Rainfall Index Over Oceans Derived from SSM/I Data

Accurate measurements of global precipitation are vital to the advancement of our knowledge of the dynamics of the atmosphere and oceans. The rapidly varying spatial and temporal distribution of precipitation makes it difficult to obtain adequate data for analysis. Conventional precipitation measurements generally are not considered adequate for quantitative understanding of these global processes. In some areas, there are ground radar systems which could extend the gauge measurements. Satellite-borne sensor systems which can cover a large area in a short time period are ideal for the study of precipitation. The SSM/I (Special Sensor, Microwave Imager) on board the DMSP (Defense Meteorological Satellite Program) satellite was launched in June, 1987. This sensor measures microwave radiation at four frequencies (19.35, 22.235, 37.0 and 85.5 GHz) with a swath width of 1400 km. It provides an opportunity to study global precipitation distributions.