ON THE ISOTROPY OF LARGE-SCALE DISTURRANCES IN THE UPPER TROPOSPHERE

Abstract

As a preliminary attempt to investigate the applicability of the turbulence theory to the large-scale atmospheric phenomena, the experimental test is made of the isotropy for the large-scale motion of the atmosphere at the 300-mb level. Uses are made of one-dimensional power- and cross-spectra of wind velocities, presented recently by Benton and Kahn (1957). The requirement of isotropy seems to be satisfied at lat 20N and 70N, for the harmonics whose wave lengths lie between 60 deg and 20 deg of longitude. The latter is the shortest wave length analyzed. In the region between lat 30N and 60N, the amount of kinetic energy in the north-south component of eddy velocities, in comparison with that in east-west component, is found to be more than that expected from the isotropic relations for the same domain of wave number.