Oil source-fingerprinting in support of polarimetric radar mapping of Macondo-252 oil in Gulf Coast marshes

Highlights

• Oil source-fingerprinting (OSF) identified Macondo-252 oil in coastal marshes.

• OSF supports polarimetric SAR remote sensing detection of oil in interior marshes.

• Shoreline and interior marsh sediments were collected a year after the oil spill.

• Diagnostic ratio analyses (DRA) quantified categories of oil sediment occurrence.

• Similarity analyses extended DRA oil sediment categories to non-conclusive samples.

Abstract

Polarimetric synthetic aperture radar (PolSAR) data exhibited dramatic, spatially extensive changes from June 2009 to June 2010 in Barataria Bay, Louisiana. To determine whether these changes were associated with the Deepwater Horizon (DWH) oil spill, twenty-nine sediment samples were collected in 2011 from shoreline and nearshore–interior coastal marsh locations where oil was not observed visually or with optical sensors during the spill. Oil source-fingerprinting and polytopic vector analysis were used to link DWH oil to PolSAR changes. Our results prove that DWH oil extended beyond shorelines and confirm the association between presence of DWH oil and PolSAR change. These results show that the DWH oil spill probably affected much more of the southeastern Louisiana marshland than originally concluded from ground and aerial surveys and verify that PolSAR is a powerful tool for tracking oil intrusion into marshes with high probability even where contamination is not visible from above the canopy.