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| Titel |
Turbulent viscosity optimized by data assimilation |
| VerfasserIn |
Y. Leredde, J.-L. Devenon, I. Dekeyser |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 17, no. 11 ; Nr. 17, no. 11, S.1463-1477 |
| Datensatznummer |
250013839
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| Publikation (Nr.) |
 copernicus.org/angeo-17-1463-1999.pdf |
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| Zusammenfassung |
As an alternative approach to classical
turbulence modelling using a first or second order closure, the data
assimilation method of optimal control is applied to estimate a time and
space-dependent turbulent viscosity in a three-dimensional oceanic circulation
model. The optimal control method, described for a 3-D primitive equation model,
involves the minimization of a cost function that quantifies the discrepancies
between the simulations and the observations. An iterative algorithm is obtained
via the adjoint model resolution. In a first experiment, a k + L
model is used to simulate the one-dimensional development of inertial
oscillations resulting from a wind stress at the sea surface and with the
presence of a halocline. These results are used as synthetic observations to be
assimilated. The turbulent viscosity is then recovered without the k + L
closure, even with sparse and noisy observations. The problems of
controllability and of the dimensions of the control are then discussed. A
second experiment consists of a two-dimensional schematic simulation. A 2-D
turbulent viscosity field is estimated from data on the initial and final states
of a coastal upwelling event.
Key words. Oceanography: general (numerical modelling)
· Oceanography: physical (turbulence · diffusion · and mixing processes) |
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