Testing of the New USGS K Index Algorithm at Bear Lake Observatory

摘要

The K index was developed by Bartels in 1939 as an estimate of the level of geomagnetic activity caused by the Sun. This index was computed manually every three hours at geomagnetic observatories using the magnetic traces of the surface planetary magnetic field. In 1991, the International Association of Geomagnetism and Aeronomy approved four additional methods to compute the K index; all of them were computer algorithms. One of the approved methods, the Wilson code, recently underwent some modifications. The new algorithm is now part of a Windows-based computer program being developed by the United States Geological Survey (USGS). After successfully evaluating a beta version of this new program, it was used to compute the K index for a new location. This new location is the Bear Lake Observatory (BLO), where the Utah State University has been collecting geomagnetic data from their magnetometer. Statistical techniques were applied to correlate K indices among existing stations in an effort to develop a test for the validity of the K index of a station. These statistical tests were applied to the BLO K index proving that the technique works and that the BLO K index was computed properly.