Sponsored by NASA's Atmospheric Composition Focus Area in Earth Science

Mission

The scientific objectives of the ALE/GAGE/AGAGE programs are several in number and of considerable importance in furthering our understanding of a number of important global chemical and climatic phenomena. They are:

1. To optimally determine from observations, the rate of emission and/or chemical destruction (i.e.  lifetime) of the anthropogenic chemicals (e.g. chlorocarbons, chlorofluorocarbons (CFCs), and bromocarbons) that contribute most of the reactive chlorine and bromine released into the stratosphere and/or are strong infrared absorbers.

2. To accurately document the global distributions and temporal behavior of the biogenic/anthropogenic gases N₂O, CH₄, CO, H₂, CH₃Cl, CH₃Br, CH₂Cl₂, and CHCl₃.

3. To optimally determine the average concentrations and trends of OH radicals in the troposphere by determining the rates of destruction of atmospheric CH₃CCl₃ and other hydrohalocarbons from continuous measurements of their concentrations together with industrial estimates of their emissions.

4. To determine optimally, using high frequency trace gas data (and theoretical estimates of their rates of destruction), the magnitudes and distributions by region of the surface sources of these gases.

5. To provide an accurate data base on the rates of accumulation of trace gases over the globe which can be used to test the synoptic-, regional- and global-scale circulation predicted by three dimensional models and/or to determine characteristics of the sources of these gases near the stations.

6. To provide routine measurements of CH₄, CO and H₂, and estimates of OH levels that can be used to test primary oxidation pathways in the atmosphere.

AGAGE project official: Ron Prinn, curator: Ray H.J. Wang

 Last update: July 2010