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| Titel |
Efficient estimation of time-mean states of ocean models using 4D-Var and implicit time-stepping |
| VerfasserIn |
A. D. Terwisscha van Scheltinga, H. A. Dijkstra |
| 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 ; 14, no. 6 ; Nr. 14, no. 6 (2007-11-30), S.777-788 |
| Datensatznummer |
250012313
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| Publikation (Nr.) |
 copernicus.org/npg-14-777-2007.pdf |
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| Zusammenfassung |
| We propose an efficient method for estimating a time-mean state of an ocean
model subject to given observations using implicit time-stepping. The new
method uses (i) an implicit implementation of the 4D-Var method to fit the
model trajectory to the observations, and (ii) a pre-processor which applies
a multi-channel singular spectrum analysis to enhance the signal-to-noise
ratio of the observational data and to filter out the high frequency
variability. This approach enables one to estimate the time-mean model state
using larger time-steps than is possible with an explicit model. The
performance of the method is presented for two test cases within a barotropic
quasi-geostrophic nonlinear model of the wind-driven double-gyre ocean
circulation. The method turns out to be accurate and, in comparison with the
time-mean state computed with an explicit version of the model, relatively
cheap in computational cost. |
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