Lapse rate

The lapse rate is the rate at which an atmospheric variable, normally <a href="/facts/Temperature/QyGe4gmj">temperature</a> in <a href="/facts/Earth%27s_atmosphere/FV97Am25">Earth's atmosphere</a>, falls with <a href="/facts/Altitude/B5eNVurK">altitude</a>. Lapse rate arises from the word lapse (in its "becoming less" sense, not its "interruption" sense). In dry air, the adiabatic lapse rate (i.e., decrease in temperature of a parcel of air that rises in the atmosphere without exchanging energy with surrounding air) is 9.8 °C/km (5.4 °F per 1,000 ft). The saturated adiabatic lapse rate (SALR), or moist adiabatic lapse rate (MALR), is the decrease in temperature of a parcel of water-saturated air that rises in the atmosphere. It varies with the temperature and pressure of the parcel and is often in the range 3.6 to 9.2 °C/km (2 to 5 °F/1000 ft), as obtained from the <a href="/facts/International_Civil_Aviation_Organization/TzrL1mLr">International Civil Aviation Organization</a> (ICAO). The environmental lapse rate is the decrease in temperature of air with altitude for a specific time and place (see below). It can be highly variable between circumstances.
Lapse rate corresponds to the vertical component of the <a href="/facts/Spatial_gradient/2cmoCezd">spatial gradient</a> of <a href="/facts/Temperature_gradient/YhWj21zy">temperature</a>. Although this concept is most often applied to the Earth's <a href="/facts/Troposphere/JPDQq8cL">troposphere</a>, it can be extended to any gravitationally supported <a href="/facts/Fluid_parcel/yk70LICD">parcel of gas</a>.

Lapse rate open-in-new

Lapse rate