Regional wave climate projections forced by EURO-CORDEX winds for the Black Sea and Sea of Azov towards the end of the 21st century

Abstract

Wave phenomena impact high commercial value coastal and offshore activities, infrastructures and transportation. The knowledge of future wave conditions allows for consistent long-term planning and decision-making. The present study aims to provide robust, reliable projections of the potential future wave conditions of the Black Sea under the influence of climate change. For this purpose, an eight-member dynamic wave climate ensemble that accurately represents the Black Sea's present wave climate has been produced, and future projections are assessed and analysed here. The wave climate ensemble was obtained by forcing the Simulating Waves Nearshore spectral wave model with eight regional wind fields from the EURO-CORDEX. The future simulations of the regional wind fields are based on the RCP8.5 high-emission scenario. The historical wave climate of the ensemble was evaluated against ERA5 reanalysis data. Projected changes in the mean wind and wave characteristics are examined by comparing historical and future simulations. In addition, the projected trends in the annual means during the future period of the wave simulations for significant wave height (H-s) and wave energy flux are also analysed. The projections for H-s and wind speeds are pronounced with significant decreases down to -10% across the basin, especially in the eastern region of the Black Sea. Changes in the H-s 99% percentiles of up to 16% are projected to occur. The projected changes in the annual mean of the wave energy flux are close to the projected changes in H-s means, while the seasonal changes (between -15% and 12%) are expected to be higher.