Abstract Heterogeneous landscape leads to large variations of urban microclimate in all dimensions, yet the vertical variability of meteorological elements within the urban canopy layer (UCL) has been rarely examined. In the present study, we developed an urban vertical diffusion model coupled with a single‐layer urban canopy model. Evaluated against reduced scale outdoor measurements and full‐scale CFD‐based simulations, the UVDM‐SLUCM demonstrates a good capacity to reproduce vertical profiles of air temperature, specific humidity, and wind speed in urban canyons. Root mean square errors of simulated air temperatures across all heights of UVDM‐SLUCM against reduced scale measurements and full‐scale simulations are 1.40°C and 0.78°C, respectively for both summer and winter. A series of simulations were then conducted to explore the effect of aspect ratio, vegetation, and building type on the vertical meteorological profiles in different urban neighborhoods. Results reveal a temperature inversion in the compact canyon: air temperature of the upper canyon exceeds that at the bottom, creating a stable UCL that hinders ventilation. Solar radiation dominates the daytime air temperature despite the intense waste heat released into the canyon. In terms of the effect of vegetation, it is found that the cooling effect of trees is much larger than that of grass, and could extend upward to above the tree crown. The UVDM‐SLUCM model enables quantitative investigation of the interaction between urban configurations and vertical meteorological profiles, and provides a better measure for optimization of the urban thermal environment and building energy performance toward sustainable urban development.
Chen et al. (Sun,) studied this question.