Monitoring sandstorms and desertification in northern China using SSM/I data and Getis statistics

摘要

A massive sandstorm enveloped most of northern China during Spring 2002. Monitoring the evolution of sandstorm and desertification has become one of the most serious problems for China's environment. Since 1989, one of the most advanced and operational passive microwave sensors is the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I) operated at seven channels (19, 37, 85 GHz with vertical and horizontal polarization and 22 GHz with vertical polarization only). In this paper, the sandstorm and desertification indexes, SDI and DI, are derived from the radiative transfer equation, and are employed with multi-channel measurements of the DMSP SSM/I for monitoring the sandstorm and desertification in northern China. Some SSM/I data in 1997 and 2001 are employed. The algorithm of the Getis statistics is developed to categorize the spatial correlation and its evolution during these days. It is demonstrated that the SSM/I indexes, SDI and DI, and its Getis statistics are well applicable for monitoring the sandstorm and desertification.