Microclimate Characterization and Analysis of Pedestrian Zones in Transportation Hubs: A Case Study of China's Hot and Dry Regions

Against the backdrop of global climate change exacerbating extreme heat events in arid regions, this study investigates the pedestrian microclimatic differences between traditional and modern transportation hubs in Urumqi, a large city in China's BWk climate zone, and comprehensively examines the pedestrian outdoor thermal comfort characteristics. By integrating multidimensional data from in-situ monitoring, thermal perception surveys, and microclimate simulations, a dynamic assessment model based on Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) was developed. The results indicate that in summer, within the transportation hub buildings in Urumqi, the neutral temperature ranges of PET and UTCI are 19.9-28.3 degrees C and 25.7-30.0 degrees C, respectively, while their acceptable temperature ranges are 13.8-33.3 degrees C and 18.5-31.1 degrees C, respectively. Meanwhile, the thermal stress grades of transportation hub spaces in Urumqi during summer were revised. In addition, with a prediction accuracy of 28.9%, UTCI was identified as the optimal index applicable to Urumqi in summer. Finally, through comparisons with different hot-arid cities, it is found that the BWk climate zone exhibits a wider threshold span and a low-temperature adaptive shift compared to the BWh climate zone and hot-humid cities, revealing the regional thermal perception differences in arid regions. This research quantifies key thermal benchmark parameters and establishes a thermal safety threshold model tailored to arid transportation spaces. It provides theoretical guidance for enhancing thermal comfort of pedestrian microclimate and optimizing the design of outdoor areas in transportation hubs, thereby strengthening their resilience and adaptability to future climate change.