Space images show spreading oil spill
26 May 2010
Millions of people in the southern United States are watching with bated breath as a huge, brown monster swirls around offshore, preparing to smother the nearby coast. The monster in question is a massive oil slick, which is drifting at the mercy of winds and ocean currents. If it comes ashore, important fishing grounds, tourist beaches and wildlife breeding areas will be buried beneath thick, clinging sludge. A major environmental disaster is threatened.
Remote sensing spacecraft from many countries, including ESA’s Envisat, are monitoring the slick’s movements 24/7. Optical instruments on the spacecraft are able to detect the surface spill in daytime, when the area is cloud-free. Radar instruments can see the slick at night and under cloud, whilst providing information about surface roughness and current flow. This makes it possible to calculate the direction in which the pollution may spread.
The crisis began on 22 April, after a drilling rig exploded and sank in the Gulf of Mexico. Since then, thousands of barrels of crude oil have been escaping each day from a damaged oil well, 1.5 km under the drilling rig. Within four days, the spill had spread over an area 77 km long and 63 km wide. At first, satellite images showed that the oil was being driven toward the Louisiana shore, but, fortunately, the winds changed and the slick has remained mainly in the open sea.
However, images from space now show a long tongue of oil which is spreading southwards. By 19 May, radar images from Envisat indicated that it had entered a powerful ocean current which could carry the oil south towards Florida’s beautiful coral reefs.