Regional Features of the Secular Variation of the Geomagnetic Field in China Area
Regional Features of the Secular Variation of the Geomagnetic Field in China Area
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DOI：
10.1002/cjg2.694
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发表时间：
2005-05
期刊：
影响因子：
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通讯作者：
Wen-yao Xu;Zigang Wei;G. Xia
中科院分区：
文献类型：
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作者：
Wen-yao Xu;Zigang Wei;G. Xia
在1998 ~ 2001年地磁实测资料的基础上，建立了2000年中国地磁基准场长期变化模型CGRF-SV2000。该模型显示了中国地区磁场的缓慢而平稳的变化。X、Y、Z、H、D、I和F 7个元素的年均无符号速率分别为12.2nT/a、8.2nT/a、43.8nT/a、11.8nT/a、0.96′/a、2.99′/a和22.4nT/a。这些比率比IGRF的全球比率低1/3到1/2。不同要素的变化在中国表现出统一的SV格局：北磁极向中国移动，或中国以3′/a的速度向高纬度移动。此外，赤纬D的变化表明东西部D的对比增强。作为对比和检验，对第8代国际地磁场（IGRF）模型进行分析。与CGRF-SV2000相比，IGRF模型估算的全球SV具有相似的特征，尽管IGRF-SV的年增长率大于CGRF-SV，并且注意到一些区域（或局部）异常。
On the basis of the magnetic survey data during 1998-2001, the China Geomagnetic Reference Field Secular Variation model for 2000, CGRF-SV2000, is established. The model shows a slow and smooth variation of the magnetic field in China area. The unsigned average annual rates are 12.2nT/a, 8.2nT/a, 43.8nT/a, 11.8nT/a, 0.96'/a, 2.99'/a and 22.4nT/a for seven elements X,Y,Z,H,D,I and F, respectively. These rates are less than the global rates of IGRF by 1/3 to 1/2. The variations of different elements show an unified SV pattern in China: the north geomagnetic pole is moving to China, or China is moving toward high latitude at a rate 3'/a. In addition, the variation of declination D shows that the contrast of D between Eastern and Western China is enhanced. As a comparison and test, the 8-th generation of the International Geomagnetic Reference Field (IGRF) models is analyzed. The global SV estimated by IGRF models shows similar characteristics compared with CGRF-SV2000, although the annual rates of IGRF-SV are greater than those of CGRF-SV, and some regional (or local) anomalies are noted.