Ocean surface slick characterization by multi-polarization Radarsat-2 data

Abstract

Marine oil spills are an important environmental problem, and satellite SAR remote sensing have become a valuable tool for the detection and monitoring of these spills. Natural phenomena with similar appearance as oil in SAR images, producing false detections, compose a challenge for oil spill observation services. One such lookalike phenomena is biogenic slicks produced by marine organisms. In this study we evaluate multi-polarization features for oil spill characterization and oil versus biogenic slick discrimination. During large-scale oil-on-water exercises conducted in the North Sea in June 2011 and June 2012, both mineral oil and plant oil were released and imaged by Radarsat-2 in Fine Quad-polarization mode. The plant oil will form a lm resembling biogenic slicks. The mineral oil spill and simulated look-alike are in this study compared based on multi-polarization features, combining the information in HH and VV channels. The polarimetric measurements from 2011 have earlier been analysed, and a potential for discrimination between mineral oil and biogenic slicks is found. The aim of the current study is to repeat the polarimetric analysis on the new independent data set from 2012. Preliminary results of the 2012 data set reveal both internal and between slick type variations, giving support to our previous findings from 2011.