Research On Improvement Strategy Of Thermal Environment Planning Based On Local Climate Zones

Global warming and accelerated urbanization have led to a decrease in thermal comfort in outdoor environments.Due to the heterogeneity of urban space,climate responsiveness also varies from place to place.Based on this,many national policies require that climate change factors be taken into account in urban planning,and the planning and layout of related fields are enhanced through urban design to create comfortable urban spaces,which has become an important research topic in the stage of high-quality urban development.Local Climate Zones(hereinafter referred to as LCZs)are important research divisions in recent years based on climate-responsive urban planning.In this study,a methodological system for outdoor thermal environment assessment from the perspective of local climate zones is constructed in the Soyobo Bay area of Dalian City as an example.The spatial distribution of Tmrt in the Soyobo Bay area is calculated using the SOLWEIG model,and the influence mechanism of morphological parameters in relation to thermal comfort on a typical summer day is investigated by quantitative analysis methods such as Pearson correlation coefficient,ordinary least squares and geographically weighted regression models.The WUDAPT tool was used to map the local climatic zoning of Dalian city,and the Tmrt within the zoning was counted according to the LCZs results to initially explore the differences in thermal environment due to spatial heterogeneity.Further,the weighted regression coefficients of each partition are counted to explore the role of spatial heterogeneity in the microclimate environment and provide more methods and suggestions for improving outdoor thermal comfort.The study includes five parts: construction of outdoor thermal comfort assessment method from LCZs perspective-assessment of average outdoor radiation temperature in summer in Soyobo Bay area-quantitative analysis of urban morphological parameters and average radiation temperature--Statistical analysis of outdoor thermal environment in Dalian based on LCZs-Planning improvement strategies for enhancing outdoor thermal comfort from the perspective of LCZs.First,by summarizing the current research methods,the planning research ideas of climate response are refined and formed,and the relevant outdoor thermal environment assessment method system is established.Secondly,we selected Dalian Soyobo Bay area as the research object,used Bigemap to download the geographic elevation information of Dalian city,obtained the summer meteorological data of Dalian from the National Meteorological Data Center,calculated and analyzed the time-by-time spatial variation of Tmrt on a typical day in summer;and explored the intra-city variation of Tmrt using the spatial distribution of the average value of Tmrt during the hottest daytime hours.Third,the urban morphological indicators within the study area are collated as explanatory variables,and Pearson correlation coefficients,global regression models and geographically weighted regression models are calculated with the help of Arc GIS Pro,SPSS,and Geo Da to explore the effects of different morphological parameters on the outdoor thermal environment and the spatial non-smoothness with Tmrt.Fourth,based on the map of LCZs drawn by WUDAPT tool to count Tmrt differences and geographically weighted regression coefficients,the performance of each planning index in LCZs under different urban morphological characteristics is explored.The thermal stress intensity index is defined from the perspective of thermal comfort,and the LCZs are used as the study unit to classify the levels of thermal stress zones in space,providing a methodological basis for identifying thermal risk areas.Fifth,LCZs-based adaptive master planning strategies are proposed from various aspects,including thermal risk,spatial structure,building morphology,cold island protection,urban ventilation,green space system,and high temperature disaster avoidance,and planning improvement design guidelines are formed with key areas as examples.The findings from three levels of mean radiation temperature assessment,quantitative analysis of morphological parameters and thermal environment,and thermal environment analysis from LCZs perspective found that(1)(1)Tmrt varies greatly in the study area at different time periods,with higher Tmrt occurring at 10:00-11:00 AM and 14:00-16:00 PM,which are highly correlated with direct solar radiation and air temperature.(2)The average radiation temperature at different locations at the same time varies greatly,and the difference in Tmrt between the sunlit area and the shaded area is about 30℃.(3)From the average value of Tmrt,we can get the intra-city difference of outdoor thermal environment.Zhongshan Square area,Xi’an Road shopping area and each high-rise residential area have better thermal environment due to the high building height blocking most of the short-wave radiation from the sun,and the Tmrt is higher in the city center area than in the coastal area.(2)(1)The Pearson correlation coefficient shows that the correlation size of urban morphological parameters is ranked as BD > SVF > FAR > ISR > AH > GR.(2)The OLS model results show that the three-dimensional morphological variables have a stronger effect on human thermal comfort than the two-dimensional morphological variables.(3)The results of the geographically weighted regression model showed that FAR,BD,and GR showed negative correlation with Tmrt in space,the estimated coefficients of ISR and AH were negative in most spaces,and the thermal effect of SVF was significantly positive.(3)(1)The mean values of average radiation temperature in the built-up area are ranked as follows: LCZ3 compact low-rise zone > LCZ10 heavy industrial zone > LCZ5 open mid-rise zone > LCZ4 open high-rise zone > LCZ2 compact mid-rise zone > LCZ7 simple low-rise zone > LCZ1 compact high-rise zone.(2)BD and GR are more sensitive to thermal environment in LCZ5 and LCZ2.Overall,Tmrt in LCZ3,LCZ7 and LCZ10 showed positive correlation with AH.The regression coefficients of FAR in LCZ3,LCZ7 and LCZ10 were negative,and ISR was globally positive in LCZ1,LCZ3,LCZ4 and LCZ7.This study innovatively introduces urban thermal radiation environment assessment into urban planning and design,establishes the correlation between microclimate,urban form and human thermal comfort,and forms a "microclimate-planning synergy" working mechanism and systematic climate response planning improvement strategy.It plays a pioneering role in the theory and methodology of climate-resilient urban planning under the goal of "double carbon",and has practical significance for achieving the goal of high-quality urban development.