Credibility assessment of a Lagrangian-based model for long-term simulation of oil spill dynamics: A case study on Sanchi incident

The long-term risks of marine oil pollution to biodiversity, fisheries, and human health necessitate effective oil spill assessments in coastal management, particularly in highly ship-trafficked regions like the East China Sea (ECS). Numerical models, especially Lagrangian models, excel in simulating oil spill behavior under diverse meteorological conditions and incorporating complex processes like weathering. In this study, gaps in prior research are addressed by evaluating the performance of the Lagrangian GNOME model, coupled with the ADIOS, in relation to the disastrous Sanchi incident that happened in the ECS. This assessment is notable for its extended spatiotemporal resolution of Sanchi oil spill modeling. The models of this study were configured to simulate key processes for both heavy fuel oil (HFO) and condensate, and validation was achieved through location comparison between remotely observed and simulated oil spills. Subsequently, the obtained results indicated that one year post-release, 132 metric tons of HFO had evaporated and 101 metric tons had become stranded along shorelines, while 687 metric tons of condensate disappeared from the water surface within approximately 8 hours. Spatial analysis identified Japanese coastal zones as the most impacted, where the interplay of meteorological conditions resulted in 29,000 kilograms of oil beaching. The obtained results confirm the efficacy of the GNOME in a high-traffic shipping zone such as the ECS as an environmental management system for refining spill response strategies and environmental risk management, while also emphasizing the necessity of long-term oil pollution assessments, as oil slicks persisted for a year after the incident.