Dynamical Modeling and Excitation Reconstruction as Fundamental of Earth Rotation Prediction

Though pure mathematical approximations such as regression models and neural networks show good results in Earth rotation forecasting, dynamical modeling remains the only base for the physically meaningful prediction. That assumes the knowledge of cause-effect relationships and physical model of the rotating Earth. Excitation reconstruction from the observed Earth orientation parameters (EOP) is a crucial stage, needed for comparison with known causes, such as tidal forcing, atmospheric (AAM), oceanic (OAM) angular momentum changes, and uncovering unknown ones. We demonstrate different approaches, which can be used to avoid ill-conditionality and amplification of noises during the inversion. We present amplitude and phase studies of the model and reconstructed excitations of Chandler wobble. We found out, that modulation of Chandler excitation is synchronous with 18-yr tidal effects in the Earth's rotation rate changes. The results of the study can be used for excitation and EOP forecast. The key issues of the EOP prediction are discussed.