Thermal Environment Risk Assessment and Optimization of Urban Residents in Hot and Humid Climate:A Case Study Based on Shenzhen City
The urban heat island effect is intensifying in response to rapid urbanization,which has caused substantial impacts on the health,stability,and sustainability of cities.Therefore,how to accurately recognize key regions of high-temperature supply-demand imbalance in urban streets and conduct high-temperature relief in cities is an urgent topic that current society must solve.A case study based on Shenzhen was carried out.First,indicators were chosen from three influencing factors—risks,exposure,and vulnerability—based on the supply and demand of ecosystem services.Then,the demand for thermal environmental regulation services was calculated using the analytic hierarchy process and entropy value method to characterize the demand level of thermal environmental regulation services in urban streets and make spatial autocorrelation analysis.Second,the thermal environmental regulation service supply was calculated from the cold island effect provided by the blue-green spaces to characterize the supply capacity of thermal environmental regulation services in urban streets and make spatial autocorrelation analysis.Finally,quadrant division and spatial matching were applied to the comprehensive supply-demand indicators gained through Z-score normalization.Later,the priority order of planning intervention was gained through the priority index.Results show that 1)there is a significant spatial heterogeneity in the demand level of thermal environment regulation services in Shenzhen,with an overall spatial distribution pattern of"high in the west and low in the east."High-demand areas are predominantly located in subdistricts primarily characterized by residential zones and central business districts.2)The demand level of heat environment regulation services in Shenzhen exhibits an overall spatial distribution pattern of"low in the west and high in the east".There is an inverse relationship between local spatial clustering and demand levels,indicating that blue-green space planning plays a significant role in cooling effects.3)In Shenzhen,32 subdistricts face supply shortages in the low supply-high demand state in thermal environment regulation services.These subdistricts are primarily residential and commercial areas with high population and building densities and insufficient blue-green space provision.In contrast,27 subdistricts are in the high supply-low demand state.These subdistricts are adjacent to large natural parks,forests,and mountainous areas,with abundant green space and water resources.They provide significant thermal environment regulation capacity for Shenzhen and should be prioritized for protection.4)The study area is classified into five different intervention priority levels according to the priority index.Among them,seven subdistricts are identified as high-priority areas,predominantly concentrated in the central urban area and its surrounding districts.Generally speaking,key areas of supply-demand imbalance are identified through the overall planning of the supply-demand relationships.Moreover,the priority index can more clearly determine the priority of urban heat regulation to make specific planning strategies.This guarantees the scientific distribution of limited ecological resources and service functions to first meet the needs of groups and regions.This study cannot only provide references to make plans and emergency management pre-arranged plans for Shenzhen and similar cities but also disclose spatial features between ecological land use and thermal environment,thus enabling the coping with challenges brought by thermal risks in the future.
万方数据
