AGRICULTURAL WATER SUPPLIES IN CALIFORNIA ARE HEAVILY DEPENDENT ON NATURAL WATER STORAGE IN THE THE SIERRA NEVADA SNOWPACK WHICH STORES APPROXIMATELY 14 MILLION ACRE FEET (~17 KM3) OF WATER ANNUALLY. SNOWMELT FROM THIS NATURAL STORAGE FILLS RESERVOIRS IN THE SACRAMENTO AND SAN JOAQUIN RIVER VALLEYS EQUIVALENT TO 13.5 AND 11.5 MILLION ACRE FEET RESPECTIVELY. DEMANDS ON THESE SOURCES OF WATER STORAGE MEET OR EXCEED SUPPLY UNDER NORMAL CLIMATIC CONDITIONS. THE RECENT CALIFORNIA DROUGHT SIGNIFICANTLY REDUCED THIS NATURAL WATER STORAGE LEADING TO SIGNIFICANT WATER SUPPLY-DEMAND IMBALANCES THAT HAVE HAD PROFOUND ECONOMIC AND SOCIETAL IMPACTS. THE CURRENT DROUGHT IS THE MOST SEVERE ON RECORD WITH FOUR CONSECUTIVE YEARS OF SIGNIFICANTLY BELOW NORMAL SNOWPACK (E.G.<10% OFAVERAGE IN 2015) AND ABOVE AVERAGE AIR TEMPERATURE. THE CALIFORNIA FARM WATER COALITION APPROXIMATED THAT THE CURRENT DROUGHT HAS RESULTED IN 800 000 ACRES OF FALLOWED FARMLAND NEARLY 10 PERCENT OF THE STATES AGRICULTURAL LAND. MOREOVER IT IS ESTIMATED THAT EVENUE FOR THE STATES $45 BILLION AGRICULTURE INDUSTRY DECREASED BY $2.7 BILLION IN 2015 ALONE. DESPITE THE CONSIDERABLE ATTENTIONFOCUSED ON DROUGHT IN CALIFORNIA LITTLE WORK HAS BEEN DONE TO EVALUATE TIPPING POINTS IN SURFACE WATER SUPPLY - WATER DEMAND IMBALANCES THAT LEAD TO CHANGES IN LAND USE.USING MODIS-BASED SNOW WATER EQUIVALENT (SWE) ESTIMATES AND LANDSAT AND MODIS-BASED ET ESTIMATES FROM THE NASA SATELLITEIRRIGATION MANAGEMENT SUPPORT PROJECT (SIMS) FROM 2000 THROUGH THE FUNDING CYCLE (I.E. 2019); THE PRIMARY OBJECTIVE OF THIS RESEARCH IS TO PROVIDE SATELLITE-BASED TOOLS FOR EVALUATING AGRICULTURAL WATER SUPPLY-DEMAND IMBALANCES DURING EXTREME DROUGHT CONDITIONS. RELATED SECONDARY AND TERTIARY OBJECTIVES AIM TO: MIGRATE REMOTELY SENSED SWE AND ET ANALYSES INTO CA DWR COMPUTATIONALENVIRONMENT; AND TO CONDUCT QUANTITATIVE AND QUALITATIVE ASSESSMENT OF THE UTILITY OF THE SIMS ET AND MODIS-BASED SNOWPACK INFORMATION WITH REGARD TO INFORMING WATER RESOURCE DECISIONS DURING DROUGHT. THE PROPOSED RESEARCH FOCUSES ON INGESTION OF REMOTELY SENSED OBSERVATIONS WITHIN OPERATIONAL MODELS USED BY THE CA DWR. THE FOLLOWING QUESTIONS WILL BE ADDRESSED:1) CAN SATELLITE-BASED ESTIMATES OF AGRICULTURAL WATER SUPPLY-DEMAND IMBALANCES IMPROVE WATER RESOURCE DECISION MAKING UNDER DROUGHT CONDITIONS?2) ARE RELATIVE IMPROVEMENTS TO WATER SUPPLY-DEMAND INFORMATION PROVIDED BY REMOTELY SENSED DATA GREATER DURING ANOMALOUS CONDITIONS SUCH AS THE CURRENT CALIFORNIA DROUGHT?3) WHAT IS THE UTILITY OF SATELLITE-BASED INFORMATION FOR WATER RESOURCE DECISION MAKING?THE PROPOSED WORK IS HIGHLY RELEVANT TO THIS ANNOUNCEMENT IN THAT WE WILL CHARACTERIZE ANOMALIES IN WATER SUPPLY AND DEMAND CONDITIONS USING A COMBINATION OF NASA SATELLITE OBSERVATIONS AND NASA PHYSICALLY BASED LAND SURFACE MODELS. THESE EFFORTS WILL BE DIRECTLY LINKED TO EXISTING WATER SUPPLY FORECAST PROCEDURES AT THE CA DWR AND THE DEMAND-RELEVANT DECISIONS WHICH DERIVE FROM THESE FORECASTS. OUR EXISTING PARTNERSHIP WITH CA DWR WILL ENSURE THE INTEGRATION OF THE PROJECT RESULTS INTO THE DECISION MAKINGPROCESS. MOREOVER THE PARTICIPATION OF EXPERT IN STAKEHOLDER DECISION SUPPORT WILL ENSURE CONTINUAL ITERATION BETWEEN RESEARCHERS AND STAKEHOLDERS. THE PROPOSED RESEARCH IS ALSO HIGHLY RELEVANT TO BROADERNASA STRATEGIC GOALS BY CONNECTING IMPROVED UNDERSTANDING OF EARTH SYSTEM SCIENCE (I.E. SNOW DISTRIBUTION AND ET) TO MITIGATION OF AND ADAPTATION TO GLOBAL CHANGE.