The Lhomme’s model (1988a), that extended Penmann's formulae to a multi-layer model, is redefined as a function of micrometeorological and physiological profiles of crop canopy. The sources and sinks of sensible and latent heat fluxes are assumed to lie on a fictitious plane called zero-displacement plane. Algorithms are given to compute sensible and latent heat flux densities. Performance of the algorithms is compared with that of earlier algorithms.

Two models have been developed by applying conditions of continuity between the roughness sublayer and the top of vegetation canopy having constant foliage distribution. Massman's cosh-type of wind profile and Albini's exponential wind profile have been used to derive expressions for shear stress, displacement height and roughness length in analytical forms. The computed results compared with those of Massman models (1987, 1997) show similarity with the present models.