Effect of parametric and nonlinear perturbations on statistical dynamics of the Earth’s pole

We study the influence of additive and parametric slowly varying harmonic (at the Chandler frequency and doubled frequency) and stochastic Gaussian broadband perturbations on mathematical expectations, variances, and covariations of oscillations of the Earth’s pole. The influence of perturbations on both regular and irregular stochastic oscillations is considered in detail. Results of numerical experiments are presented. The developed models and software are included into information resources on the fundamental problem “Statistical dynamics of the Earth’s rotation” of Russian Academy of Sciences.     

Amplitude—frequency analysis of Chandler oscillations of the Earth’s pole

An approximate nonlinear spectral-correlation model of fluctuations of the amplitude—frequency characteristics of the Chandler self-excited oscillations of the Earth’s pole is considered. The sensitivity of the model parameters to the asymmetry and anisotropy of fluctuation-dissipative moments of forces and to the effect of harmonic gravitation-tidal moments of forces is studied at Chandler frequency and frequencies close to it. The results of analytical and statistical modeling of the stability of the amplitude—frequency characteristics are presented. The influence of fluctuation disturbances of the white noise type on spectral-correlation characteristics of the oscillations is investigated.