GASLab/AGGON

The Global Atmospheric Sampling LABoratory (GASLAB) and Australian Greenhouse Gas Observation Network (AGGON) programs maintain atmospheric monitoring networks with a focus on the main anthropogenic greenhouse gases.

This map shows GASLAB flask sampling and AGGON in-situ monitoring sites. Also shown here is the in-situ monitoring network of the international AGAGE program of which CSIRO is a partner.

The GASLAB program maintains high precision analytical capability for the key greenhouse gases: carbon dioxide (CO₂) and its isotopes (¹³C/¹²C and ¹⁸O/¹⁶O), methane (CH₄), nitrous oxide (N₂O) and the biogeochemically related gases hydrogen (H₂) and carbon monoxide (CO).

Its global flask sampling network measures the changing background atmospheric composition from a range of latitudes that stretches from the South Pole at 90°S to Alert Station in the Canadian Arctic at 82°N. A particular focus is the Southern Hemisphere, taking in Australia and the Southern Ocean / Antarctic region to the south. Data records from most sites are unbroken since the 1980s-1990s.

GASLAB is linked to other international networks as part of a coordinated and collaborative effort to study the global atmosphere. Observational data are routinely submitted to international data archives (e.g. the World Data Center for Greenhouse Gases, WDCGG) where they are accessible to atmospheric researchers worldwide, and are used extensively by scientists within CSIRO and across the world to improve our understanding of the changing atmosphere.

Data are used for many research applications including:

national and global budgets of greenhouse and other gases,
uptake of fossil fuel-derived carbon by the oceans and terrestrial biosphere,
atmospheric chemistry in clean Southern Hemisphere air,
characterising global atmospheric circulation.

Example flask air sampling records back to 1990 from Cape Grim, with retained data in blue, rejected data in green and a smoothed curve (fit to retained data) in red.

Data from the global sampling network can be used to construct a 3-dimensional picture of how trace gas concentrations vary with time and latitude. This example for methane shows the concentration increasing with time, and a strong inter-hemispheric gradient with higher concentrations in the Northern Hemisphere where the dominant source regions are located.

The records are used to understand the sources of these gases (how they enter the atmosphere), the sinks (how they leave) and their atmospheric lifetimes. This knowledge is used to make projections of future atmospheric greenhouse gas loading for different emissions scenarios (of fossil fuels emissions etc.) and resulting climate change.

Another role of the central GASLAB analytical facility is to calibrate air standards used at field sites. Continuously operating in-situ analysers are presently located at Cape Grim, Gunn Point, Macquarie Island and Casey as part of the AGGON program. Observations made by these instruments inform us not only about the clean, background atmosphere but also about trace gas exchange processes that have occurred upwind under non-background conditions. For example, background measurements at Cape Grim, Macquarie Island and Casey constrain uptake of atmospheric CO₂ by the Southern Ocean. At other times Cape Grim encounters air masses that have passed over the large city of Melbourne 200 km to the north or from rural areas, especially in Tasmania and Victoria. In-situ observations of these events have been used to quantify emissions of various gases from Melbourne and south-east Australia. Gunn Point is well positioned to capture atmospheric signals from significant exchange processes in the tropics, such as seasonal biomass burning in northern Australia. An expanded AGGON observational network has the potential to monitor Australia’s national emissions of greenhouse and other gases but awaits suitable resourcing.