Winter Microclimate Optimization Of Urban Parks In Zhengzhou Based On ENVI-met

As an important part of green infrastructure,urban parks not only bear the social and natural functions of regional recreation,recreation and fitness,but also bear the regulatory functions of regulating urban microclimate and balancing urban ecological environment.To create a suitable natural space,we should not only focus on the configuration of components but also focus on the design of climate adaptability,so as to create a satisfactory space environment for residents.Previous studies on the microclimate of urban parks paid more attention to the overall thermal comfort of parks in summer,but few studies on the correlation between multiple elements of parks in winter and the synergistic effects on the microclimate of parks.This paper focuses on the influencing factors of winter microclimatic environment of urban parks in Zhengzhou city,analyzes the interaction between various park components and the synergistic effects on the microclimatic environment of parks,and summarizes the optimization strategies for improving the microclimatic environment of parks.Firstly,31 major urban parks in Zhengzhou were investigated,and 6 of them were selected as research samples.10 components of the parks were obtained through Loca Space Viewer measurement analysis and Arc GIS vectozed area calculation.Meanwhile,flow observation method was used to obtain the average air temperature in the park during the same period.Then Pearson correlation analysis was conducted between the average air temperature of these 6 parks and 10 park components,and 5components with high correlation with park air temperature were selected for follow-up study.The types of microclimate numerical simulation software were summarized,ENVI-met was selected as the simulation software,and the simulation accuracy and reliability were verified.By changing the value range of the five components,different parameter control models were established with each other.The meteorological data of typical winter meteorological days in Zhengzhou were taken as the initial simulation parameters,and 76 groups of models were selected to carry out simulation research.Four simulation results(air temperature AT,relative humidity RH,wind speed WS and mean radiation temperature MRT)of five components,including park area(PA),length-width ratio(AR),green area ratio(GAP),hardened area ratio(HAP)and water area ratio(WAP),were analyzed respectively.The synergistic effect of various elements on the microclimate of the park was explored,and the simulation results were evaluated by PET,a human comfort index.At the same time,the influence degree of each element on the park microclimate was analyzed.The results showed that: The contribution rate of hardened area to PET of the park was the largest(63.33%),followed by the contribution rate of green area to PET of the park(26.02%),and the contribution rate of water area,park area and length-width ratio to PET of the park were 7.98%,1.51% and 1.16%,respectively.When the area and length-width ratio were the same,PET decreased about 0.17℃ with the increase of 10% of the green area.When hardening area increases by 10%,PET in the garden increases by about 0.26℃.When the water area increases by 10%,PET in the garden decreases by about 0.08℃.According to the optimal combination of waterless and waterless parks,the green area of waterless parks accounted for 60%,the hardened area accounted for40%,and the water area accounted for 0%,which had the most suitable thermal environment in winter,and the average PET was about 22.27℃.The green area with water park accounts for 60%,the hardened area accounts for 30%,and the water area accounts for 10%.In winter,the park has the most suitable thermal environment,and the average PET is about 22℃.According to the optimal combination model,the thermal comfort optimization strategy of Zhengzhou urban parks in winter is formulated.For parks with water,it is recommended that the park area should be about 15 hectares,the length-width ratio of the park should be controlled around 1.0,and the appropriate area is about 60% green space,30% hardened area and 10% water area.For waterless parks,it is recommended that the park area should be about 15 hectares,the length to width ratio of the park should be controlled around 1.0,and the appropriate area should be about 60% green space,about 40% hardened area and about 0% water area.Typical urban parks in Zhengzhou were selected as the project verification site to verify the science of thermal comfort optimization strategy of Zhengzhou urban parks in winter.The results showed that the PET in the park increased significantly after the renovation,which played an optimization role.The results show that the optimization strategy is scientific and operable,and has a strong practical guiding significance for the planning and construction of urban parks in Zhengzhou.