Impact Of Synergistic Cooling Of Greenspace And Bluespace On The Residential Area Of Chongqing

With the deepening of urbanization in China,it is necessary to build a large number of residential buildings.However,the Urban Heat Island(UHI)has intensified with the impact of factors such as underlying surface changes,traffic and building heat removal,the thermal environment problems in urban residential areas have become increasingly prominent.Although the synergistic cooling of greenspace and bluespace is highlighted as providing ecosystem benefits including cooling,there are few types of research on the effect of this synergistic cooling on the residential areas in local climate.This study carried out quantitative research on the waterfront thermal environment of typical residential areas combined with observation measurements and numerical simulation in Chongqing.This paper focuses on the following aspects:In this study,a comparative observation based on synergistic dynamics was conducted in Chongqing,China from July to August in 2018.The air temperature,relative humidity,black ball temperature and air circulation in 20 m range of littoral zone were illustrated by on-site measurements,meanwhile,the measurements were also conducted on the similar separate vegetation in contrast.The results showed that the microclimate of the littoral area showed the synergistic effect,more extensive cooling distribution than single greenspace was convinced in 7-12 m range,and the middy depression of vegetation was mitigated.The cooling effect of the waterfront trees is still 3.3°C higher than that of the individual trees excluding the waterbody cooling effect.A suitable database featured by Chongqing climate characteristics,building envelope structure and commonly used green plants were established in ENVI-met,and the waterfront residential area model was built based on the previous survey research of the residential area,and the simulation results were verified by measured data.Then an in-depth analyze was conducted to compare the cooling differences of synergistic cooling on three littoral building layouts and types,the best cooling effect was found on the thermal environment of dot layout villa areas,while the worst effect was found on an enclosed multi-story residential building.Based on the above ENVI-met model,several littoral greening scenarios were set for the tree species with different leaf area indexes,which was conducted to explore the effects of different aspects on the improvement of the thermal environment of residential areas,and to investigate the differences in the improvement of different littoral greening allocation modes on the thermal environment.It was found that the trees with higher LAI had better improvement on outdoor thermal comfort in the waterfront residential area in the morning,and that of the lower LAI trees was better from afternoon to night.This study reveals the synergistic cooling effect of greenspace and bluespace on the thermal environment of littoral areas and UHI.Additionally,it is committed to exploring the design pattern of the waterfront greenspace in the residential area in Chongqing,providing guidance for the planning and design of the littoral areas.