Robust Satellite Techniques (RST) for Oil Spill Detection and Monitoring

Satellite remote sensing is an useful tool supporting the management of marine technological hazards, especially for what concern oil discharge. Nowadays, the most reliable satellite techniques are based on SAR (Synthetic Aperture Radar) active sensors operating in the microwave region of the electromagnetic (EM) spectrum. Such methods (even if not in whatever wind condition), assure good sensitivity for oil spill detection and high spatial resolution for a detailed description of the polluted area. Unfortunately, they cannot be used for real-time monitoring at all latitudes because of a revisiting cycles which ranges from few days up to 5 weeks moving from polar to equatorial zones respectively. Passive optical sensors on board meteorological satellites could be, in principle, also used for oil spill monitoring provided that suitable data analysis techniques (still lacking) are developed. In fact, thanks to a time resolution which is better than of few hours (up to few minutes) and despite their lower spatial resolution (not better than 250 m in the visible spectral range) they could represent the unique possibility when a timely detection is crucial in order to mitigate the damages. In this paper a new satellite technique for oil spill detection and monitoring is discussed. It is based on the general RST (Robust Satellite Techniques) approach applied to AVHRR1 observations in the Thermal Infrared (TIR) region of the EM spectrum. The proposed approach, which exploits the analysis of multi-temporal satellite records, seems able to detect the anomalous signals on the sea due to the oil polluted areas with excellent reliability (0% of false alarms) and good sensitivity in different observational conditions. It is applied in this paper to the "San George" Argentina -Uruguay oil spill event occurred in February 1997. Preliminary results so far achieved confirm the reliability of the proposed approach which promises to offer new (economically sustainable too) opportuniti- es for building a real-time monitoring system for oil spill at the global scale.