The Role of the Benthic Boundary Layer in Frontal Stability and Cross-shelf Exchange: An Idealized Model of the East Coast of the United States

We are developing a three-dimensional, nonhydrostatic, high-resolution model with idealized bathymetry to simulate the shelf and shelf-break front circulations of an archetypical passive margin off the eastern coast of the United States. Studies have suggested that a convergence occurs at the foot of the front, in the benthic boundary layer, driving upwelling of nutrient- and CO2-rich water at the frontal boundary (Chapman and Lentz, 1994; Houghton, 1997). Our goal is to understand the relationship between the benthic boundary layer, stratification, and the cross-shelf exchange of carbon dioxide and nutrients. We find that the horizontal density gradient and stratification interact and control the benthic boundary layer velocity magnitudes and directions. We assess the effect of physical factors such as stratification, horizontal density gradient, and wind direction on the supply of nutrients to the surface waters and exchange with the open ocean. Chapman, D.C. and Lentz, S.J., 1994, Jour. Phys. Oceanogr., vol. 24, pp. 1464-1479. Houghton, R.W., 1997, Geophys. Res. Let., vol. 24, no. 16, pp. 2035-2038.