Chandler摆动周期和Q值对激发函数估计与比较的影响  

EFFECTS OF DIFFERENT CHANDLER PERIODS AND Q ON ESTIMATES OF THE EXCITATION FUNCTION AND THEIR COMPARISONS

作　　者：廖德春[1,2] 廖新浩[1,2] 周永宏[1,2] 

机构地区：[1]中国科学院上海天文台,上海200030 [2]中国科学院国家天文台,北京100012

出　　处：《中国科学院上海天文台年刊》2002年第23期12-20,共9页Annals Shanghai Astronomical Observatory Chinese Academy of Sciences

基　　金：国家自然科学基金重点项目 (198330 30;10 1330 10 );国家自然科学基金项目 (199730 11);上海市科技发展基金项目 (JC140 12 )资助

摘　　要：用 198 4～ 1999年期间的地极坐标序列和两个大气角动量序列 ,分析了不同Chandler周期和品质因子Q的取值对Chandler摆动观测激发的功率谱密度 ,以及观测激发与大气激发之间的相干系数和相干相位的影响。结果表明 ,不同Chandler周期和品质因子Q的取值对观测激发的功率谱密度 ,以及观测激发与大气激发之间的相干系数有很大影响。因此 ,在分析Chandler摆动的观测激发与地球物理激发的关系时 ,不能仅以观测激发与某个地球物理激发序列 (如大气激发 )的更好逼近来选择Chandler摆动的最佳周期 。By using the data series of the polar coordinates and atmospheric angular momentum (AAM) during 1984～1999, effects of different Chandler periods and quality factor Q on the estimates of power spectral density (psd) of the observed polar motion excitation, and of squared coherence and coherent phases between the observed excitation and the AAM excitation are analyzed. Results show large differences in psd of the observed excitation, and in squared coherence between the observed excitation and the AAM excitations for different Chandler periods and Q. Thus, when comparing the observed polar motion excitation with one of the geophysical excitations (e.g. AAM excitation), one should not choose the Chandler period by a better approximation of the observed one to the geophysical one, because the observed excitation is a comprehensive results of various geophysical excitation sources.

关 键 词：Chandler摆动周期 大气激发 地极移动 激发机制 品质因子 

分 类 号：P127.4[天文地球—天体测量]