IGF::OT::IGF THIS NASA RESEARCH ANNOUNCEMENT AWARD IS FOR THE PRODUCTION AND STUDY OF OCEAN VECTOR WINDS FROM SOIL MOISTURE ACTIVE-PASSIVE (SMAP) WITH A FOCUS ON TROPICAL AND EXTRA-TROPICAL CYCLONES OVER THE OCEAN. AS COMPARED TO MOST OTHER SATELLITE WIND SENSORS, SMAP HAS THE UNIQUE CAPABILITY TO MEASURE HIGH WINDS THROUGH HEAVY RAIN IN STORMS. SMAP COMBINES THE PASSIVE THROUGH-RAIN L-BAND CAPABILITY OF AQUARIUS WITH THE TWO-LOOK POLARIMETRIC CAPABILITY OF WINDSAT INTO A SENSOR THAT IS VERY WELL SUITED FOR MEASURING OCEAN STORM WINDS. WE WANT TO TAKE THIS OPPORTUNITY AND ADAPT AND APPLY OUR EXISTING RETRIEVAL ALGORITHMS TO SMAP IN ORDER TO PROVIDE THE SCIENTIFIC COMMUNITY WITH A UNIQUE OCEAN VECTOR WIND DATASET. THE PROPOSED INVESTIGATION WILL CONSIST OF: 1) THE AQUARIUS/WINDSAT VECTOR WIND ALGORITHM ADAPTATION TO SMAP; AND 2) AN EXTENSIVE WIND VALIDATION BASED ON COLLOCATED PRODUCTS FROM OTHER SATELLITES AND INSTRUMENTS, INCLUDING THE AIRBORNE STEP FREQUENCY MICROWAVE RADIOMETER (SFMR), NCEP GDAS, AND MEASUREMENTS FROM MOORED BUOYS. EACH SMAP RETRIEVED OCEAN VECTOR WIND WE PRODUCE WILL BE ACCOMPANIED BY A QUANTITATIVE ESTIMATE OF ITS RANDOM AND SYSTEMATIC UNCERTAINTIES, WHOSE VALUES WE OBTAIN BY RUNNING THE RETRIEVAL ALGORITHM WITH PERTURBED CONDITIONS. AN ATBD DESCRIBING DETAILS OF THE ALGORITHM STEPS WILL BE PRODUCED AS WELL AS A VALIDATION REPORT AND SCIENTIFIC PAPERS DESCRIBING OUR RESULTS AND PRODUCTS. THE WIND DATA WILL BE DISTRIBUTED TO THE SCIENTIFIC COMMUNITY THROUGH WEB AND FTP SITES. USER SUPPORT WILL BE PROVIDED. OUR PROPOSED VECTOR WIND RETRIEVAL ALGORITHM WILL INGEST ONLY SMAP RADIOMETER BRIGHTNESS TEMPERATURE MEASUREMENTS WITHOUT USING RADAR DATA. PART OF THE STUDY WILL INCLUDE EVALUATING THE LIMITED TIME PERIOD OVER WHICH RADAR BACKSCATTER MEASUREMENTS WERE AVAILABLE AND ASSESS THE PERFORMANCE ENHANCEMENT IN OCEAN VECTOR WIND RETRIEVALS THAT CAN BE OBTAINED BY COMBINING ACTIVE AND PASSIVE SMAP MEASUREMENTS.