Abstract
We present a scheme for parameterising scalar transfer in the urban boundary layer, which is divided into an inertial layer and a roughness layer. The latter is further divided into a shear layer and a canyon layer. In the inertial layer, scalar transfer is determined by turbulence related to canyon macroscopic features, while in the roughness layer, it is determined by shear-generated turbulence, canyon vortex and vortex-generated turbulence. We first describe a conceptual model for the canyon flow and the aerodynamic resistance network, and then estimate the resistances from the point of view of drag partition and vortex advection. The results are compared with the measurements from wind-tunnel experiments. It is found that for small canyon aspect ratio, σc, the transfer velocity increases with σc, reaching a maximum at around σc=0.5 and then decreases with σc. We also show that the scheme is not sensitive to adjustable parameters
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Yang, Y., Shao, Y. A Scheme for Scalar Exchange in the Urban Boundary Layer. Boundary-Layer Meteorol 120, 111–132 (2006). https://doi.org/10.1007/s10546-005-9033-5
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DOI: https://doi.org/10.1007/s10546-005-9033-5