Characteristics of Perturbations in Recent Length of Day and Polar Motion

Journal of Astronomy and Space Sciences

Sung-Moon Yoo¹  Sung-Ho Na¹  Younghee Kwak¹  Sungki Cho¹  Jung-Ho Cho¹ 

[1] Korea Astronomy and Space Science Institute, Daejeon 305-348, Korea;

关键词: length of day;    polar motion;   

DOI  :  10.5140/JASS.2013.30.1.033

来源: DOAJ

【 摘 要 】

Various features of the existing perturbations in the Earth’s spin rotation are investigated for the recent and most reliable data by spectral analysis, filtering, and comparison with idealized model. First, theory of Earth’s spin rotational perturbation is briefly re-derived in the Earth-fixed coordinate frame. By spectral windowings, different periodic components of the length of day perturbation are separated, and their characters and excitations are discussed. Different periodic components of polar motion are acquired similarly and described with further discussion of their excitations. Causes of the long time trends of both the length of day and polar motion are discussed. Three possible causes are considered for the newly discovered 490-day period component in the polar motion.

【 授权许可】

Unknown