Regional frequency analysis of extreme storm surges using the extremogram approach
Résumé
To withstand coastal flooding, protection of coastal facilities and structures must be designed with the most accurate estimate of extreme storm surge return levels (SSRLs). However, because of the paucity of data, local statistical analyses often lead to poor frequency estimations. Regional Frequency Analysis (RFA) reduces the uncertainties associated with these estimations, by extending the dataset from local (only available data at the target site) to regional (data at all the neighbouring sites including the target site) and by assuming, at the scale of a region, a similar extremal behaviour. In this work, Empirical Spatial Extremogram (ESE) approach is used. It is a graph representing all the coefficients of extremal dependence between a given target site and all the other sites in the whole region. It allows quantifying the pairwise closeness between sites based on the extremal dependence. The ESE approach, which should help being more confident about the physical homogeneity of the region of interest, is applied on a database of extreme skew storm surges (SSSs) and used to perform a RFA.
Domaines
Sciences de l'environnement
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