Space shuttle observations of open ocean oil slicks

We observed oil slicks along a ship wake in the northern Arabian Sea. The slicks were recorded on photographs taken by astronauts onboard Space Shuttle Columbia during mission STS62 in March 1994. The longest slick had a length of 21.25 km and an average width of 1.67 km. The total volume of oil discharged into the sea was estimated at 108±37 m3 assuming a reasonable thickness of the oil film to be 3±1 μm. The oil slick width increased with the distance from the ship. This image feature was converted into information in the time domain with the ship speed being a conversion parameter. Using this method, we determined that the average oil slick spreading velocity with respect to the ship wake was 13.6 cm s−1. The analysis indicated that turbulent diffusion and wind drag were the dominant forcing for the oil slick spreading.