Radars unveil ocean currents
Satellite data is revealing clues about ocean currents
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Friday, 25, Jan 2008 11:00
A new technique based on the same principle as police speed-measuring radar guns is helping scientists to understand more about ocean currents.
According to the European Space Agency (Esa), the satellite radar data shows essential aspects of the currents, including the strength and variability of surface current regimes and their relevance for climate change.
Observations of the Earth's oceans are being made by the advanced synthetic aperture radar (Asar) instrument aboard Esa's Envisat satellite,
By using the new information embedded in the radar signal - the Doppler shift of the electromagnetic waves reflected from the water surface - scientists were able to determine how surface winds and currents contribute to the Doppler shift.
"These measurements are very useful for advancing the understanding of surface current dynamics and mesoscale variability, as well as for determining surface drift, important for oil dispersion and pollution transport and for wave-current interaction, probably influencing the existence of extreme waves," said Dr Johnny Johannessen of Norway's Nansen Environmental and Remote Sensing Centre).
Dr Bertrand Chapron of the French Research Institute for Exploitation of the Sea added: "The method at this very high resolution could also complement the use of additional information sources to improve 3D ocean models.
"Its use for sensor synergy with radiometry, spectrometry and altimetry is very promising."