|Author||Boteler, D H|
|Source||Encyclopedia of natural hazards; by Bowbrowski, P T (ed.); Encyclopedia of Earth Sciences Series vol. 41, 2013 p. 986, https://doi.org/10.1007/978-1-4020-4399-4 337|
|Alt Series||Earth Sciences Sector, Contribution Series 20120149|
|Media||paper; on-line; digital|
|Subjects||geophysics; extraterrestrial geology; solar energy; solar variations; geomagnetism; geomagnetic fields; geomagnetic variations; magnetic disturbances; magnetic storms|
|Program||Public Safety Geoscience Targeted Hazard Assessments in Northern Canada|
|Abstract||Sunspots are dark regions on the Sun's surface. The number of sunspots varies with an approximately 11-year cycle and is used as an indicator of the level of solar activity that drives space weather.