Evaluating Snow Melt Onset Date in the United States using Satellite Observation of Passive Microwave Temperature Brightness

Abstract:

The timing and magnitude of Spring snowmelt events impact riverine flooding and inform reservoir operations. While the melt water volume is a primary concern, the timing of the snowmelt is also important. Melt timing determination is challenging because snowpack ripening observations are seldom available. Diurnal Amplitude Variation (DAV) is a method that uses remotely sensed passive microwave observations to determine snowpack ripening and snowmelt onset. Previous studies have successfully used the DAV method in northern latitudes. This study evaluates the ability of the DAV approach to be used to determine melt onset dates in mid-latitudes. The analysis is conducted for 675 Soil Climate Analysis Network (SCAN) and Snow Telemetry (SNOTEL) stations in the United States. The Special Sensor Microwave Imager (SSM/I) and Advanced Microwave Scanning Radiometer – EOS (AMSR-E) products are used to calculate the DAV signal at each location. Methods for determining the melt onset date at each station are presented and applied to all pixels in the United States. Preliminary results will also be presented which characterize the DAV derived melt onset timing for the United States using the long-term SSM/I record.