Washington: NASA for the first time, participated in Norway's annual oil spill cleanup exercise in the North Sea from June 8 to 11.

Scientists flew a specialised NASA airborne instrument, called the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), on NASA's C-20A piloted research aircraft to monitor a controlled release of oil into the sea, testing the radar's ability to distinguish between more and less damaging types of oil slicks, NASA said in a statement.

Norway's Oil on Water exercise has been held annually since the 1980s and in these drills, oil is released onto the ocean and then recovered, giving responders experience with existing cleanup techniques and equipment and a chance to test new technologies.

"This year was special, because we had our own dedicated science experiment in the middle of the training exercise," said Camilla Brekke, associate professor in the department of physics and technology, at the University of Tromso, Norway.

Brekke invited scientists Cathleen Jones and Ben Holt from NASA's Jet Propulsion Laboratory, Pasadena, California, to participate in the experiment.

Radars "see" an oil spill, because of a characteristic that the Greek philosopher Aristotle first wrote about 2,500 years ago: pouring oil on water smooths the surface.

The Norwegian exercise released emulsions of differing thicknesses, so that the scientists could have a range of conditions to calibrate the UAVSAR data.

The experiment also tested the instrument's ability to distinguish between petroleum, and plant-based oil, found in algal blooms.

Norway is one of a few nations worldwide that allow oil to be discharged at sea, to test new cleanup technologies and procedures. (IANS)