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| Titel |
Multiple-scale error growth in a convection-resolving model |
| VerfasserIn |
F. Uboldi, A. Trevisan |
| 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 ; 22, no. 1 ; Nr. 22, no. 1 (2015-01-06), S.1-13 |
| Datensatznummer |
250120959
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| Publikation (Nr.) |
 copernicus.org/npg-22-1-2015.pdf |
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| Zusammenfassung |
| The properties of the multiple-scale instabilities present in a
non-hydrostatic forecast model are investigated. The model simulates intense
convection episodes occurring in northern Italy. A breeding technique is used
to construct ensembles of perturbations of the model trajectories aimed at
representing the instabilities that are responsible for error growth on
various timescales and space scales. By means of perfect model twin
experiments it is found that, for initial errors of the order of present-day
analysis error, a non-negligible fraction of the forecast error can be
explained by a bred vector ensemble of reasonable size representing the
growth of errors on intermediate scales. In contrast, when the initial error
is much smaller, the spectrum of bred vectors representing the fast
convective-scale instabilities becomes flat, and the number of ensemble
members needed to explain even a small fraction of the forecast error
becomes extremely large. The conclusion is that as the analysis error is
decreased, it becomes more and more computationally demanding to construct an
ensemble that can describe the high-dimensional subspace of convective
instabilities and that can thus be potentially useful for controlling the
error growth. |
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