Rather like a speed trap, Scientists at the SeaSAR 2008 workshop in Frascati, Italy demonstrated the use of satellite radar technology to measure ocean currents and wave formation.
An Advanced Synthetic Aperture Radar (ASAR)device mounted on ESA’s Envisat can track the movement of surface ocean currents. This device records microwave radar backscatter. By looking at the doppler shift of electromagnetic waves reflected from the ocean surface they are able to gain an insight on how winds and surface currents affect this doppler shift.
"The Doppler shift occurs due to changing relative velocities, experienced in everyday life in the way the pitch of a siren on a passing ambulance goes up as it approaches, then goes down as the vehicle recedes away."
"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,"
Read more at the Underwater Times
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