Comparison of Radarsat-2 and RCM Simulated Data for the Detection of Actionable Ocean Surface Oil

Abstract

Simulated RCM SC50 compact polarimetry (CP) imagery was compared to RADARSAT-2 for detection of actionable or thick oil. The SC50 has 50 m resolution and a 350 km swath width. A key advantage of CP data is the acquisition of two data channels and the retention of the relative phase between the data channels. Although there are numerous CP parameter that are applicable for oil slick characterization, the degree of polarization ( $p$ ) was selected for this study. $p$ varies between 1 (completely polarized wave) and 0 (completely depolarized wave). Scattering from the ocean surface is dominated by Bragg scattering meaning $p$ is polarized so approaches 1. In contrast, scattering from thick oil is generally depolarized, so $p$ approaches 0. $p$ for RADARSAT-2 and SC50 was compared to an oil thickness map derived from ASTER and Worldview imagery. Overall there was good visual agreement between the oil thickness classes and the spatial variability of the degree of polarization. There were, however, differences between the RADARSAT-2 and SC50 that were attributed to resolution and the noise floor. Overall the results suggest that the use of the SC50 CP mode, which balances resolution and spatial coverage, provides information on relative oil thickness that can effectively be used for operational oil spill response.