WE PROPOSE TO INVESTIGATE THE DYNAMIC RESPONSE OF THE INTERIOR GREENLAND ICE SHEET TO RECENT RETREAT AND ACCELERATION OF COASTAL OUTLET GLACIERS WITH THE OBJECTIVE OF IMPROVING PREDICTIONS OF THE CONTRIBUTION OF THE ICE SHEET TO SEA LEVEL RISE. OUR APPROACH INTEGRATES OBSERVATIONS FROM REMOTE SENSING, FIELD MEASUREMENTS AND NUMERICAL ICE-FLOW MODELING. USING MULTIPLE SOURCES OF REPEAT-ALTIMETER DATA AND SUPPORTING SURFACE ACCUMULATION AND FIRN COMPACTION RATE MODEL OUTPUT, WE WILL CONSTRUCT ANNUAL, ICE SHEET-WIDE MAPS OF ICE THINNING DUE TO CHANGES IN FLOW DYNAMICS (I.E. DYNAMIC THINNING). REMOTE-SENSING DERIVED MAPS WILL BE AUGMENTED WITH FIELD-DERIVED MEASUREMENTS OF DYNAMIC THINNING, FIRN COMPACTION AND SURFACE ACCUMULATION FROM THE CATCHMENTS OF TWO RAPIDLY-CHANGING OUTLET GLACIERS (JAKOBSHAVN AND KANGERDLUGSSUAQ). FIELD OBSERVATIONS WILL ALSO BE USED TO ASSESS THE ABILITY OF AIR AND SPACEBORNE REPEAT-ALTIMETRY TO RESOLVE DYNAMIC THINNING. REMOTE SENSING AND FIELD OBSERVATIONS WILL BE USED TO CONSTRAIN A NUMERICAL ICE FLOW MODEL THAT WILL SIMULATE THE RESPONSE OF THE INTERIOR ICE SHEET TO OBSERVED PERTURBATIONS IN OUTLET GLACIER FLUX. WE WILL USE THIS MODEL TO (1) INVESTIGATE HOW GEOMETRY AND OTHER GLACIOLOGICAL CHARACTERISTICS OF OUTLET GLACIERS AND THEIR CATCHMENTS REGULATE THEIR DYNAMIC RESPONSE TO PERTURBATIONS AT THEIR FRONTS AND (2) ESTIMATE THE CONTRIBUTION OF CHANGES IN ICE SHEET DYNAMICS TO SEA LEVEL RISE BY 2100 FOR A RANGE IN POSSIBLE FORCING SCENARIOS OUR PROPOSAL DIRECTLY ADDRESSES THE OBJECTIVE OF THE NRA TO ADVANCE UNDERSTANDING OF LAND-ICE PROCESSES, ESPECIALLY ... DETERMINING HOW THE ICE SHEET INTERIOR IS TAPPED BY OUTLET GLACIERS AND MAKES EXTENSIVE USE OF NASA DATA, INCLUDING ICEBRIDGE REPEAT-ALTIMETRY DATA. THE SCIENCE DELIVERABLES OF THIS STUDY WILL INCLUDE (1) INTEGRATED, GRIDDED MEASUREMENTS OF SURFACE ELEVATION CHANGE INTO A SINGLE, ANNUAL TIME SERIES, (2) CALIBRATION AND VALIDATION OF RADAR ALTIMETER MEASUREMENTS OVER ICE SHEETS (INCLUDING THE NEWLY-LAUNCHED SIRAL ABOARD CRYOSAT-2), (3) CONSTRAINTS ON THE CAPABILITIES AND UNCERTAINTY OF MEASURING DYNAMIC THINNING WITH ALTIMETRY TO AID IN MISSION PLANNING (SUCH AS ICEBRIDGE, ICESAT-2 AND DESDYNI), (4) A QUANTITATIVE DESCRIPTION OF THE GLACIOLOGICAL CONTROLS ON ICE SHEET DYNAMIC SENSITIVITY TO OUTLET GLACIER CHANGE AND (5) ESTIMATES OF THE DYNAMIC COMPONENT OF ICE SHEET CONTRIBUTIONS TO SEA LEVEL BY 2100.