摘要
本文利用CHAMP卫星磁测资料建立的新一代地磁场模型POMME-4.2S,分析了全球和中国地区地磁长期变化■ 7个分量以及长期加速度、■、■ 3个分量的分布特征,比较了POMME-4.2S长期变化模型与中国长期变模型CGRF-SV的磁异常分布差异.主要结果表明,地磁长期变化磁四极子起主要贡献,长期加速度变化磁八极子贡献最大.2004.0年全球长期变化的减小要比增加大得多,地磁场总体在减弱.长期加速度在中低纬度地区变化较大,高纬度地区变化小.■和■分量磁异常沿经度方向正、负交错形成几个大片区,分量主要正负磁异常成对分布于赤道两侧.长期加速度、■、■ 3个分量的磁异常分布存在明显的关系:在■异常焦点的南北两边出现的异常焦点,东西两边出现■的异常焦点.中国地区的长期变化和长期加速度变化量小,分布相对均匀.
Using the new geomagnetic model POMME-4. 2S derived from the CHAMP satellite data, we have analyzed the characteristics of the distributions of seven secular variation components X, Y, Z, H, F, I, D and three secular acceleration components X, Y, Z in the global area and in China. We also compared the differences of the distributions between the secular variation models POMME-4. 2S and CGRF-SV （Chinese Geomagnetic Reference Field- Secular Variation）. The results suggest that the quadrupole plays the main role in the geomagnetic secular variation, and the octupole occupies the largest portion in the contribution to the secular acceleration. The global secular variation decreased more than that increased in 2004.0 A.D., under the background of a decreasing trend of the geomagnetic field. The secular acceleration changes more in the middle and lower latitudes than that in the higher latitude. Moreover, the negative and positive magnetic anomalies of Y and Z components form several interlaced areas along the longitude, and these two kinds of anomalies of X component are nearly symmetrical to the equator. An evident relationship is available for the magnetic anomaly distributions of the three secular acceleration components X, Y, Z. That is, the loci of X magnetic anomalies are present by the south and north, and Y by the east and west sides of the loci of Z magnetic anomalies. The amount of change of the secular variation and acceleration in China are small and their distributions are relatively uniform.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第8期1976-1984,共9页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(40864002)资助
关键词
主磁场
长期变化
长期加速度
空间分布
Main geomagnetic field, Secular variation, Secular acceleration, Spatial distribution
