US: Researchers at NASA”s Jet Propulsion Laboratory and the California Institute of Technology in Pasadena have developed a method to use a specialised NASA 3D imaging radar to characterise the oil in oil spills, such as the 2010 BP Deepwater Horizon spill in the Gulf of Mexico. The research can be used to improve response operations during future marine oil spills.
Caltech graduate student Brent Minchew and JPL researchers Cathleen Jones and Ben Holt analysed NASA radar imagery collected over the main slick of the BP Deepwater Horizon oil spill on June 22 and June 23, 2010. The data were acquired by the JPL-developed Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) during the first of its three deployments over the spill area between June 2010 and July 2012. The UAVSAR was carried in a pod mounted beneath a NASA C-20A piloted aircraft, a version of the Gulfstream III business jet, based at NASA”s Dryden Aircraft Operations Facility. The researchers demonstrated, for the first time, that a radar system like UAVSAR can be used to characterise the oil within a slick, distinguishing very thin films like oil sheen from more damaging thick oil emulsions.
“Our research demonstrates the tremendous potential of UAVSAR to automate the classification of oil in a slick and mitigate the effects of future oil spill tragedies,” said Jones. “Such information can help spill incidence response commanders direct cleanup operations, such as the mechanical recovery of oil, to the areas of thick oil that would have the most damaging environmental impacts,” he added.
Current visual oil classification techniques are qualitative, and depend upon the skill of the people doing the assessment and the availability of skilled observers during an emergency. Remote sensing allows larger areas to be covered in a consistent manner in a shorter amount of time. Radar can be used at night or in other low-light or poor weather conditions when visual surveys can”t be conducted.
UAVSAR characterises an oil spill by detecting variations in the roughness of its surface and, for thick slicks, changes in the electrical conductivity of its surface layer. Just as an airport runway looks smooth compared to surrounding fields, UAVSAR “sees” an oil spill at sea as a smoother (radar-dark) area against the rougher (radar-bright) ocean surface because most of the radar energy that hits the smoother surface is deflected away from the radar antenna. UAVSAR”s high sensitivity and other capabilities enabled the team to separate thick and thin oil for the first time using a radar system.