ENSEMBLE MODELING OF SWE DISTRIBUTION IN THE BITTERROOT MOUNTAINS, MONTANA, USA
The spatial distribution of snow remains poorly understood at the landscape scale, particularly at high elevation where snow can be under-represented by our current system of monitoring. The transferability of the processes and physiography that drive the spatial distribution of snow require further study. We apply an ensemble of three semi-independent snow models to the down-sloping side of the Bitterroot Mountains of Western Montana, which features an array of drainages of remarkably similar size and aspect. We modeled the snow water equivalent equal to the maximum snow accumulation plus any positive contributions to the snowpack during the melt season, for the years 2000-2010. The three models yield similar magnitudes and patterns of snow water equivalent distribution. We find that upwards of 70% of the snow water equivalent is found above the elevation of 1950 meters and this snow water equivalent is represented by a single SNOTEL station within our 1200 km2 study area. The difference in snow water equivalent on north and south facing aspects within in individual drainages is found to be small. At lower elevations snow water equivalent increases with elevation, while above the elevation of 2000 meters snow water equivalent remains constant as elevation increases. The difference in snow water equivalent at lower and higher elevations within the study area is driven by snow accumulation processes that differ between valleys and valley sidewalls/ridgetops within the study area. The processes that control the spatial distribution of snow water equivalent within this study area are site specific and are likely not transferable to other regions.
© Copyright 2013 Frederick Kellner