Wave energy balance in wave models (SWAN) for semi-enclosed domains: application to the Catalan coast

Abstract

This study has been motivated by the limited accuracy of wave models under short-duration, fetch-limited conditions. This applies particularly to the wave period, in semi-enclosed domains with highly variable wind patterns as along the Catalan coast. The wave model SWAN version 40.91A is used here in three nested grids covering all the North-western Mediterranean Sea with a grid resolution from 9 to 1 km, forced with high resolution wind patterns from BSC (Barcelona Supercomputing Center) for two study periods, the winter 2010 and the spring 2011. The results are validated in eight locations with different types of instrumentations. In order to improve the results, a modification of the whitecapping term parameters is performed. Also the appropriate frequency integral range used to calculate the integral wave parameters is tested to be sure to compare the simulation results and the measurements for the same frequency interval. The results obtained show a clear improvement of the mean wave period and the peak period for the study area, decreasing considerably the negative bias observed previously, while almost no change is observed in wave height due to the proposed modifications. These results can be generalized to the Spanish Mediterranean coast and may be applicable to study areas with similar characteristics as the ones presented here: semi-enclosed domains with fetch-limited conditions and young sea waves.