according to observation data at geomagnetic stations in hebei province from 1986 to 2005, we sum up and analyze the laws of the geomagnetic secular variation in this paper.
利用河北省地磁台1986~2005年的地磁观测资料,对该地区地磁场长期变化规律进行总结分析。
according to the observation data at guangzhou geomagnetic observatory from 1958 to 1995, we summarize the laws of the geomagnetic secular variation in guangzhou geomagnetic observatory.