Deacon Cell

The Deacon Cell is an apparent meridional overturning cell in the Southern Ocean that appears in Eulerian-mean averages of the flow, showing equatorward surface Ekman transport and a return at depth. It is largely an artifact of averaging at fixed latitude, because the eddy-driven bolus transport along sloping isopycnals nearly cancels the wind-driven Eulerian cell. In the residual-mean framework, this cancellation leaves a much weaker residual circulation that is the dynamically meaningful overturning. The concept clarifies why Southern Ocean transport must be analyzed in density coordinates rather than at fixed depth.