Shelf circulation and cross-shelf transport out of a bay driven by eddies from an open-ocean current. Part I : interaction between a barotropic vortex and a steplike topography
Citable URI
https://hdl.handle.net/1912/4646As published
https://doi.org/10.1175/2010JPO4496.1DOI
10.1175/2010JPO4496.1Keyword
Transport; Eddies; Barotropic flow; Topographic effects; Vortices; Currents; Potential vorticity; Rossby wavesAbstract
This paper examines interaction between a barotropic point vortex and a steplike topography with a bay-shaped shelf. The interaction is governed by two mechanisms: propagation of topographic Rossby waves and advection by the forcing vortex. Topographic waves are supported by the potential vorticity (PV) jump across the topography and propagate along the step only in one direction, having higher PV on the right. Near one side boundary of the bay, which is in the wave propagation direction and has a narrow shelf, waves are blocked by the boundary, inducing strong out-of-bay transport in the form of detached crests. The wave–boundary interaction as well as out-of-bay transport is strengthened as the minimum shelf width is decreased. The two control mechanisms are related differently in anticyclone- and cyclone-induced interactions. In anticyclone-induced interactions, the PV front deformations are moved in opposite directions by the point vortex and topographic waves; a topographic cyclone forms out of the balance between the two opposing mechanisms and is advected by the forcing vortex into the deep ocean. In cyclone-induced interactions, the PV front deformations are moved in the same direction by the two mechanisms; a topographic cyclone forms out of the wave–boundary interaction but is confined to the coast. Therefore, anticyclonic vortices are more capable of driving water off the topography. The anticyclone-induced transport is enhanced for smaller vortex–step distance or smaller topography when the vortex advection is relatively strong compared to the wave propagation mechanism.
Description
Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 41 (2011): 889–910, doi:10.1175/2010JPO4496.1.
Collections
Suggested Citation
Journal of Physical Oceanography 41 (2011): 889–910Related items
Showing items related by title, author, creator and subject.
-
A barotropic vorticity budget for the subtropical North Atlantic based on observations
Le Bras, Isabela A.; Sonnewald, Maike; Toole, John M. (American Meteorological Society, 2019-10-17)To ground truth the large-scale dynamical balance of the North Atlantic subtropical gyre with observations, a barotropic vorticity budget is constructed in the ECCO state estimate and compared with hydrographic observations ... -
The adjustment of barotropic currents at the shelf break to a sharp bend in the shelf topography
Williams, William J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-02)During January-March, Scotian Shelf water has been observed to flow episodically from the southwestern Scotian Shelf directly across the Northeast Channel to Georges Bank. The possible factors that allow Scotian Shelf ... -
Potential vorticity constraint on the flow between two basins
Yang, Jiayan; Price, James F. (American Meteorological Society, 2007-09)This paper examines the role of potential vorticity (PV) balance in source- and sink-driven flows between two basins. As shown in previous studies, PV advection into a basin, say a positive PV advection, requires a negative ...