Oil spill, radar imaging and surface current charts
 |
Since 21 August 2009, oil has been leaking from the West Atlas drill rig in the Timor Sea. Aircraft are periodically spraying the oil slick with dispersants and another mobile rig arrived on the scene mid-September to provide assistance. Attention quickly focused on fears that the slick could pollute the Kimberley coast in the northern part of West Australia and its globally important barrier reef system.
Envisat satellite trains its eye on the oil slick
On 8 September 2009, the Envisat satellite acquired an image of the area with its Advanced Synthetic Aperture Radar (ASAR) instrument. Spot Image received the image the same day and contacted Infoterra UK to identify the oil slick.
|
|
|
|
||||||||||||||||||||||||||||||||||||
|
Oil slick zigzagging north-eastward
The satellite image revealed that the oil slick was still a long way from the Kimberley coast, stretching for more than 150 km north-east of the drill rig. But the flow of the slick was not linear, sharply changing direction twice. To understand why, Spot Image contacted Mercator-Ocean.
Surface current charts explain the oil slick’s trajectory
Mercator-Ocean’s numerical models are capable of predicting sea-state parameters (temperature, salinity, etc.) and ocean currents around the globe, from the surface to the sea floor. It conducted a survey of the zone between 21 August 2009, when oil began leaking from the rig, and 8 September 2009, when the Envisat image was acquired.
|
|
|
|||||||||||||||||||
|
The small arrows on the charts indicate the direction of surface currents. The black dot marks the position of the drill rig, while the thick black arrow shows the zigzag trajectory of the slick as it drifts north-eastward with the currents.
|