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Titel |
Gradient evolution for potential vorticity flows |
VerfasserIn |
S. Balasuriya |
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 ; 8, no. 4/5 ; Nr. 8, no. 4/5, S.253-263 |
Datensatznummer |
250005298
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Publikation (Nr.) |
copernicus.org/npg-8-253-2001.pdf |
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Zusammenfassung |
Two-dimensional
unsteady incompressible flows in which the potential vorticity (PV) plays
a key role are examined in this study, through the development of the
evolution equation for the PV gradient. For the case where the PV is
conserved, precise statements concerning topology-conservation are
presented. While establishing some intuitively well-known results (the
numbers of eddies and saddles is conserved), other less obvious
consequences (PV patches cannot be generated, some types of Lagrangian and
Eulerian entities are equivalent) are obtained. This approach enables an
improvement on an integrability result for PV conserving flows (if there
were no PV patches at time zero, the flow would be integrable). The
evolution of the PV gradient is also determined for the nonconservative
case, and a plausible experiment for estimating eddy diffusivity is
suggested. The theory is applied to an analytical diffusive Rossby wave
example. |
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