Impact of wind field horizontal resolution on sea waves hindcast around Calabrian coasts

Abstract

We investigated the impact of wind field enhanced horizontal resolution on sea wind-wave hindcast around the Calabrian coasts, which lie at the southernmost tip of the Italian peninsula. Simulations have been performed using WAM (WAve Model), a third-generation state of the art wave-model. In order to study this topic, we shall discuss two simulations sets. The first set forces WAM by ECMWF (European Centre for Medium-Range Weather Forecasts) surface wind field analysis, used in this paper with a resolution of 0.5◦; whilefor these cond simulation set RAMS (Regional Atmospheric Modelling System) surface wind field forcesWAM. Initial and dynamic boundary conditions for RAMS simulations, which have a 20 km horizontal resolution, are derived from ECMWF analysis. To obtain a reliable statistical data set, integrations have been performed over six months from 1 October 2003 to 31 March 2004. We have evaluated performance comparing the WAM modelled wave heights and directions against data of Wave measuring Buoys (WBs) moored off Cetraro and Crotone. Statistical tests are performed to assess differences between modelled data and measurements and between modelled data sets. Results show better performance for wave height fields when RAMS forces WAM. The best results are obtained for Crotone but differences between simulated and measured wave height distributions are significant at a 99% statistical level. Simulated wave directions are generally good for the model set-up used in this paper and the differences between modelled data sets are minor.