Updated System for the Sea Wave Operational Forecast of the Black Sea Marine Forecasting Center

Abstract

Purpose. The work is aimed at updating the sea wave forecasting system developed in the Black Sea Marine Forecasting Center by including the block of wind wave forecast in the Sevastopol region and by improving the wave forecast accuracy using the proposed procedure for the SWAN model tuning. Methods and Results. In the updated forecasting system, the possibility of performing the joint operational sea wave forecasts for the Black Sea and the Sevastopol region (with the 5 and 1 km spatial resolutions, respectively) became possible due to the nested grid method applied. To improve accuracy of the wave forecasts, the procedure for the SWAN model tuning was proposed. It is based on changing the parameterization of the surface friction coefficient Cd(V), where V is the surface wind speed. This permits to reduce the deviations of the forecasted wave heights from those obtained from the satellite altimetry measurements. Efficiency of the proposed procedure was assessed through comparison of the forecasting results with the remote sensing data. It is shown that in the forecasts supplied with an optimal choice of functional dependence Cd(V), the scattering index between the forecasted and measured values can be reduced by 20 %. Conclusions. Represented is the updated system of the Black Sea Marine Forecasting Center intended for the joint operational sea wave forecasts in the Black Sea and in the Sevastopol region. The results of model validation have shown that the procedure proposed for tuning the SWAN model makes it possible to reduce the deviations of the forecasted wave heights from those measured by the sensors installed at the altimetry satellites.