Oil spill detection by imaging radars: Challenges and pitfalls

We challenge the often-made claim that fully polarimetric synthetic aperture radars (SARs) are beneficial for discriminating between mineral oil films and biogenic slicks. We conjecture that the results obtained from previous analyses of spaceborne polarimetric SAR data, which seem to show differences in the scattering mechanism between radar scattering from mineral oil films and biogenic slicks, result from instrument noise. Measurements carried out with the Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) of NASA/JPL, which has an extremely low noise floor, confirm this view and show that Bragg scattering theory applies also for scattering from mineral oil films. However, measured differences in the statistics of the radar backscattering from mineral oil films and biogenic slicks, may be real and not noise-related.