RAINFALL ESTIMATION OVER THE OCEANS FROM 37 GHZ RADIOMETRIC MEASUREMENTS

An improved algorithm to estimate rainfall over the oceans, utilising the observations made by the Special Sensor Microwave/Imager (SSM/I) r adiometer at 37 GHz, is developed. The algorithm is based on an earlie r analysis that included the satellite microwave data from SSM/I and t he Scanning Multichannel Microwave Radiometer (SMMR), and the radar da ta obtained during the GATE experiment. The modified algorithm was tes ted by comparing the SSM/I-derived rainfall with the corresponding val ues obtained by radar and rain gauges in the framework of the GPCP pro gramme, over the seas around Japan. While good agreement of +/- 25% is obtained in this test, the analysis of the results suggests that furt her improvements are possible. An attempt to separate rain originated from convective and stratiform clouds is made, based on multichannel m easurements obtained from SSM/I.