Oil movement to horizontal direction at sea surface is predicted to consider the following three effects in numerical simulation. First is spreading by oil slick itself characteristics. Second is eddy diffusion by current turbulence. Third is transport by current at sea surface like tidal current, ocean current, wind current and so on.
　In this study, we developed a particle model to simulate oil transport at sea surface. The oil particle model can treat spreading, diffusion and transport. We developed a new calculation model using particle model about spreading by oil slick itself characteristics. The model can treat instantaneous oil spill.
　We conducted hindcast simulations of oil spill incident off the Taean Coast in South Korea in 2007, and the validity of the model was verified by comparing to observation. The results were similar to observation area of oil slick. We conducted sensitivity analysis of eddy diffusion coefficient, horizontal eddy kinematic viscosity coefficient and vertical eddy kinematic viscosity coefficient.
　Calculation results was better when oil eddy coefficient and horizontal eddy kinematic coefficient are equal to 30m2/s and vertical eddy kinematic coefficient is equal to 0.10m2/s in this weather condition, marine condition and calculation condition.
　It is necessary to take small calculation mesh vertically near the water surface to reproduce a wind current by numerical simulation. But calculation time is longer to calculate in small mesh condition, it is not good for use at real time oil spill prediction. Therefore, we propose wind coefficient method is better for prediction of oil transport.