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| Titel |
A mechanism for catastrophic filter divergence in data assimilation for sparse observation networks |
| VerfasserIn |
G. A. Gottwald, A. J. Majda |
| 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 ; 20, no. 5 ; Nr. 20, no. 5 (2013-09-25), S.705-712 |
| Datensatznummer |
250086050
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| Publikation (Nr.) |
 copernicus.org/npg-20-705-2013.pdf |
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| Zusammenfassung |
| We study catastrophic filter divergence in data assimilation procedures
whereby the forecast model develops severe numerical instabilities leading to
a blow-up of the solution. Catastrophic filter divergence can occur in sparse
observational grids with small observational noise for intermediate
observation intervals and finite ensemble sizes. Using a minimal five-dimensional
model, we establish that catastrophic filter divergence is a
numerical instability of the underlying forecast model caused by the
filtering procedure producing analyses which are not consistent with the true
dynamics, and stiffness caused by the fast attraction of the inconsistent
analyses towards the attractor during the forecast step. |
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