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arXiv · 1103.4445

Stochastic variability of oceanic flows above topography anomalies

Antoine Venaille·Julien Le Sommer·J. -M. Molines·B. Barnier
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Abstract

We describe a stochastic variability mechanism which is genuinely internal to the ocean, i.e. not due to fluctuations in atmospheric forcing. % The key ingredient is the existence of closed contours of bottom topography surrounded by a stirring region of enhanced eddy activity. This configuration leads to the formation of a robust but highly variable vortex above the topography anomaly. The vortex dynamics integrates the white noise forcing of oceanic eddies into a red noise signal for the large scale volume transport of the vortex. The strong interannual fluctuations of the transport of the Zapiola anticyclone ($\sim 100 \ Sv$) in the Argentine basin are argued to be partly due to such eddy-driven stochastic variability, on the basis of a 310 years long simulation of a comprehensive global ocean model run driven by a repeated-year forcing.

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Antoine Venaille, Julien Le Sommer, J. -M. Molines, B. Barnier. 2011-07-24. Stochastic variability of oceanic flows above topography anomalies. https://doi.org/10.1029/2011gl048401

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