| Methane is, after carbon dioxide, the second most important anthropogenic greenhouse gas. To improve our knowledge about the effect of methane on the Earth climate it is needed to reduce the present uncertainties on the spatial and temporal distribution of methane sources. Here, satellite measurements can be of great benefit complementary to the ground-based surface network measuring methane. The proposed study concerns the retrieval of methane from both GOSAT shortwave infrared and thermal infrared measurements. In this project we will use our experience with methane retrievals from SCIAMACHY which we will further extent to fully exploit the GOSAT measurement capabilities. Firstly, we will apply the retrieval method successfully used for SCIAMACHY. We will then develop and apply a different approach where we retrieve the scattering parameters (aerosols and thin cirrus) together with methane using in addition O2 and CO2 absorption bands. For the final retrieval we will combine the short wave infrared with the thermal infrared measurements to obtain more vertical profile information on methane. The various approaches will be compared, also with SCIAMACHY CH4, and validated. Validation will be done using ground-based FTIR measurements. In addition the existing emission inversion system developed for SCIAMACHY methane in combination with the in-situ surface methane measurements will be used to provide feedback on the quality of the GOSAT methane data. |
