Circulation mechanisms of oscillations in the atmospheric climate

The concept of atmospheric centers of action (ACAs) viewed as characteristi cs of the atmospheric general circulation and the climate an the whole is d iscussed. The variability of ACAs is analyzed using 105-year (1891-1995) ti me series of monthly mean coordinates and intensities of all eight ACAs occ urring in the Northern Hemisphere. Climate theory is regarded as the statis tical dynamics of an oscillating system with a very large number of strongl y interacting degrees of freedom. Specific features of the system are exter nal forcings with one-day and one-year periods, as well as with an 11.86-ye ar Jupiter period and a 60-year main period of revolution of the Sun, Jupit er, and Saturn around the center of inertia of the solar system, etc.; a pa rametric resonant strengthening of disturbances on doubled periods; and tra nsformation of periods into cycles. Evidence for cycle occurrence in climat ic series is given.