THE GPM MISSION COMPRISES AN INTERNATIONAL NETWORK OF SATELLITES AND SEEKS TO PROVIDE THE NEXT GENERATION OF GLOBAL ESTIMATES OF PRECIPITATION. THE PROPOSED RESEARCH WILL FOCUS ON THE DEVELOPMENT OF ASSIMILATION METHODOLOGIES THAT COMBINE INFORMATION FROM OBSERVATIONS AND MODELS TO IMPROVE NUMERICAL WEATHER PREDICTION AND TO PRODUCE IMPROVED ANALYSES OF PRECIPITATION AND DOWNSCALING OF SATELLITE PRECIPITATION ESTIMATES. WE PROPOSE CONTRIBUTIONS TO THE PMM SCIENCE TEAM BY PROVIDING PROTOTYPE LEVEL-4 GLOBAL PRECIPITATION PRODUCT DERIVED FROM THE GODDARD EARTH OBSERVING SYSTEM (GEOS) ATMOSPHERIC ANALYSES ASSIMILATING ALL-SKY MICROWAVE RADIANCE DATA FROM MULTIPLE SENSORS IN GPM CONSTELLATION SATELLITE PLATFORMS. THIS EFFORT BUILDS UPON ONGOING FUNDED RESEARCH LED BY NASA S GLOBAL MODELING AND ASSIMILATION OFFICE (GMAO) TO ASSIMILATE CLOUD- AND PRECIPITATION-AFFECTED SATELLITE RADIANCE DATA IN THE GEOS. AS PART OF THE SCIENCE TEAM WE PROPOSE TO CONTRIBUTING GLOBAL ANALYSES AND DOWNSCALED DATASETS OF PRECIPITATION AND THE CORRESPONDING ATMOSPHERIC AND SURFACE PARAMETERS DERIVED FROM GEOS. THIS WORK DIRECTLY ADDRESSES THE RESEARCH CATEGORY 2.3 METHODOLOGY DEVELOPMENT FOR IMPROVED APPLICATIONS OF SATELLITE PRODUCTS . SPECIFIC ACTIVITIES INCLUDE: (1) EXPANSION OF THE EXISTING GEOS ALL-SKY GPM MICROWAVE RADIANCE DATA ASSIMILATION SYSTEM TO UTILIZE ALL-SKY MICROWAVE RADIANCE FROM OTHER MICROWAVE SENSORS ON THE GPM CONSTELLATION SATELLITES (2) DEVELOPMENT OF FOUR-DIMENSIONAL LEVEL-4 GLOBAL ATMOSPHERIC AND SURFACE ANALYSIS DATA SETS BY ASSIMILATING ALL-SKY MICROWAVE RADIANCES FROM MULTIPLE SENSORS USING THE GEOS MODELING AND ASSIMILATION AT A SPATIAL RESOLUTION OF AT LEAST 25 KM (3) GENERATION OF DOWNSCALED PRECIPITATION LEVEL-4 DATASETS BY EXTENDING THE DATASETS DEVELOPED IN (2) TO HIGHER SPATIAL RESOLUTIONS (~ 7 KM) AND (4) VALIDATION AND EVALUATION OF THE LEVEL-4 PRECIPITATION PRODUCTS FROM THIS PROPOSED WORK INCLUDING COMPARISON WITH THE GPM LEVEL-3 IMERG PRODUCTS AND INDEPENDENT RAIN GAUGE DATASETS. THIS WILL BE PERFORMED TO EVALUATE THE BIAS AND ERROR CHARACTERISTICS OF LEVEL-4 PRODUCTS AS WELL AS TO COMPARE THE DATASET PERFORMANCE IN THE ANALYSIS OF HIGH-IMPACT EVENTS. THE AFOREMENTIONED EFFORTS WILL SUPPORT THE ORIGINAL GOAL OF THE GPM MISSION TO GAIN ADVANCED SCIENTIFIC UNDERSTANDING OF THE EARTH'S WATER AND ENERGY CYCLE AND TO PROVIDES NEAR REAL-TIME DATA FOR A WIDE ARRAY OF SOCIETAL APPLICATIONS WHILE ENHANCING THE GMAO S SATELLITE DATA ASSIMILATION COMPONENTS IN GEOS SYSTEM.