Synchronism of Variations in the Main Geomagnetic Field and Earth Rotation Velocity Fluctuations

Variations in the value of the source magnetic moment, responsible for the dipole component of the main geomagnetic field, and Earth rotation velocity fluctuations have been studied comparatively. Three quasi-harmonic components with close periods, for which their own phase shifts were obtained, have been detected in time series of the analyzed processes. The mantle conductivity effect on these shifts has been studied in the scope of a one-layer model; for this purpose, the amplitude-phase characteristic of the mantle as a filter has been constructed. The mantle conductivity has been estimated (sigma = 270 +/- 20 S m(-1)) on the assumption that the phase shift mainly depends on the mantle effect. It has been assumed that the variations in the time series of the analyzed processes are almost cophased and can be caused by one external factor, e. g., tides.