The Study Of Infrared Emissivity Of Sea Surface With Oil Pollution

Emissivity is a key parameter in infrared measuring. In ocean remote sensing, emissivity plays an important role, for example, detecting the sea surface temperature, salinity, ocean current, and so on. Moreover, as ocean exploitation developed, oil pollution on the sea surface is becoming a striking problem. Detecting such pollution in time helps reduce the damage. As oil and clean sea surface have different emissivity, it is possible to detection the oil pollution on the sea surface by measuring the sea surface emissivity. In this article, existing models of sea surface emissivity are studied. By studying the difference between a clean sea surface and an oil layer, a model for calculating the emissivity of an oil-polluted sea surface is developed. As the sea surface is rough, shadowing effect is considered. Simulation is then carried out, with the help of Matlab, where the wavelength of interest is chosen as 3.4 m and 10 m. It is shown that emissivity of clean sea surface decreases as detection angle increases, with a maximum of about 0.95 when viewing in 90o and a minimum slightly above 0.5 when viewing in 90o. Similar situation is obtained for oil-polluted sea surface. However, when the wavelength equals 10 m, the difference in emissivity between the two is obvious, which is significant enough for detection. Moreover, the difference in emissivity is sensitive of thickness of the oil layer, which makes it possible to detect the thickness of the oil-layer. It can be concluded that detecting oil pollution on the sea surface by measuring the emissivity of the sea surface is very promising.