New possibilities for geophysical parameter retrievals opened by GCOM-W1 AMSR2

The new Advanced Microwave Scanning Radiometer 2 (AMSR2) onboard the GCOM-W1 satellite has additional - comparatively to its predecessor AMSR-E - two channels working in C-band. It is demonstrated in this paper that the measurements at these additional channels can be effectively used for rain pixel identification and rain rate (RR) estimation. It is shown that the rain radiation constituent to the total microwave radiation measured at C- and X-band channels can be calculated. After the rain radiation constituent having been excluded from the brightness temperature, sea surface wind speed (SWS) is possible to be retrieved as if it were no rain, using the retrieval algorithms, developed for non-rain conditions using physical modeling of brightness temperatures. The suggested approach has been applied to several case studies of tropical typhoons including Haiyan case. Sea surface wind speeds retrieved from AMSR2 have been compared with those from Soil Moisture and Ocean Salinity (SMOS) instrument. High correlation has been detected indicating the great potential of AMSR2 SWS retrievals in hurricanes.