SEASONAL RELATIONSHIP BETWEEN TEMPERATURE, PRECIPITATION AND SNOW COVER IN A MOUNTAINOUS REGION

An analysis of correlation coefficients for climatological data coveri ng the period 1901-1994 or 1931-1994 for six locations in Switzerland has been made in order to highlight the relationships between temperat ure, precipitation (rain and snow) and snow in summer and in winter. T he results show that colder summers tend to be associated with more pr ecipitation, mainly in terms of the frequency of occurrence of precipi tation, but also in terms of its abundancy. In winter, sites located a t lower altitudes behave differently from those at higher elevations. At lower altitudes, warmer winters tend to be rainier and to have less snow (only a small part of winter precipitation falls in the form of snow). Above 1000-1500 m, correlations between temperature on the one hand, and precipitation or snow on the other, tend to be weaker than a t lower elevations; warmer winters are associated with less snow but a lso with less precipitation in general, while the relationship between precipitation and snow is stronger. These results confirm that during cold periods of the past, such as Lobben Phase (1400 BC-1230 BC) cold summers were probably linked to frequent and abundant precipitation. These conditions led to increased mortality as well as to population m igrations. In terms of potential future global warming if the current temperature/precipitation relationships remain unchanged, then warmer summers will likely be linked to a decrease in precipitation. Higher w inter temperatures can be expected to lead to a general decrease of sn ow and to a decrease in precipitation, but only at higher elevations; warmer winters would conversely be associated with an increase in prec ipitation at lower altitudes.