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Article Dans Une Revue Annales Geophysicae Année : 1999

Turbulent viscosity optimized by data assimilation

Résumé

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.
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Dates et versions

hal-00329142 , version 1 (18-06-2008)

Identifiants

  • HAL Id : hal-00329142 , version 1

Citer

Y. Leredde, J.L. Devenon, I. Dekeyser. Turbulent viscosity optimized by data assimilation. Annales Geophysicae, 1999, 17 (11), pp.1463-1477. ⟨hal-00329142⟩
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