Simulation Study of Urban Residential Development and Urban Climate Change in Xi'an, China

Increased awareness of the urban heat island (UHI) effect has drawn attention to monitoring and evaluating outdoor thermal comfort in cities worldwide. Especially in China, rapid, large-scale urban development is producing urban climate change in large cities, creating other urban environmental problems such as haze weather. Currently, studies are being conducted in China to reveal the impact of urban development on urban climate change. Few studies, however, have focused on microscale urban planning styles and urban typology. High-density building development will change the urban typology, leading to changes in the urban sky view factor (SVF) and microclimate. Our previous study explored the relationship between SVF and the UHI effect by assessing the effect of SVF on the urban thermal environment. Since the energy consumed by indoor heating and air conditioning is affected by mean air temperature (Ta), a high SVF should be considered in the urban planning stage. In this study, we analyzed typical urban planning styles in China. We selected microscale residential districts in Xi'an to represent the typical urban typology of residential districts that developed during different periods and used the numerical urban simulation system ENVI-met to evaluate the impact of urban typology change on urban climate change. Using this approach, we determined the effects of building density, building styles, and vegetation system design, thus demonstrating the mechanism of urban climate change in China's larger cities. This analysis of planning styles can provide guidance for future environmental urban development.