Identifying urban ventilation corridors through quantitative analysis of ventilation potential and wind characteristics

Abstract

Urban heat islands (UHIs) are mainly caused by mismanaged urban development. Urban ventilation corridors (UVCs) can effectively reduce UHIs. Hangzhou, a large, dense city in eastern China, is one of the nation's hottest cities and must urgently improve its ventilation. In this study, a newly developed method combining land surface temperature retrieval, GIS spatial analysis, and weather data was employed to design city-level UVCs. The functional space and compensation space of UVCs are identified based on the LandsatETM8 image data inversion of surface temperature. The contribution of affect factors, such as building density, building height, green land area, waterbody, roads, and urban terrain, to the urban ventilation potential is calculated using AHP and GIS. Areas with tremendous ventilation potential were identified as possible ventilation corridors by using an evaluation model and considering wind characteristics. Fifty-four high-temperature zones and 48 low-temperature zones were identified as functional and compensative spaces in Hangzhou, respectively. On the urban scale, green space (area >500ha), water bodies (area >300ha or width >100 m), and roads (width >50 m) were considered to be the factors that have the greatest impact on urban ventilation potential. The LCP method was used to verify the accuracy and rationality of the method proposed in this study to determine the city-scale UVC. UVC planning schemes and construction measures were proposed to provide rich information and a reference basis for the new general land and space planning of Hangzhou. However, to improve the accuracy of the potential ventilation results, the urban underlying surface criteria should be re-evaluated more comprehensively.