Dynamical budgets of the Antarctic Circumpolar Current using ocean general-circulation models

2005 ◽  
Vol 131 (607) ◽  
pp. 833-860 ◽  
Author(s):  
A. Grezio ◽  
N. C. Wells ◽  
V. O. Ivchenko ◽  
B. A. de Cuevas
Author(s):  
Hongjie Li ◽  
Yongsheng Xu

AbstractStratified geostrophic turbulence theory predicts an inverse energy cascade for the barotropic (BT) mode. Satellite altimetry has revealed a net inverse cascade in the baroclinic (BC) mode. Here the spatial variabilities of BT and BC kinetic energy fluxes in the Antarctic Circumpolar Current (ACC) were investigated using ECCO2 data, which synthesizes satellite data and in situ measurements with an eddy-permitting general circulation models containing realistic bathymetry and wind forcing. The BT and BC inverse kinetic energy cascades both reveal complex spatial variations that could not be explained fully by classical arguments. For example, the BC injection scales match better with most unstable scales than with the first-mode deformation scales, but the opposite is true for the BT mode. In addition, the BT and BC arrest scales do not follow the Rhines scale well in term of spatial variation, but show better consistency with their own energy-containing scales. The reverse cascade of the BT and BC modes was found related to their EKE, and better correlation was found between the BT inverse cascade and barotropization. Speculations of the findings were proposed. however, further observations and modeling experiments are needed to test these interpretations. Spectral flux anisotropy exhibits a feature associated with oceanic jets that is consistent with classical expectations. Specifically, the spectral flux along the along-stream direction remains negative at scales up to that of the studied domain (~2000km), while that in the perpendicular direction becomes positive close to the scale of the width of a typical jet.


2000 ◽  
Vol 14 (4) ◽  
pp. 1267-1281 ◽  
Author(s):  
J. L. Sarmiento ◽  
P. Monfray ◽  
E. Maier-Reimer ◽  
O. Aumont ◽  
R. J. Murnane ◽  
...  

2005 ◽  
Vol 35 (4) ◽  
pp. 474-488 ◽  
Author(s):  
Hideyuki Nakano ◽  
Hiroyasu Hasumi

Abstract A series of zonal currents in the Pacific Ocean is investigated using eddy-permitting ocean general circulation models. The zonal currents in the subsurface are classified into two parts: one is a series of broad zonal flows that has the meridional pattern slanting poleward with increasing depth and the other is finescale zonal jets with the meridional scale of 3°–5° formed in each broad zonal flow. The basic pattern for the broad zonal flows is similar between the coarse-resolution model and the eddy-permitting model and is thought to be the response to the wind forcing. A part of the zonal jets embedded in each zonal flow is explained by the anomalous local wind forcing. Most of them, however, seem to be mainly created by the rectification of turbulent processes on a β plane (the Rhines effect), and zonal jets in this study have common features with the zonally elongated flows obtained in previous modeling studies conducted in idealized basins. The position of zonal jets is not stable when the ocean floor is flat, whereas it oscillates only within a few degrees under realistic bottom topography.


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