Mean Snow Cover Duration from November to June Under the REMO Regional Climate Trend and the Baseline Climate Variant

Abstract

The change in snow cover under the conditions of climate change is of great importance for the hydrological conditions of the Upper Danube basin. In addition to snow depth, which is quite heterogeneous in space, a particularly meaningful parameter is the duration of snow cover, SD. This variable is defined by the number of days with a snow cover greater than 1 mm water equivalent within the winter, which in the Alps is generally from November to June of the following year (see also Chap. 30). SD is significant for both ecological and economic reasons.

The map for this chapter illustrates the change in the snow cover duration in the Danube drainage basin as 30-year means for the model years 2011–2040, 2021–2050 and 2031–2060; these changes are based on the results of modelling with DANUBIA and the Snow snow model presented in Chap. 30 under the conditions of the REMO regional climate trend and the Baseline climate variant (see Chaps. 48, 49, 50).

The simulation results indicate that in a warmer climate, a snow cover in the lowlands would become even rarer than before, although absolutely no snow is not expected, even in the lowest areas. Otherwise in the future SD will be shortened at any altitude. The most far-reaching effect will be manifested in the glaciated regions, where the snow-free areas of the glaciers will continue to enlarge and the ablation period will continue to be extended. This mainly contributes to an accelerated retreat of glaciers (see Chap. 56).