Simulation of 3D oil spill trajectories and weathering processes based on the SCHISM

With the development of marine resources and maritime transportation industry in Zhoushan City, the petroleum industry has become the prime driver of the city's future development. Additionally, the developed shipping industry, alongside numerous oil reserve islands and crude oil refineries in Zhoushan City, may lead to frequent oil spill accidents, which could severely endanger the local environment and hinder economic development. Based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM), a three-dimensional baroclinic hydrodynamic model of the Zhoushan sea area was established and verified in this study. Utilizing the particle tracking module of the SCHISM, a three-dimensional oil spill model and an oil spill weathering model were developed. The locations of the oil particles predicted by the model were verified using released oil buoys. The weathering model primarily simulated four weathering processes of the oil spill: mechanical spreading, evaporation, emulsification and dispersion. Compared with the original model, the inclusion of the weathering module significantly improves the accuracy of instantaneous oil spill simulations. The model was applied to the Zhoushan sea area to simulate the fate of oil after spills in both summer and winter. In summer, due to southerly winds, oil spills mainly affect the sea area north of Yushan Island. In winter, due to northerly winds, oil spills primarily affect the sea area south of Yushan Island.