Estimation of precipitation over Asia by combined use of gauge and multi-satellite sensor observations at fine scale

In the present study an effort is made to estimate the 3-hourly rainfall using gauge and satellite observations over the land and ocean region of Asia (40°S-50°N, 40°E-130°E) at 0.25° ×0.25° spatial resolution. The study utilizes the observations from rain gauge, Special Sensor Microwave/Imager (SSM/I) onboard Defense Meteorological Satellite Program (DMSP), Precipitation Radar (PR) onboard Tropical Rainfall Measuring Mission (TRMM) and geo-stationary satellite Meteosat from Eumetsat. The present study makes use of rainfall estimates by synergistic use of multi-satellite sensors using Meteosat Infrared and Water Vapor absorption channel and PR observations (Mishra et al., 2009, 2010) and SSM/I derived microwave estimates using regional scattering index developed by Mishra et al. (2009). Over orographic region a new relationship is developed using meteosat and rain-gauge observations between rainfall and brightness temperature. The rain areas over the land portion of area of study is filled by available rain gauge observations but if the rain gauge observations are unavailable the vacant area is filled by available microwave observations followed by the microwave calibrated infrared observations over the land and oceanic region of area of study. The precipitation estimates from the present approach is validated against rain gauge observations and other available standard rainfall products. The validation results show that present approach of precipitation estimation is able to estimate the rainfall with a very good accuracy.