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| Titel |
Storm tracks near marginal stability |
| VerfasserIn |
Maarten Ambaum, Lenka Novak |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105804
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| Publikation (Nr.) |
 EGU/EGU2015-5383.pdf |
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| Zusammenfassung |
| The variance of atmospheric storm tracks is characterised by intermittent bursts of
activity interspersed with relatively quiescent periods. Most of the poleward heat
transport by storm tracks is due to a limited number of strong heat flux events, which
occur in a quasi-periodic fashion. This behaviour is in contradiction with the usual
conceptual model of the storm tracks, which relies on high growth rate background
flows which then spawn weather systems that grow in an exponential or non-normal
fashion.
Here we present a different conceptual model of the atmospheric storm tracks which is
built on the observation that, when including diabatic and other dissipative effects, the storm
track region is in fact most of the time marginally stable. The ensuing model is
a nonlinear oscillator, very similar to Volterra-Lotka predator–prey models. We
demonstrate the extensions of this model to a stochastically driven nonlinear oscillator.
The model produces quasi-periodic behaviour dominated by intermittent heat flux
events.
Perhaps most surprisingly, we will show strong evidence from re-analysis data
for our conceptual model: the re-analysis data produces a phase-space plot that
is very similar indeed to the phase-space plot for our nonlinear oscillator model. |
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