Satellite image of Louisiana oil spill

In this radar image, acquired from Envisat's Advanced Synthetic Aperture Radar (ASAR) on 2 May 2010 03:45 UTC (Saturday night local time), the oil spill is visible due east of the Delta National Wildlife Refuge extending into the Gulf of Mexico. The white dots are oil rigs and ships. Radar is especially suited for detecting oil spills because it works day and night, can see through clouds (unlike optical sensors) and is particularly sensitive to the smoother water surface caused by the oil.

Wind can easily spread oil on the water, with the course determined by the wind's direction and speed. Following the explosion of the drilling rig on 22 April that produced the oil leak, the winds were blowing west-northwest. On Saturday winds were blowing from the southeast, pushing the slick toward Louisiana.

Radar
Radar is especially suited for detecting oil spills because it works day and night, can see through clouds (unlike optical sensors) and is particularly sensitive to the smoother water surface caused by the oil. Depending on the situation, oil is harder to detect in optical satellite observations because the surface changes are not as pronounced.

The next ASAR and MERIS images of the