We present the organization, instrumentation, datasets, data interpretation,
modeling, and accomplishments of the multinational global atmospheric
measurement program AGAGE (Advanced Global Atmospheric Gases Experiment).
AGAGE is distinguished by its capability to measure globally, at high
frequency, and at multiple sites all the important species in the Montreal
Protocol and all the important non-carbon-dioxide (non-CO2) gases
assessed by the Intergovernmental Panel on Climate Change (CO2 is
also measured at several sites). The scientific objectives of AGAGE are
important in furthering our understanding of global chemical and climatic
phenomena. They are the following: (1) to accurately measure the temporal and
spatial distributions of anthropogenic gases that contribute the majority of
reactive halogen to the stratosphere and/or are strong infrared absorbers
(chlorocarbons, chlorofluorocarbons – CFCs, bromocarbons,
hydrochlorofluorocarbons – HCFCs, hydrofluorocarbons – HFCs and
polyfluorinated compounds (perfluorocarbons – PFCs), nitrogen trifluoride –
NF3, sulfuryl fluoride – SO2F2, and sulfur hexafluoride –
SF6) and use these measurements to determine the global rates of
their emission and/or destruction (i.e., lifetimes); (2) to accurately
measure the global distributions and temporal behaviors and determine the
sources and sinks of non-CO2 biogenic–anthropogenic gases important
to climate change and/or ozone depletion (methane – CH4, nitrous
oxide – N2O,
carbon monoxide – CO, molecular hydrogen – H2, methyl chloride
– CH3Cl, and methyl bromide – CH3Br); (3) to identify new
long-lived greenhouse and ozone-depleting gases (e.g., SO2F2,
NF3, heavy PFCs (C4F10, C5F12,
C6F14, C7F16, and C8F18) and
hydrofluoroolefins (HFOs; e.g., CH2 = CFCF3) have been
identified in AGAGE), initiate the real-time monitoring of these new gases,
and reconstruct their past histories from AGAGE, air archive, and firn air
measurements; (4) to determine the average concentrations and trends of
tropospheric hydroxyl radicals (OH) from the rates of destruction of
atmospheric trichloroethane (CH3CCl3), HFCs, and HCFCs and estimates
of their emissions; (5) to determine from atmospheric observations and
estimates of their destruction rates the magnitudes and distributions by
region of surface sources and sinks of all measured gases; (6) to provide
accurate data on the global accumulation of many of these trace gases that
are used to test the synoptic-, regional-, and global-scale circulations
predicted by three-dimensional models; and (7) to provide global and regional
measurements of methane, carbon monoxide, and molecular hydrogen and
estimates of hydroxyl levels to test primary atmospheric oxidation pathways
at midlatitudes and the tropics. Network Information and Data Repository:
http://agage.mit.edu/data or
http://cdiac.ess-dive.lbl.gov/ndps/alegage.html
(https://doi.org/10.3334/CDIAC/atg.db1001)....

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE)

10.5194/essd-10-985-2018