Simulation of Past Changes in the Austrian Snow Cover 1948–2009

A distributed snow model is applied to simulate the spatiotemporal evolution of the Austrian snow cover at 1 km x 1 km spatial and daily temporal resolution for the period 1948-2009. After a comprehensive model validation, changes in snow cover conditions are analyzed for all of Austria as well as for different Austrian subregions and elevation belts focusing on the change in snow cover days (SCDs). The comparison of SCDs for the period 1950-79 to those achieved for 1980-2009 for all of Austria shows a decrease in SCDs with a maximum of >35 SCDs near Villach (Carinthia). The analysis of SCD changes in different subregions of Austria reveals mean changes between -11 and -15 days with highest absolute change in SCDs for southern Austria. Two decrease maxima could be identified in elevations of 500-2000 m MSL (between -13 and -18 SCDs depending on the subregion considered) and above 2500 m MSL (over -20 SCDs in the case of central Austria). The temporal distribution of SCD change in the Austrian subregions is characterized by a reduction of SCDs in midwinter and at the end of winter rather than by fewer SCDs in early winter. With respect to the temporal distribution of SCD change in different elevation belts, changes in elevations below 1000 m MSL are characterized by a distinct reduction of SCDs in January. With increasing elevation the maximum change in SCDs shifts toward the summer season, reaching a maximum decrease in the months of June-August above 2500 m MSL.