Testing theories of the vertical stratification of the ACC against observations.
(Karsten, RH and Marshall, J), DYNAMICS OF ATMOSPHERES AND OCEANS, vol. 36, no. 1-3, pp. pages, 2002.
Recent theories of the Antarctic Circumpolar Current (ACC) suggest that its lateral and vertical stratification is controlled by its baroclinic instability: eddies in the ACC not only feed-off the available potential energy stored in sloping isopycnals but play a central role is setting up that stratification. Simple theory makes predictions about how the depth of the thermocline in the ACC depends on the surface winds, the air-sea buoyancy flux and transfer by baroclinic eddies. By examining gridded hydrographic data, here we test some of these predictions against observations. We show that, to a remarkable degree, the buoyancy field in the ACC decays exponentially with depth beneath the mixed layer. The e-folding depth increases equatorward, from less than 500 m on the poleward flank of the ACC to greater than 1000 m on its equatorial flank, in a manner that is broadly consistent with the theory. (C) 2002 Elsevier Science B.V. All rights reserved.