An Experimental Study of X-Band Synthetic Aperture Radar ( SAR ) Imagery for Marine Oil Slick Monitoring

In this study, the usefulness of multi-polarization X-band SAR data for oil slick monitoring is investigated. The effect of incidence angles and noise contamination, and the combination of HH and VV polarization channels for oil slick monitoring is discussed. Dualpolarization data collected by TerraSAR-X and COSMO-SkyMed during two large-scale oil spill exercises in the North Sea is analysed. Oil slicks are detected in low wind speeds (1.6-5 m/s) over a range of incidence angles. While the noise contamination of the signal is seen to increase with increasing incidence angles, the multi-polarization features provide less information at the lowest incidence angles here available (~20°-21° for TerraSAR-X and ~24°-26° for COSMOSkyMed). When slick characterization utilizing multi-polarization features is desired, intermediate incidence angles seem preferable. For TerraSAR-X data at incidence angles ~27°29° and ~ 41°-42°, consistency in feature values between scenes is seen to some extent. No clear variations with slick age are observed. TerraSAR-X data, being coherent in phase, is found more useful for multi-polarization analysis than COSMO-SkyMed in this data set.