#magnetometer

The K-index is an indication of the level of disturbances in the Earth's magnetic field and ranges from 0-9. 1 on the K-index is relatively calm, whereas 5 or more indicates a geomagnetic storm (and therefore aurorae are more likely). Introduced by Julius Bartels in 1938, the K-index ('K' comes from the German “Kennziffer” meaning “characteristic number”) reflects the maximum fluctuations observed by a magnetometer during a three-hour interval. Canadian K-Index Map: https://www.spaceweather.gc.ca/forecast-prevision/short-court/sfst-2-en.php Australian K-Index Map: http://www.ips.gov.au/Geophysical/1/3/1 -CJ Image: Australian K-index map (updated every 20 minutes, see link above): Australian Government's Bureau of Meteorology, Radio and Space Weather Services Further Reading: http://www.swpc.noaa.gov/info/Kindex.html