Item: Understanding snow transport processes shaping the mountain snow-cover
Title: Understanding snow transport processes shaping the mountain snow-cover
Proceedings: International Snow Science Workshop, Davos 2009, Proceedings
Authors: Rebecca Mott, Michael Schirmer, Thomas Grünewald, Michael Lehning, WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Abstract: In alpine terrain the snow cover is heterogeneously distributed as a result of wind and precipitation interacting with the snow cover at various scales. The aim of this study is to achieve a better understanding of snow deposition and drifting and blowing snow at different scales, analyzing major drift events of an accumulation period. We want to examine snow deposition features at ridge scale as well as at smaller scales, in particular we investigate two huge cross-slope accumulation zones. High resolution (10 m) wind fields were computed with the atmospheric model Advanced Regional Prediction System (ARPS) and used as input for a model of surface processes in alpine terrain (Alpine3D) in order to quantify preferential deposition and redistribution of snow via saltation and suspension. We used a unique data set consisting of a high density network of automatic weather stations and Terrestrial Laser Scanning measurements of snow depth to validate the model results. The snow distributions were measured in a high spatial resolution at the end of the accumulation season 2007/2008 and before and after major snow drift events during the season 2008/2009. The results show that the observed snow deposition patterns have their correspondence in the mean flow field computed for those small scales.
Keywords: spatial variability, small scale wind fields, snow transport processes
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