An automated algorithm for calculating the ocean contrast in support of oil spill response

Abstract

In remote sensing of the ocean, contrast in the measured intensity between clean water and other features is used to identify different objects on the ocean surface either directly or indirectly via alteration of the ocean wave spectrum. The damping ratio, a measure of contrast, is increasingly used for operational oil spill monitoring as an aid or alternative to visual inspections by trained personnel, and can in some cases identify thicker oil in a slick. A method is proposed for automatically calculating the contrast based upon the statistical properties of the measured intensity signals from the ocean surface, and shown to work well even for complex slick geometries. The algorithm is demonstrated using synthetic aperture radar (SAR) data from UAVSAR and Sentinel-1 to show that it can handle multi-frequency and medium-to-high resolution data. The algorithm's flexibility and computational simplicity makes it suitable for real-time processing to support oil spill response.