The Forcing of the Meridional Circulation of the Isentropic Zonally Averaged Circumpolar Vortex

Abstract

Abstract For the axisymmetric general circulation, Eliassen (1951) showed that stable meridional circulations are controlled by large-scale diabatic heating and friction torque. Because the real atmosphere is longitudinally disturbed, a direct meridional response to large-scale diabatic heating is not readily found by conventional zonal averaging in isobaric coordinates. By introducing, the concept of a zonally averaged general circulation in isentropic coordinates, a direct meridional response to diabatic heating is isolated. Using an approach analogous to Eliassen's, this study has extended the concept of diabatically forced isentropic meridional circulations to include the role of angular momentum torques within the circumpolar vortex. The absolute angular momentum torques comprise three terms: divergence of eddy relative momentum transport, friction and zonal pressure torques. The heating is composed of hemispheric-scale diabatic processes. For a hydrodynamically and statically stable atmosphere, a co...