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).
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