Seasonal and inter-annual variations of length of day and polar motion observed by SLR in 1993―2006

作     者：GUO JinYun HAN YanBen 

作者机构：National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China College of Geodesy and Geomatics Shandong University of Science and Technology Qingdao 266510 China 

出 版 物：《Chinese Science Bulletin》 (CHINESE SCIENCE BULLETIN)

年 卷 期：2009年第54卷第1期

页      面：46-52页

核心收录：

学科分类：070801[理学-固体地球物理学] 07[理学] 08[工学] 0708[理学-地球物理学] 0816[工学-测绘科学与技术] 

基　　金：Supported by the International S&T Cooperation Program of China (Grant No.2006DFA21980) Hi-Tech Research and Development Program of China (Grant No.2006AA12z303) National Natural Science Foundation of China (Grant No.40774009) 

主　　题：卫星激光距离修正 白昼长度 极地运动 地球转动 

摘      要：A time series of length of the day (LOD) and polar motion (PM) were estimated from the range data measured by the satellite laser ranging technique (SLR) to LAGEOS 1/2 through 1993 to 2006. Com-pared with EOPC04 released by the International Earth Rotation and Reference Systems Service (IERS),the root mean squares errors for LOD,X and Y of PM are 0.0067 milliseconds (ms),0.18 milli-arc-sec-onds (mas) and 0.20 mas,respectively. Then the time series are analyzed with the wavelet transforma-tion and least squares method. Wavelet analysis shows that there are the obvious seasonal and inter-annual variations of LOD and PM,but the annual variation cannot be distinguished from the Chandler variation because these two frequencies are very close. The trends and periodic variations of LOD and PM are given in the least squares sense. LOD changes with the annual and semiannual periods. The annual and Chandler variations for PM are also detected,but the semiannual motion for PM is not found. The trend rate of the LOD change in 1993―2006 is ?0.18 ms per year,and the difference from the well-known 1.7 ms per century showed that the trend rate is diverse in different periods possibly. The trend rates of PM in the X and Y directions are 2.25 and 1.67 mas per year respectively,and the North Pole moves to 36.5°E relative to the crust,which is different from the direction of Greenland.