Pseudoadiabatic lapse rate

From Glossary of Meteorology

pseudoadiabatic lapse rate

The rate of decrease of temperature with height of a parcel undergoing a pseudoadiabatic process.

It is given by
where Γps is the pseudoadiabatic lapse rate, g is gravitational acceleration, rv is the mixing ratio of water vapor, cpd and cpv are the specific heats at constant pressure of dry air and water vapor, Lv is the latent heat of vaporization, R is the dry air gas constant, ε ≈ 0.62 is the ratio of the gas constants of dry air and water vapor, and T is temperature. The above lapse rate is usually within 1 percent of those shown under moist-adiabatic lapse rate and reversible moist-adiabatic lapse rate.