Computer generated K indices adopted by the British Geological Survey

Abstract

On 1 January 1991 the British Geological Survey adopted a computer method for generating K indices from its three geomagnetic observatories. This replaced the traditional handscaling method, resulting in saving of staff time. Other advantages are the ability to distribute K indices to users in real time and the fact that there will not be any change in bias of the K index caused by a change of handscaler in future. The computer algorithm is described. The results of a comparison between the computed and handscaled K indices are presented, which show the computer method to be compatible with handscaling.