Reversed polarity patches at the CMB and geomagnetic field reversal
文献类型：期刊论文
| 作者 | Xu, WY; Wei, ZG |
| 刊名 | SCIENCE IN CHINA SERIES D-EARTH SCIENCES
 |
| 出版日期 | 2002-06-01 |
| 卷号 | 45期号:6页码:540-549 |
| 关键词 | geomagnetic field core-mantle boundary reversed polarity patch reversed polarity column polarity reversal of the geomagnetic field |
| ISSN号 | 1006-9313 |
| 文献子类 | Article |
| 英文摘要 | The International Geomagnetic Reference Field models (IGRF) for 1900-2000 are used to calculate the geomagnetic field distribution in the Earth' interior from the ground surface to the core-mantle boundary (CMB) under the assumption of insulated mantle. Four reversed polarity patches, as one of the most important features of the CMB field, are revealed. Two patches with +Z polarity (downward) at the southern African and the southern American regions stand out against the background of -Z polarity (upward) in the southern hemisphere, and two patches of -Z polarity at the North Polar and the northern Pacific regions stand out against the +Z background in the northern hemisphere. During the 1900-2000 period the southern African (SAF) patch has quickly drifted westward at a speed of 0.2-0.3degrees/a; meanwhile its area has expanded 5 times, and the magnetic flux crossing the area has intensified 30 times. On the other hand, other three patches show little if any change during this 100-year period. Extending upward, each of the reversed polarity patches at the CMB forms a chimney-shaped "reversed polarity column" in the mantle with the bottom at the CMB. The height of the SAF column has grown rapidly from 200km in 1900 to 900km in 2000. If the column grows steadily at the same rate in the future, its top will reach to the ground surface in 600-700 years. And then a reversed polarity patch will be observed at the Earth's surface, which will be an indicator of the beginning of a magnetic field reversal. On the basis of this study, one can describe the process of a geomagnetic polarity reversal, the polarity reversal may be observed firstly in one or several local regions; then the areas of these regions expand, and at the same time, other new reversed polarity regions may appear. Thus several poles may exist during a polarity reversal. |
| WOS关键词 | EARTHS MAGNETIC-FIELD ; SECULAR VARIATION ; ELECTRICAL-CONDUCTIVITY ; GLOBAL CHANGES ; OUTER-CORE ; SURFACE ; DYNAMO ; MANTLE ; FLOW |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000175593200007 |
| 出版者 | SCIENCE CHINA PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/77777]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Xu, WY |
| 作者单位 | Acad Sinica, Inst Geol & Geophys, Beijing 100101, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xu, WY,Wei, ZG. Reversed polarity patches at the CMB and geomagnetic field reversal[J]. SCIENCE IN CHINA SERIES D-EARTH SCIENCES,2002,45(6):540-549. |
| APA | Xu, WY,&Wei, ZG.(2002).Reversed polarity patches at the CMB and geomagnetic field reversal.SCIENCE IN CHINA SERIES D-EARTH SCIENCES,45(6),540-549. |
| MLA | Xu, WY,et al."Reversed polarity patches at the CMB and geomagnetic field reversal".SCIENCE IN CHINA SERIES D-EARTH SCIENCES 45.6(2002):540-549. |
入库方式： OAI收割
来源：地质与地球物理研究所
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