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:
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.
To accurately document the global distributions and temporal behavior of
the biogenic/anthropogenic gases N2O, CH4, CO, H2,
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.
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.
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.
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.