Water and surface energy balance model with a multilayer canopy representation for remote sensing purposes

A surface energy balance model with a multilayer canopy representation has been developed to simulate the vertical temperature distribution of the foliage elements and the soil underneath. This model allows one to simulate the radiative temperature of the complex vegetation‐covered surface as a function of the angle of observation. The model was implemented for a two‐layer canopy and has been tested by comparing simulated radiative surface temperatures (observed under a look angle of 45°), latent heat, sensible heat, momentum, and ground heat fluxes, and soil temperatures at different depths, with observed data, gathered in a maize field. The fluxes above the canopy were measured by eddy correlation methods. This paper describes the model structure and simulation results as compared with the field measurements. Except for the ground heat fluxes, all the simulated and measured parameters match reasonably well. Further, the model was used to study the sensitivity of the radiative temperature of the complex surface to variations in the roughness length z 0 , the leaf area index LAI , and the drag coefficient C d . The radiative surface temperature turned out to be very insensitive to variations in C d and LAI , and it was found that resulting variations in the radiative surface temperature fall well within the detection error of the remotely sensed surface temperature.