Explaining the discrepancy in the Chandler period and the prediction of the changes in the Earths rotation dynamics

Abstract: In this paper, in the first instance the attitude dynamics of the Earth is modelled based on physical principles so as to correctly predict the Chandler wobble and its features such as its period. To this end not only the steady state and dynamic gravity gradient torques were included, but also the effects of centrifugal acceleration on the deformable viscoelastic model of the planet. After validating the Chandler wobble response, the paper seeks to go beyond and predict the attitude response of the Earth not just over a few years but over much longer term. This requires modelling of the energy balance effects of the entire planet as a whole and not just the redistribution of mass and inertia but also the changes in the inertial properties. To this end simpler physical model of the energy balance process was included to demonstrate the sustained changes in the length of day response of the Earth over a long term. The over aim of the paper is to bring into focus the key physical processes responsible for the changes to the attitude dynamics of the Earth over a reasonable longer time frame. The overall responses of the attitude dynamics over, the short and medium terms are presented.