AGAGE

The multi-national AGAGE measures accurately, at high frequency, the important species in the Montreal Protocol (ozone depletion) and the important species in the Paris Agreement (climate change). Using advanced statistical methods to merge these measurements with accurate atmospheric circulation models, AGAGE then estimates, regionally and globally, the surface fluxes and/or atmospheric sinks (lifetimes) of these trace gases.

The trace gases measured and interpreted in this way are:

1. The anthropogenic gases that contribute the majority of reactive halogen to the stratosphere and/or are strong infrared absorbers → CFCs, bromocarbons, HCFCs, PFCs, NF₃, SO₂F₂, and SF₆

2. The non-CO₂ biogenic-anthropogenic gases important to climate change and/or ozone depletion → CH₄, N₂O, CO, H₂, methyl chloride (CH₃Cl) and methyl bromide (CH₃Br)

3. Newly identified long-lived greenhouse and ozone-depleting gases → SO₂F₂, NF₃, heavy PFCs and hydrofluro-olefins (HFOs)

AGAGE also:

• determines the average concentrations and trends of tropospheric hydroxyl radicals (OH) from the rates of destruction of measured trichloroethane (CH₃CCl₃), HFCs and HCFCs and estimates their emissions and;

• provides global and regional measurements of methane, carbon monoxide and molecular hydrogen, and estimates of hydroxyl levels to test primary atmospheric oxidation pathways.