A comparative study of the coordinates of the Earth's pole from 1900 to 1990

Three series of coordinates for the Earth's pole covering the period from 1 900 to 1990 are compared. The two most uniform and prolonged series (the "K iev series" in the frame of the mean pole at the observation epoch and the series obtained by Yumi and Yokoyama in the CIO frame) are compared with po lar coordinate data processed using a new global determination of the Earth orientation parameters. Periodogram and two-channel autoregression analyse s did not reveal any significant discrepancies in the main periodic compone nts in the coordinate series compared (the Chandler and annual components). The relative positions of the coordinate-frame origins were calculated bef ore and after eliminating trends.