AP Index - Geomagnetic disturbancesDaily AP index back to 2015-01-01.
Geomagnetic disturbances can be monitored by ground-based magnetic observatories recording the three magnetic field components. The global Kp index is obtained as the mean value of the disturbance levels in the two horizontal field components, observed at 13 selected, subauroral stations . The name Kp originates from "planetarische Kennziffer" ( = planetary index).
The three-hour index ap and the daily indices Ap, Cp and C9 are directly related to the Kp index. In order to obtain a linear scale from Kp, J. Bartels gave the following table to derive a three-hour equivalent range, named ap index.
Geomagnetic Ap Index: The daily index Ap is obtained by averaging the eight values of ap for each day.
Based on the data from Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences.
