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Scale effect in hazard assessment - application to daily rainfall

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

Advances in Geosciences, 2005, núm. 2, p. 117-121

European Geosciences Union (EGU)

Author: Pawlowsky-Glahn, Vera
Tolosana Delgado, Raimon
Egozcue, Juan José
Date: 2005
Abstract: 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
Format: application/pdf
ISSN: 1680-7340 (versió paper)
1680-7359 (versió electrònica)
Document access: http://hdl.handle.net/10256/8999
Language: eng
Publisher: European Geosciences Union (EGU)
Collection: Reproducció digital del document publicat a: http://dx.doi.org/10.5194/adgeo-2-117-2005
Articles publicats (D-IMA)
Is part of: Advances in Geosciences, 2005, núm. 2, p. 117-121
Rights: Attribution-NonCommercial-ShareAlike 3.0 Spain
Rights URI: http://creativecommons.org/licenses/by-nc-sa/3.0/es/
Subject: Poisson, Processos de
Poisson processes
Precipitacions (Meteorologia) -- Models matemàtics
Precipitation (Meteorology) -- Mathematical methods
Title: Scale effect in hazard assessment - application to daily rainfall
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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