Free decay and excitation of the chandler wobble: self-consistent estimates of the period and quality factor
Wei Chen, Yifei Chen, Jim Ray, Jiesi Luo, Jian Cheng Li
Abstract
Abstract The period T CW and quality factor Q CW of the Chandler wobble (CW) as well as polar motion (PM) transfer functions are all determined by the Earth’s layered structure, mass distribution, elasticity, rheology and energy dissipation, via the Earth’s dynamic figure parameters and complex degree-2 Love numbers. However, most previous studies used geophysical excitations derived from real-valued PM transfer functions to invert for T CW and Q CW , thus leading to results that are not self-consistent. By separating the observed PM into the freely decaying CW and the excited PM, a traverse-based method is proposed to search values of T CW and Q CW that can fit both sides simultaneously, yielding the self-consistent estimates of T CW = 430.4 mean solar days and Q CW = 130. This implies the degree-2 tidal Love number k = 0.35011 − 0.00226i and load Love number k' = − 0.36090 + 0.00233i, and the PM transfer functions T NL = 1.80001 − 0.00692i (non-loading) and T L = 1.15040 − 0.00023i (loading) valid at the Chandler period.