A snow-transport model for complex terrain

As part of the winter environment in middle- and high-latitude regions, the interactions between wind, vegetation, topography and snowfall produce sno w covers of non-uniform depth and snow water-equivalent distribution. A phy sically based numerical snow-transport model (SnowTran-3D) is developed and used to simulate this three-dimensional snow-depth evolution over topograp hically variable terrain. The mass-transport model includes processes relat ed to vegetation snow-holding capacity, topographic modification of wind sp eeds, snow-cover shear strength, wind-induced surface-shear stress, snow tr ansport resulting from saltation and suspension, snow accumulation and eros ion, and sublimation of the blowing and drifting snow. The model simulates the cold-season evolution of snow-depth distribution when forced with input s of vegetation type and topography, and atmospheric forcings of air temper atures, humidity, wind speed and direction, and precipitation Moder outputs include the spatial and temporal evolution of snow depth resulting from va riations in precipitation, saltation and suspension transport, and sublimat ion. Using 4 years of snow-depth distribution observations from the foothil ls north of the Brooks Range in Arctic Alaska, the model is found to simula te closely the observed snow-depth distribution patterns and the interannua l variability.