大气和极移的高频变化比较  

COMPARE OF HIGH FREQUENCY VARIATION IN ATMOSPHERE AND POLAR MOTION

作　　者：王保卫[1] 顾震年[1] 金文敬[1] 

机构地区：[1]中国科学院上海天文台,上海200030

出　　处：《天文学报》2001年第3期278-286,共9页Acta Astronomica Sinica

基　　金：自然科学资金重点项目 (1 983 3 0 3 0 ) ;中国科学院九五重大项目 (KJ95 1 1 3 0 4);中国科学院重点项目 (93 1 1 3 6)

摘　　要：采用从 1 988 1 999年的现代技术测定的高精度极移序列EOP(IERS97C0 4 )推导出激发函数 (χm)和美国国家环境预测中心和美国国家大气研究中心 (NCEP/NCAR)提供的大气角动量激发函数 χp 和 χpib,使用几种数据分析方法 ,分析了大气对极移高频振荡 (1 2 42cpy)激发贡献 .复数小波变换和功率谱分析表明 ,χm 和 χp 序列在高频段内呈现比较强的谱峰 ,它们具有相似的谱特征 .比较而言 ,χpib在这个频率段内比 χp 要弱些 .χm 和 χp 之间的相关系数分别为 0 .75 (逆向 )和 0 .6 (顺向 ) ,两个序列之间的平方相关谱的估计值分别在 0 .5 0 .8之间(负频 )和 0 .4 0 .6 (正频 ) .相位谱表明 χp(AAM)超前 χm 一天左右 .这些结果表明大气是极移高频变化的主要激发源 ,特别是在逆向运动上具有更大的贡献 .由于它们之间位相差和振幅变化的不稳定性 ,说明可能存在AAM以外的其他激发源 。The inferred excitation function( χ m) derived from geodetic motion series EOP(IERS 97C04) and χ p of the atmospheric angular momentum(AAM) provided by NCEP/NCAR during 1988 1999 are used to compare the AAM contribution to the polar motion excitation in high frequency variation(12 42 cpy) by several analysis methods in this paper. It is shown by complex Wavelet Transform and power spectra that there are high peaks and the similar feature between χ p and χ m.The peaks for χ p ib are lower in comparison with those in χ p. Their cross correlation coefficients are 0.75(retrograde) and 0.6 (prograde) respectively.The squared coherence phase show χ p is about one day ahead of χ m. These results indicate that atmosphere variation is the main source of the polar motion excitation in high frequency range. Additionally. It has more contribution on the retrograde component. However, because of the non stationary features on phase and amplitude, it suggests that these may be excitation sources other than AAM for the polar motion in high frequency. More investigation should be down.

关 键 词：激发函数 大气角动量 高频振荡 极移 小波变换 功率谱 

分 类 号：P127[天文地球—天体测量]