Lagrangian Measurements of Orbital Velocities in the Surf Zone

Abstract

Eulerian and Lagrangian measurements of orbital velocities in waves approaching a beach are analyzed with the goal of understanding the relative influence of wave-by-wave variations in mean-water level, wave height and incipient wave breaking on mass transport properties of waves in the surf zone. It is shown quantitatively that elevated local mean-water level correlates positively with increased Lagrangian mass transport at the free surface. Eulerian ADV measurements in the fluid column suggest that the depth-integrated wave-by-wave mass transport also correlates positively with the local mean-water level, and is only weakly linked to wave height and wave-breaking events.