WET ADIABATIC LAPSE RATE

The rate of temperature decrease as a parcel of air saturated with water rises and the pressure decreases, given by: ðs = -dT/dz where: dT is the temperature change; dz is the change in altitude; and ðs is the saturated (wet) Adiabatic Lapse Rate. dT is the temperature change; dz is the change in altitude; and ðs is the saturated (wet) Adiabatic Lapse Rate. Because moisture is condensing in the rising parcel of air and releasing latent heat, the temperature drop with increasing altitude is less than the (dry) adiabatic lapse rate, or about 0.6C per 100 meters (3.3F per 1,000 feet). The rate assumes that there is no exchange of heat between the parcel and the surrounding air by conduction or mixing.