How does HF-Radar work ?
© Klaus-Werner Gurgel, University of Hamburg, Germany
A decametric waves radar (HF-Radar) is a shore- or ship-based system,
- transmits electromagnetic waves of 6 MHz to 30 MHz,
(50 m to 10 m wavelength),
- which travel along the sea surface beyond the horizon by
ground wave propagation and
- are scattered back from ocean waves of half the electromagnetic
wavelength (Bragg scattering);
- measures the Doppler spectrum
caused by moving ocean waves;
- measures the speed of the surface current carrying the
- measures ocean wave height and the wave directional
spectrum using the second-order sea echos of the Doppler spectrum.
HF-Radar is a tool for synoptic on-line mapping of surface current fields
and the spatial distribution of the wave directional spectrum.