# Penman-monteith method

From AMS Glossary

## Penman–Monteith method

A micrometeorological method to determine the rate of moisture transport (i.e., evaporation rate

*E*or latent heat flux) away from a surface employing the concept of aerodynamic resistance and requiring measurements of net radiation*R*_{n}, ground heat flux*G*, temperature, humidity and wind speed.The latent heat flux is given by where λ is the latent heat of vaporization;

*r*_{c}and*r*_{a}are aerodynamic resistances;*C*_{p}and ρ are the specific heat and density of air, respectively;*S*is the rate of change of saturation vapor pressure with temperature; γ is the psychrometric constant;*e*_{s}is the saturation vapor pressure;*T*_{z}is the temperature at a height*z*above the surface; and*e*is the vapor pressure. The product λ*E*is the latent heat flux.Stull, R. B. 1988. An Introduction to Boundary Layer Meteorology. 666 pp.