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| Titel |
Local predictability in a simple model of atmospheric balance |
| VerfasserIn |
G. Gyarmati, I. Szunyogh, D. J. Patil |
| 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 ; 10, no. 3 ; Nr. 10, no. 3, S.183-196 |
| Datensatznummer |
250007989
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| Publikation (Nr.) |
 copernicus.org/npg-10-183-2003.pdf |
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| Zusammenfassung |
| The 2
degree-of-freedom elastic pendulum equations can be considered as the
lowest order analogue of interacting low-frequency (slow) Rossby-Haurwitz
and high-frequency (fast) gravity waves in the atmosphere. The strength of
the coupling between the low and the high frequency waves is controlled by
a single coupling parameter, e,
defined by the ratio of the fast and slow characteristic time scales. In
this paper, efficient, high accuracy, and symplectic structure preserving
numerical solutions are designed for the elastic pendulum equation in
order to study the role balanced dynamics play in local predictability. To
quantify changes in the local predictability, two measures are considered:
the local Lyapunov number and the leading singular value of the tangent
linear map. It is shown, both based on theoretical considerations and
numerical experiments, that there exist regions of the phase space where
the local Lyapunov number indicates exceptionally high predictability,
while the dominant singular value indicates exceptionally low
predictability. It is also demonstrated that the local Lyapunov number has
a tendency to choose instabilities associated with balanced motions, while
the dominant singular value favors instabilities related to highly
unbalanced motions. The implications of these findings for atmospheric
dynamics are also discussed. |
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