Snow pack in the Swiss Alps under changing climatic conditions: an empirical approach for climate impacts studies

Abstract

In many instances, snow cover and duration are a major controlling factor on a range of environmental systems in mountain regions. When assessing the impacts of climatic change on mountain ecosystems and river basins whose origin lie in the Alps, one of the key controls on such systems will reside in changes in snow amount and duration. At present, regional climate models or statistical downscaling techniques, which are the principal methods applied to the derivation of climatic variables in a future, changing climate, do not provide adequate information at the scales required for investigations in which snow is playing a major role. A study has thus been undertaken on the behavior of snow in the Swiss Alps, in particular the duration of the seasonal snow-pack, on the basis of observational data from a number of Swiss climatological stations. It is seen that there is a distinct link between snow-cover duration and height (i.e., temperature), and that this link has a specific "signature" according to the type of winter. Milder winters are associated with higher precipitation levels than colder winters, but with more solid precipitation at elevations exceeding 1,700 -2,000 m above sea-level, and more liquid precipitation below. These results can be combined within a single diagram, linking winter minimum temperature, winter precipitation, and snow-cover duration. The resulting contour surfaces can then be used to assess the manner in which the length of the snow-season may change according to specified shifts in temperature and precipitation. While the technique is clearly empirical, it can be combined with regional climate model information to provide a useful estimate of the length of the snow season with snow cover, for various climate-impacts studies.

Winter severity and snowiness and their multiannual variability in the Karkonosze Mountains and Jizera Mountains

“…The nature of this relationship depends on the type of winter. Milder winters are usually associated with higher precipitation than colder ones (Beniston et al 2003). Thus, in spite of the considerable variability of snow cover in subsequent years and the increase in air temperatures, average long-term climatic conditions in the Swiss Alps in the twentieth century were conducive to long snow cover retention times.…”

“…This is due, inter alia, to the fact that mild winters are associated with an increase in snowfall in high locations, and rain in lower ones (Laternser and Schneebeli 2003). Nevertheless, any change in one or both of these factors may lead to significant changes in snow cover retention time (Beniston et al 2003). The indirect influence of temperature conditions, which affect type (solid, liquid) of precipitation, on snow cover in the Carpathians was pointed out by Obrębka-Starklowa et al (1995).…”

“…Snow cover and its multiannual trends are the result of the direct or indirect simultaneous impact of multiple climate components and factors and of their changes in subsequent years (Foster et al 1983;Falarz 2004). Any changes in snow cover thickness and retention time may have longlasting environmental and economic implications (Beniston 1997(Beniston , 2000Beniston et al 2003). Economic losses related to snow cover deficits are of particular importance in mountain areas where a significant proportion of tourism income is derived from winter sports (Beniston 2000).…”

“…The phenomenon of snowy or severe winters is of interest to many people and institutions, e.g. in connection with the considerable damage these can wreak in many economies (Beniston et al 2003;Bednorz 2008Bednorz , 2013Kulasová and Bubeníčková 2009).…”

On interpreting hydrological change from regional climate models

“…As a complement to modelling approaches, observational studies of the behavior of the alpine snowpack were applied (Beniston et al 2003a). This resulted in empirical relationships of how both the amount and duration of snow changes at various altitudes as a function of the type of winter (i.e., warm/moist, warm/dry, cold/moist, or cold/dry).…”