Kp index

From Glossary of Meteorology

Kp index

The common index used to indicate the severity of global magnetic disturbances in near-Earth space. It is based on the average weighted K indices at 13 ground magnetic observatories and is derived from the magnetic field variation over 3-hour intervals by other-than-diurnal and long time variations. The Kp range is from 0 (quiet) to 9 (extreme), and the maximum achieved value during each 3-hour synoptic period is considered the Kp value for those 3 hours. An estimated Kp is also calculated in near–real time using 8 of the 13 observatories.

GFZ German Research Centre for Geosciences, 2018: Indices of global geomagnetic activity. Accessed 14 August 2018. Available at

Space Weather Prediction Center, 2018: Station K and A indices. Accessed 14 August 2018. Available at

Term edited 14 August 2018.