Nighttime detection of oil spills in the Gulf of Mexico using satellite infrared images

Oil spills on water have an enormous impact on the complex ecosystem as a results of the interplay between physical and biochemical processes that occur over a large area and a long period of time. On April 20, 2010, the worst oil spill disaster followed the explosion that recently destroyed the Deepwater Horizon oil platform in the Gulf of Mexico. Passive and active remote-sensing technologies for oil spill surveillance have been devised by many researchers. Current satellite-based oil spill detection methods are mainly used during the daytime. In general, detection becomes difficult on cloudy days or at night, when there is little solar heating. Infrared oil spill detection relies on either temperature or emissivity contrast of oil-covered surfaces during the daytime. This study provides a unique method for detecting oil spills at nighttime using the physical properties by decomposing the unpolarized surface reflectivities and by using the refractive index of water and oil. We use the Moderate Resolution Imaging Spectroradiometer (MODIS) data in this investigation. As a result, the decomposed reflectivities show the spreading of the oil in the Gulf of Mexico. The retrieved refractive index values range from 1.1 to 1.25 for water and from 1.25 to 1.4 for oil. Consequently, this proposed method is effective and useful for detecting an oil spill on the sea-water in the nighttime.