Review of new developments for oil spill remote sensing

摘要

Remote-sensors for application to oil spills are assessed and new developments summarized. A common sensor is an infrared camera or an IR/UV (infrared/ultraviolet) system. The inherent weaknesses include the inability to discriminate oil on beaches, among weeds or debris. There are many new developments in economical infrared cameras in the past few years. The laser fluorosensor is a most-useful instrument because of its unique ability to identify oil on backgrounds that include water, soil, ice and snow. It is the only sensor that can positively discriminate oil on most backgrounds. Disadvantages include the large size, weight and high cost. The laser fluorosensor has proven to be a most useful and powerful tool. Developments are limited in fluorosensors, however, new units are built about every five years. Radar, although low in priority for purchase, offers the only potential for large area searches and foul weather remote sensing. Developments are few and only a small number of commercial units are available. Radar is costly, requires a dedicated aircraft, and is prone to many interferences. A major weakness of radar is that it is limited to operation over seas with winds of about 2 to 8 m/s. Equipment that measures relative slick thickness is still under development. Passive microwave has been studied for several years, but instruments lack sufficient spatial resolution to be practical, operational instruments. A laser-acoustic instrument, which provides the only technology to measure absolute oil thickness, is under development and has recently been tested in an aircraft. Equipment operating in the visible region of the spectrum, such as cameras and scanners, is useful for documentation or providing a basis for the overlay of other data. It is not useful beyond this because oil shows no spectral characteristics in the visible region which can be used to discriminate oil. Despite low-cost developments in this field, these sensors are not recommended as providing additional utility over visual surveillance.