Infragravity rip current pulsations

Abstract

The origins of rip current pulsations within the infragravity frequency band (0.004–0.04 Hz) are determined from measurements made with arrays of colocated pressure and velocity sensors deployed on a beach with persistent rip current channels. The observations indicate significant energy in cross‐shore infragravity velocities that varies spatially in the alongshore due to the presence of rip channels. Infragravity velocities are smaller within the rip channel than on the shore‐connected shoal owing to differences in water depth. Rip current pulsations at infragravity frequencies are linked to standing infragravity motions but not to the ponding and subsequent release of water by wave group pumping.