Polar Motion — An Overview

Abstract

After one hundred years of intensive study, some aspects of polar motion remain poorly understood. This motion of the Earth’s axis of rotation with respect to its mantle and crust has been observed and studied since the creation of the International Latitude Service. Research has shown that the motion of the pole is quite complicated and distinguished by components over all time scales. Observationally, the secular, Chandler and annual components of polar motion are well documented, and various geophysical processes have been suggested as likely causes. Other components such as the approximately thirty-year motion, the high-frequency motion and the daily/sub-daily motion remain as subjects of extensive research.