网络释义
1)magnetic period,磁变周期2)year of magnetic cycle transformation,磁周期转变年3)short period geomagnetic variation,地磁短周期变化4)period geomagnetic variation,地磁周期性变化5)Anomaly of short period geomagnetic variation,地磁短周期变化异常6)geomagnetic annual variation,地磁1年周期变化