Die Änderungen der Sonnenscheindauer in Österreich in neuerer Zeit

Changes in Mountain Climate and Glacio-Hydrological Responses

“…Sunshine duration in the eastern Alps has been analyzed for three mountain stations and four lowland ones by Steinhauser (1973). Five-year running means of annual duration at the lowland stations for 1928-32 to 1968-72 agree well with one another and also with records at Villach (2,140 m) and, except for the 1940s-early 1950s, with Sonnblick (3,106 m), for both timing and amplitude of the fluctuations ( Figure 5).…”

“…In a number of cases these have been developed in marginal areas, necessitating frequent and costly use of snow-making equipment. The types of data necessary to examine the changing possibilities of snowfall and snow cover are illustrated by Steinhauser (1974) and by Wittmer (1983 snow would be reduced, although the net effect on avalanche frequencies is not directly obvious. Historical analogues for more favorable climatic environments in mountain areas have received relatively little attention; in contrast, Pfister (1985a) and Grove (1988), for example, illustrate many cases of economic deterioration associated with severe episodes of the Little Ice Age in the Alps and Norway, respectively.…”

“…Mean summer temperature over the same interval rose about 0.50C. It is worth noting that the temporal decrease in snow cover is substantially greater than would be estimated by comparing snow cover durations at stations 100 m apart (corresponding to the mean lapse rate 0.50C/100 m) in the Alps; mean data show a change of only 10-11 days per 100 m altitudinal increment (Steinhauser, 1974).…”

“…Duration relates to the altitude of freezing temperatures, whereas snowfall is determined by temperatures and atmospheric moisture flux convergence. Steinhauser, 1974).…”

“…This translates into an increase of 28 days on an annual total of 200 days with snow cover at the median altitude. Steinhauser (1970) demonstrates that the long-term trends in snow cover duration in Austria differ considerably between regions. Stations in western Austria and the southern Alps declined from about 1905 to the late 1920s, and reached their lowest values in the late 1950s, whereas in the northern Alpine Foreland and northeastern Austria only large irregular fluctuations are apparent with large 1955-70 (B6hm, 1986:149).…”