Ananabatic wind, from theGreekanabatos, verbal ofanabainein meaning "moving upward", is a warm wind which blows up a steep slope ormountain side, driven by heating of the slope throughinsolation.[1][2] It is also known asupslope flow. These winds typically occur during the daytime in calm sunny weather. Ahill or mountain top will beradiatively warmed by theSun which in turnheats theair just above it. Air at a similaraltitude over an adjacentvalley orplain does not get warmed so much because of the greater distance to the ground below it.
The air over the hill top is now warmer than the air at a similar altitude around it and will rise throughconvection. This creates a lower pressure region into which the air at the bottom of the slope flows, causing the wind. It is common for the air rising from the tops of large mountains to reach a height where it coolsadiabatically to below itsdew point and formscumulus clouds. These can then producerain or eventhunderstorms.[2]
Anabatic winds are particularly useful to soaringglider pilots who can use them to increase the aircraft's altitude. Anabatic winds can be detrimental to the maximum downhill speed of cyclists. Conversely,katabatic winds are down-slope winds, frequently produced at night by the opposite effect, the air near to the ground losing heat to it faster than air at a similar altitude over adjacent low-lying land.
