Residual method of the energy balance

Residual method of the energy balance, here, the evapotranspiration, otherwise referred to as the latent heat flux (λE), is calculated as the residual term in the general energy balance equation. In this case, the combination of sensible and latent heat flux is assumed equal to the total available energy flux (Ershadi et al., 2011).

Sources
Ershadi, Ali, Matthew McCabe, Jason Evans, and Jeffrey Walker. 2011. Evaluation Of Energy Balance, Combination, And Complementary Schemes For Estimation Of Evaporation. Vol. 344. IAHS-AISH Publication.