Quantification and Analysis of Greenland Glacier and Ice Cap Discharge using Automated Landsat Terminus Change Time Series and NASA Data Products

OVERVIEW: THE OVERALL OBJECTIVES OF THE PROPOSED PROJECT ARE TO 1) DEVELOP AND VALIDATE AN AUTOMATED TERMINUS TRACKING ALGORITHM FOR LANDSAT OPTICAL IMAGERY AND 2) QUANTIFY ICE DISCHARGE FROM GREENLAND S PERIPHERAL GLACIERS AND ICE CAPS (GICS) USING THE GENERATED TERMINUS CHANGE TIME SERIES HIGH-RESOLUTION DIGITAL ELEVATION MODELS AND NASA DATASETS. THE DEVELOPMENT OF AN AUTOMATED TERMINUS TRACKING ALGORITHM WILL ENABLE THE EFFICIENT CONSTRUCTION OF TERMINUS CHANGE TIME SERIES FOR MARINE-TERMINATING GLACIERS WORLDWIDE WITHOUT THE NEED FOR TIME-CONSUMING AND SUBJECTIVE MANUAL TERMINUS TRACING. THE TERMINUS CHANGE TIME SERIES WILL BE COMBINED WITH ICE FLUX ESTIMATES TO GENERATE ICE DISCHARGE TIME SERIES FOR GREENLAND S GICS. THE DISCHARGE TIME SERIES WILL BE PAIRED WITH SURFACE MASS RUNOFF ESTIMATES TO CONSTRUCT THE FIRST PARTITIONED MASS LOSS TIME SERIES FOR GREENLAND S GICS. ANALYSIS OF DYNAMIC CHANGE PATTERNS FOR GREENLAND S GICS WITH RESPECT TO ATMOSPHERIC AND OCEANIC CONDITIONS AS WELL AS ICE SHEET OUTLET GLACIER DISCHARGE WILL YIELD INSIGHTS ON VARIATIONS IN DYNAMIC MASS LOSS FROM MARINE-TERMINATING GLACIERS. APPROACH: AN AUTOMATED ALGORITHM THAT EXPLOITS IMAGE INTENSITY GRADIENTS TO AUTOMATICALLY SEGMENT IMAGES CALLED THE 2D WAVELET- TRANSFORM MODULUS MAXIMA APPROACH WILL BE USED TO DELINEATE GLACIER TERMINUS POSITIONS IN CLOUD-FREE OPTICAL LANDSAT IMAGES. THE ALGORITHM WILL BE USED TO CONSTRUCT SUB-ANNUAL TERMINUS POSITION TIME SERIES FOR>600 PERIPHERAL MARINE-TERMINATING GLACIERS SPANNING THE GREENLAND PERIPHERY. THE RESULTS OF THE AUTOMATED APPROACH WILL BE VALIDATED USING MANUALLY-TRACED TERMINUS MAPS. THE TERMINUS CHANGE TIME SERIES WILL BE PAIRED WITH NASA GOLIVE AND MEASURES SURFACE SPEED TIME SERIES AND ICE THICKNESS ESTIMATES TO CONSTRUCT TIME SERIES OF ICE DISCHARGE FROM GREENLAND S GICS. NASA ICEBRIDGE RADAR OBSERVATIONS WILL BE USED TO DIRECTLY ESTIMATE ICE THICKNESS WHEN AND WHERE THEY ARE AVAILABLE AS WELL AS TO DEVELOP THICKNESS-SCALING PARAMETERIZATIONS IN REGIONS WHERE NO THICKNESS ESTIMATES EXIST. SPATIAL PATTERNS AND TEMPORAL TRENDS IN GREENLAND GIC ICE DISCHARGE WILL BE COMPARED TO VARIATIONS IN GREENLAND ICE SHEET DISCHARGE RACMO SURFACE MELTWATER RUNOFF ESTIMATES NASA OCEANS MELTING GREENLAND DATASETS AND NOAA SEA ICE CONCENTRATION DATASETS. VALUE TO NASA: TERMINUS CHANGE TIME SERIES ARE OFTEN USED AS A METRIC TO INFER CHANGES IN GLACIER DYNAMICS FROM READILY AVAILABLE OBSERVATIONAL DATA AND AS A MEANS TO VALIDATE THE PERFORMANCE OF NUMERICAL ICE FLOW MODELS. MANUAL TERMINUS CHANGE TRACKING IS A TEDIOUS PROCESS THAT IS OFTEN REPEATED BY MULTIPLE INVESTIGATORS AT DIFFERENT INSTITUTIONS. THE TERMINUS TRACKING ALGORITHM DEVELOPED FOR THIS PROJECT WILL REPRESENT A STEP ADVANCE IN OUR ABILITY TO EFFICIENTLY MEASURE CHANGES IN GLACIER LENGTH USING OPTICAL SATELLITE IMAGES WHICH IS VALUABLE FOR THE OBSERVATIONAL ANALYSIS OF MODERN CHANGES IN GLACIER DYNAMICS FOR GREENLAND S GICS HERE AND FOR FUTURE ANALYSES OF MARINE-TERMINATING GLACIERS ACROSS THE GLOBE. THE ICE DISCHARGE AND RACMO RUNOFF TIME SERIES WILL BE USED TO CONSTRUCT A NEARLY TWO DECADE-LONG RECORD OF MASS LOSS FROM GREENLAND GICS DIRECTLY ADDRESSING THE NASA CRYOSPHERIC SCIENCE PROGRAM OBJECTIVE TO [S]TUDY POLAR AND NONPOLAR MOUNTAIN GLACIERS AND SMALL ICE CAPS TO UNDERSTAND SYSTEMATIC IMPACTS OF GLOBAL CHANGE AND CONTRIBUTIONS TO SEA LEVEL RISE. IF WE TREAT GREENLAND GICS AS ANALOGS FOR THE ICE SHEET S MARINE-TERMINATING GLACIERS AS THEY RECEDE FROM THEIR DEEP MARINE TROUGHS IN THE COMING DECADES THEN THE RESPONSE OF GREENLAND GICS TO ATMOSPHERIC AND OCEANIC CHANGE REVEALED BY THIS STUDY WILL ALSO YIELD VALUABLE INSIGHTS INTO CHANGES IN DYNAMIC MASS LOSS FROM THE GREENLAND ICE SHEET IN THE COMING DECADES. THUS THIS PROJECT ALSO CONTRIBUTES TO THE NASA CRYOSPHERIC SCIENCE PROGRAM OBJECTIVE TO IMPROVE OUR UNDERSTANDING OF THE MECHANISMS CONTROLLING THE MASS BALANCE AND DYNAMICS OF THE GREENLAND ICE SHEET .