Kp-index is derived based on K indices obtained at NOAA’s (National Oceanic and Atmospheric Administration) SWPC (Space Weather Prediction Center) in the United States using data from eight observatories for the geomagnetic field located from 44 to 60 degrees in latitudes. Using minute-by-minute observed geomagnetic data, SWPC conducts real-time monitoring for Kp-index values. When data from the observatories are not available in real-time, the most appropriate estimated values are measured based on available data. In order to reflect geomagnetic activity over the Korea Peninsula, KSWC providing geomagnetic data observed at Jeju station to SWPC in real-time for Kp-index improvement.

Earth's surrounding geomagnetic field features the same magnetic properties as magnets. The shape of the field is not fixed but changes regularly. However, due to external factors (solar wind, CME, etc.), additional geomagnetic disturbances sometimes occur. K-index uses the logarithmic scale to display the variation levels in the geomagnetic field over specific regions. The values range from 0 to 9 at 3-hour intervals with 0 being quiet and 9 indicative of radical change.