Variability in Sublimation in the Upper Colorado River Basin

Snowpack is the primary source of water for the population and environment of much of the western United States, and the loss of water through direct evaporation is a significant factor in the amount of runoff realized from snow melt. A land surface modeling study was carried out in order to quantify the magnitude of inter-annual and spatial variability of sublimation over a large mountain basin in North America. This was accomplished through the use of a spatially distributed snow-evolution model known as SnowModel, which has been used in many other applications of land-atmosphere interactions to investigate energy and mass fluxes associated with snow processes. SnowModel is capable of calculating both surface and blowing snow sublimation, and provides a comprehensive tool for estimating sublimated water loss from the snow-pack. The simulations relied on forcing from high resolution atmospheric analysis data from the North American Land Data Assimilation System (NLDAS). These data were used to simulate snow sublimation for several years over a 400 by 400 km domain in the Upper Colorado River Basin at a horizontal resolution of 250 m. Some results from this study will be presented and characteristics of model performance discussed.