Long-period nutational-precessional movements of the instantaneous pole of the earth’s rotation

The influence of the rotational regime on real long-period nutational-precessional motions of the instantaneous pole of the Earth's rotation is considered. The solar-magnetospheric (through changes of the angular velocity of rotation) mechanism of action is discussed. The observed 12-month oscillations of the instantaneous axis of rotation are explained by the influence of the variable centrifugal force arising when the angular velocity changes and causing deformation of the figure that is not uniform in different longitudinal zones, without involving the baric-circulational processes as an intermediate link. Thus, both 14-month free (Chandler) and forced 12-month fluctuations of the pole location are considered from a single point of view – as a result of the variability of the rotational regime of the Earth. The analysis of heliogeophysical data for 1900-2017 confirms the validity of the proposed relationship mechanism.