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The topographic control of planetary-scale flow

Published online by Cambridge University Press:  26 April 2006

Andrew W. Woods
Andrew W. Woods
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, Silver Street, Cambridge, CB3 9EW, UK
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Abstract

We develop a theory to describe the topographic control of planetary-scale flows resulting from the variation of the Earth's rotation with latitude. We show that on passing over topography, an inertial, zonal current on an equatorial β-plane may pass through a control at which the flow changes from a subcritical to a supercritical solution branch. Downstream of this control, a transition back to the subcritical solution branch may occur, for example, by the generation of planetary eddies or radiating Rossby waves. We calculate the energy dissipated across such a transition and discuss the relevance of this theory for a number of atmospheric and oceanic phenomena. We also show that this phenomenon is analogous to the hydraulic control of a non-rotating, stratified flow passing through a channel of variable width.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 247 , February 1993 , pp. 603 - 621
Copyright
© 1993 Cambridge University Press

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