Eddy activity and mixing in upwelling systems: a comparative study of Northwest Africa and California regions (original) (raw)

Abstract

A comparative modeling approach is used to study the mesoscale dynamics of coastal transition zones in the upwelling systems of Western Sahara and central California. It is shown that large differences in eddy activity and mixing exist between the two systems. Since upwelling-favorable winds off Central California and Western Sahara have similar amplitudes, we suggest that observed and modeled differences in eddy activity are due to differences in configuration parameters. It is argued that two of these parameters, stratification and topography, eventually affect the energy available for the mesoscales through baroclinic instability. The large difference in stratification appears to be linked to the salinity structure formed by the large-scale circulation and is directly related to available potential energy. The shape of the continental shelf affects the position, structure, and scale of the Ekman divergence, hence upwelling intensity, and frontal formation. The potential impact of mesoscale eddy mixing and its variability on upwelling ecosystems is discussed.

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Acknowledgments

Support for this study was provided by the IRD/France. This is also a contribution to the PATOM InterUp project. We are thankful to Dominique Dagorne for his help with satellite SST images.

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Authors and Affiliations

1. Institut de Recherche pour le Développement, Noumea Center, BP A5, 98848, Noumea Cedex, New Caledonia
   P. Marchesiello
2. Climate and Environmental Dynamics Laboratory, University of New South Wales, Sydney, NSW 2052, Australia
   P. Estrade

Authors

1. P. Marchesiello
2. P. Estrade

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Correspondence toP. Marchesiello.

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Marchesiello, P., Estrade, P. Eddy activity and mixing in upwelling systems: a comparative study of Northwest Africa and California regions.Int J Earth Sci (Geol Rundsch) 98, 299–308 (2009). https://doi.org/10.1007/s00531-007-0235-6

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• Received: 14 December 2005
• Accepted: 01 September 2006
• Published: 22 August 2007
• Issue Date: March 2009
• DOI: https://doi.org/10.1007/s00531-007-0235-6

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