Wind-wave hindcast using modified ECMWF ERA-Interim wind field in the Mediterranean Sea

Abstract

This study evaluates the usage of the SWAN model forced with modified wind field along the Mediterranean Sea. ECMWF ERA-Interim wind field was used to force the model. Third-generation SWAN model was applied in non-stationary mode with linear and exponential growth from wind including both deep and shallow water wave dissipation processes. Four locations have been considered to calibrate and validate the model on spatial and temporal scales, two wave buoys at Alghero and Mazara, Italy in the western Mediterranean during years 1990 and 1998; and two S4DW devices along the Egyptian Mediterranean Coast in the eastern Mediterranean during the years 2004 and 2010. ECMWF wind field and its influence on the different wave parameters were assessed. Model calibration results revealed that enhancing the ECMWF ERA-Interim wind field by 20%–25% gives good matching results in hindcasting significant wave height with better estimates of extreme events using a 25% enhancement factor. However, no considerable improvements were observed in simulating the wave period that is underestimated by the SWAN model. The validation results showed the high performance of the calibrated SWAN model with the modified wind field with an average RMSE and scatter index of about 0.29 m and 31% respectively. Increasing the wind field higher than 25% gives comparable results but with significant overestimation of the storm conditions. Considerable underestimations were detected for significant wave height below 1 m even with using Wind Enhancement Factor (WEF). These results were also validated by comparison with previous studies. A 31-years (1988–2018) wave atlas was obtained from which the general description of wave climate along the Mediterranean Sea was explained. The high-resolution SWAN model allows us to study the wave climate and extreme wave conditions along the southeastern Mediterranean basin providing necessary information for the development of this coastal zone.