Numerical investigation of the coastal dynamics over the western Black sea

The Black Sea is one of the largest enclosed seas in the world. More than 160 million people live in its coastal areas and large rivers flow into it, as  the Danube, the Dniester, the Dnieper and the Don. The Danube river, located on the western coast, is the most important European waterway whose catchment area is shared by more than fifteen countries. Black sea coastal waters are also often characterized by high suspended sediment concentrations derived from coastal runoff and local sediment re-suspension from the river sources. Measuring coastal sediment transport in field situations is notoriously difficult and generally subject to great uncertainty, and model estimates are often used in practice. The specific objectives of the current study are to understand the present state of the western Black Sea, and to study current and wave dynamics with the assistance of state-of-the-art numerical models for simulating waves, currents, and their interactions with the sediment loads. We used the hydrodynamic model named SHYFEM, hard coupled with the Wavewatch III wave model for the current study, while the coupled Sedtrans05 model will be used in the future for sediment modeling. The numerical models are applied on an unstructured grid representing the western Black Sea and the Danube Delta through the use of triangular elements of different shapes and sizes.

The simulations of the coupled SHYFEM-WW3 were compared with the significant wave heights (Hs) measured by the Jason-3 and Sentinel-3. Despite some discrepancies, SHYFEM-WW3 provides good agreements with the altimeter data. The preliminary comparison done on the basin scale application show better performance of the model for the western area (Correlation coefficient = 0.89 in the western Black sea, while Correlation coefficient = 0.81 in the basin scale). Next steps will be dedicated to a coastal application on the western Black Sea coupling circulation, waves and sediment transport.

All of the modeling activities are developed within the framework and funded by the Horizon 2020 DOORS (Developing Optimal and Open Research support for the Black sea) project, (Grant no. 101000518) https://www.doorsblacksea.eu/.