Observed Circulation and Inferred Sediment Transport in Hudson Submarine Canyon.

Velocity and temperature time series from Hudson Submarine Canyon and hydrographic surveys of seven canyons of the Middle Atlantic Bight indicate that the effects of storms, tides, and incoming internal waves are intensified in submarine canyons. Storms with strong eastward and westward wind stress cause strong upwelling and downwelling through the upper layers of Hudson Canyon. Internal waves are concentrated in the canyon head and near the floor, in agreement with theoretical predictions. Slope water in the outer part of the canyon is mixed in near-floor layers which could be caused by breaking internal waves. Internal tides are generated in the central part of the canyon. Oscillations at tidal frequencies dominate the near-floor velocity field below the thermocline, accompanied by high-frequency spikes that may be nonlinear interface waves propagating on top of a bottom mixed layer caused by unstable density gradients during flood tide. Energetic internal wave activity is apparently responsible for sediment sorting in the canyon head the internal waves become more energetic as the sediment grain increases. Below the thermocline, the tidal oscillations vary in amplitude with the phases of the moon the observed deposition of mud can easily occur during weeks of low velocity. Author