Seminars

Seminar Abstract

Diagnosing Large-Scale Processes Using Observations of Atmospheric Trace Gases: The AGAGE Program

AGAGE (Advanced Global Atmospheric Gases Experiment) is a global atmospheric measurement and modeling program which focuses on the non-CO2 anthropogenic and biogenic atmospheric trace gases which modulate stratospheric ozone and/or the radiative forcing of climate.

AGAGE operates a global network of ground-based real-time high-frequency measurement stations using custom-designed automated instrumentation. An overview of the network, its instrumentation and its calibration will be given, with an emphasis on the new Medusa cryofocusing gas-chromatograph mass-spectrometer system which measures 40 different atmospheric compounds ranging in concentration from 0.1 to 550 parts-per-trillion. Examples of long-term atmospheric records illustrating the effectiveness of the Montreal Protocol and the rise of new “substitute” ozone-friendly compounds will be shown.

Measurements of methyl chloroform provide a powerful tool for quantifying the cleansing capacity of the troposphere (by hydroxyl radical) and its changes over time. The seasonal cycle in high-precision measurements of atmospheric nitrous oxide (N2O) at Cape Grim, Tasmania, provides a means to quantify the Southern Ocean air-sea exchange rate and thus to separate the roles of ventilation and biological production in oxygen budget of this important oceanic region.

Examples of new AGAGE global observations of atmospheric carbon tetrafluoride (CF4, lifetime order 50,000 years, and a potential ocean tracer), and of the fumigant sulfuryl fluoride (SO2F2) will also be shown, time permitting.

* Member of Advanced Global Atmospheric Gases Experiment (AGAGE)

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CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
Karen Wild-Allen, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5010
Piers Dunstan, (Biological seminars) CSIRO Marine and Atmospheric Research (03) 6232 5382
Sandra Zicus, Antarctic Climate and Ecosystems CRC (03) 6226 7888 & Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2509