Urban street canyon morphology and its effect on climate-responsive outdoor thermal environment in severe cold regions: a case study of Hohhot, China

Climate-responsive urban design requires a thorough understanding of how street canyon morphology affects the thermal environment, especially for the severe cold regions in Northern China. Individual geometric parameters often overlook other geometric characteristics of real street canyons, making it impossible to establish precise correlations between morphological parameters and thermal environments. This study investigates the influence of six key geometric parameters on thermal conditions in Hohhot, China. Mobile measurements revealed a significant quadratic relationship between the asymmetrical aspect ratio and mean air temperature at 12:00 (R-2 = 0.91654). We also found that the aspect ratio, the complementary index closing ratio, and the smoothness rate were negatively correlated with mean air temperature at various times, while height variation positively influenced air temperature (R-2 = 0.67946). Furthermore, the building coverage ratio in adjacent areas significantly impacted mean radiant intensity (R-2 = 0.700 and 0.679 at 11:00 and 12:00, respectively, p < 0.05). Multiple regression analyses underscored the collective impact of these parameters on thermal conditions. These findings provide valuable insights for optimizing street canyon design to improve thermal comfort, thereby contributing to more effective climate-responsive urban planning.