[ACG49-02] Greenhouse gas concentrations retrieved from a combined use of SWIR and TIR observations by the GOSAT series satellites
Keywords:greenhouse gas, retrieval algorithm, GOSAT
Another unique feature of GOSAT and GOSAT-2 is polarization measurement in the SWIR windows, which can be used to correct undesirable effects of aerosols on the accurate retrieval of the greenhouse gas concentrations. It seems clear that retrievals of greenhouse gas concentrations from the GOSAT series satellites are best performed by the algorithm that uses all the measurements from the FTS sensors.
We have developed an experimental algorithm which can be applied to both GOSAT and GOSAT-2 observations. Our approach is a so-called full physics algorithm, which uses TIR and polarimetric SWIR spectra simultaneously as measurement. Gas concentrations were retrieved as a maximum a posteriori solution. We adopted total 5 layers to represent vertical profiles of carbon dioxide and methane, with 2 layers in the troposphere. Column-averaged concentrations of carbon monoxide were derived from GOSAT-2 observations.
We compared our retrievals with ground truth data as well as other satellite retrievals including OCO-2 and TROPOMI. Preliminary result shows that our GOSAT and GOSAT-2 retrievals are both promising. In this paper we will present some of our recent progress including greenhouse gas concentrations in the north hemisphere permafrost regions and Austrian wildfire regions.