Performance of a VHF ocean surface radar in the surf zone

In the high VHF band (152.2 MHz) the Bragg scattering waves on the sea surface have wavelengths of about 1 m. The radar Doppler spectrum of echoes can be heavily modulated by swell in open water, and in the surf zone the effect is enhanced. Under these conditions the Bragg first-order lines are broadened This paper reports on a study to evaluate the integrity of the surface current maps produced by the VHF coastal ocean surface radar within the surf zone. Comparisons are made with radar data under calm conditions, and with currents measured with an acoustic current profiler mounted on the bottom. The radar current measurements are slightly more noisy under rough conditions, but it is clear that this technology has potential to monitor rip currents and coastal vortices in the surf zone when conventional techniques become strained.