Kp index

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Term: Kp index

Kp is a common index used to indicate the severity of the global magnetic disturbances in near-Earth space. Kp is an index based on the average of weighted K indices at 13 ground magnetic field observatories. It is based on the range of the magnetic field variation within 3 hour intervals that is caused by phenomena other than the diurnal variation and the long-term components of the storm time variations. The values of the Kp range from 0 (very quiet) to 9 (very disturbed) in 28 discrete steps, resulting in values of 0, 0+, 1-, 1, 1+, 2-, 2, 2+,...9.
An Estimated Kp is calculated by NOAA in near-real-time.
The official, after-the-fact, 3-hourly planetary index of geomagnetic activity is calculated twice per month by the the German GeoForschungsZentrum (GFZ) (Research Center for Geosciences), from the K indexes observed at 13 stations primarily in the Northern Hemisphere. The Kp indices, which date from 1932, are used to determine the ap indices.

Created 2023.04.16
Last Modified 2023.04.16
Contributed by Ryan McGranaghan