Lessons Learned from the French Drift Committee (CODER): An Operational, Collaborative Approach to Refine Oil Drift Modeling at Sea—Case Study of the RAMOGEPOL 2025 Exercise

Marine oil spill management requires rapid and accurate forecasts to mitigate environmental and operational risks. Created in 2002 during the Prestige spill and formally established in 2006, the French Drift Committee (CODER) unites expertise from CEDRE, Météo-France, Ifremer and Shom to refine oil drift modeling and response strategies. CODER’s operational scope combines multi-model forecasting, including MOTHY and OILMAP, integrated with real-time observations from drifting buoys, satellite/aerial observations and high-resolution environmental data, such as Copernicus Marine Environment Monitoring Service (CMEMS) current forecasts and Météo-France’s ARPEGE and AROME wind models. Annual exercises, such as RAMOGEPOL 2025, provide a controlled environment to test model performance in diverse hydrodynamic conditions and recalibrate simulations using real-time buoy data. During this exercise, the French Navy’s Anti-Pollution Practical Expertise Center (CEPPOL) deployed buoys in the Mediterranean Sea, off the coast of Saint-Tropez, France, in both the Northern Current and wind-driven coastal waters, enabling CODER to assess model performance and refine simulations by comparing buoy trajectories with model outputs. This process enhances the accuracy of drift predictions, improves the understanding of local hydrodynamics, and identifies models’ strengths and limitations. By systematically evaluating and adjusting models using operational data, CODER strengthens the reliability of drift forecasts, ensuring more effective and adaptive responses to marine pollution incidents.