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| Titel |
Baroclinic instability of a symmetric, rotating, stratified flow: a study of the nonlinear stabilisation mechanisms in the presence of viscosity |
| VerfasserIn |
R. Mantovani, A. Speranza |
| 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 ; 9, no. 5/6 ; Nr. 9, no. 5/6, S.487-496 |
| Datensatznummer |
250006563
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| Publikation (Nr.) |
 copernicus.org/npg-9-487-2002.pdf |
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| Zusammenfassung |
| This paper presents
the analysis of symmetric circulations of a rotating baroclinic flow,
forced by a steady thermal wind and dissipated by Laplacian friction. The
analysis is performed with numerical time-integration. Symmetric flows,
vertically bound by horizontal walls and subject to either periodic or
vertical wall lateral boundary conditions, are investigated in the region
of parameter-space where unstable small amplitude modes evolve into stable
stationary nonlinear solutions. The distribution of solutions in
parameter-space is analysed up to the threshold of chaotic behaviour and
the physical nature of the nonlinear interaction operating on the finite
amplitude unstable modes is investigated. In particular, analysis of
time-dependent energy-conversions allows understanding of the physical
mechanisms operating from the initial phase of linear instability to the
finite amplitude stable state. Vertical shear of the basic flow is shown
to play a direct role in injecting energy into symmetric flow since the
stage of linear growth. Dissipation proves essential not only in limiting
the energy of linearly unstable modes, but also in selecting their
dominant space-scales in the finite amplitude stage. |
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