What is it?
An individual K index is an integer in the range 0 to 9 corresponding to a class that contains, after eliminating the regular daily variation (SR), the largest range of geomagnetic disturbances in the two horizontal components (X and Y) during a 3-hour interval. These are given for a particular observatory with the intent of producing a geomagnetic disturbance characterisation. You can get more information here.
Below is a real-time display reflecting magnetic activity in France mainland using CLF data. This a is development in collaboration with the University of Zagreb, Faculty of Science, Department of Geophysics.
Access to data:
You can access to CLF K-indices from 2012 in text format here.