HIGHER-RESOLUTION RAIN INFORMATION MUST BE EXTRACTED FROM IMERG IN ORDER TO USE REMOTELY-SENSED RAIN DATA TO STUDY AIR-SEA INTERACTION INCLUDING OCEAN FRESHENING THE SENSIBLE HEAT FLUX DUE TO RAIN AND THE OCEAN BUOYANCY FLUX DUE TO RAIN. WE PROPOSE TO USE DATA FROM 64 ACOUSTIC RAIN SENSORS (PALS) AND 11 SURFACE RAIN GAUGES MOUNTED ON BUOYS TO TEST STRATEGIES FOR DOWNSCALING IMERG OVER THE OCEAN. THEN WE WILL COMPARE THE DOWNSCALED IMERG PRODUCTS IN TERMS OF THEIR ABILITY TO ESTIMATE OCEAN FRESHENING THE RAIN HEAT FLUX AND THE RAIN BUOYANCY FLUX WHICH WERE MEASURED DIRECTLY BY MOORING OBSERVATIONS. THESE PROCESSES ARE AFFECTED BY RAIN ARE RELEVANT TO UNDERSTANDING THE CURRENT CLIMATE SYSTEM AND PREDICTING CLIMATE CHANGE BECAUSE THEY IMPACT THE GLOBAL WATER CYCLE THE NET OCEAN SURFACE HEAT BUDGET AND UPPER OCEAN TURBULENCE AND STRATIFICATION. DEVELOPING METHODS TO PRODUCE TRUSTWORTHY DEPICTIONS OF PRECIPITATION EXTREMES OVER OCEANS WITH TIMESCALES ON ORDER OF SEVERAL MINUTES IS ALSO IMPORTANT FOR MONITORING HAZARDOUS WEATHER SYSTEMS PREDICTING THEIR EVOLUTION AND BETTER UNDERSTANDING THEIR RELATIONSHIP TO THE SURROUNDING COUPLED AIR-SEA ENVIRONMENT. TO TEST THESE HYPOTHESES THE PROPOSED PROJECT WILL COMPLETE THE FOLLOWING OBJECTIVES: 1) PRODUCE DATASETS OF IN-SITU RAIN RATE AND WIND SPEED FROM THE 64 PALS DEPLOYED FROM 2004-PRESENT. DOWNSCALE IMERG TO PAL SPATIOTEMPORAL SCALES OVER THE LOCATIONS OF 64 PALS AND 11 RESEARCH MOORINGS. 2) COMPARE THE PAL OCEANIC ACOUSTIC RAIN MEASUREMENT TO ORIGINAL AND DOWNSCALED IMERG RAIN IN DIFFERENT REGIONS SEASONS AND INTERANNUAL STATES AS A FUNCTION OF ATMOSPHERIC OCEANIC AND RAIN CHARACTERISTICS. 3) USING ORIGINAL AND DOWNSCALED IMERG RAIN PRODUCTS MOORING GAUGE RAIN AND PAL RAIN AT MOORING LOCATIONS COMPARE ESTIMATED AND MEASURED IMPACTS OF RAIN ON AIR-SEA INTERACTION: OCEAN FRESHENING RAIN HEAT FLUX AND RAIN BUOYANCY FLUX. THROUGH THIS EFFORT WE WILL PROVIDE THE GLOBAL 14-YEAR ACOUSTIC RAIN RATE DATASET TO THE PMM TEAM AND OTHER NASA USERS.