Empiric Models of the Earth's Free Core Nutation

TL;DR

This paper compares various free core nutation (FCN) models, demonstrating that the proposed model improves Earth's rotation modeling accuracy and aids in geophysical studies of Earth's core.

Contribution

The paper introduces a new FCN model that outperforms existing models in extracting geophysical signals from observational data.

Findings

The proposed FCN model yields higher accuracy in Earth's rotation modeling.

The model effectively extracts amplitude and phase of FCN for geophysical analysis.

Comparison shows the new model is superior to previous models.

Abstract

Free core nutation (FCN) is the main factor that limits the accuracy of the modeling of the motion of Earth's rotational axis in the celestial coordinate system. Several FCN models have been proposed. A comparative analysis is made of the known models including the model proposed by the author. The use of the FCN model is shown to substantially increase the accuracy of the modeling of Earth's rotation. Furthermore, the FCN component extracted from the observed motion of Earth's rotational axis is an important source for the study of the shape and rotation of the Earth's core. A comparison of different FCN models has shown that the proposed model is better than other models if used to extract the geophysical signal (the amplitude and phase of FCN) from observational data.