Snow cover modelling as a tool for climate change assessment in a Swiss Alpine catchment

The daily step conceptual hydrological model IRMB (Integrated Runoff Model - Bultot) is further developed by the addition of a module designed to calc ulate the energy balance in high spatial resolution in a basin with very di stinct relief and to simulate the surface related processes in a distribute d way. The basin considered, the Landquart basin (area at the outlet Felsen bach : 616 km(2), mean altitude 1,800 m a.s.l.), situated in the eastern pa rt of the Swiss Alps, has been subdivided with GIS-methodology into 2,704 h omogeneous units (altitude and aspect). Among all other water balance eleme nts snow water equivalent is simulated for a period of 15 years. Climate sc enarios for the 21st century from three climate change experiments are used in order to estimate the change in the distribution of the snow water equi valent in the basin. Finally, impacts on the potentiality of Alpine skiing activities in this region are discussed. It shows that the areas where prof itability minimum requirements is reached from the point of view of snow am ounts, are decreasing, because this limit would go Lip by about 250 m from 1,500 to 1,750 m a.s.l. for the 2020 scenario. Statistical tests indicate, however, that this change is still within the natural variability observed in the reference period 1981-1995.