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Convection in a rotating cavity: modelling ocean circulation

Published online by Cambridge University Press:  26 April 2006

Scott A. Condie  and
Ross W. Griffiths
Scott A. Condie
Affiliation:
Research School of Earth Sciences, Australian National University, GPO Box 4, Canberra, ACT 2601, Australia Present address: Department of Oceanography, Old Dominion University, Norfolk, VA 23529, USA.
Ross W. Griffiths
Affiliation:
Research School of Earth Sciences, Australian National University, GPO Box 4, Canberra, ACT 2601, Australia
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Abstract

Large-scale oceanic flows, ranging from large estuaries to basin-scale abyssal circulation, can be driven by imposed lateral density gradients and are significantly influenced by the Earth's rotation. Some essential features of such flows have been incorporated into a laboratory model by differentially heating and cooling the vertical endwalls of a shallow rectangular cavity, rotating about a vertical axis through its centre. In this paper, the flow observed after this system had been allowed to develop to a steady mean state is described. Measurements were made of the velocity and temperature fields, as well as the variability in temperature field associated with eddy motions. The temperature data were also used to calculate the potential vorticity distribution within the cavity. These results indicate that the heated and cooled end-walls acted not only as continuous sources of buoyancy, but also of anomalous potential vorticity. It is shown that the potential vorticity served as an indicator and tracer of the laboratory flow. The structure and location of boundary currents were largely determined by nonlinear potential vorticity dynamics which resulted in a mean circulation consisting of two basin-scale counter-rotating gyres. This flow differed markedly from the initial boundary currents set up by Kelvin waves.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 207 , October 1989 , pp. 453 - 474
Copyright
© 1989 Cambridge University Press

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