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Mapping sea surface oil slicks using RADARSAT‐2 quad‐polarization SAR image
Author(s) -
Zhang Biao,
Perrie William,
Li Xiaofeng,
Pichel William G.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl047013
Subject(s) - racing slick , remote sensing , synthetic aperture radar , geology , scattering , polarimetry , environmental science , polarization (electrochemistry) , optics , physics , chemistry
Polarimetric SAR decomposition parameters, average alpha angle () and entropy ( H ) are estimated for oil‐slick contaminated sea surfaces and slick‐free conditions using a RADARSAT‐2 quad‐polarization SAR image. The values of H and within oil slick areas are significantly higher than those of the ambient sea surface, indicating the dominance of Bragg scattering for the slick‐free ocean and non‐Bragg scattering for the oil‐slick area. In land classification, the conformity coefficient ( μ ) is often used to discriminate surface scattering with double‐bounce or volume scattering. Based on this rationale, we also develop a method using μ as a logical scalar descriptor to map oil slicks under low‐to‐moderate wind conditions. The proposed method is assessed using a RADARSAT‐2 quad‐polarization SAR image of oil slicks in the Gulf of Mexico. Analysis shows that when μ is positive the sea surface is slick‐free, whereas μ is negative for oil‐slick areas. This method provides a simple and effective mapping technique for oil slick detection.