The error source analysis of oil spill transport modeling: a case study

Numerical modeling is an important tool to study and predict the transport of oil spills.However,the accuracy of numerical models is not always good enough to provide reliable information for oil spill transport. It is necessary to analyze and identify major error sources for the models.A case study was conducted to analyze error sources of a three-dimensional oil spill model that was used operationally for oil spill forecasting in the National Marine Environmental Forecasting Center(NMEFC),the State Oceanic Administration, China.On June 4,2011,oil from sea bed spilled into seawater in Penglai 19-3 region,the largest offshore oil field of China,and polluted an area of thousands of square kilometers in the Bohai Sea.Satellite remote sensing images were collected to locate oil slicks.By performing a series of model sensitivity experiments with different wind and current forcings and comparing the model results with the satellite images,it was identified that the major errors of the long-term simulation for oil spill transport were from the wind fields, and the wind-induced surface currents.An inverse model was developed to estimate the temporal variability of emission intensity at the oil spill source,which revealed the importance of the accuracy in oil spill source emission time function.