|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.