MONITORING OIL SPILL PROGRESSION AND OIL SPILL VOLUME USING SATELLITE IMAGES

Abstract

Satellite imagery is an indispensable tool in operational oil spills mapping. The smooth surface of oil sleeks make them visible in Synthetic Aperture Radar (SAR) imagery due to the low backscatter values making the oil spills distinctly dark in SAR images compared to the surrounding water. Oil extent delineation using SAR is very common but aside from using SAR images, optical satellite images are also of great help by capitalizing on the spectral characteristics of the oil surface to isolate the oil extents. The delineated extents are post-processed in a Geographic Information System (GIS) software where the oil spill area is calculated and published as oil extent maps. Though the area can be calculated, estimating the volume of oil present in the extent map remains to be a challenge. To answer this problem, this paper proposes a Physics-based solution to calculate the thickness of the oil by analysing local maxima in the reflectance spectrum of oil-covered water. Using this technique, oil thickness was estimated from Sentinel-2 multispectral images of an oil spill. It yielded an average oil thickness estimate of 0.560 ± 0.164 microns. The calculated thickness is used to estimate the volume of spilled oil.