Editing Pressure system (section)

== High-pressure system ==
{{Main article|High-pressure area|Anticyclone}}
[[File:High Pressure.jpg|thumb|250px|Satellite image of a high-pressure area south of Australia, evidenced by the clearing in the clouds<ref>{{cite web|url=http://earthobservatory.nasa.gov/IOTD/view.php?id=78208|title=An Australian "Anti-storm"|date=2012-06-08|access-date=2013-02-12|publisher=NASA}}</ref>]]
High-pressure systems are frequently associated with light winds at the surface and [[Subsidence (atmosphere)|subsidence]] through the lower portion of the [[troposphere]]. In general, subsidence will dry out an air mass by [[adiabatic process|adiabatic]] or compressional heating.<ref>Office of the Federal Coordinator for Meteorology (2006). [http://www.ofcm.gov/fmh3/pdf/15-app-g.pdf Appendix G: Glossary.] {{webarchive|url=https://web.archive.org/web/20090225025158/http://www.ofcm.gov/fmh3/pdf/15-app-g.pdf |date=2009-02-25 }} [[NOAA]]. Retrieved on 2009-02-16.</ref> Thus, high pressure typically brings clear skies.<ref>Jack Williams (2007). [https://www.usatoday.com/weather/tg/whighlow/whighlow.htm What's happening inside highs and lows.] [[USA Today]]. Retrieved on 2009-02-16.</ref>  During the day, since no clouds are present to reflect sunlight, there is more incoming shortwave [[solar radiation]] and temperatures rise.  At night, the absence of clouds means that [[outgoing longwave radiation]] (i.e. heat energy from the surface) is not absorbed, giving cooler [[Diurnal temperature variation|diurnal]] low temperatures in all seasons.  When surface winds become light, the subsidence produced directly under a high-pressure system can lead to a buildup of particulates in urban areas under the ridge, leading to widespread [[haze]].<ref>{{cite web|author=Myanmar government|year=2007|url=http://www.kjc.gov.my/english/education/weather/haze01.html |title=Haze|publisher=Internet Wayback Machine|access-date=2007-02-11 |archive-url = https://web.archive.org/web/20080224035453/http://www.kjc.gov.my/english/education/weather/haze01.html |archive-date = 2008-02-24}}</ref>  If the low-level [[relative humidity]] rises towards 100 percent overnight, [[fog]] can form.<ref>Robert Tardif (2002). [http://www.rap.ucar.edu/staff/tardif/Documents/CUprojects/ATOC5600/fog_characteristics.htm Fog characteristics.] {{webarchive|url=https://web.archive.org/web/20110520021633/http://www.rap.ucar.edu/staff/tardif/Documents/CUprojects/ATOC5600/fog_characteristics.htm |date=2011-05-20 }} [[NCAR]] National Research Laboratory. Retrieved on 2007-02-11.</ref>

Strong but vertically shallow high-pressure systems moving from higher latitudes to lower latitudes in the northern hemisphere are associated with continental arctic air masses.<ref>[[CBC News]] (2009). [https://www.cbc.ca/news/canada/north/blame-yukon-arctic-air-mass-chills-rest-of-north-america-1.860626?ref=rss Blame Yukon: Arctic air mass chills rest of North America.] Canadian Broadcasting Centre. Retrieved on 2009-02-16.</ref>  The low, sharp [[inversion (meteorology)|temperature inversion]] can lead to areas of persistent [[stratocumulus]] or [[stratus cloud]], known in colloquial terms as anticyclonic gloom. The type of weather brought about by an anticyclone depends on its origin. For example, extensions of the Azores high bubble pressure may bring about anticyclonic gloom during the winter, as they are warmed at the base and will trap moisture as they move over the warmer oceans. High pressure systems that build to the north and extend southwards will often bring clear weather. This is due to being cooled at the base (as opposed to warmed), which helps prevent clouds from forming.  The highest barometric pressure ever recorded on Earth was {{convert|1085.7|hPa|inHg}} measured in [[Tosontsengel, Zavkhan|Tonsontsengel, Mongolia]] on 19 December 2001.<ref>{{cite book|page=[https://archive.org/details/extremeweathergu00burt_0/page/234 234]|title=Extreme Weather|author=Christopher C. Burt|year=2004|edition=1|isbn=978-0-393-32658-1|publisher=Twin Age Ltd.|url-access=registration|url=https://archive.org/details/extremeweathergu00burt_0/page/234}}</ref>