Values for the 15-minute Index of Geomagnetic Activity at High Latitude Stations (Geomagnetic Latitude 58 Degrees)

The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) receives, on a monthly basis, Q indices from Sodankyla. These data are available from July 1957 to the present. Sodankyla indices are the most complete records of Q indices that NCEI has. The archive also contains Q indices from 15 other observatories. The Q index is a measure of geomagnetic activity assigned by high latitude (geomagnetic latitude > 58 degrees) geomagnetic observatories for each 15 minute interval. The index is designed to study auroral and ionospheric phenomena over a time scale smaller than that possible with KP. The Q scale is loosely logarithmic, with possible values from 0 to 11.