Hostname: page-component-848d4c4894-p2v8j Total loading time: 0 Render date: 2024-06-08T23:16:43.532Z Has data issue: false hasContentIssue false
  • English
  • Français

Baroclinic instability of quasi-geostrophic flows localized in a thin layer

Published online by Cambridge University Press:  26 April 2006

E. S. Benilov
E. S. Benilov
Affiliation:
Department of Applied Computing and Mathematics, University of Tasmania, PO Box 1214, Launceston, 7250, Australia
Get access Rights & Permissions [Opens in a new window]

Abstract

This paper examines the baroclinic instability of a quasi-geostrophic flow with vertical shear in a continuously stratified fluid. The flow and density stratification are both localized in a thin upper layer. (i) Disturbances whose wavelength is much smaller than the deformation radius (based on the depth of the upper layer) are demonstrated to satisfy an ‘equivalent two-layer model’ with properly chosen parameters. (ii) For disturbances whose wavelength is of the order of, or greater than, the deformation radius we derive a sufficient stability criterion. The above analysis is applied to the subtropical and subarctic frontal currents in the Northern Pacific. The effective time of growth of disturbances (i) is found to be 16–22 days, the characteristic spatial scale is 130–150 km.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 288 , 10 April 1995 , pp. 175 - 199
Copyright
© 1995 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Benilov, E. S. 1993 Baroclinic instability of large-amplitude geostrophic flows. J. Fluid Mech. 251, 501–514.Google Scholar
Benilov, E. S. 1994 Dynamics of large-amplitude geostrophic flows: the case of ‘strong’ beta-effect. J. Fluid Mech. 262, 157–169.Google Scholar
Benilov, E. S. 1995 Stability of large-amplitude geostrophic flows localized in a thin layer. J. Fluid Mech. 288, 157–174.Google Scholar
Benilov, E. S. & Reznik, G. M. 1995 The complete classification of large-amplitude geostrophic flows. Dyn. Atmos. Oceans (Submitted).Google Scholar
Dikiy, L. A. 1976 Hydrodynamic Stability and Dynamics of the Atmosphere. Leningrad: Gidrometeoizdat (in Russian).
Killworth, P. D. 1980 Barotropic and baroclinic instability in rotating stratified fluids. Dyn. Atmos. Oceans 4, 143–184.Google Scholar
Pedlosky, J. 1987 Geophysical Fluid Dynamics. Springer.
Roden, G. I. 1975 On North Pacific temperature, salinity, sound velocity and density fronts and their relation to the wind and energy flux fields. J. Phys. Oceanogr. 5, 557–571.Google Scholar