WE PROPOSE TO USE THE HIGHEST-QUALITY AND COMPLEMENTARY PRECIPITATION DATA FROM TRMM PRECIPITATION RADAR CLOUDSAT AND AMSR-E ON AQUA TO CREATE A REFERENCE PRECIPITATION DATASET TO IDENTIFY QUANTIFY DIAGNOSE AND REDUCE UNCERTAINTIES IN THE PRECIPITATION OBSERVATIONAL RECORD. WE WILL FOCUS ON TWO AREAS WITH MAJOR UNCERTAINTIES IN THE GLOBAL PRECIPITATION CLIMATOLOGY PROJECT (GPCP) RECORD: HIGH LATITUDES AND OCEANIC REGIONS (ADLER ET AL. 2012). WE WILL ESTABLISH OCEAN AND HIGH LATITUDE BASELINE FOR THE LONGER-TERM GPCP RECORD FOR COMPARISONS AND ADJUSTMENT.