A regional parameterisation method for oil spill susceptibility assessment in Beibu Gulf

The Beibu Gulf, surrounded by multiple countries north of the South China Sea, has numerous oil-platforms around it putting it at a high-susceptibility for oil-spills. Oil-spill-models play an important role in susceptibility assessment by estimating oil-spill trajectories in this gulf. These trajectories are affected by factors that vary with time on a regional or basin scale. However, these factors are typically assumed to be constant in most oil-spill-models. Their determination is challenging due to the influence of current dynamics, tidal cycles and other related environmental parameters. Particular attention should be paid to the role of wind in the regional parameterisation of oil-spill-models, since it is particularly sensitive to the coastal characteristics. The drifter data in the Beibu Gulf provide an effective way to evaluate the local parameters. This paper proposes a regional oil-spill-susceptibility-assessment (OSSA) method for the Beibu Gulf. The assessment makes use of an oil-spill-model, whose wind-induced factor is parameterised using the drifter data. Results were validated using data from the Weizhou Oilfield oil-spill accident in August 2008. Combined with the local geographical attributes, an enhanced oil spill susceptibility map of the Beibu Gulf is presented, which more accurately describes the seasonal characteristics of the susceptibility in this area.