GLOBAL PRECIPITATION ESTIMATIONS USING DEFENSE METEOROLOGICAL SATELLITE PROGRAM F10 AND F11 SPECIAL SENSOR MICROWAVE IMAGER DATA

F10 and F11 satellites from the Defense Meteorological Satellite Program currently observe the earth-atmosphere system four times a day, at 0530, 1030, 1730, and 2230 local solar time. This study uses the special sensor microwave imager data from both satellites to retrieve precipitation over land and ocean and presents some preliminary results of the spatial and temporal variations of rainfall during a month. Diurnal variations of precipitation over the globe are analyzed for August 1993 using measurements from both satellites. Over most oceans, precipitation displays the well-known morning maximum. However, over land, precipitation is highly variable for the study period. Error analyses indicate that over ocean the monthly precipitation estimates from the F11 satellite alone may result in 20-25% errors due to insufficient temporal sampling. This error increases over some land regions to as much as 50-70%. This study also analyses the difference between the monthly rainfall estimates using a sample-averaging method and that using a lognormal probability density function. It is found that an overall difference over the globe is small with less than 5%.