A dynamic model of diurnal irregularity in the nonrigid earth rotation

The previously constructed mathematical model of the Earth’s axial rotation irregularity is refined with the methods of celestial mechanics by considering secondary terms in the expansion of the lunisolar gravitational tidal torque and by using corrections (residuum) for zonal tidal perturbations. The diurnal and sub-diurnal variations in the Earth’s axial rotation were investigated; namely, a celestial mechanics model adequately describing the observation data and revealing the cause of the diurnal and sub-diurnal oscillations of the angular velocity of the Earth’s rotation was constructed. Some examples of predicting the Earth’s axial rotation are given.