On classification of sea surface oil films using TerraSAR-X satellite polarization data

The paper presents the results of applying a new polarization method proposed in [28] to identify the type of surface pollution and differentiate between mineral oil films (crude oil and its emulsion and petroleum products) and films of other origin in sea surface radar images. The method is based on calculation of the quantitative characteristics for the ratios of suppression or intensification of scattered radio signals of different physical nature, viz., caused by capillary ripples several centimeters long, or wave breaking. TerraSAR-X satellite coaxial-polarized (VV/HH) SAR images are used. The data for analysis have been collected in areas where spots and slicks of known origin regularly occur, such as oil spills and natural oil seeps in the Gulf of Mexico and the Caspian Sea, and biogenic films in the Caspian Sea. The results of analyzing radar images from the TerraSAR-X satellite with controlled experimental oil emulsion spills in the North Sea are used for comparison. Based on the analysis of ten TerraSAR-X radar polarization images with surface sensing angles greater than 30°, it is shown that this method makes it possible to distinguish between oil spills and slicks formed by natural oil seeps and biogenic films with an accuracy higher than 80% regardless of the observation area.