Laboratory measurements of the vertical structure of rip currents

[1] This paper describes the three-dimensional variation of rip currents through the use of experimental measurements of rip currents in a directional wave basin. The rip currents are unstable, appearing sporadically at any given location. The vertical profile of the rip current is found to vary from depth-uniform inside the channel to depth-varying further offshore. Offshore from the channel the rip current has much stronger velocities at the surface than near the bottom. The instantaneous profiles twist rapidly over depth farther offshore and are fairly uniform in the channel. The depth variations are shown to be sensitive to the total volume flux in the rip.