Distributions of fluctuations in motion of the Earth’s pole

Abstract

1. According to observation data and measurements made by the International Earth Rotation Service in the last 15‐20 years, motion of the Earth’s pole involves a principal component (free nutation and Chandlers wobble) with an amplitude of 0.20  —0.25  and a period of 433 ∠ 2 sidereal days [1], a regular annual component (365 sidereal days) with an amplitude of about 0.07  — 0.08  , and a comparatively slow irregular drift (trend) of the axis of the Earth’s figure. The annual wobbles of the Earth’s axis are caused by the moment of gravitational forces of the Sun, the Earth’s revolution around the Sun, and the diurnal tides of the mantle [2, 3]. The causes and mechanism of exciting the annual wobbles are usually attributed to seasonal geophysical phenomena [4, 5]. Measurements of motion of the Earth’s pole were statistically analyzed in many works (see, e.g., [6]). Analytical stochastic spectrally correlation models of motion of the Earth’s pole were developed in [7‐9] on the basis of celestial mechanics. In this paper continuing studies [7‐9], we consider one-dimensional distributions of fluctuations in motion of the deformable Earth.