uII-uII lUll! WA!Il
Geophysical monitoring for climatic SOUTH POLE 79 change, Amundsen-Scott South Pole Station, 1979-1981
GREGORY
N
WIND ROSE
M. SIEDELBERG
NOAAlEnvironmental Research Laboratories Geophysical Monitoring for Climatic Change Boulder, Colorado 80303 W
The Geophysical Monitoring for Climatic Change (GMCC) program maintains four remote baseline stations, including one at the Amundsen-Scott South Pole Station. Part of the Air Resources Laboratories of the National Oceanic and Atmospheric Administration (NOAA), the GMCC program monitors levels of various atmospheric trace constituents to determine any changes in background levels relevant to climatic change and the anthropogenic impact related to those changes. During the 1979-80 season, carbon dioxide, surface ozone, solar radiation, aerosols, meteorology, and halocarbons were monitored continuously. A Data General (NOVA 1220) computer was used for control, scaling, and data logging of the instrument measurements (Herbert et al. 1981). Also, GMCC maintained cooperative programs with the U.S. Department of Energy, Scripps Institution of Oceanography, the State University of New York at Albany, the University of Maryland, the University of Arizona, NOAA Air Resources Labs, and the University of California at Los Angeles. GMCC activities are carried out at the Clean Air Facility (CAF), located 90 meters upwind from the main station, in order to minimize local contamination. During the 1978-79 season the program was operated by LuG J . C. Bortniak, NOAA Corps (observer) and C. Smythe (engineer). In November 1979 they were relieved by LTJG W. L. Hiscox, NOAA Corps, and G. M. Siedelberg, respectively. This article gives a brief description of the continuous and discrete measurement activities of CMCC. 1. Meteorology. Measurements were made of wind speed and direction, pressure, moisture, air temperature, and snow temperature. The wind and temperature sensors are located on a 10-meter tower 30 meters grid 00 from the CAF. Continuous atmospheric moisture measurements were made with a Dupont 303 moisture monitor provided by the State University of New York. The mean temperature from November 1979 through October 1980 was —49.5°C, with a low of —74.2°C and a high of —19.2°C. Mean wind direction was 045° and mean wind speed was 9.7 knots, with a maximum wind of 40 knots. The maximum wind chill factor was —118.3°C. A wind rose of the surface winds at the Clean Air Facility is shown in figure 1. The steadiness of the surface wind is readily seen. 2. Aerosols. Continuous measurements of the number concentrations of aerosols were made using a modified General Electric condensation nuclei counter. Until late January 1980, a four-wavelength nephelometer was used to measure the scattering properties of aerosols. This marks the first time the scattering properties of aerosols have been measured at the South Pole (see figure 2). Discrete measurements of Aitken nuclei concentrations were made three times a day in the summer and two times a day in the winter months with a Pollack counter (Bodhaine and Murphy 1980). A long-tube Gardner counter also was used, but it proved ineffective in the 1981 REVIEW
E
S
WIND FREQ.
Figure 1. Wind rose for the South Pole observatory in 1979 (Herbert 1980, p. 54). M/S = meters per second.
midwinter months of May through August; during these months, concentrations of surface aerosols are reduced when a strong surface temperature inversion prevents good vertical mixing with aerosol-enriched air aloft. 3. Carbon dioxide. The Uras 2T CO 2 non-dispersive infrared analyzer was put back on line in November 1979 and was used for continuous carbon dioxide (CO2) measurements throughout 1980. Also, 0.5-liter flasks were aspirated by hand
• ------....uII-uII lUll! WA!Il Figure 2. Daily geometric mean condensation nuclei concentration (bottom), four wavelength aerosol light scattering (middle), and angstrom exponent (top)for 1979 at the South Pole. Note the event that occurred in early August and the corresponding large peak in light scattering, which suggests that there were increases in the larger atmospheric aerosols that cause high light scattering.
193
and by vacuum pump at regular intervals. In March 1980 a CO2 -in-air reference tank was added to the weekly calibration as a surveillance gas. 4. Ozone. During the austral summer, total ozone measurements were taken three times a day at the South Pole using a Dobson spectrophotometer. Focused moon observations were made when possible during the austral winter. Surface ozone measurements were made continuously using a Dasibi photometer. 5. Solar radiation. Solar irradiance was monitored continuously using four Eppley global pyranometers with quartz, GG-22, OG-1, and RG-8 Schott glass hemispheric filter domes, an Eppley ultraviolet pyranometer with diffusing disk and an Eppley normal incidence pyrheliometer mounted on a solar tracker (see figure 3). In addition, discrete measurements were made three times daily using a pyrheliometer with a rotating filter wheel containing quartz, OG-1, RG-2, and RG-8 filters. Discrete measurements of turbidity were also made three times
daily using a sun photometer at 380- and 500-nanometer wavelengths. 6. Halocarbons. Three-hundred-milliliter flasks were used to collect samples of CFC-11, CFC-12, and nitrous oxide once a week in summer and twice a month in winter for analysis at the NOAA GMCC central laboratory in Boulder. 7. Instrument Control and Data Acquisition System (IcDAs). Continuous measurements are fed into ICDAS for real-time scaling and then are transferred to magnetic tape for transport to Boulder. In addition, ICDAS initiates and monitors instrument calibrations. Through the use of preventive maintenance and a well-stocked spare parts supply, ICDAS had an online efficiency of 98.9 percent. The building facility housing the GMCC program at the South Pole is supported by the National Science Foundation. For a review of all GMCC activities see Herbert (1980). Data from past years have been archived and are available from the World Data Center in Ashville, North Carolina.
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Figure 3. Solar irradiance of the normal Incidence pyrheliometer (NIP) for a 5-day period, from 1 through 5 November 1980. The lowest excursions represent shadows cast on the NIP from sampling stacks on the roof of the Clean Air Facility. MW/CM xX2 = milliwatts per square centimeter.
194
ANTARCTIC JOURNAL
References Bodhaine, B. A., and Murphy, M. E. 1980. Calibration of an automatic condensation nuclei counter at the South Pole. Journal of Aerosol Science, 11, 305-312. Herbert, G. A. (Ed.). 1980. Geophysical monitoring for climatic change (Summary Report 8, 1979). Boulder, Cob.: U.S. Department of Com-
Atmospheric processes and energy transfers at the South Pole JOHN J . CARROLL
Department of Land, Air, and Water Resources University of California Davis, California 95616 During the past year I continued several aspects of a study of the lower atmosphere at the South Pole, as reported in previous issues of this journal (see, e.g., Carroll 1980). The investigation of surface albedos has been extended to consider the effect of periodic surface macroscale structures (i.e., ripples) on the effective shortwave albedo of liquid water and snow surfaces (Carroll 1981b). Preliminary results of this work indicate that at low latitudes, the effect of surface ripples is to increase weakly the effective albedo. At high latitudes, a rippled surface absorbs significantly more radiation than does a flat surface. The magnitude of the effect depends on the amplitude of the ripples, the dependence of the surface reflectivity on angle of incidence of the radiation, and the orientation of the axis of the ripples. I have completed analysis of the mean energy balance components and related atmospheric variables and parameters obtained between March 1975 and December 1977. A description of all data processing procedures has been prepared (Carroll 1981c) and tables of daily mean values of these quantities have been published (Carroll and Eby 1981). I have continued efforts to model the atmospheric boundary layer/snow layer energy transfer processes and have revised the prototype model reported previously (Carroll and Fitzjarrald 1979), and am now comparing model predictions and a real sequence of events recorded at the South Pole. The model is driven by the pressure gradient determined from the observed, time-dependent, 500-millibar wind, the observed
1981 REVIEW
merce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories. Herbert, C. A., Harris, J . M., Johnson, M. S., and Jordan, J . R. 1981. The acquisition and processing of continuous data from GMCC observatories (N0AA Technical Memorandum ERL ARL-93). Silver Spring, Md.: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories.
changes in surface net radiation, and the observed snow temperature at 100 centimeters. Initial fields are established from measured snow temperature profiles, air temperature and wind profiles to 8 meters, and radiosonde temperature and wind data up to 500 millibars. Preliminary results (Carroll 1981a) indicate that the surface fluxes of heat and momentum vary in the correct sense, but with less amplitude than those estimated from surface layer observations. A major discrepancy is that the turbulence model rapidly reduces the temperature gradient in most of the outer layer, whereas this is not generally observed. This work was supported by National Science Foundation grants DPP 77-19362 and DPP 80-90525.
References Carroll, J. J. 1980. Surface energy exchange at the South Pole. Antarctic Journal of the U.S., 15(5), 180-182. Carroll, J . J . 1981. A comparison of model calculations with real behavior of a time dependent, cloud free stable planetary boundary layer. Paper presented at the Third Scientific Assembly, International Association of Meterology and Atmospheric Physics/International Union of Geodesy and Geophysics, Hamburg, Germany, August 1981. (a) Carroll, J . J . 1981. The effect of surface striations on the absorption of short wave radiation. Paper presented at the Third Scientific Assembly, International Association of Meteorology and Atmospheric Physics! International Union of Geodesy and Geophysics, Hamburg, Germany, August 1981. (b) Carroll, J . J . 1981. South Pole energy balance experiment: Data processing quality control and general results (Contributions to Atmospheric Science 16). Davis: University of California. (c) Carroll, J . J . , and Eby, E. B. 1981. South Pole energy balance experiment: Tabulations of daily mean energy components and conditions (Contributions to Atmospheric Science 17). Davis: University of California. Carroll, J . J . , and Fitzjarrald, D. E. 1979. Atmosphere-surface interactions in the unsteady, stable planetary boundary layer. Paper presented at the International Committee on Polar Meteorology Symposium on Progress in Antarctic Meteorology, 17th General Assembly of the International Union on Geodesy and Geophysics, Canberra, Australia, December 1979.
195
GREGORY
N
WIND ROSE
M. SIEDELBERG
NOAAlEnvironmental Research Laboratories Geophysical Monitoring for Climatic Change Boulder, Colorado 80303 W
The Geophysical Monitoring for Climatic Change (GMCC) program maintains four remote baseline stations, including one at the Amundsen-Scott South Pole Station. Part of the Air Resources Laboratories of the National Oceanic and Atmospheric Administration (NOAA), the GMCC program monitors levels of various atmospheric trace constituents to determine any changes in background levels relevant to climatic change and the anthropogenic impact related to those changes. During the 1979-80 season, carbon dioxide, surface ozone, solar radiation, aerosols, meteorology, and halocarbons were monitored continuously. A Data General (NOVA 1220) computer was used for control, scaling, and data logging of the instrument measurements (Herbert et al. 1981). Also, GMCC maintained cooperative programs with the U.S. Department of Energy, Scripps Institution of Oceanography, the State University of New York at Albany, the University of Maryland, the University of Arizona, NOAA Air Resources Labs, and the University of California at Los Angeles. GMCC activities are carried out at the Clean Air Facility (CAF), located 90 meters upwind from the main station, in order to minimize local contamination. During the 1978-79 season the program was operated by LuG J . C. Bortniak, NOAA Corps (observer) and C. Smythe (engineer). In November 1979 they were relieved by LTJG W. L. Hiscox, NOAA Corps, and G. M. Siedelberg, respectively. This article gives a brief description of the continuous and discrete measurement activities of CMCC. 1. Meteorology. Measurements were made of wind speed and direction, pressure, moisture, air temperature, and snow temperature. The wind and temperature sensors are located on a 10-meter tower 30 meters grid 00 from the CAF. Continuous atmospheric moisture measurements were made with a Dupont 303 moisture monitor provided by the State University of New York. The mean temperature from November 1979 through October 1980 was —49.5°C, with a low of —74.2°C and a high of —19.2°C. Mean wind direction was 045° and mean wind speed was 9.7 knots, with a maximum wind of 40 knots. The maximum wind chill factor was —118.3°C. A wind rose of the surface winds at the Clean Air Facility is shown in figure 1. The steadiness of the surface wind is readily seen. 2. Aerosols. Continuous measurements of the number concentrations of aerosols were made using a modified General Electric condensation nuclei counter. Until late January 1980, a four-wavelength nephelometer was used to measure the scattering properties of aerosols. This marks the first time the scattering properties of aerosols have been measured at the South Pole (see figure 2). Discrete measurements of Aitken nuclei concentrations were made three times a day in the summer and two times a day in the winter months with a Pollack counter (Bodhaine and Murphy 1980). A long-tube Gardner counter also was used, but it proved ineffective in the 1981 REVIEW
E
S
WIND FREQ.
Figure 1. Wind rose for the South Pole observatory in 1979 (Herbert 1980, p. 54). M/S = meters per second.
midwinter months of May through August; during these months, concentrations of surface aerosols are reduced when a strong surface temperature inversion prevents good vertical mixing with aerosol-enriched air aloft. 3. Carbon dioxide. The Uras 2T CO 2 non-dispersive infrared analyzer was put back on line in November 1979 and was used for continuous carbon dioxide (CO2) measurements throughout 1980. Also, 0.5-liter flasks were aspirated by hand
• ------....uII-uII lUll! WA!Il Figure 2. Daily geometric mean condensation nuclei concentration (bottom), four wavelength aerosol light scattering (middle), and angstrom exponent (top)for 1979 at the South Pole. Note the event that occurred in early August and the corresponding large peak in light scattering, which suggests that there were increases in the larger atmospheric aerosols that cause high light scattering.
193
and by vacuum pump at regular intervals. In March 1980 a CO2 -in-air reference tank was added to the weekly calibration as a surveillance gas. 4. Ozone. During the austral summer, total ozone measurements were taken three times a day at the South Pole using a Dobson spectrophotometer. Focused moon observations were made when possible during the austral winter. Surface ozone measurements were made continuously using a Dasibi photometer. 5. Solar radiation. Solar irradiance was monitored continuously using four Eppley global pyranometers with quartz, GG-22, OG-1, and RG-8 Schott glass hemispheric filter domes, an Eppley ultraviolet pyranometer with diffusing disk and an Eppley normal incidence pyrheliometer mounted on a solar tracker (see figure 3). In addition, discrete measurements were made three times daily using a pyrheliometer with a rotating filter wheel containing quartz, OG-1, RG-2, and RG-8 filters. Discrete measurements of turbidity were also made three times
daily using a sun photometer at 380- and 500-nanometer wavelengths. 6. Halocarbons. Three-hundred-milliliter flasks were used to collect samples of CFC-11, CFC-12, and nitrous oxide once a week in summer and twice a month in winter for analysis at the NOAA GMCC central laboratory in Boulder. 7. Instrument Control and Data Acquisition System (IcDAs). Continuous measurements are fed into ICDAS for real-time scaling and then are transferred to magnetic tape for transport to Boulder. In addition, ICDAS initiates and monitors instrument calibrations. Through the use of preventive maintenance and a well-stocked spare parts supply, ICDAS had an online efficiency of 98.9 percent. The building facility housing the GMCC program at the South Pole is supported by the National Science Foundation. For a review of all GMCC activities see Herbert (1980). Data from past years have been archived and are available from the World Data Center in Ashville, North Carolina.
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C) C,
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it
9
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t
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* :z I a: '
ry
9
C3
c-I a
C) C)
0.0
1.0
2.0
3.0
4.0
-
-
5.0
DAY (1-5 NOV 80)
Figure 3. Solar irradiance of the normal Incidence pyrheliometer (NIP) for a 5-day period, from 1 through 5 November 1980. The lowest excursions represent shadows cast on the NIP from sampling stacks on the roof of the Clean Air Facility. MW/CM xX2 = milliwatts per square centimeter.
194
ANTARCTIC JOURNAL
References Bodhaine, B. A., and Murphy, M. E. 1980. Calibration of an automatic condensation nuclei counter at the South Pole. Journal of Aerosol Science, 11, 305-312. Herbert, G. A. (Ed.). 1980. Geophysical monitoring for climatic change (Summary Report 8, 1979). Boulder, Cob.: U.S. Department of Com-
Atmospheric processes and energy transfers at the South Pole JOHN J . CARROLL
Department of Land, Air, and Water Resources University of California Davis, California 95616 During the past year I continued several aspects of a study of the lower atmosphere at the South Pole, as reported in previous issues of this journal (see, e.g., Carroll 1980). The investigation of surface albedos has been extended to consider the effect of periodic surface macroscale structures (i.e., ripples) on the effective shortwave albedo of liquid water and snow surfaces (Carroll 1981b). Preliminary results of this work indicate that at low latitudes, the effect of surface ripples is to increase weakly the effective albedo. At high latitudes, a rippled surface absorbs significantly more radiation than does a flat surface. The magnitude of the effect depends on the amplitude of the ripples, the dependence of the surface reflectivity on angle of incidence of the radiation, and the orientation of the axis of the ripples. I have completed analysis of the mean energy balance components and related atmospheric variables and parameters obtained between March 1975 and December 1977. A description of all data processing procedures has been prepared (Carroll 1981c) and tables of daily mean values of these quantities have been published (Carroll and Eby 1981). I have continued efforts to model the atmospheric boundary layer/snow layer energy transfer processes and have revised the prototype model reported previously (Carroll and Fitzjarrald 1979), and am now comparing model predictions and a real sequence of events recorded at the South Pole. The model is driven by the pressure gradient determined from the observed, time-dependent, 500-millibar wind, the observed
1981 REVIEW
merce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories. Herbert, C. A., Harris, J . M., Johnson, M. S., and Jordan, J . R. 1981. The acquisition and processing of continuous data from GMCC observatories (N0AA Technical Memorandum ERL ARL-93). Silver Spring, Md.: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories.
changes in surface net radiation, and the observed snow temperature at 100 centimeters. Initial fields are established from measured snow temperature profiles, air temperature and wind profiles to 8 meters, and radiosonde temperature and wind data up to 500 millibars. Preliminary results (Carroll 1981a) indicate that the surface fluxes of heat and momentum vary in the correct sense, but with less amplitude than those estimated from surface layer observations. A major discrepancy is that the turbulence model rapidly reduces the temperature gradient in most of the outer layer, whereas this is not generally observed. This work was supported by National Science Foundation grants DPP 77-19362 and DPP 80-90525.
References Carroll, J. J. 1980. Surface energy exchange at the South Pole. Antarctic Journal of the U.S., 15(5), 180-182. Carroll, J . J . 1981. A comparison of model calculations with real behavior of a time dependent, cloud free stable planetary boundary layer. Paper presented at the Third Scientific Assembly, International Association of Meterology and Atmospheric Physics/International Union of Geodesy and Geophysics, Hamburg, Germany, August 1981. (a) Carroll, J . J . 1981. The effect of surface striations on the absorption of short wave radiation. Paper presented at the Third Scientific Assembly, International Association of Meteorology and Atmospheric Physics! International Union of Geodesy and Geophysics, Hamburg, Germany, August 1981. (b) Carroll, J . J . 1981. South Pole energy balance experiment: Data processing quality control and general results (Contributions to Atmospheric Science 16). Davis: University of California. (c) Carroll, J . J . , and Eby, E. B. 1981. South Pole energy balance experiment: Tabulations of daily mean energy components and conditions (Contributions to Atmospheric Science 17). Davis: University of California. Carroll, J . J . , and Fitzjarrald, D. E. 1979. Atmosphere-surface interactions in the unsteady, stable planetary boundary layer. Paper presented at the International Committee on Polar Meteorology Symposium on Progress in Antarctic Meteorology, 17th General Assembly of the International Union on Geodesy and Geophysics, Canberra, Australia, December 1979.
195
