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Titel |
Scale effect in hazard assessment - application to daily rainfall |
VerfasserIn |
V. Pawlowsky-Glahn, R. Tolosana-Delgado, J. J. Egozcue |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7340
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Digitales Dokument |
URL |
Erschienen |
In: 6th Plinius Conference on Mediterranean Storms (2004) ; Nr. 2 (2005-05-09), S.117-121 |
Datensatznummer |
250000306
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Publikation (Nr.) |
copernicus.org/adgeo-2-117-2005.pdf |
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Zusammenfassung |
Daily precipitation is recorded as the total amount of water
collected by a rain-gauge in 24h. Events are modelled as a
Poisson process and the 24h precipitation by a Generalized
Pareto Distribution (GPD) of excesses. Hazard assessment is
complete when estimates of the Poisson rate and the distribution
parameters, together with a measure of their uncertainty, are
obtained. The shape parameter of the GPD determines the support of
the variable: Weibull domain of attraction (DA) corresponds to
finite support variables, as should be for natural phenomena.
However, Fréchet DA has been reported for daily precipitation,
which implies an infinite support and a heavy-tailed distribution.
We use the fact that a log-scale is better suited to the type of
variable analyzed to overcome this inconsistency, thus showing
that using the appropriate natural scale can be extremely
important for proper hazard assessment. The approach is
illustrated with precipitation data from the Eastern coast of the
Iberian Peninsula affected by severe convective precipitation. The
estimation is carried out by using Bayesian techniques. |
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