geomagnetic secular variation

基本解释

No anomalous local secular geomagnetic variation has been found in the area.
测区内未发现有局部地磁长期变化异常。
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.
本文利用1958～1995年已正式出版的《地磁观测报告》资料对广州地磁台地磁场的长期变化进行分析研究。