OHP Geomagnetic Field Data One minute values of magnetic field data taken at OHP geomagnetic stations (see the following map ) can be downloaded from this site. The data files contain four components of magnetic field (Hx, Hy, Hz by fluxgate magnetometer and F by proton magnetometer) and temperature of the fluxgate sensor. These data are compiled into monthly files for each station and stored as ascii (text) files. Please see the readme.txt for the details of the data format. One-minute values of the vector components and temperature are calculated from one-second data. Original one-second data (about 2Mb/day) are available upon request. Result of absolute field measurements (typically once per year) is also available and can be downloaded. Please write to shimizu@eri.u-tokyo.ac.jp for request of the data and for questions regarding the magnetic field data. Magnetic Field Data readme.txt