# Saturation point

From AMS Glossary

## saturation point

A point on a thermodynamic diagram representing the state of the air defined by a pair of variables:

*P*_{sat}and*T*_{sat}, where*P*_{sat}is the saturation pressure and*T*_{sat}is the saturation temperature.These latter variables are the pressure and temperature of an air parcel that was raised dry- adiabatically or lowered moist-adiabatically until it was just at saturation. The

**saturation point**is a conserved variable for adiabatic motion and thus serves as a tracer for the air parcel on a thermodynamic diagram.