Editing Katabatic wind (section)

== Mechanism ==
[[File:Katabatic-wind hg.png|thumb|Sketch of the generation of katabatic winds in Antarctica]]
A katabatic wind originates from the difference of density of two air masses located above a slope. This density difference usually comes from temperature difference, even if humidity may also play a role. Schematically katabatic winds can be divided into two types for which the mechanisms are slightly different: the katabatic winds due to radiative cooling (the most common) and the [[Fall wind|fall winds]]. 

In the first case, the slope surface cools down radiatively after sunset, which cools down the air near the slope. This cooler air layer then flows down in the valley. This type of katabatic is very often observed during the night in the mountains. The term katabatic actually often refer to this type of wind.<ref>{{Cite journal |last1=Poulos |first1=Greg |last2=Zhong |first2=Shiyuan (Sharon) |date=November 2008 |title=An Observational History of Small-Scale Katabatic Winds in Mid-Latitudes |url=https://compass.onlinelibrary.wiley.com/doi/10.1111/j.1749-8198.2008.00166.x |journal=Geography Compass |language=en |volume=2 |issue=6 |pages=1798–1821 |doi=10.1111/j.1749-8198.2008.00166.x |bibcode=2008GComp...2.1798P |issn=1749-8198|url-access=subscription }}</ref>

In contrast, fall wind do not come from radiative cooling of the air, but rather from the [[advection]] of a relatively cold air mass to the top of a slope.<ref>{{Cite web |title=fall wind |url=https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095809391 |access-date=2024-12-22 |website=Oxford Reference |language=en }}</ref><ref>{{Cite web |title=Fall wind - Glossary of Meteorology |url=https://glossary.ametsoc.org/wiki/Fall_wind |archive-url=https://web.archive.org/web/20220819172311/https://glossary.ametsoc.org/wiki/Fall_wind |archive-date=2022-08-19 |access-date=2024-12-22 |website=glossary.ametsoc.org |language=en |url-status=live }}</ref> This cold air mass can come from the arrival of a cold front (see [[Bora (wind)|Bora]]),<ref>{{Cite web |last=Stull |first=Roland |date=2020-03-31 |title=17.10: Downslope Winds |url=https://geo.libretexts.org/Bookshelves/Meteorology_and_Climate_Science/Practical_Meteorology_(Stull)/17:_Regional_Winds/17.10:_Downslope_Winds |access-date=2024-12-22 |website=Geosciences LibreTexts |language=en}}</ref> or from the advection of cool marine air by a sea-breeze.<ref name=":0">{{Cite journal |last1=Lunel |first1=Tanguy |last2=Jimenez |first2=Maria Antonia |last3=Cuxart |first3=Joan |last4=Martinez-Villagrasa |first4=Daniel |last5=Boone |first5=Aaron |last6=Le Moigne |first6=Patrick |date=2024-07-05 |title=The marinada fall wind in the eastern Ebro sub-basin: physical mechanisms and role of the sea, orography and irrigation |url=https://acp.copernicus.org/articles/24/7637/2024/ |journal=Atmospheric Chemistry and Physics |language=en |volume=24 |issue=13 |pages=7637–7666 |doi=10.5194/acp-24-7637-2024 |doi-access=free |bibcode=2024ACP....24.7637L |issn=1680-7324}}</ref>