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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 |
2198-5634
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics Discussions ; 1, no. 1 ; Nr. 1, no. 1 (2014-04-04), S.447-478 |
| Datensatznummer |
250115082
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| Publikation (Nr.) |
 copernicus.org/npgd-1-447-2014.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 to represent the instabilities
that are responsible for error growth at various time and space scales.
It is found that for initial errors of the order of present-day analysis error,
error growth is mainly determined by intermediate scale instabilities, and that
a non-negligible fraction of the forecast error can be explained by
an ensemble of bred vectors of reasonable size.
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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