Editing Cloud physics (section)

===Adding moisture to the air===
There are five main ways water vapor can be added to the air. Increased vapor content can result from wind convergence over water or moist ground into areas of upward motion.<ref name="convection">{{cite book |author=Pearce, Robert Penrose |year=2002 |url=https://books.google.com/books?id=QECy_UBdyrcC&pg=PA66|title=Meteorology at the Millennium |publisher=Academic Press |page=66 |isbn=978-0-12-548035-2 }}</ref> Precipitation or virga falling from above also enhances moisture content.<ref>{{cite web |author=[[National Weather Service]] Office, Spokane, Washington |year=2009 |publisher=[[National Oceanic and Atmospheric Administration]] |url=http://www.wrh.noaa.gov/otx/outreach/ttalk/virga.php |title=Virga and Dry Thunderstorms |access-date=2 January 2009}}</ref> Daytime heating causes water to evaporate from the surface of oceans, water bodies or wet land.<ref>{{cite web|author1=Bart van den Hurk |author2=Eleanor Blyth |year=2008 |url=http://www.knmi.nl/~hurkvd/Loco_workshop/Workshop_report.pdf |title=Global maps of Local Land-Atmosphere coupling |publisher=KNMI |access-date=2 January 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090225074154/http://www.knmi.nl/~hurkvd/Loco_workshop/Workshop_report.pdf |archive-date=25 February 2009 }}</ref> [[Transpiration]] from plants is another typical source of water vapor.<ref>{{cite book |author1=Reiley, H. Edward  |author2=Shry, Carroll L. |year=2002 |url=https://books.google.com/books?id=jZvsnsLIkNsC&pg=PA40|title=Introductory horticulture |publisher=Cengage Learning |page=40 |isbn=978-0-7668-1567-4}}</ref> Lastly, cool or dry air moving over warmer water will become more humid. As with daytime heating, the addition of moisture to the air increases its heat content and instability and helps set into motion those processes that lead to the formation of cloud or fog.<ref>{{cite web |publisher=[[National Weather Service]] |author=JetStream |year=2008 |url=http://www.srh.weather.gov/srh/jetstream/synoptic/airmass.htm |title=Air Masses |access-date=2 January 2009 |archive-url=https://web.archive.org/web/20081224062959/http://www.srh.weather.gov/srh/jetstream/synoptic/airmass.htm |archive-date=24 December 2008 |url-status=dead }}</ref>