Baroclinic vortices over a sloping bottom
Citable URI
https://hdl.handle.net/1912/2457DOI
10.1575/1912/2457Abstract
Nonlinear quasigeostrophic flows in two layers over a topographic slope are
considered. The evolution depends on the size of two parameters which indicate
the degree of nonlinearity at depth. The first measures the importance of relative
vorticity advection and the second of stretching vorticity.
Two types of isolated vortex are used to examine the parameter dependence.
An initially barotropic vortex remains barotropic only when the first parameter
is large, otherwise topographic waves dominate at depth. An Initially surface-trapped
vortex larger than deformation scale is baroclinically unstable when the
second is large, but is stabilized by the slope otherwise.
Both parameters are also relevant to cascading geostrophic turbulence. If the
stretching parameter is large, a "barotropic cascade" occurs at the deformation
radius (Rhines, 1977) and the cascade "arrests" when the relative vorticity parameter
is order unity. If small, layer coupling is hindered and the cascade is
arrested at the deformation scale, with the flow dominated by isotropic surface
vortices.
In both cases, the distinction between vortices and waves is transparent when
viewing potential vorticity. It is more difficult to identify waves and vortices from
the streamfunction fields, because the waves are present in both layers.
Description
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1996
Collections
Suggested Citation
Thesis: LaCasce, Joseph H., "Baroclinic vortices over a sloping bottom", 1996-09, DOI:10.1575/1912/2457, https://hdl.handle.net/1912/2457Related items
Showing items related by title, author, creator and subject.
-
Interaction of high frequency internal waves and the boundary layer on the continental shelf
Sanford, Lawrence P. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1984-08)Intermittent, shoreward propagating packets of high frequency first mode internal waves are common on the continental shelf when the water column is stratified and may induce large fluctuations in near bottom velocity. ... -
Variability of currents in Great South Channel and over Georges Bank : observation and modeling
Chen, Changsheng (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1992-06)This thesis consists of two parts: (I) variability of currents and water properties in late spring in the northern Great South Channel and (II) numerical study of stratified tidal rectification over Georges Bank. In part ... -
When an eddy encounters shelf-slope topography
Cherian, Deepak A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2016-09)Eddies in the ocean move westwards. Those shed by western boundary currents must then interact with continental shelf-slope topography at the western boundary. The presence of other eddies and mean lows complicates this ...