# Psychrometric constant

From AMS Glossary

## psychrometric constant

The ratio of specific heat (

*C*_{p}) of moist air at constant pressure to latent heat (*L*_{v}) of vaporization of water.This constant has a value of γ =

*C*_{p}/*L*_{v}≅ 0.4 (g_{water}/kg_{air}) K^{-1}. Latent heat flux, when multiplied by this constant, yields a moisture flux.