Improving the Wave Forecasting in the Catalan Coast (WAM Cycle 4.5)

The present study investigates the conspicuous shortcomings of the whitecapping dissipation model implemented in WAM Cycle 4.5 [1], following the lead of the work of [2] and [3]. Its dependence on an overall wave steepness unavoidably yields systematic errors when more than one wave system is propagating. The complex orography and highly variable winds at the Catalan coast lead to fetchand duration-limited wave conditions near the Ebro delta. The incidence of swell trains during the development of these wind-seas coming from land favors the development of bimodal spectra. Although a comprehensive tuning of the free parameters of the dissipation function is performed, effectively improving the general subestimation of wave periods, it is strongly recommended to incorporate updated dissipation models, which avoid the dependence on an overall wave steepness and provide a more physical description of the wave breaking mechanism[4]; [5].