An ocean-wave-trajectory forecasting system for the eastern Baltic Sea: Validation against drifting buoys and implementation for oil spill modeling

We present the implementation and validation of OpenDrift, an open-source Lagrangian particle trajectory modeling framework for oil spill modeling in the coastal waters of Estonia in the Baltic Sea. The framework was coupled with ECMWF winds, NEMO-EST05 hydrodynamical model, and SWAN-EST wave model, and validated using six drift experiments from 2022. The sensitivity analysis revealed the importance of incorporating additional forcing factors, such as Stokes drift and currents, which generally improved the accuracy of the trajectory model compared to using wind alone. Nevertheless, the benefits of providing OpenDrift with, for example, the Stokes drift seemed to depend on whether currents are also included or not. The wind drift factors of the utilized drifters align closely with those commonly employed in oil spill modeling. Furthermore, the modeling results for hypothetical oil spills in severe weather conditions and high-risk regions emphasize the critical need for preparedness and rapid response strategies.