Development of over-ocean SSM/I rain retrieval algorithm in the GSMaP project

摘要

The Special Sensor Microwave/Imager (SSM/I) is essential in the Global Satellite Mapping of Precipitation (GSMaP) project for the reduction of sampling error. In this study, the SSM/I rain rate retrieval is simulated by the GSMaP core algorithm for the Tropical Rainfall Measuring Mission (TRMM)/TRMM Microwave Imager (TMI) to evaluate the influence of the lack of the 10-GHz frequency channel and to demonstrate the extent that dual-polarization increases the range of the sensitivity of the vertically-polarized brightness temperature (Tb) at 19 GHz. The simplified normalized polarization difference is expected to perform best near the saturation of the vertically-polarized Tb avoiding the underestimation of rain rate in the vertically-polarized Tb at 19 GHz.