Estimating Bottom Stress on Continental Shelves from Tidal and Wave Models

Abstract

A numerical model was developed to estimate bottom stresses induced by waves and tides, in order to obtain multiyear statistics on the occurrence of sediment resuspension over the continental shelf. The model consists of a tidal module which predicts tidal currents at level 1 m above the seabed by employing 20 tidal constituents, and a wave module supplying near-bottom orbital velocities averaged over a wave spectrum. Predicted waves and tides were combined to provide bottom stress estimations at the temporal interval of one hour. The model was tested at the Yellow/East China Sea and compared with observations. Tidal currents and wave heights predicted in the model was consistent with observations, and the temporal pattern of predicted bottom stress matched with that of suspended sediment concentrations observed. It was found that the temporal resolution of several hours is required to resolve extreme events which cause resuspensions and that tidal constituents other than M_2 would be necessary to reproduce tidal currents used in the bottom stress estimation