GLOBAL AND REGIONAL CHANGES IN THE DISTRIBUTION OF TERRESTRIAL WATER OF GREAT IMPORTANCE TO MANY OF THE THEMES IN THE NATIONAL CLIMATE ASSESSMENT HAVE TRADITIONALLY BEEN CHALLENGING TO MEASURE. RECENT TIME-VARYING GRAVITY MEASUREMENTS FROM NASA'S GRAVITY RECOVERY AND CLIMATE EXPERIMENT (GRACE) MISSION HAVE MADE POSSIBLE NEW ESTIMATES OF TERRESTRIAL WATER STORAGE BY SENSING WATER MASS CHANGES DIRECTLY BUT THESE DATA HAVE RELATIVELY LOW SPATIOTEMPORAL RESOLUTION AND LONG LATENCIES LIMITING THEIR USE IN PRACTICAL APPLICATIONS SUCH AS WATER RESOURCE MANAGEMENT AND CLIMATE PREDICTION. AT THE SAME TIME RESEARCH OVER THE PAST DECADE AND A HALF HAS SHOWN THAT THE GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS) CAN DETECT SURFACE DISPLACEMENTS DUE TO SEASONAL AND LONGER-TERM CHANGES IN WATER LOADING AT REGIONAL TO GLOBAL SCALES. WE PROPOSE TO USE GNSS DATA FROM NASA'S SESES PROGRAM TO PRODUCE A SET OF DATA PRODUCTS THAT MAP TERRESTRIAL WATER STORAGE CHANGES OVER THE CONTINENTAL UNITED STATES AT UNRIVALED SPATIOTEMPORAL RESOLUTION WITH LATENCIES OF ONE WEEK OR LESS. WE WILL CROSS-VALIDATE THESE PRODUCTS AGAINST SIMILAR ESTIMATES FROM GRACE AND PRODUCE A COMBINED PRODUCT THAT LEVERAGES THE STRENGTHS OF BOTH DATASETS. FINALLY WE WILL EXPERIMENT WITH USING SURFACE WATER DATA AND HIGH-LEVEL DATA PRODUCTS FROM NASA'S UPCOMING SOIL MOISTURE ACTIVE PASSIVE (SMAP) MISSION TO ATTEMPT TO DISAGGREGATE CHANGES IN SURFACE AND NEAR-SURFACE WATER FROM THAT OF GROUNDWATER. OUR GOAL IS TO USE CUTTING-EDGE METHODS AND THE BEST AVAILABLE DATA TO PRODUCE UNPRECEDENTEDLY DETAILED TERRESTRIAL WATER STORAGE ESTIMATES FOR THE UNITED STATES FROM 2005 TO THE PRESENT IN NEAR-REAL TIME AND SPATIALLY AGGREGATED ON MULTIPLE SCALES TO MEET THE NEEDS OF DIFFERENT USERS. WE WILL ALSO BUILD THE CYBER-INFRASTRUCTURE NEEDED FOR PRODUCING THESE PRODUCTS ON AN ONGOING BASIS AND FOR DELIVERING PRODUCTS AND VISUALIZATIONS TO ALL STAKEHOLDERS IN THE NATIONAL CLIMATE ASSESSMENT EFFORT.