Trmm Satellite-borne Microwave Imager (tmi) Data Inversion, China Precipitation Cases

In this thesis, the data of TRMM Microwave Imager (TMI) from the satellite of Tropical Rainfall Measuring Mission (TRMM) are used. The study of precipitation retrieval by empirical algorithms is to get the precipitation parameters in China region (for example, thresholds in given methods) and to enhance quantitative research on the precipitation retrieval. By case analysis, the interaction, such as absorption, emission, scattering etc. between cloud, rain, ice and microwave are better understood, and this is the base of consequent study.Land rain and sea rain cases are used to show the typical characters on microwave i mages, t hen t he causes o f formation are i nterpreted. Typhoon is a kind of hazardous weather system that affects the coastal provinces. The research of typhoon structure in microwave images indicates that TMI can show better position of typhoon eye than other remote sensing methods. Although the capabilities of TMI o n typhoon study have been proved, the future applications of the microwave data obtained from satellite are still very wide.Four kinds of empirical algorithms, i.e., Frequency Algorithms (FA), Polarization Algorithms (PA) , GSCAT (Goddard Scattering Algorithm) and Polarization Corrected Temperature (PCT) Algorithm are studied and tested for precipitation estimation. By comparing five different channels of FA, it is proved that the 37V-85V method has better result than others. There are three PA methods, and every method is testified. The result shows that the 37V-37H' method gives closer precipitation with NASA retrieval than the other two. Being single channel method, GSCAT has more uncertainty. The threshold is supposed to be a constant in FA, PA or GSCAT, and this is not true in fact. The PCT Algorithm overcomes this problem, because it is based on the microwave radiative transfer equation. The PCT Algorithm is suitable to the rainfall retrieval over coastal area which covers both land and sea. Compared with NASA rain retrieval from TMI, the PCT Algorithm gives better result than that from the other three methods in the rain area estimation.