Airborne Snow Observatory: Next Generation of Basin Snow Measurement, Modeling, and Forecasting

The Airborne Snow Observatory (ASO) demonstration mission will collect detailed basin-wide snow information for portions of the Tuolumne Basin in California and the Uncompahgre Basin in Colorado in spring of 2013. The ASO uses an imaging spectrometer and LiDAR system mounted in an aircraft for collecting data allowing determination of snow water equivalent, snow depth, and snow albedo. Weekly flights over the Tuolumne will produce both basin-wide and detailed sub-basin SWE estimates that will be used in a hydrologic simulation model to improve the accuracy and timing of runoff forecasting tools used to manage Hetch Hetchy Reservoir, the source of 85% of the water supply for 2.5 million people on the San Francisco Peninsula. The USGS PRMS simulation model will be calibrated to the 459 square mile basin and will be updated at weekly time steps with both weather forecast data and distributed snow information from ASO flights to inform the reservoir operators of predicted inflow volumes and timing. Information produced by the ASO data collection and PRMS modeling is expected to improve the ability of reservoir operators to more efficiently allocate the last half of the recession limb of snowmelt inflow and be more assured of meeting operational mandates. This presentation will provide preliminary results from the project as it begins its first year.