FAO-56 Reference evapotranspiration

symbols, variables and units

ET₀：mm/d；R_n,G：MJ/(m²·d)；T：°C；u₂：m/s；e：kPa；Δ,γ：kPa/°C。

applicable conditions and boundaries

Daily scale FAO-56 standard reference surface and 2 m wind speed; hourly scale coefficients are different.

formula source code

The following is a copyable LaTeX expression.

ET_0=\frac{0.408\Delta(R_n-G)+\gamma\frac{900}{T+273}u_2(e_s-e_a)}{\Delta+\gamma(1+0.34u_2)}

Reference and Extended Learning

is organized according to model definition and assumptions. Please check actual conditions and original literature before engineering, research and clinical use.