As clearly revealed for Hurricane Ike, wind speeds around the hurricane's eye can far exceed 40m/s (about 80 knots).
The sea surface roughness map clearly shows a minimum in the well-delineated eye where the conditions are relatively calm. Around the eye of the storm, the sea surface velocities also capture the circular direction of the prevailing wind and waves, as visible in this image over Great Inagua Island in the Bahamas on 7 September.
This analysis of the residual Doppler from the radar echoes allows for the retrieval of radial velocities which are used to provide systematically and in Near Real Time a map of the radial component of sea surface velocity.
The colour of the graphics shown in the 'current' section is representative of a very strong eastward motion in the southern part of the hurricane and a symmetrical strong westward motion in the northern part. These observations are clearly in line with the hurricane winds turning counter clockwise.
In the future, these combined instantaneous wind speed, wave heights and surface velocity maps will be integrated into models to improve storm track and intensity forecasts.
"Sentinel-1, the follow on to Envisat's SAR mission, will have an improved instrument capability with dual polarisation and higher imaging resolution, and will benefit from this demonstration to achieve better winds accuracy in extreme conditions," Dr Collard said.
|Contact: Mariangela D'Acunto|
European Space Agency