Drevillon¹, Marie, Guillaume Charria¹, Isabelle Dadou¹, Veronique Garcon¹, Pierre De Mey¹, Mounir Benkiran², Eric Greiner² and Benoit Tranchant³

¹LEGOS, 14 avenue Edouard Belin, 31400 Toulouse, FRANCE, Tel: 33 5 61 33 29 41, Fax: 33 5 61 25 32 05, E-mail: drevillo@notos.cst.cnes.fr, ²CLS, 8-10 rue Hermes, parc Technologique du canal, 31526 Ramonville, FRANCE and ³CERFACS, 42 Avenue Gaspard Coriolis, 31057 Toulouse cedex, FRANCE

Primary and export production in the North Atlantic with a 3D coupled physical/biogeochemical model during the SeaWiFS years

The impact of ocean circulation, especially at mesoscale, on the biogeochemical cycles at interannual scales still needs to be better understood and quantified. Physical/biogeochemical coupled models can answer such questions, especially if the models are constrained with the SeaWiFS ocean colour data. A three dimensional ocean circulation model of the North Atlantic with a horizontal grid spacing of 1/3rd of a degree and 43 vertical levels, assimilating Topex/Poseidon-ERS altimetry data, was developed by the French GODAE/MERCATOR project for operational oceanography. This eddy-permitting physical model is coupled to a nitrogen-based ecosystem model (Nutrients, Phytoplankton, Zooplankton, Detritus and Dissolved Organic Matter), in order to simulate primary and export production in the basin from 1995 to 2001, including the SeaWiFS years. Modeled seasonal and interannual variability of various physical and biological variables are discussed over this period. A validation of the modeled chlorophyll fields is performed over the SeaWiFS years prior to sensitivity studies to ocean colour data.