INDICATOR DEFINITION Measurement of air samples for values of the primary greenhouse gases (carbon dioxide, methane and nitrous oxide) and associated species (carbon monoxide, hydrogen and isotopes of carbon dioxide) in the Southern Hemisphere atmosphere.
TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important ... elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system.
This indicator is one of: CONDITION
RATIONALE FOR INDICATOR SELECTION Over the last century the concentration of greenhouse gases has risen in the atmosphere. The average rise is about half that expected from human activities, predominantly the burning of fossil fuel. Thus observations of the concentration of these gases provides a measure of anthropogenic greenhouse forcing in the atmosphere, and for example, monitors the effectiveness of oceans and terrestrial biomes in removing the excess CO2.
Measurements of long-lived trace gas levels in Antarctic air generally provide an accurate integration of global exchanges between the surface and the atmosphere. The climate-influencing gases of main interest are gases released as a result of human activity, as well as from (climate-driven) physical, chemical and biological processes in both land and oceans. The Antarctic monitoring, in concert with other global network results, exploits trace gas ratios to identify and locate globally significant exchanges.
DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial Scale: High latitude Southern Hemisphere air samples are collected from AAD sites by BoM personnel at Mawson station, Casey station and Macquarie Island, and by NOAA staff at South Pole. These complement CSIRO supervised sites at Cape Grim, Tasmania and ~7 other globally distributed locations.
Frequency: Typical sites collect ~4 flasks of air per month for subsequent analysis at CSIRO.
Measurement Technique: Various chemical analysis techniques (Francey et al. 1996).
RESEARCH ISSUES For global trace gas monitoring, improvements are sought in network intercalibration and in increased sampling, e.g. continuous CO2 monitoring, vertical profiles, continental sites. More generally, improved coordination of atmospheric composition modeling, surface flux measurements and atmospheric transport representations are sought to serve new 'multiple-constraint modeling frameworks'.
LINKS TO OTHER INDICATORS Monthly averages of daily maximum and minimum temperatures for Australian Antarctic Stations Mean sea level Average Summer chlorophyll concentrations in the Southern Ocean, from latitude bands 40-50 deg S, 50-60 deg S, 60 deg S-continent Average sea surface temperatures in latitude bands 40-50 deg S, 50-60 deg S, 60 deg S-continent Antarctic sea ice extent and concentration
Because all these gases have long lifetimes in the atmosphere, the measurements at mid-to-high southern latitudes are representative of global values (after allowance for seasonal differences and transport between hemispheres). Trends in these gases would be recorded and compared with emission rates. The values should also be compared with pre-industrial levels.
CSIRO ... sites contribute to integrated global networks as part of the WMO Global Atmospheric Watch program. The small differences between sites are used, along with atmospheric transport models and prior (independent) information on regional processes, to monitor regional contributions to the global changes. The southern hemisphere sites in particular need to be reconciled with CO2 partial pressure measurements (from ships) and monitored for possible Southern Ocean circulation changes due to global warming.
See the URL below for State of the Environment indicator 11 for access to these data.
A copy of the raw data are also available for download from the URL given below.
CSIRO Marine and Atmospheric Research
Private Bag #1
Province or State:
Francey, Roger J., Paul (L.P.) Steele, Ray L. Langenfelds, Marco Lucarelli, Colin E. Allison, David J. Beardsmore, Scott A. Coram, Nada Derek, Fred de Silva, David M. Etheridge, Paul J. Fraser, Reg J. Henry, Brian Turner and Emily D. Welch (1996), Global Atmospheric Sampling Laboratory (GASLAB): supporting and extending the Cape Grim trace gas programs, Baseline Atmospheric Program (Australia) 1993., 8-29, Bureau of Meteorology and CSIRO Division of Atmospheric Research, Melbourne, (eds. R.J.Francey, A.L.Dick and N.Derek)
Francey, R.J., P.J. Rayner and C.E. Allison (2001), Constraining the global carbon budget from global to regional scales - the measurement challenge., In Global Biogeochemical Cycles in the Climate System, 245-252, Academic Press, New York