For a complete understanding of Earth’s climate, it is essential to understand the full basket of atmospheric gases that exhibit a large global warming potential or a strong impact on the ozone layer. ESA's Climate Change Initiative is already generating robust satellite-based timeseries for the greenhouse gases water vapour, carbon dioxide (CO₂) and methane (CH₄).  However, several other long-lived greenhouse gases (OLLGHGs) warrant systematic observation, in particular, nitrous oxide (N₂O) and halogenated carbon compounds (CFCs, HFCs, HCFCs, PFCs) are also considered by GCOS as Essential Climate Variables (ECVs, GCOS-defined Essential Climate Variables). These gases exhibit significant global warming potentials and provide a major contribution to radiative forcing uncertainty estimates.

Nitrous oxide and chlorine-containing OLLGHGs are also the main source of anthropogenic ozone depletion, with the latter group regulated internationally under the 1989 UN Montreal Protocol. Several satellite instruments provide information on the atmospheric abundance and distribution of the OLLGHGs, notable examples being: Envisat MIPAS, Scisat ACE-FTS, MetOp IASI, and Aura HIRDLS. Taken together, these and other instruments provide a valuable multi-mission resource for monitoring and understanding the role OLLGHGs in the atmosphere over the last two decades. Full exploitation of this satellite data will contribute to narrowing-down uncertainties related to the greenhouse-warming and ozone-depleting effects of the OLLGHGs by providing complementary information to the ground-based in-situ monitoring networks.

IMKASF contribution: provide MIPAS/Envisat data processed at IMK and contribute to intercomparison and validation efforts.