MOTIVATION: COMPREHENSIVE MEASUREMENT OF CHANGE IN THE AMOUNT OF LAND-BASED ICE IS REQUIRED TO ESTIMATE THE CRYOSPHERIC IMPACT ON SEA LEVEL AND NASA HAS INVESTED HEAVILY IN MULTIPLE MEASUREMENT STRATEGIES TO ACHIEVE THIS. MAXIMIZING USE OF THE RESULTING TIME SERIES REQUIRES CLOSING THE TIME-VARYING ICE MASS BUDGET UNDERLYING EACH MEASURED GEOPHYSICAL SIGNAL. TIME-VARYING DISCHARGE OF ICE IS A CRITICAL COMPONENT OF THAT BUDGET. WE HAVE BUILT A PROCESSING SYSTEM LEVERAGING THE LANDSAT RECORD ESPECIALLY THE DENSE SPACE AND TIME SAMPLING OF LANDSAT 8 THAT IS CAPABLE OF PRODUCING A GLOBAL RECORD OF TIME-VARYING ICE FLOW. WE CAN NOW SYSTEMATICALLY MAP ICE FLOW ACROSS MULTIPLE TIMESCALES GLOBALLY REMOVING TIME-VARYING ICE FLOW AND ITS IMPACT ON DISCHARGE FROM THE LIST OF UNKNOWNS THAT MAKES CLOSING MASS BUDGETS A CHALLENGE.APPROACH: LANDSAT 8 ACQUIRES BY FAR THE MOST DENSELY TIME-SAMPLED IMAGE ARCHIVE OF LAND ICE AT DECAMETER SCALE YET AVAILABLE. AS DESCRIBED BELOW OUR TEAM HAS DEVELOPED A SET OF PROCESSING CHAINS FOR THESE DATA AND EARLIER LANDSAT IMAGERY BASED ON IMAGE PAIR CORRELATION. IMPROVEMENTS IN COMPUTING SPEED GEOLOCATION AND ENHANCEMENT OF RADIOMETRIC SENSITIVITY RESULT IN SIGNIFICANTLY IMPROVED THROUGHPUT AND HIGHLY ACCURATE ICE FLOW MAPS. WE CAN NOW EXTRACT A DETAILED GLOBAL NEAR-REAL-TIME RECORD OF ICE FLOW VARIATION FROM JUNE 2013 ONWARD FOR ALL SIGNIFICANT GLACIERS AND ICE SHEET OUTLET AREAS (WIDER THAN 500 M) AND AT THE SAME TIME PRODUCE AN INTERNALLY CONSISTENT RECORD OF PAST FLOW CHANGES OVER THE LENGTH OF THE LANDSAT RECORD (TM ETM+ AND OLI: 1984- PRESENT).INNOVATION: IT WAS NOT PREVIOUSLY POSSIBLE TO UNIFORMLY DOCUMENT ICE FLOW VARIATIONS ON A GLOBAL SCALE. THE LANDSAT 8 DATA STREAM AND OUR PROCESSING SYSTEM ALLOW US TO EXTRACT A RECORD OF ICE FLOW VARIATION THAT IS COMPLEMENTARY TO INSAR RECORDS AND IS MORE DENSELY TIME SAMPLED. WE WILL PROCESS NEW IMAGES AS THEY ARE ACQUIRED UPDATING OUR PICTURE OF ICE FLOW VARIATIONS IN NEAR REAL-TIME. ONE-QUARTER OF THE REQUESTED PROJECT SUPPORT IS TARGETED AT BUILDING A WEB-BASED ACCESS SYSTEM AT NSIDC SO THE ICE VELOCITY DATA CAN BE AVAILABLE TO THE COMMUNITY IN NEAR REAL TIME (A FIVE-DAY DELAY IS ENVISIONED POSSIBLY LESS). OUR WORK WILL BE THE FIRST GLOBAL DOCUMENTATION OF ICE FLOW VARIABILITY ACROSS MULTIPLE TIMESCALES. WE WILL USE THIS RECORD TO: 1) CHARACTERIZE THE ICE FLOW PATTERN AND ICEFLUX FROM THE LARGE ICE SHEETS AND TRACK AREAS OF CHANGE 2) MAP THE MAGNITUDE SPATIAL EXTENT AND TIMING OF SEASONAL CHANGES IN GLACIER FLOW AND PATTERNS OF VELOCITY CHANGE VERSUS TIME ACROSS ACCELERATING OUTLET SYSTEMS AND 3) PRODUCE AN INTERNALLY-CONSISTENT ICE FLOW RECORD ACROSS THE LANDSAT MISSIONS TO ADD EXTENSIVELY TO THE AVAILABLE INSAR ICE FLOW HISTORY. VALUE TO NASA CRYOSPHERIC SCIENCE: THE RESULTING MAPS OF ICE FLOW CHANGE WILL ISOLATE THE IMPACT OF FLOW-RELATED THINNING ON ALTIMETRY AND TIME-VARYING GRAVITY RECORDS AN IMPORTANT STEP IN DECONVOLVING CHANGING FLOW AND SURFACE MASS BUDGET SIGNALS. OUR WORK WILLCOMPREHENSIVELY LEVERAGE THE LANDSAT ARCHIVE DELIVER A SYSTEMATIC VIEW OF ICE FLOW VARIATIONS AND CREATE ICE FLOW VARIATION RECORDS FROM LANDSAT 8 ACCESSIBLE TO THE COMMUNITY IN NEAR REAL TIME THAT WILL CAPTURE ALL FUTURE CHANGES IN DISCHARGE. SUCH A RECORD IS FUNDAMENTAL TO UNDERSTANDING THE MASS BUDGETS OF LAND-BASED ICE THAT UNDERLIE ACTIVE AND PROPOSED MEASUREMENT CAMPAIGNS BYICEBRIDGE ICESAT-2 CRYOSAT-2 GRACE AND THE GRACE FOLLOW ON MISSION.