中国大陆两次地磁急变分析  

The 1991 and 1999 Jerks in China

作　　者：张素琴[1] 杨冬梅[1] 李琪[1] 赵永芬[1] 

机构地区：[1]中国地震局地球物理研究所,北京市民族大学南路5号100081

出　　处：《中国地震》2008年第3期253-260,共8页Earthquake Research in China

基　　金：地震行业科研专项(200708043)资助

摘　　要：通过分析我国9个地磁台站1985-2003年间Y分量和Z分量的年变率曲线,发现1991年在Y分量上有明显地磁急变（Jerk）反映,Z分量并没有明显反映。同时在2000-2001年附近发现Z分量的年变率曲线斜率普遍出现急剧的转折,而在Y分量上则没有发现这种现象。其次,利用地磁场月均值与AP指数月均值的相关性,通过一个确定的模式,从地磁场月均值中除掉外源场的影响。研究发现,对于Y分量和Z分量来说,是否去掉外源场对地磁急变的鉴别并无明显影响。最后,用年变率的等值线图分析了我国地磁台网范围内地磁急变的时空分布演化特征。The study of the annual means （annual rate） for Y and Z components from 9 magnetic observatories in China during 1985～2002 reveals that the 1991 jerk was obvious in Y component but not clear in Z component. The abrupt changes in Z component were popular during 2000～2001 but not seen in Y component. External effects were removed from the monthly means by comparing the monthly mean of the geomagnetic field components at the observatories with the monthly time series of the A_p geomagnetic index. The research result shows whether external effects are removed or not, there is no marked distinction in determining the jerks in China for Y component and Z component. Finally, the isolines of the first differences of annual means are used to analyze the spatial and temporal distributions of jerks in the network of magnetic observatories in China.

关 键 词：急变 年变率 外源场 等值线 AP指数 

分 类 号：P315[天文地球—地震学]