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Sensitivity of Alpine snow cover to European temperature
Author(s) -
Hantel Michael,
HirtlWielke LuciaMaria
Publication year - 2007
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.1472
Subject(s) - snow , environmental science , climatology , snow cover , tangent , logistic function , standard deviation , climate change , sensitivity (control systems) , degree (music) , hyperbolic function , mean radiant temperature , atmospheric temperature , atmospheric sciences , meteorology , mathematics , geology , statistics , geography , geometry , physics , oceanography , electronic engineering , acoustics , engineering
The number of days with snow cover at 268 Alpine climate stations in the winters of 1961–2000 has been investigated with respect to the mean winter temperature over Europe. The corresponding description, originally developed for Austria and recently applied to Switzerland, consists in fitting a logistic curve to the observed data. The slope of this curve, originally the hyperbolic tangent function, is interpreted as the sensitivity of the snow duration‐temperature relationship. Here we first demonstrate with a physical‐statistical model that the proper logistic curve is not the hyperbolic tangent, but the error function, generated through the pdf of the fluctuating temperature; the slope of this curve is inversely proportional to the standard deviation of temperature. Since the station temperature used for this local model is on a scale much too small for global climate models, we simulate, secondly, the temperature with the concept of the Alpine temperature : It is the spatial Taylor expansion of the seasonal European temperature in vertical and horizontal directions. This improved model yields, for the same Austrian and Swiss data, both a better fit and a slightly smaller sensitivity of the snow‐temperature curve than the original hyperbolic model. Thirdly we apply our improved model to a considerably larger Alpine data set comprising also data from France, Germany, Italy and Slovenia and find a sensitivity of about − 0.33 ( ± 0.03) per degree warming. It is representative for the entire Alpine region and corresponds to a maximum reduction of the snow cover of 30 days in winter at a height of 700 m for 1° European warming. The implication is that the relation between the natural fluctuations of winter snow duration and European temperature may be an estimate for a trend of snow duration in case of a future European temperature trend. Copyright © 2007 Royal Meteorological Society