Show simple item record

contributor authorThompson, Andrew F.
contributor authorNaveira Garabato, Alberto C.
date accessioned2017-06-09T17:20:09Z
date available2017-06-09T17:20:09Z
date copyright2014/07/01
date issued2014
identifier issn0022-3670
identifier otherams-83387.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4226606
description abstracthe insensitivity of the Antarctic Circumpolar Current (ACC)?s prominent isopycnal slope to changes in wind stress is thought to stem from the action of mesoscale eddies that counterbalance the wind-driven Ekman overturning?a framework verified in zonally symmetric circumpolar flows. Substantial zonal variations in eddy characteristics suggest that local dynamics may modify this balance along the path of the ACC. Analysis of an eddy-resolving ocean GCM shows that the ACC can be broken into broad regions of weak eddy activity, where surface winds steepen isopycnals, and a small number of standing meanders, across which the isopycnals relax. Meanders are coincident with sites of (i) strong eddy-induced modification of the mean flow and its vertical structure as measured by the divergence of the Eliassen?Palm flux and (ii) enhancement of deep eddy kinetic energy by up to two orders of magnitude over surrounding regions. Within meanders, the vorticity budget shows a balance between the advection of relative vorticity and horizontal divergence, providing a mechanism for the generation of strong vertical velocities and rapid changes in stratification. Temporal fluctuations in these diagnostics are correlated with variability in both the Eliassen?Palm flux and bottom speed, implying a link to dissipative processes at the ocean floor. At larger scales, bottom pressure torque is spatially correlated with the barotropic advection of planetary vorticity, which links to variations in meander structure. From these results, it is proposed that the ?flexing? of standing meanders provides an alternative mechanism for reducing the sensitivity of the ACC?s baroclinicity to changes in forcing, separate from an ACC-wide change in transient eddy characteristics.
publisherAmerican Meteorological Society
titleEquilibration of the Antarctic Circumpolar Current by Standing Meanders
typeJournal Paper
journal volume44
journal issue7
journal titleJournal of Physical Oceanography
identifier doi10.1175/JPO-D-13-0163.1
journal fristpage1811
journal lastpage1828
treeJournal of Physical Oceanography:;2014:;Volume( 044 ):;issue: 007
contenttypeFulltext


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record