Eighteen near-shore current records within area 11 km2 on the Long Island inner shelf have been examined for indication of small-scale topographic influence. In the fricitonally influenced near-shore water column, currents over the 39-day records are generally oriented slightly clockwise of the longshore direction toward the principal axis of the local ridge-and-swale topography. This orientation angle is largest and closest to the local topographic axis when semidiurnal tidal currents dominate other flows, a result which may suggest that tidal currents play a role in molding the local topography. Viscous tidal current theory for a constant depth surface described the observed dependence of the semidiurnal (M2) tidal current ellipticity and ellipse orientation on depth. The inferred vertical eddy viscosity coefficient ranges from 5 to 35 cm 2/s. |