MODELLING SNOW MELT PROCESSES IN ALPINE AREAS

The Water Supply Department of the Vienna City Council (MA31) operates a number of water supply catchments in a Karstic region of the Alps some 80 km south west of Vienna where the springs are fed by snow melt water during a substantial part of the year. To better understand and ultimately predict the space-time patterns of melt water, MA31 initiated a research initiative which is the subject of this paper. We set up a hydrological snow accumulation and melt model based on the 20 m grid of the DTM which simulates the energy balance components at the snow surface and the coupled heat and mass flow within the snowpack for each grid element. The snow model is driven by meteorological observations at an hourly time step. Some of the model parameters of the snow model need to be calibrated and we did that by comparing snow cover patterns (snow/no snow) simulated by the snow model with snow cover patterns derived from the SPOT based snow classification. This comparison enabled us to find reliable model parameters. The snow model can be used to simulate, among other things, the space-time patterns of snow water equivalent and snow melt within the study domain. The snow model still needs some refinement and ultimately we are planning to combine the model with an operational forecasting procedure. KURZFASSUNG