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Trapped internal gravity waves in a geostrophic boundary current

Published online by Cambridge University Press:  26 April 2006

Hong Ma
Hong Ma
Affiliation:
Department of Atmospheric, Oceanic and Space Sciences and Laboratory for Scientific Computing, The University of Michigan, Ann Arbor, MI 48109, USA Present address: Department of Applied Science, Building 515, Brookhaven National Laboratory, Upton, NY 11973, USA.
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Abstract

The effect of a geostrophic boundary current on internal gravity waves is studied with a reduced-gravity model. We found that the boundary current not only modifies the coastal Kelvin wave, but also forms wave guides for short internal gravity waves. The combined effects of current shear, the boundary, and the slope of the interface create the trapping mechanism. These trapped internal gravity waves appear as groups of discrete zonal modes. They have wavelengths comparable to or shorter than the internal Rossby radius of deformation. Their phase speeds are close to that of the internal Kelvin wave. However, they can propagate both in, or opposite to, the direction of the Kelvin wave. The results of the present work suggest the possibility of finding an energetic internal gravity wave phenomenon with near-inertial frequency in a broad geostrophic boundary current.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 247 , February 1993 , pp. 205 - 229
Copyright
© 1993 Cambridge University Press

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