SPATIOTEMPORAL PATTERNS IN GROUND-BASED SNOW REMOTE SENSING AND IN-SITU OBSERVATIONS: ANALYSIS OF CLPX-II, COREH2O, AND SNOWEX Y1 DATA FOR SAMPLING DESIGN AND SITE SELECTION

SPATIOTEMPORAL PATTERNS IN GROUND-BASED SNOW REMOTE SENSING AND IN-SITU OBSERVATIONS: ANALYSIS OF CLPX-II COREH2O ANDSNOWEX Y1 DATA FOR SAMPLING DESIGN AND SITE SELECTIONOVER 2 BILLION PEOPLE WORLDWIDE DEPEND ON SNOW-MELT FOR WATER SUPPLY. ESTIMATING THE SNOW WATER EQUIVALENT (SWE)- THE AMOUNT OF FRESH WATER THAT A GIVEN AREA OF SNOW REPRESENTS - IS REQUIRED FOR WATER RESOURCE MANAGEMENT HYDRO-POWER AND FLOOD FORECASTING. INCREASES IN TEMPERATURE AND PRECIPITATION WILL SIGNIFICANTLY ALTER THE DISTRIBUTION OF SNOW GREATLY COMPLICATING PREDICTION OF THIS ALREADY POORLY UNDERSTOOD BUT IMPORTANT WATER RESOURCE. ESTIMATING SWE USING REMOTE SENSING TECHNIQUES REMAINS PROBLEMATIC AS MANUAL GROUND-TRUTH MEASUREMENTS IN TYPICALLY HIGHLY VARIABLE SNOW CONDITIONS ARE TIME-CONSUMING. MICROWAVE REMOTE SENSING HAS GREAT POTENTIAL FOR GIVING SCIENTISTS AND PRACTITIONERS INFORMATION ABOUT SWE AT A GLOBAL SCALE THROUGHOUT THE YEAR HOWEVER CURRENTLY THERE DOES NOT EXIST AN OPERATIONAL SWE PRODUCT IN THE MOUNTAINOUS REGIONS WHERE MOST OF THE WATER IS STORED. ONE OF THE MAIN LIMITATIONS THAT HAS CHALLENGED PREVIOUS MICROWAVE REMOTE SENSING EFFORTS IN MOUNTAINOUS TERRAIN HAS BEEN DIFFERENCES IN SCALE BETWEEN THE LARGE SPACEBORNE FOOTPRINTS AND THE POINT IN-SITU OBSERVATIONS. GROUND-BASED REMOTE SENSING (GBRS) PROVIDES A CRITICAL LINK BETWEEN IN-SITU POINT MEASUREMENTS AND AIR/SPACEBORNE OBSERVATIONS. ACTIVE AND PASSIVE MICROWAVE GBRS INSTRUMENTS HAVE SMALL FOOTPRINTS WHICH REMOVE THE COMPLEXITIES OF SUB-PIXEL HETEROGENEITY AND ALLOW HIGH-RESOLUTION SPATIAL OBSERVATIONS TO BE USED TO STUDY SCALING EFFECTS. THEY ALSO CAN BE OPERATED CONTINUOUSLY FROM A TOWER PROVIDING A TEMPORAL CONTEXT FOR SNAP-SHOT AIRBORNE AND SPACEBORNE MICROWAVE MEASUREMENTS. THIS PROJECT WILL LEVERAGE LARGE SPATIOTEMPORAL DATABASES OF GROUND-BASED REMOTE SENSING (GBRS) AND IN-SITU OBSERVATIONS COLLECTED AS PART OF NUMEROUS SNOW REMOTE SENSING EFFORTS (NASA CLPX-II CLPX-III WISM SNOWEX ESA COREH2O CRYOSAT). DATABASES WERE COLLECTED USING GROUND-BASED MICROWAVE RADARS AND RADIOMETERS COVERING A WIDE RANGE OF SENSOR PARAMETERS AND IN A WIDE RANGE OF WELL-CHARACTERIZED SNOWPACK CONDITIONS SPANNING THE SPATIAL AND TEMPORAL VARIABILITY OF SNOW COMMONLY OBSERVED IN BOTH MOUNTAINOUS AND ARCTIC ENVIRONMENTS. THIS PROJECT IS LOW RISK AND OFFERS A LARGE BENEFIT AT LOW COST AS THE DATA HAVE ALREADY BEEN COLLECTED. THIS WORK WILL RESULT IN SPATIAL AND TEMPORAL ANALYSIS OF GMRS AND IN-SITU DATASETS COVERING THE RANGE OF SNOW CLIMATES WILL DEFINE REQUIREMENTS FOR FIELD SITES FOR FUTURE SNOW REMOTE SENSING EFFORTS AND WILL DESIGN OPTIMAL SAMPLING STRATEGIES THAT DEPEND ON SITE LOCATION AND TIME OF YEAR.