The role of geometric factors in urban canyon modeling: new parameterizations and sensitivity analysis

In numerical forecasting models the description of the Urban-atmosphere interaction, is carried out by parametric schemes that provide an estimation of turbulent heat fluxes exchanged by Urban surfaces with the air aloft. Among the various existing models, the Town Energy Budget (TEB) employs an accurate description of physical phenomena usually observed in an Urban environment. To calculate the radiative budget and the turbulent flows, TEB considers the canyon as an element placed in the Urban space with an averaged orientation. To evaluate the role of the canyon orientation on the turbulent heat flux calculation exchanged with atmosphere, TEB scheme has been modified through the development and inclusion of new parameterizations. A sensitivity analysis was performed to verify the weight associated with the introduction of these new parameterizations, using the TEB model coupled with the mesoscale atmospheric model RAMS. The results show a relatively significant impact of the orientation, on the energy budget, although the walls surface temperatures modeled with the original TEB scheme differ noticeably from those calculated with the new parameterizations.