Kirchhoff's equation
From Glossary of Meteorology
A relation that equates the variation with temperature of the latent heat of a phase change to the difference between the specific heats of the two phases.
For the heat of vaporization this may be written as
where Lv is the latent heat of vaporization, cpv is the specific heat at constant pressure of water vapor, and cw is the specific heat of liquid water.
