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Eddy stirring in the Southern Ocean

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Show simple item record Ferrari, Raffaele Garabato, Alberto C. Naveira Polzin, K. L. 2012-10-09T16:20:10Z 2012-10-09T16:20:10Z 2011-09 2011-06
dc.identifier.issn 0148-0227
dc.description.abstract There is an ongoing debate concerning the distribution of eddy stirring across the Antarctic Circumpolar Current (ACC) and the nature of its controlling processes. The problem is addressed here by estimating the isentropic eddy diffusivity Kappa from a collection of hydrographic and altimetric observations, analyzed in a mixing length theoretical framework. It is shown that, typically, Kappa is suppressed by an order of magnitude in the upper kilometer of the ACC frontal jets relative to their surroundings, primarily as a result of a local reduction of the mixing length. This observation is reproduced by a quasi-geostrophic theory of eddy stirring across a broad barotropic jet based on the scaling law derived by Ferrari and Nikurashin (2010). The theory interprets the observed widespread suppression of the mixing length and Kappa in the upper layers of frontal jets as the kinematic consequence of eddy propagation relative to the mean flow within jet cores. Deviations from the prevalent regime of mixing suppression in the core of upper-ocean jets are encountered in a few special sites. Such ‘leaky jet’ segments appear to be associated with sharp stationary meanders of the mean flow that are generated by the interaction of the ACC with major topographic features. It is contended that the characteristic thermohaline structure of the Southern Ocean, consisting of multiple upper-ocean thermohaline fronts separated and underlaid by regions of homogenized properties, is largely a result of the widespread suppression of eddy stirring by parallel jets. en_US
dc.description.sponsorship National Science Foundation (U.S.) (Award OCE‐0825376) en_US
dc.language.iso en_US
dc.publisher American Geophysical Union (AGU) en_US
dc.relation.isversionof en_US
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. en_US
dc.source MIT web domain en_US
dc.title Eddy stirring in the Southern Ocean en_US
dc.type Article en_US
dc.identifier.citation Naveira Garabato, A. C., R. Ferrari, and K. L. Polzin. “Eddy Stirring in the Southern Ocean.” Journal of Geophysical Research 116.C9 (2011). ©2011 American Geophysical Union en_US
dc.contributor.department Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences en_US
dc.contributor.mitauthor Ferrari, Raffaele
dc.relation.journal Journal of Geophysical Research en_US
dc.identifier.mitlicense PUBLISHER_POLICY en_US
dc.eprint.version Final published version en_US
dc.type.uri en_US
eprint.status en_US
dspace.orderedauthors Naveira Garabato, A. C.; Ferrari, R.; Polzin, K. L. en

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