The influence of lateral snow redistribution processes on snow melt and sublimation in alpine regions

摘要

Snow plays a crucial role in determining moisture and energy exchanges between the land surface and atmosphere. Numerous studies have demonstrated that the accurate simulation of the Alpine snow cover is difficult due to the manifold interactions of preferential snow deposition, wind induced snow transport, and snow slides. The presented study discusses the spatial snow distribution as well as the associated sublimation and melt rates within the Berchtesgaden National Park area by using a collection of basic and medium complex models (SnowModel, SnowTran-3D, SnowSlide). A comparison between model results and classified satellite images was done for a general model validation. It was shown that the inclusion of snow transport processes into the model environment, can improve the accuracy of the predicted snow distribution. Sublimation from turbulent-suspended snow was analysed and it could be seen that the inclusion of gravitational snow transport processes is able to reduce the predicted sublimation rates at the crest regions by 44%. Furthermore, an analysis was performed to identify critical spatial scales, associated with snow redistribution and melt-water generation to define when snow transport processes should be accounted for. It was seen that the effect of snow cover redistribution on the predicted melt rates is only detectable if the observed area is small and in the range of a slope or a face. There was no effect detectable if the total catchment area was considered.