Brussels, 31 Aug 2005
The European Space Agency (ESA) is contributing to Hurricane Katrina alert and rescue efforts in the US, providing images and data captured by its satellites.
The International Charter on Space and Major Disasters was activated on August by the US Geological Service. ESA is a founding member of the Charter, which stipulates that global space agencies will put their resources at the service of rescue authorities facing major natural or man-made disasters. The Charter has already been activated more than 80 times since it was signed in 2000.
ESA's Envisat satellite captured images of Hurricane Katrina as it moved from the Gulf of Mexico into the US. Further ESA images and data will also be made available.
An optical image from Envisat shows the spiralling cloud patterns expected in a hurricane. A radar observation also pierces through the clouds to show how the hurricane's 250 km/hour winds scour the sea's surface. Envisat gathered the images using its medium resolution imaging spectrometer (MERIS) and advanced synthetic aperture radar (ASAR).
The ASAR instrument works by recording signal backscatter based on the sea's surface roughness. The storm's centre, which is wind-free, appears as a dark ring measuring approximately 60 km across. It shows up darker in the images because the water here is hardly rippled in comparison with the surrounding sea.
Casualties have been reported in the Gulf coast area, but exact numbers are yet to be determined. Much of New Orleans is currently underwater.
Hurricane Katrina formed in the Bahamas in mid-August, and struck South Florida on 25 August, killing nine people and leaving around a million without electricity.