Climate sensitivity of snow cover duration in Austria

Abstract

The number of days with snow cover at Austrian climate stations, normalized by the maximum possible snow days within a season, is denoted n. This seasonal relative snow cover duration is considered a function of station height H and of the seasonal mean temperature T over Europe. When T increases, n decreases and vice versa. The function becomes saturated both for high stations at low European temperature (‘always snow’, n=1) and for low stations at high temperature (‘never snow’, n=0). In the saturated regions, the sensitivity s≡∂n(H, T)/∂T is practically zero, while in the transition region, s is extreme. The observed interannual fluctuations of T are considered here as simulation of a possible climate shift. s is determined for the climate stations of Austria from its snow cover record [1961–1990, 84 stations between 153 and 3105 m above sea level (a.s.1.)] by fitting the data of n for each individual station (local mode) as well as for all Austrian stations (global mode) with a hyperbolic tangent function. In the global mode, s reaches an extreme value of −0.34±0.04 K−1 in winter and −0.46±0.13 K−1 in spring. The implications of these results are discussed. Included in this discussion is the fact that a rise in the European temperature by 1 K may reduce the length of the snow cover period in the Austrian Alps by about 4 weeks in winter and 6 weeks in spring. However, these extreme values apply only to the height of maximum sensitivity (575 m in winter, 1373 m in spring); the actual sensitivity of individual stations located at higher or lower levels is less. Copyright © 2000 Royal Meteorological Society

European snow cover extent variability and associations with atmospheric forcings

“…Cotemporaneous temperature/snow cover associations have been investigated over North America; however, these relationships tend to be complex due to complicating atmospheric conditions (Leathers and Robinson, 1993). Anomalous positive (negative) snow cover and negative (positive) temperature anomalies were found to coincide in several studies (Foster et al, 1983;Cohen and Rind, 1991;Groisman et al, 1994;Leathers et al, 1995;Hantel et al, 2000). In a study considering only Europe, the influence of snow cover upon subsequent spring and summer temperatures was investigated (Chaoimh, 1998).…”

Trends in Swiss Alpine snow days: The role of local‐ and large‐scale climate variability

“…Figure 1). The station height of maximum trends ($600 m) is of the same order as the current height of maximum sensitivity in Switzerland and Austria [Hantel et al, 2000]. Absolute trends are less dependent on altitude, but the largest trends are again found for relatively low stations (Figure 2 (bottom)).…”

Snow cover in eastern Europe in relation to temperature, precipitation and circulation

“…The situation is different in regions where the mean winter temperature is well below zero, where increases in snow depth are controlled mainly by precipitation (Clark et al, 1999). Hantel et al (2000) have defined precisely the relationship between the mean temperature in Europe and the number of DSC for climate stations in Austria. A mean European temperature increase by 1 K corresponds to a decrease of snow cover duration in the Austrian Alps by 31 days in winter (DJF).…”

“…The relation fits best to a height of 575 m a.s.l. and it becomes saturated for high-elevation stations with low European temperatures (always snow) and for low-elevation stations with high European temperatures (never snow; Hantel et al, 2000). On the other hand, physical features of snow (high albedo, low conductivity) strongly influence the boundary-layer climate, mostly by lowering the air temperature (Wagner, 1973;Dewey, 1977;Walsh et al, 1982;Leathers et al, 1995).…”

“…Several analyses have concerned the local European scale: Jackson (1978) has described snow occurrence in Great Britain; Hantel et al (2000) have defined the relationship between temperature and number of DSC for climate stations in Austria; basic snow-cover characteristics for Poland have been given by Paczos (1985); the strong influence of the North Atlantic oscillation (NAO) on the number of DSC in Poland has been discussed by Bednorz (2002); Dobrovolny (1993) has investigated long-term snow conditions in the Czech Republic; and Jaagus (1997) has developed a spatial regression model for the influence of climatic changes on snow cover in Estonia.…”