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| Titel |
A method to characterize the different extreme waves for islands exposed to various wave regimes: a case study devoted to Reunion Island |
| VerfasserIn |
S. Lecacheux, R. Pedreros, G. Cozannet, J. Thiébot, Y. Torre, T. Bulteau |
| 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 ; 12, no. 7 ; Nr. 12, no. 7 (2012-07-31), S.2425-2437 |
| Datensatznummer |
250011002
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| Publikation (Nr.) |
 copernicus.org/nhess-12-2425-2012.pdf |
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| Zusammenfassung |
This paper outlines a new approach devoted to the analysis of extreme waves
in presence of several wave regimes. It entails discriminating the
different wave regimes from offshore wave data using classification
algorithms, before conducting the extreme wave analysis for each regime
separately. The concept is applied to the pilot site of Reunion Island which
is affected by three main wave regimes: southern waves, trade-wind waves and
cyclonic waves. Several extreme wave scenarios are determined for each
regime, based on real historical cases (for cyclonic waves) and extreme
value analysis (for non-cyclonic waves). For each scenario, the nearshore
wave characteristics are modelled all around Reunion Island and the linear
theory equations are used to back calculate the equivalent deep-water wave
characteristics for each portion of the coast. The relative exposure of the
coastline to the extreme waves of each regime is determined by comparing the
equivalent deep-water wave characteristics.
This method provides a practical framework to perform an analysis of
extremes within a complex environment presenting several sources of extreme
waves. First, at a particular coastal location, it allows for
inter-comparison between various kinds of extreme waves that are generated
by different processes and that may occur at different periods of the year.
Then, it enables us to analyse the alongshore variability in wave exposition,
which is a good indicator of potential runup extreme values. For the case of
Reunion Island, cyclonic waves are dominant offshore around the island, with
equivalent deep-water wave heights up to 18 m for the northern part.
Nevertheless, due to nearshore wave refraction, southern waves may become as
energetic as cyclonic waves on the western part of the island and induce
similar impacts in terms of runup and submersion. This method can be easily
transposed to other case studies and can be adapted, depending on the data
availability. |
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