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Hydraulic control of zonal currents on a β-plane

Published online by Cambridge University Press:  26 April 2006

Laurence Armi
Laurence Armi
Affiliation:
Scripps Institution of Oceanography, La Jolla, CA 92093, USA
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Abstract

Eastward-flowing zonal currents on a thin rotating shell, such as a planetary atmosphere or ocean, have integral properties analogous to open channel flows, the latitudinal width of the zonal current being the analogue of the depth of an open channel flow. The purpose here is to apply the formalism and some of the concepts of open channel flow hydraulics to zonal flows and demonstrate the results with laboratory experiments. In particular a critical relationship is found between a representative zonal velocity, U, and the half-width of the current, a. A dimensionless parameter (U/βa2), the Froude/Rossby number, is found analogous to the Froude number of open channel flow. Westward-flowing currents do not have an equivalent analogue.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 201 , April 1989 , pp. 357 - 377
Copyright
© 1989 Cambridge University Press

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