The Saturated Adiabatic Lapse Rate (SALR) is the rate at which the temperature of a parcel of air saturated with water vapour changes as the parcel ascends or descends.
The SALR is often taken as 1.
Saturated Adiabatic Lapse Rate. The rate at which the temperature of saturated air (air at 100% relative humidity) will vary as it is raised or lowered through the atmosphere. The SALR varies with temperature and pressure, however it is always less than the DALR.
Problems arise when, on ascent, the dew point of the air is reached, and the rate of cooling is therefore less - it follows the SALR figure. If, however, the parcel is still warmer/less dense, then it will continue to rise, and the condition of the air is said to be CONDITIONALLY UNSTABLE .. i.e.
When the air is saturated with water vapour (reached its dew point), the moist adiabatic lapse rate (MALR) or saturated adiabatic lapse rate (SALR) applies. It varies with temperature and pressure, but is usually near 4.9 °C/km (2.7 °F/1000 ft).
POTENTIAL INSTABILITY- Also known as convective instability. Instability caused by dry air advecting over warm and humid PBL air. Lapse rate of temperature increases if lifting occurs since the low level air cools at the SALR while the mid-level air cools at the DALR.
See also: Temperature, Forecast, High, Cloud, Surface