Surface and bottom boundary layer dynamics on a shallow submarine bank : southern flank of Georges Bank

Abstract

The thesis investigates the circulation at a 76-m deep study site on the southern flank of Georges Bank, a shallow submarine bank located between the deeper Gulf of Maine and the continental slope. Emphasis is placed on the vertical structure of the bottom boundary layer driven by the semi diurnal tides and the flow field's response to wind forcing. The observational analysis presented here is based on a combination of moored array and bottom tripod-mounted current, temperature, conductivity, and meteorological data taken between February and August 1995. Results from the bottom boundary layer analysis are compared to numerical model predictions for tidal flow over rough bottom topography. The flow response to wind forcing is examined and brought into context with the existing understanding of the wind-induced circulation in the Georges Bank region. Particular attention is given to the vertical distribution of the wind-driven currents, whose variation with background stratification is discussed and compared to observations from open ocean studies.