A comparison of field data and theoretical models for wave-current interactions at the bed on the continental shelf

Models for the combined effect of waves and currents on the continental shelf developed by Smith and by Grant and Madsen predict near-bottom velocity profiles and values of boundary shear stress that agree reasonably well with reanalyzed data collected by Cacchione and Drake ( Journal of Geophysical Research, 87, 1952–1960, 1982) using the Geoprobe system in Norton Sound, Alaska. The data set includes velocity profiles recorded during a two-day storm, sequences of which were averaged to indicate the mean flow conditions during two periods of relatively steady flow. Estimates of the reduction in vertical diffusion of momentum and mass as a result of near-bottom suspended sediment indicate that no suspended sediment stratification correction is required in this case. The values of the shear velocity associated with the mean current, determined from the averaged velocity profiles after making a zero-plane adjustment, are better predicted by the wave-current interaction models than by a similar model that neglects the wave contribution. The results of the Smith ( The sea, 6, 539–577, 1977) model, presented for two different forms of the eddy viscosity, indicate a significant enhancement of the boundary shear velocity due to the current and the waves, compared to the slope of the velocity profile above the wave boundary layer, due to the current only.