Author(s)

R. Gangeskar & E. Nøst

Abstract

Oil spill incidents represent a large cost, economically and environmentally. It is of great importance to detect an oil spill as soon as possible after a leakage, in order to reduce the consequences. Wavex is a system for monitoring scaled directional wave spectra and sea surface currents from X-band radar images. The oil spill detection (OSD) system considered in this paper consists of the hardware and software modules of the Wavex system, in addition to software modules specific for oil detection purposes. The principle of measurement is based on the fact that areas covered by oil spill reflect less microwave power, due to the dampening of the sea surface capillary waves. The OSD system was thoroughly tested at a field trial carried out in October 2004 near the Troll field, off the west coast of Norway. The Norwegian Clean Seas Association for Operating Companies (NOFO) especially arranged the trial for this purpose. Six small releases of oil equivalents were discharged, and they could be detected and followed by the system during various wind and wave conditions. Images providing an average of the back-scattered intensity from various parts of the sea surface were shown to be useful for the system operator. Continuous surveillance of local areas is particularly helpful during the hours of darkness. Later, the data were reprocessed with a new and completely automatic oil detection algorithm using methods of image segmentation and object classification, and the oil was automatically detected. This algorithm is now implemented in the real-time system. More effort should be put into testing the system operation during marginal conditions, such as low wind speeds with non-optimal directions of sight and rougher sea states, as well as testing the system during various geometrical conditions. Keywords: oil spill detection, field trials, navigation radar, signal processing, image processing.

Keywords

oil spill detection, field trials, navigation radar, signal processing, image processing.