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Caractérisation des erreurs de modélisation pour l'assimilation de données dans un modèle océanique régional du Golfe de Gascogne

Abstract : A data assimilation system for ocean models, the SEEK (Singular Evolutive Extended Kalman) filter, is studied to control a Bay of Biscay configuration. This 1/15° configuration, nested in a 1/3° North Atlantic configuration, through the use of Open (sea) Boundaries Conditions, is developed using HYCOM (Hybrid Coordinate Ocean Model). This study focuses on the parametrization of the model error in the SEEK filter, and more generally in low rank Kalman filters, in order to control regional models. Classic parametrizations of these data assimilation systems, which have been developed initially for basin models, are not adapted to the regional dynamics complexity. Ensemble methods are used to get a realistic estimation of the model error due to bad determination of atmospheric and open boundary forcings. These forcings influence is supposed to be very important on regional dynamics. Model error statistics are characterized using the method of representers, which demonstrates the impact of the assimilation of various type of observations to control the oceanic state. The propagation of the error generated at open boundaries is weak. The use of the error due to atmospheric forcings to parameterize the SEEK filter for surface temperature assimilation experiments gives good results. Their comparison with those given by a more classical parametrization shows the benefits of this study on model error.
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https://tel.archives-ouvertes.fr/tel-00143004
Contributor : Grégoire Broquet <>
Submitted on : Tuesday, April 24, 2007 - 6:04:57 AM
Last modification on : Thursday, November 19, 2020 - 3:54:10 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 11:53:38 PM

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  • HAL Id : tel-00143004, version 1

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CNRS | UJF | LEGI | UGA

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Grégoire Broquet. Caractérisation des erreurs de modélisation pour l'assimilation de données dans un modèle océanique régional du Golfe de Gascogne. Océan, Atmosphère. Université Joseph-Fourier - Grenoble I, 2007. Français. ⟨tel-00143004⟩

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