SAR, AIS, and Contextual Data for the Identification of Source Mechanisms for Ship Pollution False Positives

On September 2,2015, a RADARSAT-2 ScanSAR Narrow image was acquired of the Juan de Fuca Strait and the Strait of Georgia, British Colombia, Canada as part of routine ocean-pollution surveillance. The vessel, Coastal Intrigue, and a linear, slick-like feature trailing the stern of the vessel were detected. The source of the CIF was attributed to three possible mechanisms, namely a plankton bloom, turbulent wake, or some type of discharge from the Coastal Intrigue. At the time of the RADARSAT-2 acquisition, there were no reported plankton blooms in the Juan de Fuca Strait or the Strait of Georgia, so a plankton bloom was eliminated as a mechanism. A turbulent wake was also eliminated because turbulent wakes are seldom detected in the area where the Coastal Intrigue was travelling and the vessel Eva, which was travelling on essentially a parallel course as the Coastal Intrigue, did not produce a SAR-detected wake. Therefore, the most likely source-mechanism for the CIF was discharge (either oil or similar) from the Coastal Intrigue. The analysis of the RADARSAT-2 image acquired on September 2, 2015, AIS data, and wind data supports the conclusion that the CIF was from the Coastal Intrigue. There was, however, not enough information available to definitively identify the CIF substance other than the statement that the most likely source was either bilge oil or some other type of substance.