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 calculate the energy balance in high spatial resolution in a basin with very distinct relief and to simulate the surface related processes in a distributed way. The basin considered, the Landquart basin (area at the outlet Felsenbach: 616 km², mean altitude 1,800 m a.s.l.), situated in the eastern part of the Swiss Alps, has been subdivided with GIS-methodology into 2,704 homogeneous units (altitude and aspect). Among all other water balance elements snow water equivalent is simulated for a period of 15 years. Climate scenarios for the 21^st century from three climate change experiments are used in order to estimate the change in the distribution of the snow water equivalent in the basin. Finally, impacts on the potentiality of Alpine skiing activities in this region are discussed. It shows that the areas where profitability minimum requirements is reached from the point of view of snow amounts, are decreasing, because this limit would go up 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.