A STUDY OF THE FLOW OF ANGULAR MOMENTUM IN THE ATMOSPHERE

Abstract

A study is made of the flow of angular momentum in the atmosphere for the month of January 1946. The results generally confirm the pattern proposed by Starr on theoretical grounds. Angular momentum is transferred from the earth to the atmosphere in regions of surface easterly winds (chiefly the tropical and subtropical easterlies), transported upward, then horizontally poleward, and finally downward, being removed in regions of surface westerly winds. The torques due to surface friction are found to be of the same order of magnitude as those due to differentials of pressure across mountain ranges. During a period of the length of this study or less, it is found that the change and transport of angular momentum due to shifts of mass are of the same order of magnitude as the change and transport of relative angular momentum. If one accepts the method used for estimating the surface torques, there appears to be an excess of transfer of angular momentum to the atmosphere in the northern hemisphere. From a study of the normal January pressure profile, it would appear that this excess represents a flow of angular momentum to the southern hemisphere, where it is needed to balance accounts.