|Operational K index (Kind indicator)|
This indicator performs the assessment of geomagnetic activity of natural origin by means of the real time calculation of the geomagnetic K-index. Kind indicator algorithm provides calculation of the K-index with a 10-minute interval, what significantly increases the geomagnetic disturbance response time. Three component recordings of geomagnetic field for the previous 30 days are used as input data. Five days with minimal diurnal disturbances are chosen, and quiet field is calculated as horizontal component value, averaged for these 5 days. Then the difference between maximal and minimal deviation of the measured horizontal component from the quiet level is calculated for the current 10-minute interval of the current day. The obtained value of the horizontal component is transferred into the operational value of the K-index according to the logarithmic scale and stored in the database.
The results of the application of the operational K index are classified within a 10-grade scale (0–9), where ≤3 is ‘background’; 4 is ‘weak anomaly’; 5–6 is ‘anomaly’; 7–9 is ‘strong anomaly’.
Currently used grades and corresponding threshold values for this indicator are listed in the following table:
For more details, please check the Data Science Journal paper: