Remote sensing assessment of oil spills near a damaged platform in the Gulf of Mexico

Highlights: • Over 80% of the cloud-free images show oil slicks near the MC-20 site in 2012–2016. • Average oil coverage area is 14.9 km² for all cloud-free images in 2005–2016. • A cumulative oil-contaminated footprint of 1900 km² around the site is detected. • Average oil discharge rate is estimated to range from 48 to ~1700 barrels/day. • River plume dynamics largely influences the variability in oil slick distributions. - Abstract: An oil platform in the Mississippi Canyon 20 (MC-20) site was damaged by Hurricane Ivan in September 2004. In this study, we use medium- to high-resolution (10–30 m) optical remote sensing imagery to systematically assess oil spills near this site for the period between 2004 and 2016. Image analysis detects no surface oil in 2004, but ~40% of the cloud-free images in 2005 show oil slicks, and this number increases to ~70% in 2006–2011, and >80% since 2012. For all cloud-free images from 2005 through 2016 (including those without oil slicks), delineated oil slicks show an average oil coverage of 14.9 km²/image, with an estimated oil discharge rate of 48 to ~1700 barrels/day, and a cumulative oil-contaminated area of 1900 km² around the MC-20 site. Additional analysis suggests that the detected oil slick distribution can be largely explained by surface currents, winds, and density fronts.