Validation of an Urban Surface Exchange Parameterization for Mesoscale Models— 1D Case in a Street Canyon

Abstract A detailed urban parameterization scheme is used in and above a street canyon. To validate this new scheme, the model is run offline on a vertical column (one-dimensional simulations), using measurements from a 30-m-high tower for upper boundary conditions. Measurements were obtained during the intensive observation period of the Basel Urban Boundary Layer Experiment (BUBBLE). Vertical profiles of meteorological variables are simulated in the street canyon. The validation of the parameterization is made with measurements from the tower in the street canyon and directly above roof height. The results show that the urban parameterization scheme is able to catch most of the typical processes that are induced by an urban surface near the ground. The fit to measured profiles is improved in comparison with a model using the traditional approach for urban parameterization (variation of z0 to take into account the presence of a city).