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| Titel |
Extreme value statistics of snowfall in the Swiss Alpine region |
| VerfasserIn |
J. Blanchet, C. Marty, M. Lehning |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021667
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| Zusammenfassung |
| The mountain snowcover is an important source of water but also leads to natural hazards
such as avalanches and floods. We use data collected during winters 1999/00 to
2007/08 by 239 automatic and manual measurement stations in Switzerland to
highlight spatial characteristics of extreme snowfall. With the help of extreme value
theory based on a “peaks over threshold” approach and a Poisson point process
representation, we analyse spatial patterns and correlation characteristics. Our analyses
show that a significant number of stations do not follow the Gumbel distribution. In
particular, low altitude stations in the Swiss Plateau are heavy-tailed because of rare
extraordinary snowfall events. Spatial characteristics of extreme snowfall are compared
to those of the mean snowfall. Altitudinal dependence and spatial distribution of
mean and extreme snowfall are similar. Both mean and extreme snowfall show an
increase of magnitude between 400 and 2200 m a.s.l. and a constant or slightly
decreasing magnitude at higher altitudes. Below 1200 m a.s.l., the increase with
altitude is stronger because of the rain - snow transition. Another finding is that the
spatial correlation pattern of extreme snowfall is similar to that of mean snowfall,
both of which are determined by the main climatological regions of Switzerland. |
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