Adiabatic lapse rate
adiabatic lapse rate
- Dry-adiabatic lapse rateA process lapse rate of temperature, the rate of decrease of temperature with height of a parcel of dry air lifted by a reversible adiabatic process through an atmosphere in hydrostatic equilibrium.This lapse rate is g/cpd, where g is the gravitational acceleration and cpd is the specific heat of dry air at constant pressure, approximately 9.8°C km−1. Potential temperature is constant with height in an atmospheric layer with this lapse rate.
- Moist-adiabatic lapse rate (or saturation-adiabatic lapse rate or moist-saturated adiabatic lapse rate)The rate of decrease of temperature with height along a moist adiabat.It is given approximately by Γm in the following:where g is the gravitational acceleration, cpd is the specific heat at constant pressure of dry air, rv is the mixing ratio of water vapor, Lv is the latent heat of vaporization, R is the gas constant for dry air, ϵ is the ratio of the gas constants for dry air and water vapor, and T is temperature. This expression is an approximation for both the reversible moist-adiabatic lapse rate and the pseudoadiabatic lapse rate, with more accurate expressions given under those definitions. When most of the condensed water is frozen, this may be replaced by a similar expression but with Lv replaced by the latent heat of sublimation.
Term edited 16 August 2021.
Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact email@example.com. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.