Isentropic pressure and mountain torques

Abstract

The relation of pressure torques andmountain torques is investigated on the basis of observations for the polar caps, twomidlatitude and two subtropical belts, and a tropical belt by evaluating the lagged covariances of these torques for various isentropic surfaces. It is only in the polar domains and the northernmidlatitude belts that the transfer of angularmomentumto and from the earth at themountains is associated with pressure torques acting in the same sense. The situation is more complicated in all other belts. The covariances decline with increasing potential temperature (height). The role of both torques in the angularmomentumbudget of a belt is discussed.