Editing Subtropics (section)

== Rainfall ==
{{See also|Earth rainfall climatology|Subtropical ridge|Tropical cyclone|Subtropical cyclone|Wet season}}
[[File:Earth Global Circulation - en.svg|thumb|Hadley cells on the Earth's atmospheric circulation]]
Heating of the earth by the [[sun]] near the equator leads to large amounts of upward motion and convection winds along the [[monsoon trough]] or [[Intertropical Convergence Zone]]. The upper-level divergence over the near-equatorial trough leads to air rising and moving away from the equator aloft.  As the air moves towards the mid-latitudes, it cools, gets denser and sinks, which leads to subsidence near the [[30th parallel (disambiguation)|30th parallel]] of both hemispheres. This circulation is known as the [[Hadley cell]] and leads to the formation of the [[Horse latitudes|subtropical ridge]].<ref>Dr. Owen E. Thompson (1996). [http://www.atmos.umd.edu/~owen/CHPI/IMAGES/circs02.html Hadley Circulation Cell.] {{webarchive|url=https://web.archive.org/web/20090305122318/http://www.atmos.umd.edu/~owen/CHPI/IMAGES/circs02.html |date=5 March 2009 }} Channel Video Productions. Retrieved on 11 February 2007.</ref> Many of the world's deserts are caused by these climatological [[high-pressure area]]s,<ref>ThinkQuest team 26634 (1999). [http://library.thinkquest.org/26634/desert/formation.htm The Formation of Deserts.] {{webarchive|url=https://web.archive.org/web/20121017193948/http://library.thinkquest.org/26634/desert/formation.htm |date=17 October 2012 }} Oracle ThinkQuest Education Foundation. Retrieved on 16 February 2009.</ref> within the subtropics. This regime is known as a [[Semi-arid climate|semiarid]]/[[arid]] subtropical climate, which is generally in areas adjacent to powerful cold ocean currents. Examples of this climate are the coastal areas of [[Southern Africa]] and the west coast of [[South America]].<ref name="britannica.com">{{Cite web | url=http://www.britannica.com/EBchecked/topic/606540/tropical-and-subtropical-desert-climate | title=Tropical and subtropical desert climate}}</ref>

The [[humid subtropical climate]] is often on the western side of the subtropical high. Here, unstable tropical airmasses in summer bring convective overturning and frequent tropical downpours, and summer is normally the season of peak annual rainfall. In the winter (dry season) the monsoon retreats, and the drier [[trade winds]] bring more stable airmass and often dry weather, and frequent sunny skies. Areas that have this type of subtropical climate include Australia, Southeast Asia, and parts of South America.<ref name="SAVWOOD">{{cite web|author=Susan Woodward |url=http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/savanna/savanna.html |title=Tropical Savannas |date=2 February 2005 |access-date=16 March 2008 |publisher=[[Radford University]] |url-status=dead |archive-url=https://web.archive.org/web/20080225082154/http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/savanna/savanna.html |archive-date=25 February 2008 }}</ref><ref>Randy Lascody (2008). [http://www.srh.noaa.gov/mlb/wetdry/FLrainMachine.htm The Florida Rain Machine.] [[National Weather Service]]. Retrieved on 6 February 2009.</ref><ref>{{cite journal|title=Site Treatments Have Little Effect During Wet Season in Texas|date=1 January 1960|journal=Tree Planters' Notes|author=John J. Stransky|volume=10|issue=2}}</ref> In areas bounded by warm ocean like the southeastern United States and East Asia, tropical cyclones can contribute significantly to local rainfall within the subtropics.<ref>{{cite book|url=https://books.google.com/books?id=t2FZryJtlmwC&pg=PA33|title=Australia Burning: Fire Ecology, Policy and Management Issues|author1=Geoffrey John Cary |author2=David B. Lindenmayer |author3=Stephen Dovers |page=33|year=2003|publisher=Csiro Publishing|isbn=978-0-643-06926-8}}</ref>  [[Japan]] receives over half of its rainfall from typhoons.<ref name="Whipple 54">{{cite book | author =  Whipple, Addison | year = 1982 | title = Storm | location = [[Alexandria, Virginia|Alexandria, VA]] | publisher = [[Time Life|Time Life Books]] | isbn = 978-0-8094-4312-3 | page =  54}}</ref>

The [[Mediterranean climate]] is a subtropical climate, usually found on the western side of continents, with a wet season in winter and a dry season in the summer. Regions with this type of climate include the rim lands of the [[Mediterranean Sea]], [[southwestern Australia]], parts of the west coast of South America around [[Santiago]] and the coastal areas of the lower [[West Coast of the United States|west coast of the United States.]]<ref>Remote Sensing for Migratory Creatures (2002). [https://web.archive.org/web/20041102070632/http://arsc.arid.arizona.edu/migratory/veg_tdf.html Phenology and Creature Migration: Dry season and wet season in West Mexico.] Arizona Remote Sensing Center. Retrieved on 6 February 2009.</ref><ref name="JHorel">J. Horel (2006). [http://www.met.utah.edu/jhorel/html/wx/climate/normrain.html Normal Monthly Precipitation, Inches.] {{webarchive|url=https://web.archive.org/web/20061113222938/http://www.met.utah.edu/jhorel/html/wx/climate/normrain.html |date=13 November 2006 }} University of Utah. Retrieved on 19 March 2008.</ref><ref>D. Bozkurt, O.L. Sen and M. Karaca (2008). [http://www.cosis.net/abstracts/EGU2008/04210/EGU2008-A-04210-1.pdf Wet season evaluation of RegCM3 performance for Eastern Mediterranean.] EGU General Assembly. Retrieved on 6 February 2009.</ref><ref>{{cite journal|url=http://geography.huji.ac.il/personal/Dayan/Publications/Synoptic%20Clim%20Maj%20Floods.pdf|page=869|title=Synoptic Climatology of Major Floods in the Negev Desert, Israel|author1=Ron Kahana|author2=Baruch Ziv|author3=Yehouda Enzel|author4=Uri Dayan|name-list-style=amp|journal=International Journal of Climatology|year=2002|volume=22|issue=7|doi=10.1002/joc.766|bibcode=2002IJCli..22..867K|s2cid=129438767 |url-status=dead|archive-url=https://web.archive.org/web/20110719162555/http://geography.huji.ac.il/personal/Dayan/Publications/Synoptic%20Clim%20Maj%20Floods.pdf|archive-date=19 July 2011}}</ref>