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| Titel |
A possible theory for the interaction between convective activities and vortical flows |
| VerfasserIn |
N. Zhao, X. Y. Shen, Y. H. Ding, M. Takahashi |
| 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 ; 18, no. 5 ; Nr. 18, no. 5 (2011-10-31), S.779-789 |
| Datensatznummer |
250013983
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| Publikation (Nr.) |
 copernicus.org/npg-18-779-2011.pdf |
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| Zusammenfassung |
| Theoretical studies usually attribute convections to the developments of
instabilities such as the static or symmetric instabilities of the basic
flows. However, the following three facts make the validities of these basic
theories unconvincing. First, it seems that in most cases the basic flow
with balance property cannot exist as the exact solution, so one cannot
formulate appropriate problems of stability. Second, neither linear nor
nonlinear theories of dynamical instability are able to describe a two-way
interaction between convection and its background, because the basic state
which must be an exact solution of the nonlinear equations of motion is
prescribed in these issues. And third, the dynamical instability needs some
extra initial disturbance to trigger it, which is usually another point of
uncertainty. The present study suggests that convective activities can be
recognized in the perspective of the interaction of convection with vortical
flow. It is demonstrated that convective activities can be regarded as the
superposition of free modes of convection and the response to the forcing
induced by the imbalance of the unstably stratified vortical flow. An
imbalanced vortical flow provides not only an initial condition from which
unstable free modes of convection can develop but also a forcing on the
convection. So, convection is more appropriately to be regarded as a
spontaneous phenomenon rather than a disturbance-triggered phenomenon which
is indicated by any theory of dynamical instability. Meanwhile, convection,
particularly the forced part, has also a reaction on the basic flow by
preventing the imbalance of the vortical flow from further increase and
maintaining an approximately balanced flow. |
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