Impacts of urban spatial layout and scale on local climate: A case study in Beijing

Based on the meteorological data (2009?2018) acquired by high-density automatic meteorological stations (AMSs) in Beijing, the influences of urbanization on urban heat island (UHI), wind, and humidity were described by UHI, wind speed ratio (Wsr), and specific humidity ratio (qr), respectively. For the 37 AMSs in central Beijing, the relationships between UHI, Wsr, and qr and six spatial morphological parameters (building height (BH), building density (BD), floor area ratio, sky view factor, frontal area index, and roughness length (RL)) and two land surface parameters (vegetation coverage and impervious cover) in the range of 200-3000 m from the station were studied. The scale effect of each parameter on local climate was also studied. The results showed that individually, these parameters account for 46.8?79.6 % of the change in UHI, 25.6?52.8 % of the change in Wsr, and 25.7?29.3 % of the change in qr. The impact of spatial morphological parameters on local climate has surpassed that of land surface parameters. The parameters that make the largest contributions to the annual average UHI, Wsr, and qr are RL, BH, and BD, respectively. The optimal influencing ranges of the spatial morphological parameters on UHI, Wsr, and qr are 800-1000 m, 1600-2600 m, and 1200-1400 m, respectively.