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• In solar-terrestrial terms, a localized, transient volume of the solar atmosphere in which plages, sunspots, faculae, flares, etc. may be observed.

  NOAA National Weather Service - Cite This Source - This Definition
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  Cite Definition for Active Region (AR)

  American Psychological Association (APA)

  Active Region (AR). (n.d.). National Weather Service Glossary. Retrieved March 25, 2023, from website: http://www.expertglossary.com/definition/active-region-ar.

  Chicago Manual of Style (CMS)

  Active Region (AR). www.weather.gov. National Weather Service Glossary. NOAA National Weather Service. http://www.expertglossary.com/definition/active-region-ar (accessed: March 25, 2023).

  Modern Language Association (MLA)

  "Active Region (AR)." National Weather Service Glossary. NOAA National Weather Service. 25 March. 2023 http://www.expertglossary.com/definition/active-region-ar.

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