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Titel |
Snow and weather climatic control on snow avalanche occurrence fluctuations over 50 yr in the French Alps |
VerfasserIn |
H. Castebrunet, N. Eckert, G. Giraud |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1814-9324
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Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 8, no. 2 ; Nr. 8, no. 2 (2012-04-24), S.855-875 |
Datensatznummer |
250005489
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Publikation (Nr.) |
copernicus.org/cp-8-855-2012.pdf |
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Zusammenfassung |
Snow avalanche activity is controlled to a large extent by snow and weather
patterns. However, its response to climate fluctuations remains poorly
documented. Previous studies have focused on direct extraction of trends in
avalanche and winter climate data, and this study employs a time-implicit
method to model annual avalanche activity in the French Alps during the
1958–2009 period from its most representative climatic drivers. Modelled
snow and weather data for different elevations and aspects are considered as
covariates that explain actual observed avalanche counts, modelled
instability indexes, and a combination of both avalanche activity
indicators. These three series present relatively similar fluctuations over
the period and good consistency with historically harsh winters. A stepwise
procedure is used to obtain regression models that accurately represent
trends as well as high and low peaks with a small number of physically
meaningful covariates, showing their climatic relevance. The activity
indicators and their regression models seen as time series show, within a
high interannual variability, a predominant bell-shaped pattern presumably
related to a short period of colder and snowier winters around 1980, as well
as a very slight but continuous increase between 1975 and 2000 concomitant
with warming. Furthermore, the regression models quantify the respective
weight of the different covariates, mostly temperature anomalies and
south-facing snowpack characteristics to explain the trends and most of the
exceptional winters. Regional differences are discussed as well as seasonal
variations between winter and spring activity and confirm rather different
snow and weather regimes influencing avalanche activity over the Northern
and Southern Alps, depending on the season. |
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