Computation of areas of probable detection of oil pollution on the sea surface as valuation of the spatial uncertainty in oil spill modelling

Abstract

We present a new method for a quantitative estimation of the areas of probable detection of oil pollution on the sea surface as evaluation of the spatial uncertainty in oil spill modeling. Unavoidable errors in the assessment of wind and currents forcing are the reason for presenting the simulated oil spill position as a coordinates probability density function (PDF). The Fokker-Planck equation is used to calculate the PDF at any time after oil discharge. The method allows to build a stable estimate for the boundaries of the area in which an oil spill can be detected with a given probability level. The model can be used for both instantaneous point source spill and distributed continuous source spill. The computation was illustrated by simulations that were made for a hypothetical oil spill with the use of operational hydrometeorological forecasts in the Arctic region. The described approach is suitable for joint use with any oil spill model on the sea surface as means for constructing zones of possible spill detection to support the responders’ requirements. Results of the calculations presented as polygons with a given probability assigned can be implemented in any GIS.