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Titel |
What can asymptotic expansions tell us about large-scale quasi-geostrophic anticyclonic vortices? |
VerfasserIn |
A. Stegner, V. Zeitlin |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 2, no. 3/4 ; Nr. 2, no. 3/4, S.186-193 |
Datensatznummer |
250000253
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Publikation (Nr.) |
copernicus.org/npg-2-186-1995.pdf |
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Zusammenfassung |
The problem of the large-scale quasi-geostrophic anticyclonic
vortices is studied in the framework of the baratropic rotating shallow- water equations
on the β-plane. A systematic approach based on the multiplescale asymptotic expansions is
used leading to a hierarchy of governing equations for the large-scale vortices depending
on their characteristic size, velocity and a free surface elevation. Among them are the
Charney-Obukhov equation, the intermediate geostrophic model equation, the frontal
dynamics equation and some new nonlinear quasi-geostrophic equation. We are looking for
steady-drifting axisymmetric anticyclonic solutions and find them in a consistent way only
in this last equation. These solutions are soliton-like in the sense that the effects of
weak non-linearity and dispersion balance each other. The same regimes on the paraboloidal
β-plane are studied, all giving a negative result in what concerns the
axisymmetric steady solutions, except for a strong elevation case where any circular profile is found
to be steadily propagating within the accuracy of the approximation. |
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