Psychrometric constant

From Glossary of Meteorology



psychrometric constant

The ratio of specific heat (Cp) of moist air at constant pressure to latent heat (Lv) of vaporization of water.

This constant has a value of γ = Cp/Lv ≅ 0.4 (gwater/kgair) K-1. Latent heat flux, when multiplied by this constant, yields a moisture flux.