Sea-surface current measurements with an X band radar

A measurement system is under development, which uses a coherent X band radar operating from land based stations. By measuring the radar backscattering over several tidal cycles, tidal current patterns are observed in a test area which is 500 X 700 m in size. The radar is operated from two stations to obtain radial Doppler-velocity components which are corrected for Bragg-wave velocities and wind-drift and combined to current vectors. While the operation of radar from space and current gauges from ships is elaborate, the herein presented measuring system offers a low cost facility with high mobility. It has the potential for current monitoring as well as for case studies of changes in current dynamics which have an impact on erosion and sand transport, coastline changes and safety of navigation.