主磁场长期变化十年至百年尺度的周期  

Multi-decadal to centennial secular variation of the main geomagnetic field

作　　者：白春华[1,2] 徐文耀[1] 

机构地区：[1]中国科学院地质与地球物理研究所北京空间环境国家野外观测研究站,北京100029 [2]中国科学院研究生院,北京100049

出　　处：《地球物理学报》2010年第4期904-911,共8页Chinese Journal of Geophysics

基　　金：国家重点基础研究发展计划(973计划)(2008CB425704);国家自然科学基金项目(40874089)资助

摘　　要：本文运用小波变换技术,通过分析历史地磁场模型gufml（时间跨度从1590～1990年）,考察主磁场长期变化场（B场）的周期性.结果表明,B场总磁极强度存在三个主要的周期分量：稳定的30年周期,在偶极子场的赤道分量g1/1和非偶极子场中较常见;频散的准50年周期,主要是由轴向偶极子分量g0/1贡献的,此外,四极子场也有贡献;世纪尺度的110年周期,其强度会发生变化,主要来源于偶极子场的赤道分量以及八极子场.In this paper, the technique of wavelet transform is applied to analyze the gufm1 models during 1590~1990 A.D., for detecting the periodicities in the secular variations of the main geomagnetic field. Our analysis suggests that there are three principal periodic components in the total Pole-strength of B field： a stable 30-year periodic component which is mainly seen in the equatorial component g11 of the dipole field, and it is also generally seen in the non-dipole field; second, a dispersive quasi 50-year periodic component, typically contributed by the axial component of the dipole field g01, and the quadrupole also has a definite contribution; the last one is an intensity varying 110-year periodic component on centennial time scale, which seems to be from the equatorial component of the dipole field, and the octupole field also has a contribution.

关 键 词：主磁场 长期变化 小波分析 周期性 

分 类 号：P318[天文地球—固体地球物理学]