Residual-Mean Solutions for the Antarctic Circumpolar Current and Its Associated Overturning Circulation

2003 ◽  
Vol 33 (11) ◽  
pp. 2341-2354 ◽  
Author(s):  
John Marshall ◽  
Timour Radko
Keyword(s):  
Antarctic Circumpolar Current ◽  
Overturning Circulation ◽  
Circumpolar Current ◽  
The Antarctic

The Antarctic Circumpolar Current in Three Dimensions

2006 ◽  
Vol 36 (4) ◽  
pp. 651-669 ◽  
Author(s):  
Timour Radko ◽  
John Marshall
Keyword(s):  
Antarctic Circumpolar Current ◽  
Three Dimensional ◽  
Perturbation Expansion ◽  
Dimensional Structure ◽  
Residual Circulation ◽  
Mean Flow ◽  
Overturning Circulation ◽  
The Mean ◽  
Circumpolar Current ◽  
The Antarctic

Abstract A simple theory is developed for the large-scale three-dimensional structure of the Antarctic Circumpolar Current and the upper cell of its overturning circulation. The model is based on a perturbation expansion about the zonal-average residual-mean model developed previously by Marshall and Radko. The problem is solved using the method of characteristics for idealized patterns of wind and buoyancy forcing constructed from observations. The equilibrium solutions found represent a balance between the Eulerian meridional overturning, eddy-induced circulation, and downstream advection by the mean flow. Depth and stratification of the model thermocline increase in the Atlantic–Indian Oceans sector where the mean wind stress is large. Residual circulation in the model is characterized by intensification of the overturning circulation in the Atlantic–Indian sector and reduction in strength in the Pacific Ocean region. Predicted three-dimensional patterns of stratification and residual circulation in the interior of the ACC are compared with observations.

scholarly journals A Microscale View of Mixing and Overturning across the Antarctic Circumpolar Current

2016 ◽  
Vol 46 (1) ◽  
pp. 233-254 ◽  
Author(s):  
Alberto C. Naveira Garabato ◽  
Kurt L. Polzin ◽  
Raffaele Ferrari ◽  
Jan D. Zika ◽  
Alexander Forryan
Keyword(s):  
Antarctic Circumpolar Current ◽  
Large Scale ◽  
Drake Passage ◽  
Small Scale ◽  
Overturning Circulation ◽  
Order Of Magnitude ◽  
Circumpolar Current ◽  
Scale Turbulence ◽  
Microstructure Measurements ◽  
The Antarctic

AbstractThe relative roles of isoneutral stirring by mesoscale eddies and dianeutral stirring by small-scale turbulence in setting the large-scale temperature–salinity relation of the Southern Ocean against the action of the overturning circulation are assessed by analyzing a set of shear and temperature microstructure measurements across Drake Passage in a “triple decomposition” framework. It is shown that a picture of mixing and overturning across a region of the Antarctic Circumpolar Current (ACC) may be constructed from a relatively modest number of microstructure profiles. The rates of isoneutral and dianeutral stirring are found to exhibit distinct, characteristic, and abrupt variations: most notably, a one to two orders of magnitude suppression of isoneutral stirring in the upper kilometer of the ACC frontal jets and an order of magnitude intensification of dianeutral stirring in the subpycnocline and deepest layers of the ACC. These variations balance an overturning circulation with meridional flows of O(1) mm s−1 across the ACC’s mean thermohaline structure. Isoneutral and dianeutral stirring play complementary roles in balancing the overturning, with isoneutral processes dominating in intermediate waters and the Upper Circumpolar Deep Water and dianeutral processes prevailing in lighter and denser layers.

scholarly journals Short-circuiting of the overturning circulation in the Antarctic Circumpolar Current

Nature ◽  
2007 ◽  
Vol 447 (7141) ◽  
pp. 194-197 ◽  
Author(s):  
Alberto C. Naveira Garabato ◽  
David P. Stevens ◽  
Andrew J. Watson ◽  
Wolfgang Roether
Keyword(s):  
Antarctic Circumpolar Current ◽  
Overturning Circulation ◽  
Circumpolar Current ◽  
The Antarctic

scholarly journals Multidecadal poleward shift of the southern boundary of the Antarctic Circumpolar Current off East Antarctica

2021 ◽  
Vol 7 (24) ◽  
pp. eabf8755
Author(s):  
Kaihe Yamazaki ◽  
Shigeru Aoki ◽  
Katsuro Katsumata ◽  
Daisuke Hirano ◽  
Yoshihiro Nakayama
Keyword(s):  
Antarctic Circumpolar Current ◽  
Thermal Conditions ◽  
East Antarctica ◽  
Overturning Circulation ◽  
Southern Boundary ◽  
Poleward Shift ◽  
Oceanographic Data ◽  
Circumpolar Current ◽  
The Antarctic ◽  
Mesoscale Processes

The southern boundary (SB) of the Antarctic Circumpolar Current, the southernmost extent of the upper overturning circulation, regulates the Antarctic thermal conditions. The SB’s behavior remains unconstrained because it does not have a clear surface signature. Revisited hydrographic data from off East Antarctica indicate full-depth warming from 1996 to 2019, concurrent with an extensive poleward shift of the SB subsurface isotherms (>50 km), which is most prominent at 120°E off the Sabrina Coast. The SB shift is attributable to enhanced upper overturning circulation and a depth-independent frontal shift, generally accounting for 30 and 70%, respectively. Thirty years of oceanographic data corroborate the overall and localized poleward shifts that are likely controlled by continental slope topography. Numerical experiments successfully reproduce this locality and demonstrate its sensitivity to mesoscale processes and wind forcing. The poleward SB shift under intensified westerlies potentially induces multidecadal warming of Antarctic shelf water.

scholarly journals Nonlinear Differential Equations Modeling the Antarctic Circumpolar Current

2021 ◽  
Vol 23 (4) ◽  
Author(s):  
Jifeng Chu ◽  
Kateryna Marynets
Keyword(s):  
Fixed Point ◽  
Differential Equations ◽  
Boundary Conditions ◽  
Topological Degree ◽  
Antarctic Circumpolar Current ◽  
Fixed Point Theorems ◽  
Nonlinear Differential Equations ◽  
Existence Results ◽  
Circumpolar Current ◽  
The Antarctic

AbstractThe aim of this paper is to study one class of nonlinear differential equations, which model the Antarctic circumpolar current. We prove the existence results for such equations related to the geophysical relevant boundary conditions. First, based on the weighted eigenvalues and the theory of topological degree, we study the semilinear case. Secondly, the existence results for the sublinear and superlinear cases are proved by fixed point theorems.

Sign in / Sign up

Export Citation Format

Share Document