Surface currents in the German Bight measured by
backscattered radio waves - a comparison with conventional
measurements and model results.
H.-H. ESSEN, M.M. JANOPAUL, E. MITTELSTAEDT, J. BACKHAUS
North Sea Dynamics (ed. by Sündermann and Lenz), pp. 159...165,
Springer Verlag 1983.
Abstract - -
This paper presents electromagnetic HF (high frequency) techniques which permit
the measurement of ocean surface currents from shore.
The HF technique is based on the backscatter of CW (continuous wave) radio
signals from a moving ocean surface. Ocean surface waves having wavelengths one
half of the HF wavelength and, propagating towards or away from the radar, are
responsible for backscattering. The Doppler shift, with respect to the
transmitted signal, provides the actual phase velocity of the surface waves.
Due to the known scattering mechanism, the phase velocity can also be
determined theoretically. Deviations of the measured from the expected phase
velocity are attributed to underlying currents. By this method, the radial
component of the two-dimensional surface current can be determined. Although the
mechanism was discovered by Crombie (1955), the development of measuring
systems was not possible before recent advancements in computer techniques.
Barrick et al. (1974); Stewart and Joy (1974) and Barrick et al. (1977)
contributed the essential theoretical and experimental studies.
last update: Wednesday, 25-Nov-2015 15:30:53 CET