Woods Hole Oceanographic Institution

Claudia Cenedese

»Downwelling in Basins Subject to Buoyancy Loss
»Entrainment and mixing dynamics of surface-stress-driven stratifi ed flow in a cylinder
»Laboratory experiments on two coalescing axisymmetric turbulent plumes in a rotating fluid
»Impact of fjord dynamics and glacial runoff on the circulation near Helheim Glacier
»The relationship between flux coefficient and entrainment ratio in density currents
»A new parameterization for entrainment in overflows
»Laboratory experiments on the interaction of a buoyant coastal current with a canyon: application to the East Greenland Current
»Variations in ocean surface temperature due to near surface flow: straining the cool skin layer
»Mixing in a density-driven current flowing down a slope in a rotating fluid
»Laboratory experiments on mesoscale vortices colliding with an island chain
»Laboratory observations of enhanced entrainment in dense overflows in the presence of submarine canyons and ridges
»How entraining density currents influence the stratification in a one-dimensional ocean basin
»Laboratory experiments on eddy generation by a buoyant coastal current flowing over variable bathymetry
»Laboratory experiments on mesoscale vortices interacting with two islands
»Variability of Antarctic bottom water flow into the North Atlantic
»Laboratory experiments on a mesoscale vortex colliding with topography of varying geometry in a rotating fluid
»A laboratory model of thermocline depth and exchange fluxes across circumpolar fronts
»A dense current flowing down a sloping bottom in a rotating fluid
»Laboratory experiments on mesoscale vortices colliding with a seamount
»Stability of a buoyancy-driven coastal current at the shelf break
»Eddy-shedding from a boundary current around a cape over a sloping bottom
»Cyclone and anticyclone asymmetry in a rotating stratified fluid over bottom topography

Cenedese,  C.  and  Linden,  P.F., Cyclone and anticyclone asymmetry in a rotating stratified fluid over bottom topography, J. Fluid Mech., 381, 199-223., 1999

We discuss laboratory experiments with a continuous source or sink of fluid in a two-layer rotating environment which produces anticyclonic and cyclonic vortices, respectively. Experiments were carried out with a sloping bottom in order to simulate the β-eff ect and they were conducted for different values for the source/sink flow rate Q and the Coriolis parameter f. The Rossby number Ro of these vortices was small but finite and the flow was expected to be quasi-geostrophic. The qualitative behaviour of the anticyclonic and cyclonic vortices was generally similar, but it depended on the flow rate. For low flow rates, a single vortex formed at the source and extended to the west. At higher flow rates, the vortex broke free from the source and moved to the west; this vortex was then followed sequentially by other vortices behaving similarly. The westward velocity U of these vortices was calculated and compared with the speed Us of a linear topographic Rossby wave. For multiple vortices the westward velocities were greater than Us while for a single vortex produced by a low flow rate the velocity was less than Us. Signi ficant asymmetry between the anticyclonic and cyclonic vortices was observed in the transition zone from single to multiple vortices which implies that ageostrophic e ffects were still present in the flow.

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