Baroclinic processes in coastal oceans: Observations and modeling on Georges Bank and the South Atlantic Bight continental shelf

The understanding of baroclinic processes in coastal oceans remains incomplete. The recent development of coastal ocean observing and prediction systems has provided additional observational and model data that has facilitated new insight. The application of these developments to two coastal ocean regions is described: Georges Bank and the continental shelf of the South Atlantic Bight. There are several components. First, the circulation of the tidal front along the Southern Flank of the Georges Bank region during May 1999 is examined for the purpose of understanding the transport of larval fish for periods of days to a week. Assimilation of shipboard ADCP data from several Georges Bank cruises into 3-D models is used to produce the hindcast circulation. Second, unusually cold sea-water temperatures were observed along much of the U.S. eastern seaboard during the summer of 2003. The available hydrographic and atmospheric observations were analyzed to determine the conditions and forcing mechanisms in the South Atlantic Bight. Third, the basic formulation of the potential energy associated with stratification in the South Atlantic Bight is presented. The work balance fields suggest the presence of a front in the near-shore region that fluctuates around the 10-m isobath during spring and summer. During the fall and winter, the different forcing mechanisms combined to provide conditions favoring mixing over the entire shelf. Fourth, a set of model simulations is conducted to determine the principal forcing mechanisms during the cold event of 2003. The dynamics in the inner- and mid-shelf during the intrusion event were controlled by wind, stratification and river discharge. The outer-shelf dynamics are not adequately represented in these simulations because of inappropriate characterization of Gulf Stream dynamics.