This is the planetary K-index from the NOAA SWPC. This is a preliminary Kp-index that is updated every minute by the NOAA SWPC with an estimate of the measured Kp of the past 3 hours based on eight ground-based magnetometers around the world. This estimated 3-hour planetary Kp-index consists of 10 values and ranges from 0 to 9. It is important to understand that this Kp-index isn't a forecast or an indicator of the current conditions, it always shows the Kp-value that was observed during a certain period.
This is the Quicklook Kp-index from the GFZ German Research Centre for Geosciences. This is a preliminary Kp-index which estimates the Kp-index in 3-hour periods. It is expressed in a scale of thirds and has 28 values.
This is the Wing-Kp index from the U.S. Air Force Weather Agency. The Wing Kp model uses solar wind data to produce a 1-hour advance prediction of the level of geomagnetic activity, as represented by the planetary K-index, every 15 minutes. It is expressed in a scale of thirds and has 28 values. The Wing Kp model also provides an observed Kp-value from a magnetometer network of the USAF but this is not a real-time measurement.
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