Regional Contributions to Isentropic Pressure Torques

Abstract

Transfer of axial angular momentum across isentropic surfaces due to adiabatic processes is performed by pressure torques. These torques are evaluated from observations for selected latitude belts and isentropic surfaces, focusing attention on regional contributions. It is found that downward time mean contributions culminate in the storm tracks except above and near major mountain massifs where even upward transfers may be found. Variations of these torques in time are short lived with a decay time of 1?2 days. Height perturbations of isentropic surfaces are presented for torque events. The torque patterns are compared to analyses of the more conventional vertical momentum transports in the z system.