atmospheric Chemisty 

of the Commission on Atmospheric Chemistry and Global 

Pollution, Peterborough, Ontario, Canada, August 25·29. J. 

Elkins was a coauthor of a position paper on "Intercomparisons 

of Standards and Instruments" in the Global Trends and 

Distributions section following the CACGP meeting. 

J. Elkins set up a cooperative progrrun between the NOAH 

group and N. Trivett of the Atmospheric Environment Service 

Canada. to begin taking nask samples for N,o. CFC-12, and 

CFC·II at their Alen station in the Nonhwest Territories of 

Canada. 

At the request of K. Higuchi of Atmospheric Environment 

Service Canada, G. Herbert participated in the Arctic Regional 

Modeling Workshop in Downsview, Ontario, May 24-26. He 

presented a paper titled "GMCC Long-Range Transport Models" 

at the workshop. 

H. Bridgman of the University of New Castle, NSW, 

Australia, completed a l·yr appointment at GMCC in August as 

a guest scientist. During this productive time in Boulder, he 

participated in analysis of AGASP and W ATOX data, and 

coauthored more than ten manuscripts. 

Attendees at the March OMCC Annual Meeting in Boulder 

included K. Higuchi, N. Trivet~ S. Syminton, R. Bojkov. and G. 

Shah of Canada, H. Bravo of Mexico, G. Ayers of Australia, 

and K. Labitzke of Federal Republic of Gennany. 

A Soviet delegation represented by A. Frolov, V. Ivanov, A. 

Ivanovsky, and V. Rudakov visited GMCC under Working 

Group vm during May.June. TIley received training on the use 

of ozonesondes, discussed Umkehr cooperative research, and 

planned further joint programs. J. Peterson attended the annual 

Working Group vm planning meeting in Princeton, New 

Jersey, in November. At that Lime the protocol for 1988 was 

negotiated. 

GMCC provided 60 ozonesonde systems to the U.S.S.R. 

under the WG VIII bilateral agreement. Soviet scientists were 

to fly the ozonesondes from their Antarctic base during 1988 as 

part of the Antarctic ozone hole research program. 
106 

12. Publications and Presentations by GMCC Staff, 1987 

Aimedieu, P.. W.A. Mathews, W. Aumannspacher, R. 

Hanmannsgruber, 1. Cisneros, W. Komhyr. and D,E. Robbins, 

Comparison of in sim stratospheric ozone measurements obtained 

during the MAP/GLOBUS 1983 """paign. Planet. Spoc. Sci., 35(5}, 

563-585, 1987. 

Boaunan, J., and D. Henderson, Grand Canyon wind study aids in 

smoke management, Parle Sci" 6(4), 18-19. 1987. 

Boatman, I.F., and D.L Wellman, An aerosol separator for use in 

aircraft, paper A31B-14 presented at the AGU Fall Meeting, San 

Francisco, Calif .• Decemb« 7-11. EOS, 68, 1221. 1987. 

Bodhaine, B.A., Surface aerosol measurements at Barrow, Alaska, paper 

presented at the Arctic Aerosol Symposium, Leningrad, U.S.S.R., 

Sepcember 18-27, 1987. 

Bodhaine, B.A., JJ. DeLuisi, I.M. Harris, P. Houmere, and S. Bauman, 

PIXE analysis of South Pole aerosol, NuciUJT Inslr. Melh., 822. 

241-247, 1987. 

Bodhaine. B.A., E.G. Dutton, 1.1. DeLuisi. G.A. Herbert, a.E. Shaw, 

and A.D.A. Hansen, Surface aerosol measurements at Barrow during 

AGASp·n, paper presented at the Fourth Symposium on Arctic Air 

Chemistry, Hurdal, Norway, September 29-October 2, 1987. 

Bridgman, H.A., G.A. Herbert, R.C. Schnell, A major haze event near 

Point Barrow, Alaska during AGASP·ll, April 2·3, 1986, paper 

presented at the Fourth International SymposiUJll on Arctic Air 

Chemistry, Hurdal, Norway, September 29-October2, 1987. 

Bridgman, H., B. Stunder, R. Am, G. Rolph, R. Schnell, B. BOOhaine, 

. and S. Ollmans, Meteorological and aerosol measurements from the 

NOAA WP·30 aircraft during WATOX·86, January 4-9,1986, NOAA 

Tech . Memo. ERL ARL·J56, 65 pp., NOAA Air Resources Laboratory, 

Silver Spring, Md., 1987. 

Butler, 1.H., K.B. Egan, lW. Elkins, and T.M. Thompson, Nitrous oxide 

in the atmosphere, surface water, and at depth for the western Pacific 

and eastern Indian Oceans, paper A31B-02 presented at the AGU Fall 

Meeting, San Francisco, Calif., December 7·11, EOS, 68(44), 1220, 

1987. 

Butler, 1.H., R.O. Jones, lH. Garber, and LI. Gordon, Seasonal 

distributions and turnover of reduced trace gases and hydroxylamine 

in Yaquina Bay, Oregon, Geochim. Cosmochim. Acta, 5J(3), 697·700, 

1987. 

Chaumerliac, N., E. Richard, J.P. Pinty, and E.e. Nickerson, Sulfur 

scavenging in • mesoscale model with quasi·spectral microphysics: 

two-dimensional results for continental and maritime clouds, 1. 

G.ophys. Res., 92, 3114-3126, 1987. 

Christofferson, R.D., and D.A. Gilleue, A simple estimator of the shape 

factor of the two-parameter Weibull distribution, 1. Clim. Appl. 

M".orol., 26, 323-325. 1987. 

De Foor, T. E., and E. Robinson, Stratospheric lidar proftles from 

MaWla Loa Observatory, Winter 1985·86, Geophys. Res. Lell., J4, 

618-621,1987. 

Dickerson, R.R., GJ. Huffman, W.T. Luke, LJ. Nunnennacker, K.E. 

Pickering, Ae.D, Leslie, e.G. Lindsey, W.G.N. Slinn, T.1. Kelly, 

P.H. Daum, A,C. Delany, lP. Greenberg, P.R. Zimmennan, J.P. 

Boaunan, J.D. Ray, and D.H. Stedman, Thunderstorms: An important 

mechanism in the transport of air pollutants, ScieflCe, 235, 460465, 

1987. 

Dutton, E.G., and JJ. DeLuisi, Aerosol opitcal depth and ratios of 

diffuse·sky to t()(al solar irradiance measured from aircraft following 

the eruption of El Chichon, NOAA Data Rep. ERL ARL·J2. 32 pp., 

NOAA Air Resources Laboratory, Silver Spring, Md., 1987. 

Dutton, E.G., IJ. DeLuisi, and AP. Austring, Measurements of solar 

radiation at Mauna Loa Observatory, 1978·1985, with emphasis on the 

effects of the eruption of EI Chichon, NOAA Data Rep. ERL ARL·J3, 

35 pp., NOAA Air Resources Laboratory, Boulder, Colo., 1987. 

Elkins, 1.W., Measurement techniques for aunospheric nitrous oxide, 

paper presented at the International N10 Workshop, Boulder, Colo., 

September 15 -16. 1987. 

Elkins, lW" N10 sources and sinks in aquatic ecosystems, paper 

presented at the International N10 Workshop, Boulder, Colo., 

Sepccmber 15-16, 1987. 

Elkins, 1.W., and M. Zahniser, Infrared measurements methods for 

nitrous oxide., in EPA Research and Development Report 

EPA·60018·86..o35, edited by W.S. Lanier and S.B. Robinson, 97·101, 

Energy and Environmental Research Corp., Chapel Hill, N.e., 1986. 

Elkins, J.W., T.M. Thompson, K.B, Egan, J.H. Butler, and W.O. 

Komyhr, Nitrous oxide, halocarbons F·ll and F·12 from GMCC 

baseline stations, paper DT P 16 presented at Sixth International 

Symposium of the Commission on Atmospheric Chemistry and Global 

Pollution, Trent University, Peterborough, Ontario, Canada, August 

23-29.1987. 

Feely, R.A., R.H. Gammon, B.A. Taft, P.E. Pullen, L.S. Waterman, T J, 

Conway, J.F. Gendron, and D.P. Wisegarver, Distribution of chemical 

tracers in the eastern equatorial Pacific during and after the 1982-1983 

El NifWSouthem Oscillation event, 1. Geophys. Res., 92, 6545-6558, 

1987. 

Gaudry, A., TJ. Conway, and LoS. Watennan, Report on the intercomparison between the aunospheric COl concentrations obtained at 

Amsterdam Island by the National Oceanic and Atmospheric 

Administration and the Centre des Faibles Radioactivites, Intemal 

report of the Centre des Faibles Radioactivites, 15 pp., Gig·SurYveue, France, 1987. 

Gillette, D.A., W.O. Komhyr, LoS, Watennan, LoP. Steele, and R.H. 

Gammon, The NOANGMCC continuous COl record at the South 

Pole, 1975-1982.J. Geophys. Res., 92, 4231 -4240.1987. 

Herbert, G.A., GMCC long·range transport models, paper presented at 

the Canadian Workshop on Arctic Regional Modeling, Downsview, 

Ontario, Canada, May 25·26, 1987. 

Herbert, G.A., H.A. Bridgman, 1.M. Harris, B.A. Bodhaine, and R.C. 

Schnell, Meteorology and atmospheric mnport during AGASp·n, 

paper presented at the Fourth SymposilnTl on Arctic Air Chemistry, 

Hurdal, Norway, September 28·October 2, 1987. 

Herbert, G.A., H.A. Bridgman, R.C. Schnell, B.A. Bodhaine, and SJ. 

Oltmans, The analysis of meteorological conditions and haze 

distributioo. for the second Arctic Gas and Aerosol Sampling Program 

(AGASp-m, March-April 1986. NOM T.ch. Memo. ERL ARL-158, 

67 pp., NOAA Air Resources Laboratory, Silver Spring, Md., 1987. 

Herbert, G.A., E.R. Green, G.L. Koenig, and K.W. Thaut, Monitoring 

instrumentation for the continuous measurement and quality assurance 

of !Urface wealher observations, paper presented at the Sixth 

Symposium on Meteorological Instrumentation, American 

Meteorological Society, New Orleans, La., January 12-16, 1987. 

Komhyr, W.O., Ozone measurements to 40 km with ECC ozonesondes, 

Promet, Deutcher Weuerdienst, SchOn and Wctzel GmbH, Frankfurt 

(Main), FRG. 29-31,1987. 

Komhyr, W.O., Vertical distribution of ozone at Hilo, Hawaii, 

1982·1986, paper A5IA·to presented at the Fall AGU meeting, San 

Francisco, Calif .• De<:ember 7-11 , EOS 68(44},1232, 1987. 

Komhyr, W.O., P.R. Franchois, B.C. Halter, and C,c, Wilson, ECC 

ozonesonde observations at South Pole, Antarctica, during 1986, 

NOM Data Rep. ERL ARL-ll, 213 pp., NOAA Air Resources 

Laboratory, Boulder, Colo., 1987. 

Luria, M., C.C. Van Valin, IF. Boatman, D.L Wellman, and R.F. 

Pueschel, Sulfur dioxide flux measurements over the Western Atlantic 

Ocean, Almos. Environ., 2J(7), 1631 · 1636, 1987. 

Luria, M., C.c. Van Valin, D.L Wellman, H. Sicvering, 1.F. Boatman, 

IN. Galloway, and W.C. Keene, On the relationship between dimethyl 

sulfide and sulfate ions in the mid·Atlantic Ocean atmosphere, paper 

A12-to presented at the AGU Fall Meeting, San Francisco, Calif., 

Deeember7-II.EOS,68,1212.1987. 

Mahfouf, J.F., E. Richard, P. Mascart, E.C. Nickerson, and R. Rosset, A 

comparative study of various parametcri1.8tions of the planetary 

boundary layer in a nlnTlerical mesoscale model, 1. Clim. Appl. 

M"eorol., 26,1672-1695.1987. 
Massey, D. M., T. K. Quakenbush, and B. A. Bodhaine, Condensation 

nuclei and aerosol scattering extinction measurements at Mauna Loa 

Observalory: 1974-1985, NOAA Data Rep. ERL ARL-i4, 174 pp., 

NOAA Air Resources Laboratory, Silver Spring, Md., 1987, 

Mauhews, W.A., P. Aimedieu, G. Megie, J. Pelon, W. Attmannspacher, 

W. Komhyr, P. March~ J. DeLa Noe, P. Rigaud, D.E. Robbin., and 

P.C. Simon, General comparison of ozone vertical proftles obtained by 

various techniques during the 1983 MAPIGLOBUS campaign, PIQlUt. 

Spa" Sci .. 35(5), f:(]3-607, 1987. 

Mauhews, W.A., W.O. Komhyr, and P.R. Franchois, Ozonesoo.de 

observations at Lauder, New Zealand, during the spring and early 

summer of 1986, PEL Rep. No. 960, 156 pp., Department of Scientific 

and Industrial Research, Physics and Engineering Laboratory, Lower 

Huu, New Zealand, 1987. 

Nelson, D., R. Haas, 1. DeLuisi, and G. Zerlaut, Results of the NRIP-7 

intercomparison, November 18-21, 1985, NOAA Ttch. Memo. ERL 

ARL.161, 108 pp., NOAA Air Resources Laboratory, Silver Spring, 

Md., 1987. 

Newchurch, M.J., G.W. Grams, D.M. Cunnold, and JJ. DeLuisi, A 

comparison of SAGE I, SBUV, and Umkehr ozone promes including 

a search for Umkehr aerosol effecu, J. Geophys. Res., 92, 8382-8390, 

1987. 

Peterson, J.P., Atmospheric greenhouse gases: recent trend, paper 

presented at the Eightieth Annual Meeting of the Air Pollution Control 

Association, New York, N.Y., June 21-26,1987. 

Ray, J.D., M. Luria., and e.e. Van Valin, Latitudinal changes of 

aunospheric hydrogen peroxide during summer, paper A12-02 

presented at the AGU Fall Meeting, San Francisco, Calif., December 

7-11, EOS, 68,1212, 1987. 

Reinking, R., and J.F. Boatman, Upslope precipitati.on events, in 

Mesoscale Meteorology and ForectJSling, edited by P. Ray, American 

Meteorological Society, Boston, Mass., 437-463, 1987. 

Reinsel, G.e., G.e. Tiao, A.J. Miller, OJ. Wuebbles, P.S. Connell, C.L 

Mateer, and 11. DeLuisi, Statistical analysis of total ozone and 

stratospheric Umkehr data for trends and solar cycle relationship, J. 

Geophys. Res .. 92, 2201-2209,1987. 

Richard, E., N. Chaumerliac, J.F. Mahfouf, and E.C. Nickersoo, 

Numerical simulation of orographic enhancement of rain with a 

mesoscale model, J. Clint. Appl. Meteorol., 26, 661-669,1987. 

Robinson, E., Book Review: R. E. Muon and H. Rodhe, Compendiwn 

of Meteorology, Volume II, Part 6, Air ChemislI)' and Air Pollution 

Meteorology, WMO No. 364, World Meteorological Organization, 

209 pp., Geneva, Switzerland, 1985, Waler Air Soil Poll., 33, 447-448, 

1987. 

Robinson, E., and T.E. DeFoor, Stratospheric aerosol conditions over 

Mauna Loa during recent volcanic interregnwn periods, paper M2-67 

presented at IUGGJIAMAP meeting, Vancouver, British Columbia, 

August 1987. 

Robinson, E., and J. Harris, Comment on "Seasonal and diurnal 

variability of nitric acid vapor and ionic aerosol species in the remote 

free troposphere at Mauna Loa, Hawaii" by J.F. Galasyn, K.L 

Tschudy, and B. 1. Huebert, J. Geophys. RLf., 92, 14865·14867, 1987. 

Ruhnke, L.H., and R.C. Schnell, Arctic Haze, paper presented at the 

DOD Symposium and Workshop on Arctic and Arctic-Related 

Environmental Sciences, Washington, D.e., January 27-30, 1987. 

Schnell, R.C., Arctic haze measurements from aircraft during AGASP I 

and n, paper presented at the Araic Aerosol Symposium, Leningrad, 

U.S.S.R., September 18-27, 1987. 

Schnell, R.e., Gas and aerosol distribution in the Arctic during 

AGASP·II, paper presented at the Fourth International Symposiwn on 

Arctic Air Chemistry, Hurdal, Norway, September 29-October 2, 

1987. 

Schnell, R.C., Long range transport of anthropogenic pollutants into the 

Arctic, paper presented at the Sixth International Symposium of the 

Commission on Abnosheric Chemistry and Global Pollution, 

Peterborough, Canada, August 23-29, 1987. 

Schnell, Re., Use of a NOAA WP-3D with multi-sensor gas and 

aerosol sampling systems: WATOX and AGASP·II, 1986, Proceedings, Second Airborne Science Workshop, p. 151, University of 

107 

Miami, Miami, Aa., February 3-6, 1987. 

Schnell, Re., and R M. Rosson, Geophysical Monitoring for Oirnatic 

Change, No. 15: Summary Report 1986, 155 pp., NOAA Air 

Re.!ource.s Laboratory, Boulder, Colo., 1987. 

Schnell, R.e., H.A. Bridgman, P.S. Naegele, and T. Watson, The 

NOAA WP-3D meteorological, aerosol, and gas systems and flight 

operations on W ATOX -86, W A TOX Special Issue, Global 

Biogeochem. Cycles, I, 297-3rrt, 1987. 

Sheridan, P.l, and R.C. Schnell, Cascade impactor studies of aerosol 

collected during AGASP-II, flights 201-203, paper presented at the 

Fourth International Symposium on Arctic Air Chemistry, Hurdal, 

Norway, September 29-October 2, 1987. 

Sievering, H., Comments on "Evaluation of accuracy with which dry 

deposition can be measured with current micraneteorologica1 

techniques", J. Clim. Appl. Meteorol., 26, 652,1987. 

Sievering, H., Dynamics of sulfur exchange at the airlforest canopy 

interface: A review of throughfall inferred deposition rates, Global 

Biog.ochem. Cycles,i(3), 233-249,1987. 

Sievering, H., MidwesVWestem/Eastern U.s. precipitation and aerosol 

sulfate: Differences attributable to natural source inputs?, Almos. 

En.yiron.., 21,2525-2530,1987. 

Sievenng, H., Small particle eddy flux measurements at the BAO: 

Deposition under high windspeed conditions, Almos. Enyiron. , 21, 

2179-2185,1987. 

Sievering, H., 1. Boaunan, H. Horvath, M. Luria, and e.C. Van Valin, 

Heterogeneous conversion of SOz to S04 in coarse fraction 

sea-derived aerosol, paper presented at AGU, San Francisco, Calif., 

De<:ember 7-11, 1987. 

Sievering, H., J.F. Boatman, L. Gtmter, H. Horvath, D. Wellman, and S. 

Wilkison, Size distribution of sea·source aerosol particles: A physical 

explanation of observed differences, nearshore vs. open sea, J. 

G.oplTys. Res., 92, 14850-148f:(], 1987. 

Steams, LP., Aspecu of the local circulation at the Grand Canyon 

during the fall season, J. Clint. Appl. Meleorol., 26, 1987. 

Steele, LP., PJ. Fraser, R.A. Rasmussen, M.A.K. Khalil, T.J. Conway, 

A.J. Crawford, R.H. Gammon, K.A. Masarie, and K.W. Thoning, The 

global distribution of methane in the troposphere, J. Almos. Chem., 5, 

125-171,1987. 

Steele, LP., K.A. Masarie, P.M. Lang, and R.C. Martin, The distribution 

and growth rate of atmospheric methane, paper presented at the Sixth 

International Symposium of the Commission on Aunospheric 

Chemistry and Global Pollution, Trent University, Peterborough, 

Ontario, Canada, August 23-29,1987. 

Van Valin, e.C., and E. Ganor, Air pollution measurements at the 

Boulder Aunospheric Observatory, Waler Air Soil Polllu., 35, 

357-372,1987. 

Van Valin, e.C., H. Berresheim, M.O. Andreae, and M. Luria, Dimethyl 

sulfide over the Western Atlantic Ocean, Geophys. Res. Leu., 14(7), 

715-718,1987. 

Van Valin, e.C., M. Luria, J.D. Ray, R.L. Gunter, D.L. Wellman, and 

J.F. Boatman, Seasonal variations of HzOz as observed in CURTAIN, 

paper A12..Q3 presented at the AGU Fall Meeting, San Francisco, 

Calif., December 7-11, EOS, 68, 1212, 1987. 

Van Valin, C.e., M. Luria, D.L Wellman, R.L. Gunter, and R.F. 

Pueschel, Natural sulfur flux from the Gulf of Mexico: Dimethyl 

sulfide, carbonyl sulfide, and suHur dioxide, NOAA Tech . Rep. ERL 

432-ARL 9, 14 pp., NOAA Air Resources Laboratory, Boulder, Colo., 

1987. 

Van Valin, C.C., J.D. Ray, 1.F. Boaunan, and R.L. Gunter, Hydrogen 

peroxide in air during winter over the South-Central United States, 

Geophys. R ... l.ell.,14, 1146-1149, 1987. 

Van Valin, C.C., D.L. Wellman, and L.P. Steams, Aerosol and 

cloudwater properties at Whiteface Mountain, New York, Water Air 

Soil Poll .... 34, 369-383, 1987. 

Wellman, D.L, J.F. Boaunan, e.e. Van Valin, S.W. Wilkison, R.L 

Gunter, 1.0. Ray, and M. Luria, Airborne sampling for validation of 

the regional acid deposition model-the CURTAIN experiment, paper 

A3IB-09 presented at the AGU Fall Meeting, San Francisco, Calif., 

December7-I1,EOS,68,1220,1987. 
108 

ACR 

ADN 

ADR 

AES 

AGASP 

ALE 

ANATEX 

AOML 

AOU 

ARL 

ARM 

ASCS 

ASR 

AQG 

BAPMoN 

BRAM 

BRW 

CACGP 

CAP 

CAMS 

CFC 

CFC·ll 

CFC-12 

CGO 

CIRES 

C.L. 

CMO 

CN 

CNC 

CNRS 

CRT 

CSIRO 

CSU 

CURTAIN 

DEC 

DEW 

DMS 

DOE 

DOl 

DSIR 

DOY 

DU 

DWR 

EC 

ECC 

ECD 

EC-GC 

ECMWF 

EG&G 

EKTO 

EML 

ENSO 

EPA 

ERL 

13. Acronyms and Abbreviations 

active cavity radiometer 

Automated Dobson Network 

Adrigole. Ireland (ALE/GAGE station) 

Atmospheric Environment Service, Canada 

Arctic Gas and Aerosol Sampling Program 

Atmospheric Lifetime Experiment 

Across North America Tracer Experiment 

Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida (ERL) 

apparent oxygen utilization 

Air Resources Laboratory. Silver Spring. Maryland (ERL) 

Aerosols and Radiation Monitoring Group, Boulder, Colorado (GMCC) 

Alaska Soil Conservation Service 

Aerosols and Solar Radiation 

Air Quality Group. Boulder. Colorado (GMCC) 

Background Air Pollution Monitoring Network 

battery random access memory 

Barrow Observatory. Barrow. Alaska (GMCC) 

Commission on Atmospheric Chemistry and Global Pollution 

Clean Air Facility 

Control and Monitoring System 

chlorofluorcarbon 

trichlorofluoromelhane 

dichlorooifluoromethane 

Cape Grim Observatory. Australia, (CSIRO and ALE/GAGE station) 

Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 

confidence level 

Cape Meares. Oregon (ALE/GAGE station) 

condensation nuclei 

condensation nucleus counter 

Centre National de la Recherche Scientifique 

cathode ray tube 

Commonwealth Scientific and Industrial Research Organization, Australia 

Colorado Stale University 

Central United StaleS RADM Test and Assessment Intensives 

Digital Equipment Corporation 

distant early warning 

dimethyl sulfide 

Department of Energy 

Department of Interior 

Department of Scientific and Indusoial Research, New Zealand 

day of year. Julian 

Dobson unit 

Daily Weather Report 

elemental carbon 

electrochemical concentration cell 

electron capture detector 

electron capture gas chromatograph 

European Center for Medium-Range Weather Forecasts 

Edgerton, Grier, and Gennerhausen, Inc. 

(a commercial name for a prefabricated building) 

Environmental Measurements Laboratory (DOE) 

El Nino/Southern Oscillation 

Environmental Protection Agency 

Environmental Research Laboratories, Boulder. Colorado (NOAA) 
flO 

Floo 

FRG 

Ff 

FWNIP 

GAGE 

GC 

GCM 

G.E. 

GFOL 

GLOBE 

GMCC 

GPCP 

GSA 

GTE 

HAO 

HASL 

HP 

IDM 

IGP 

IR 

ISWS 

ITCZ 

LAWS 

LEAPS 

LED 

LOPC 

LST 

LORAN 

MASC 

MLO 

M03 

MLRA 

MSL 

MTG 

NADP 

NAPAP 

NARL 

NASA 

NBS 

NCAR 

NDIR 

NESDIS 

NIP 

NOAA 

NOAH 

NRBS 

NRI 

NRIP 

NSF 

NWR 

NWS 

NWT 

NZARP 

OAO 

OGC 

PAN 

PC 

flame ionization detector 

(electronic buUetin-board system for IDM PC) 

Federal Republic of Germany (West Germany) 

Fourier transfonn 

mter wheel nonnal incidence pyrheliometer 

Global Aunospheric Gases Experiment 

gas chromatograph 

general circulation model 

General Electric 

Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey (ERL) 

Global Backscatter Experiment 

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

Global Precipitation Chemistry Project 

General Services Administration 

General Telegraphic Electronics 

High Altitude Observatory 

Health and Safety Laboratory (EPA) 

Hewlett-Packard 

International Business Machines 

Instituto GeoflSico del Peru 

infrared 

Illinois State Water Survey 

inter tropical convergence zone 

Laser Atmospheric Wind Sounder 

Low Electron Attadunent Potential Species 

light-emitting diode laser optical particle counter 

local standard lime 

long-range aid to navigation 

Mountain Administrative SupJXlrt Center, Boulder, Colorado 

Mauna Loa Observatory, Hawaii (GMCC) 

meteorology and ozone (CAMS unit) 

Major Land Resources Area 

mean sea level 

Monitoring Trace Gases Group, Boulder, Colorado (GMCC) 

National Atmospheric Deposition Program 

National Acid Precipitation Assessment Program 

Naval Arctic Research Laboratory, Barrow, Alaska 

National AeronaUlics and Space Administration 

National Bureau of Standards 

National Center for Atmospheric Research. Boulder, Colorado 

non-<iispersive infrared analyzer 

National Environmental Satellite, Data, and Infonnation Service 

nonnal incidence pyrheliometer 

National Oceanic and Atmospheric Administration 

Nitrous Oxide And Halocarbons Group, Boulder, Colorado (GMCC) 

non-Rayleigh backscatter 

National Resource Inventory 

New River Inlercomparison of Pyrheliometers 

National Science Foundation 

Niwot Ridge, Colorado 

National Weather Service 

NOrlhwest Territories. Canada 

New Zealand Antarctic Research Program 

Office of Aircraft Operations 

Oregon Graduate Center, Beaverton, Oregon 

peroxyacepyl nitrate 

personal computer 

109 
110 

P.1. 

PLOT 

PMEL 

PRECP 

PROM 

p' 

RADM 

RITS 

RL-2 

RPB 

SAFE 

SAGA 

SAGE 

SASP 

SBUV 

s.d. 

SEAS PAN 

SERI 

SIO 

SLPM 

SMO 

SOLRAD 

SUNYA 

SPO 

SRF 

SRM 

STP 

TOGA 

TOMS 

TSI 

UAF 

UIC 

UPS 

URAS 

URI 

USDA 

USGS 

UV 

WASC 

WATOX 

WERIS 

WMO 

WPL 

ZRAM 

ZSCD 

Principal Investigator 

porous-layer, open tubular (columns) 

Pacific Marine Environmental Laboratory, Seallle, Washington (ERL) 

Processing of Emissions by Clouds and Precipitation Experiment 

programmable read-only memory 

Portable Pressurizer Pack (air sampler) 

Regional Acid Deposition Model 

Radiatively Important Trace Species 

Research Laboratory No.2, Boulder, Colorado 

Ragged Point, Barbados (ALE/GAGE station) 

Southeastern Alaska Flux Experiment 

Soviet-American Gas and Aerosol (Experiment) 

Stratospheric Aerosol and Gas Experiment 

SurIace Air Sampling Program 

solar backscattered ultraviolet (satellite ozone instrument) 

standard deviation 

SEAREX South Pacific Aerosol Network 

Solar Energy Research Institute 

Scripps Institution of Oceanography, La Jolla. California 

standard liters per minute 

Samoa Observatory, American Samoa (GMCC) 

solar radiation 

State University of New York at Albany 

South Pole Observatory, Antarctica (GMCC) 

Solar Research Facility 

standard reference material 

standard temperature and pressure (O'C and 1 atm) 

Tropical Ocean Global Atmosphere 

Total Ozone Mapping Spectrometer 

Thermo Systems Incorporated 

Univer.;ity of Alaska, Fairbanks 

Ukpiagvik Inupiat Corporation 

uninterruptable power supply 

(a commercial COl analyzer) 

Univer.;ity of Rhode Island, Kingston, Rhode Island 

United SlaleS Department of Agriculture 

United Slates Geological Survey 

ullraviolet 

WesLem Administrative Sevice Center, Seattle, Washington 

Western Atlantic Ocean Experiment 

Wind Energy Resource Information System 

World Meteorological Organization, Geneva, Switzerland 

Wave Propagation Laboratory, Boulder, Colorado (ERL) 

"Z" random access memory 

zenith-sky cloud detector 

*U, S, GOVERNflliNT PRI NTI NG OFFICE:1994-673-01B/00047