Kp index

Geomagnetic index Kp (Planetary K) translates the deviation of the horizontal component of the geomagnetic field on a global scale. The geomagnetic index Kp is a weighted average of 13 local K indices obtained from magnetic observatories located at a latitude between 44° and 60° (north or south). For a given station, K-index consists in a quasi-logarithmic index characterizing the maximum deviation of the horizontal component of the geomagnetic field relative to an assumed quiet day. Kp is a 3-hour index whose values range from 0 (quiet) to 9 (severe storm).