Frequency distributions of storm surge for coastal damage prevention at Marseilles

摘要

Densely low-lying populated areas and sand beaches along the Mediterranean French coast are threatened by extreme sea levels. In micro-tidal conditions, the long term hourly water level record available at Marseilles Endoume (1885-2003) has made possible statistical analysis usually computed on continental hydrological parameters. Frequential analysis tools, applied to time series near to the million data, are implemented in order to provide a calculation method for the stochastic meteorological storm surge component to characterize coastal inundation and erosion risk. Surge probability distributions tested with an associated confidence interval (GEV, Jenkinson, Gamma, ...) and extreme values of the data fitting (Maximum Annual and Peaks-Over-Threshold) are discussed with relative tests (stationarity, independence, homogeneity,...). Surge stochastic results are compared with sea-levels of morphological significance correlated to coastal impact observations during storm events. The statistic methods and tools presented contribute to a better knowledge of intensity, frequency and duration of extreme sea levels associated with morphogenic storms and provide guidelines for coastal risk mitigation.