A Coupled Hydrodynamic–Bottom Boundary Layer Model of Storm and Tidal Flow in the Middle Atlantic Bight of North America

Abstract The effects of increased friction and tides on circulation in the Middle Atlantic Bight (MAB) during the SWADE storm of 25–28 October 1990 have been investigated using a three-dimensional hydrodynamic model coupled to a bottom boundary layer model that calculates combined wave–current bottom drag coefficients. Winds were initially parallel to the coast (downwelling favorable) throughout the MAB, first shifting to offshore within the central MAB and then in the northern MAB, while remaining parallel to the coast within the southern MAB. The wind-driven circulation was approximately alongshore, with an onshore component at the surface and an offshore component at depth associated with downwelling. Compared to model runs with a pure current bottom friction formulation, the additional bottom friction in the coupled model decreased currents uniformly in shallow water and caused slight offshore rotation during downwelling circulation, but the effects were limited because of the persistent stratificatio...