On The Applicability Of Hindcast Time Series For The Prediction Of ExtremeSea Storms

Abstract

An analytical solution for the return period R(H,>h) of a sea storm in which the maximum significant wave height H, exceeds a fixed threshold h can be based on the 'equivalent sea' assumption: each actual storm is replaced by a triangular storm, where the triangle height a gives the storm intensity and the triangle base b the storm duration. The base-height regression, which is proven to be very useful for the risk analysis, may be then estimated from (ai,bi) values of all the storms. In this paper some preliminary results concerning the applicability of the hindcast data for the risk analysis are proposed. In particular some significant wave height time series are derived for the Adriatic Sea, by using a third generation wave model (SWAN) forced with wind fields obtained from a last generation meteorological model (COAMPS). These data are firstly validated, by comparison with measured data. The hindcast data are then processed to obtain the 'equivalent sea' and finally analysed to assess the sensitivity of the equivalent triangular storm model to the sampling rate.