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| Titel |
Error dynamics in shell models for turbulence |
| VerfasserIn |
Lesley De Cruz, Stéphane Vannitsem |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072330
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| Zusammenfassung |
| A deep understanding of the error dynamics in turbulent systems is crucial to estimate the
horizon of predictability, and to quantify the impact of initial-condition (IC) and model errors
on the statistical characteristics of ensemble prediction systems.
We present a study of the dynamics of combined IC and model errors in a turbulent
system. We use the Sabra shell model [1], a spectral model which captures the characteristic
properties of a turbulent system using a low number of variables (of the order of 50). The
analytical properties of the short-term error dynamics in the Sabra shell model are
investigated using the methodology described in Ref. [2], and compared to numerical results.
Of particular interest is the property of a dissipative system that the mean squared error
(MSE) reaches a minimum shortly after the introduction of an IC error. The distribution of
the minimum-error times is investigated, and the spatial-scale dependence of the error
dynamics is discussed. At longer time scales, our simulations confirm the well-known fact
that an arbitrarily small error in the initial conditions contaminates the integral scale in a time
that is independent of the scale of the initial error. Finally, we report on the error dynamics in
the presence of a crossover between 3D and 2D turbulence, known to characterise the
atmosphere.
References
[1]   V. S. L’vov, E. Podivilov, A. Pomyalov, I. Procaccia,
and D. Vandembroucq. Improved shell model of turbulence. Physical Review E,
58:1811–1822, August 1998.
[2]   C. Nicolis, R. A. P. Perdigao, and S. Vannitsem. Dynamics of Prediction
Errors under the Combined Effect of Initial Condition and Model Errors. Journal
of Atmospheric Sciences, 66:766, 2009. |
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