Integration of the MODIS Snow Cover Products into Snowmelt Runoff Modeling

TitleIntegration of the MODIS Snow Cover Products into Snowmelt Runoff Modeling
Publication TypeConference Proceedings
Year of Conference2006
AuthorsRice, R., Painter T. H., and Bales R.
Conference Name74th Annual Western Snow Conference
Series TitleProceedings of the 74th Annual Western Snow Conference
Date PublishedApril 2006
PublisherWestern Snow Conference
Conference LocationLas Cruces, NM
KeywordsSatellite, snow covered area, SCA, MODIS, scanning radiometer, fractional snow cover, MODSCAG

Use of recently developed satellite snow covered area (SCA) products as quantitative inputs to hydrologic models require resolution of temporal noise, introduced owing to varying satellite viewing angles. For MODIS , a NASA space-borne scanning radiometer, which receives the electromagnetic radiation reflected or emitted by the earth and atmosphere, requires a multiple endmember spectral mixture analysis model, inverting MODIS surface reflectance products (MOD09) for enhanced fractional snow cover, plus the grain size and albedo of the fractional snow cover. However, to accurately incorporate SCA into snowmelt runoff models requires the resolution of a temporal inconsistent fractional snowcover product. Inconsistencies in the MODIS fractional SCA product results from daily differences in the local sensor view angle which ranges between 0-65 degrees. These daily differences in the radiometer scan angle can result in a 30% occlusion of snowcover over forest covered areas, and a proportional variation in SCA estimates. Results are presented that resolve the temporal inconsistencies from the forest occlusion of snowcover by using empirical corrections based on forest canopy densities. The empirical corrections result in a temporal consistent fractional SCA product for development of a composite spatial map that blends the MODIS fractional SCA product with interpolated snow water equivalence (SWE). This tool, the MODIS Snow Covered Area and Grain Size/Albedo (MODSCAG) model, specifically provides an accurate estimate of snowcover and albedo for regional studies in mountainous areas. (Abstract only)