secular variation

According to the observation data at Urumqi geomagnetic station since the historic times, we sum up and analyse the laws of the geomagnetic secular variation, geomagnetic short period variation and the activity of magnetic storm.

根据乌鲁木齐地磁台有史以来的地磁观测资料，对该地区地磁场的长期变，短期变及其磁暴活动规律进行了总结分析。

Study of secular variation of geomagnetic field by means of VGP

用虚地磁极（VGP）方法对地磁场随时间变化的研究

Analysis of the geomagnetic secular variation in eastern Asia during the last 30 years

近30年来东亚地区地磁长期变化分析

The temporal variation of it has secular change, seasonal variation, irregular variation, and other scales variation.

重力场的时变有长期变化 、 季节性变化 、 不规则变化和其他多尺度的变化.