The Long Period Oscillation of the Terrestrial Pole

In this article Zhao.Ming-Zheng Dawei Series of the polar coordinates of the earth in ILS system are comprehensively analysed by the AR spectral-analysis, harmonic analysis and period-modified methods.The terrestrial pole obviously oscillates with a long period of 28.7 years, the ellipticity of 0.9962 and the semimajor axis directing 39.°lE after deducing the medium and short period terms from the series.In addition, the analyses of the latitude series at both Mizusawa and Ukiah stations are also made in this paper, and the pole oscillates with the periods of 27.2 and 32.9 years at the two stations,respectively.