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SOLARCYCLE 24.com / SolarHam.com / Solar Cycle 24 / Spaceweather / Amateur Radio VHF Aurora Website / Sunspots / Solar Flares Geomagnetic storm severity info (K-Index) NOAA / Space Weather Prediction Center The K-index is a code that is related to the maximum fluctuations of horizontal components observed on a magnetometer relative to a quiet day, during a three-hour interval. The conversion table from maximum fluctuation (nT) to K-index, varies from observatory to observatory in such a way that the historical rate of occurrence of certain levels of K are about the same at all observatories. At SWPC, we monitor the preliminary values of the K-index, minute by minute, from a network of observatories that relay data in near-real time. The relationship between K, Kp, and estimated Kp The official planetary Kp index is derived by calculating a weighted average of K-indices from a network of geomagnetic observatories. Using minute-by-minute station K-indices, SWPC monitors the estimated Kp index in near real-time and issues alerts when thresholds are crossed. The relationship between K and A The relationship between the NOAA G-scale and Kp Limitations

SECCHI - Solar Physics Branch - Naval Research Laboratory STEREO