One-second USGS San Juan (SJG) magnetic observatory data collected before 2013

The USGS Geomagnetism Program operates a network of magnetic observatories that collect vector and scalar magnetometer data for use in Earth main-field modeling,...美国地质调查局（United States Geological Survey，USGS）地磁项目运营着一套地磁观测台站网络，该网络采集矢量磁力计与标量磁力计数据，用于地球主磁场建模……