| 主磁场长期变化十年至百年尺度的周期 |
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| 引用本文： | 白春华,徐文耀.主磁场长期变化十年至百年尺度的周期[J].地球物理学报,2010,53(4):904-911. |
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| 作者姓名： | 白春华 徐文耀 |
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| 作者单位： | 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 |
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| 基金项目： | 国家重点基础研究发展计划（973计划）（2008CB425704）和国家自然科学基金项目（40874089）资助. |
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| 摘 要： | 本文运用小波变换技术，通过分析历史地磁场模型gufm1（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g11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g01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.
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| 关 键 词： | 主磁场 长期变化 小波分析 周期性 |
| 收稿时间： | 2009-12-23 |
| 修稿时间： | 2010-02-24 |
Multi-decadal to centennial secular variation of the main geomagnetic field |
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| BAI Chun-Hua,XU Wen-Yao.Multi-decadal to centennial secular variation of the main geomagnetic field[J].Chinese Journal of Geophysics,2010,53(4):904-911. |
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| Authors: | BAI Chun-Hua XU Wen-Yao |
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| Institution: | 1.Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;2.Graduate University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | 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. |
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| Keywords: | Main geomagnetic field Secular variation Wavelet analysis Periodicity |
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