Deepwater Horizon ASAR

Envisat ASAR image earlier the same day (ascending overpass) shows the oil as much darker than the surrounding water due to oil damping of cm scale wind ripples. The arrows point to features of thicker and thinner oil which could be seen in the optical image, but are not distinguishable in the SAR image. On the other hand, the dark area (oil) is larger than in the optical image, because SAR is sensitive to surface oil films that are too thin to be observed in optical images. Credit: ESA LearnEO