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| Titel |
Spatial dependences among precipitation maxima over Belgium |
| VerfasserIn |
S. Vannitsem, P. Naveau |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 14, no. 5 ; Nr. 14, no. 5 (2007-09-17), S.621-630 |
| Datensatznummer |
250012278
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| Publikation (Nr.) |
 copernicus.org/npg-14-621-2007.pdf |
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| Zusammenfassung |
For a wide range of applications in hydrology, the probability distribution
of precipitation maxima represents a fundamental quantity to build dykes,
propose flood planning policies, or more generally, to mitigate the impact of
precipitation extremes. Classical Extreme Value Theory (EVT) has been applied
in this context by usually assuming that precipitation maxima can be
considered as Independent and Identically Distributed (IID) events, which
approximately follow a Generalized Extreme Value distribution (GEV) at each
recording site. In practice, weather stations records can not be considered
as independent in space.
Assessing the spatial dependences among precipitation maxima provided by two
Belgium measurement networks is the main goal of this work. The pairwise
dependences are estimated by a variogram of order one, also called madogram,
that is specially tailored to be in compliance with spatial EVT and to
capture EVT bivariate structures. Our analysis of Belgium precipitation
maxima indicates that the degree of dependence varies greatly according to
three factors: the distance between two stations, the season (summer or
winter) and the precipitation accumulation duration (hourly, daily, monthly,
etc.). Increasing the duration (from one hour to 20 days) strengthens the
spatial dependence. The full independence is reached after about 50 km (100 km)
for summer (winter) for a duration of one hour, while for long durations
only after a few hundred kilometers. In addition this dependence is always
larger in winter than in summer whatever is the duration. An explanation of
these properties in terms of the dynamical processes dominating during the
two seasons is advanced. |
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