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| Titel |
Synchronization and chaos control in a periodically forced quasi-geostrophic two-layer model of baroclinic instability |
| VerfasserIn |
F. J. R. Eccles, P. L. Read, T. W. N. Haine |
| 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 ; 13, no. 1 ; Nr. 13, no. 1 (2006-02-22), S.23-39 |
| Datensatznummer |
250011702
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| Publikation (Nr.) |
 copernicus.org/npg-13-23-2006.pdf |
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| Zusammenfassung |
| Cyclic forcing on many timescales is believed to have a significant
effect on various quasi-periodic, geophysical phenomena such as El
Niño, the Quasi-Biennial Oscillation, and glacial cycles. This
variability has been investigated by numerous previous workers, in
models ranging from simple energy balance constructions to full
general circulation models. We present a numerical study in which periodic forcing is
applied to a highly idealised, two-layer, quasi-geostrophic model on a
β-plane. The bifurcation structure and (unforced) behaviour of
this particular model has been extensively examined by Lovegrove et al. (2001) and Lovegrove et al.
(2002). We identify from their work three distinct regimes
on which we perform our investigations: a steady, travelling wave
regime, a quasi-periodic, modulated wave regime and a chaotic
regime. In the travelling wave regime a nonlinear resonance is
found. In the periodic regime, Arnol'd tongues, frequency locking and
a Devil's staircase is seen for small amplitudes of forcing. As the
forcing is increased the Arnol'd tongues undergo a period doubling
route to chaos, and for larger forcings still, the parameter space we
explored is dominated by either period 1 behaviour or chaotic
behaviour. In the chaotic regime we extract unstable periodic orbits
(UPOs) and add the periodic forcing at periods corresponding to
integer multiples of the UPO periods. We find regions of
synchronization, similar to Arnol'd tongue behaviour but more skewed
and centred approximately on these periods. The regions where chaos
suppression took place are smaller than the synchronization regions,
and are contained within them. |
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