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Values of Kp Indices, Ap Indices, Cp Indices, C9 Indices, Sunspot Number, and 10.7 cm Flux

Published by NOAA National Centers for Environmental Information | National Oceanic and Atmospheric Administration, Department of Commerce | Metadata Last Checked: December 19, 2025 | Last Modified: 1957-01-01T00:00:00.000+00:00
This data file consists of Kp indices, Ap indices, Cp indices, C9 indices, sunspot number, and 10.7 cm flux. The most often requested parameter of this file are the Kp indices. These planetary indices are derived from the K indices ( a quasi-logarithmic three-hourly measure of magnetic activity ranging from 0 for the least disturbed periods to 9 for the most disturbed) from 12 observatories located between 46 degrees north geomagneticlatitude and 63 degrees south geomagnetic latitude.

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