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Titel |
A probabilistic view on the August 2005 floods in the upper Rhine catchment |
VerfasserIn |
S. Jaun, B. Ahrens, A. Walser, T. Ewen, C. Schär |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1561-8633
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Digitales Dokument |
URL |
Erschienen |
In: Natural Hazards and Earth System Science ; 8, no. 2 ; Nr. 8, no. 2 (2008-04-02), S.281-291 |
Datensatznummer |
250005408
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Publikation (Nr.) |
copernicus.org/nhess-8-281-2008.pdf |
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Zusammenfassung |
Appropriate precautions in the case of flood occurrence often require long
lead times (several days) in hydrological forecasting. This in turn implies
large uncertainties that are mainly inherited from the meteorological
precipitation forecast. Here we present a case study of the extreme flood
event of August 2005 in the Swiss part of the Rhine catchment (total area
34 550 km2). This event caused tremendous damage and was associated with
precipitation amounts and flood peaks with return periods beyond 10 to 100
years. To deal with the underlying intrinsic predictability limitations, a
probabilistic forecasting system is tested, which is based on a
hydrological-meteorological ensemble prediction system. The meteorological
component of the system is the operational limited-area COSMO-LEPS that
downscales the ECMWF ensemble prediction system to a horizontal resolution of
10 km, while the hydrological component is based on the semi-distributed
hydrological model PREVAH with a spatial resolution of 500 m. We document
the setup of the coupled system and assess its performance for the flood
event under consideration.
We show that the probabilistic meteorological-hydrological ensemble
prediction chain is quite effective and provides additional guidance for
extreme event forecasting, in comparison to a purely deterministic
forecasting system. For the case studied, it is also shown that most of the
benefits of the probabilistic approach may be realized with a comparatively
small ensemble size of 10 members. |
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