Horizontal and Vertical Structure of the Representer Functions for Sea Surface Measurements in a Coastal Circulation Model

Vincent Echevin LEGOS/GRGS, Toulouse, France

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Pierre De Mey LEGOS/GRGS, Toulouse, France

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Geir Evensen Nansen Environmental and Remote Sensing Center, Bergen, Norway

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Abstract

The representer functions used to propagate the information from observations onto model variables in a sequential data assimilation scheme are calculated with a statistical method. The Princeton Ocean Model is used in a simple configuration simulating the North Current flowing along the French coasts in the northwestern Mediterranean Sea. The influence of sea level measurements on the models’ three-dimensional temperature and velocity fields is investigated. Inhomogeneities and directions of anisotropy are evidenced. A comparison with simplified reduced order assimilation methods suggests that such schemes will not allow for consistent assimilation of nearshore altimetric data.

* Current affiliation: LODYC, Paris, France.

Corresponding author address: Dr. Vincent Echevin, LODYC, UPMC, T26, 4E, 4 Place Jussieu, 75252 Paris, Cedex 05, France.

Email: vincent.echevin@lodyc.jussieu.fr

Abstract

The representer functions used to propagate the information from observations onto model variables in a sequential data assimilation scheme are calculated with a statistical method. The Princeton Ocean Model is used in a simple configuration simulating the North Current flowing along the French coasts in the northwestern Mediterranean Sea. The influence of sea level measurements on the models’ three-dimensional temperature and velocity fields is investigated. Inhomogeneities and directions of anisotropy are evidenced. A comparison with simplified reduced order assimilation methods suggests that such schemes will not allow for consistent assimilation of nearshore altimetric data.

* Current affiliation: LODYC, Paris, France.

Corresponding author address: Dr. Vincent Echevin, LODYC, UPMC, T26, 4E, 4 Place Jussieu, 75252 Paris, Cedex 05, France.

Email: vincent.echevin@lodyc.jussieu.fr

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