Global Distributions of Methane Retrieved from IASI and Prospects for IASI-NG/Sentinel 5
Siddans, Richard; Waterfall, Alison; Miles, Georgina; Latter, Barry; Kerridge, Brian
STFC Rutherford Appleton Laboratory, UNITED KINGDOM

Results from the large-scale application of a scheme developed at the Rutherford Appleton Laboratory to retrieve methane distributions from the IASI instrument on METOP will be presented. The RAL scheme has been extensively validated by comparison to ground-based measurements and inter-compared over the annual cycle with a range of state-of-the-art models. While IASI allows height resolved information to be usefully retrieved, its sensitivity in the lower troposphere depends strongly on the near-surface temperature profile and the surface temperature / emissivity. Short-wave infra-red observations such as those currently made by GOSAT provide vertically integrated information with sensitivity to near-surface concentrations. The potential for co-located observations made by Sentinel 5 SWIR and IASI-NG on Metop-SG will be demonstrated through quantitative retrieval simulations and through combination of IASI and GOSAT results.