Environmental group SkyTruth is investigating a likely 250km long oil slick in Sudan waters, probably discharged from a moving vessel over several hours.
On May 19, 2023, Sentinel-2 satellite images detected the discharge off the coast of Sudan. According to SkyTruth, rough preliminary estimates of the slick volume equate to at least 120,000 gallons, assuming a 1-micron-thick slick on average.
The strong spectral signature of this slick on Sentinel-2 imagery indicates that in many places it’s actually much thicker than 1 micron. The unusually large size and volume of this slick suggests it could be the result of tank washing by a petrochemical tanker, rather than bilge discharge from a cargo ship.
Out of 94 AIS vessel tracks transiting the region in the 12 hours preceding the slick, SkyTruth winnowed the potential sources down to 4: Vietnam-flagged oil tanker, a Panama-flagged container ship, a Marshall Islands-flagged bulk carrier and a Bahamas-flagged bulk carrier. They based their analysis on the following assumptions:
- The polluting vessel was not running dark; it was broadcasting Automatic Identification Systems (AIS)
- The vessel AIS track closely follows the slick as it appears on image and a Sentinel1 radar image taken just 4.5 hours earlier. The slick has not drifted appreciably since it was discharged from the vessel
- The AIS track shows it had moved beyond the footprint of the images when the satellite passed overhead. The vessel responsible for this slick is not visible on the image
https://twitter.com/SkyTruth/status/1661352045419405312
