MEAN ANNUAL ZONAL CIRCULATION OF THE ATMOSPHERE.

A semiempirical differential equation is derived from the distribution of the absolute angular momentum, showing that a change in the angular momentum in the atmosphere is determined by the balance of two angular-momentum fluxes: horizontal, occurring as a consequence of macroturbulent exchange, and vertical, related to microeddy viscosity. Its analytic solution is obtained in the case of the simplest model of variation of the exchange coefficients. It is shown that the mean annual zonal circulation occurs as a result of the redistribution of the absolute angular momentum of the air between low and high latitudes under the effect of microturbulent mixing. Microeddy viscosity weakens zonal circulation. Its steady state is reached only after accumulating in the atmosphere a certain positive value of the angular momentum, which is borrowed by the atmosphere near the earth.