Space shuttle observations of open ocean oil slicks

We observed oil slicks along a ship wake in the northern Arabian Sea. The s licks were recorded on photographs taken by astronauts onboard Space Shuttl e Columbia during mission STS62 in March 1994. The longest slick had a leng th of 21.25 km and an average width of 1.67 km. The total volume of oil dis charged into the sea was estimated at 108 +/- 37 m(3) assuming a reasonable thickness of the oil film to be 3 +/- 1 mum. The oil slick width increased with the distance from the ship. This image feature was converted into inf ormation in the time domain with the ship speed being a conversion paramete r. Using this method, we determined that the average oil slick spreading ve locity with respect to the ship wake was 13.6 cm s(-1). The analysis indica ted that turbulent diffusion and wind drag were the dominant forcing for th e oil slick spreading. (C) 2001 Elsevier Science Inc. All rights reserved.