A numerical model has been developed for the simulation of the heating and evaporation processes in the urban canopy layer. The three dimensional filtered Navier-Stokes equations, continuity equation and heat and moisture transfer equations in the air are solved using a Large Eddy Simulation (LES) technique to obtain the wind, air temperature and moisture fields in the canopy layer. The heat exchange between the roof, walls of buildings, pavement surface and the air is evaluated by solving the heat conduction equation for the roof, walls and pavement. The heat and moisture fluxes at the unpaved ground surface or porous pavement surface are evaluated by the solutions of equations coupling subsurface heat and moisture transfer, and the evaporation at the ground surface.
Using the model, the heating and evaporation process in the urban canopy layer, and its effects on the urban thermal environment can be evaluated.