Review on the numerical models for simulating the optical processes of the oil spills at sea

Motivated by the need of distinguishing between oil pollutants and clean seawater based on their different optical properties, this article provides a comparative review on three types of numerical models that can be used to simulate the optical processes of the oil spills at sea, namely, the micro-facet model, the light-tracing model, and the two-beam interference model. The micro-facet model can be used to simulate the bidirectional reflectance distribution function (BRDF) of oil surface considering the influence of wind conditions over the sea and approximately interpret the directional reflectance of oil spills obtained in practice; The light-tracing model can produce highly accurate BRDF of oil spills at sea considering both of the surface and sub-surface optical processes; The two-beam interference model establishes the relationship between absorption coefficient, oil thickness, and surface reflectance under controlled condition, and thus can be used for the quantitative inversion on the optical parameters of thin oil films. The comparison results indicate that these three types of numerical models have their corresponding advantages and disadvantages and should be chosen according to the specific scenarios of applications.