The National Geomagnetic Information Center (NGIC) of the U.S. Geological Survey recently produced a pair of CD-ROMs, using the ISO 9660 standard, that contain 1-minute values of the Earth's magnetic field from the USGS network of thirteen magnetic observatories.
One CD-ROM contains data for the years 1985–1989, and the other contains 1990 data. A third CD-ROM containing 1991 data is expected to be available soon. One-year CDROMs will be produced annually until 5 years of data have been accumulated, at which time a separate CD-ROM containing these 5 years of data will also be produced. Digital geomagnetic data for some of these USGS observatories extends back into the mid-1970's and are currently being processed for distribution on CD-ROMs as well. Figure 1 shows the locations of the U.S.magnetic observatories.