subsidence (atmosphere)

{{short description|Movement of colder, more dense air downwards within the atmosphere}}

{{distinguish|Ground subsidence}}

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In meteorology, subsidence is the downward movement of an air parcel as it cools and becomes denser. By contrast, warm air becomes less dense and moves upwards (atmospheric convection).{{Cite web|url=https://glossary.ametsoc.org/wiki/Subsidence|title=subsidence - Glossary of Meteorology}}

Atmospheric subsidence generally creates a high-pressure area as more air moves into the same space: the polar highs are areas of almost constant subsidence, as are the horse latitudes, and the areas of subsidence are the sources of much of the prevailing winds in the Earth's atmosphere.

Subsidence also causes many smaller-scale weather phenomena, such as morning fog; on the other hand, its absence may cause air stagnation. An extreme form of subsidence is a downburst, which can result in damage similar to that produced by a tornado. A milder form of subsidence is referred to as downdraft.