Research On Impacts Of Urban Parkland For Microclimate And PM2.5with ENVI-met

With the rapid development of industrialization and urbanization,environmental problems such as urban heat island effect and haze become more and more serious,especially in the our capital city of Beijing.Urban park plays a very important role in alleviating the above-mentioned environmental problems and has also become the focus of related disciplines involving smart city construction,urban planning and environmental protection.However,existing work has focused on unilateral study of parkland for improving microclimate or particulate matter diffusion.In order to analyze the two-sided effects on improving park microclimate and PM2.5 diffusion,this paper took Youth Lake Park,Ditan Park and Dongsheng Bajia Park in Beijing city as research objects,and a set of quantitative analysis techniques and the optimization strategy of the park design workflow were proposed by combination of field measurement and numerical simulation methods.First,this paper analyzed the specific factors of parkland affecting on urban park microclimate and PM2.5 based on the related concepts of characteristics of atmospheric particles and microclimate.Then the quantitative analysis factors were derived as temperature,relative humidity,wind speed and PM2.5 concentration.Secondly,according to the growth period of plants,bwhich were spring,summer and winter seasons,the above-mentioned quantitative analysis factors of the three urban parks were measured with professional equipments,and the rule of dynamic change from each factor was analyzed.Then,ENVI-MET software was used to carry out numerical simulation of dynamic changes for the quantitative analysis factors of three parks.The RMSE model was used to verify the feasibility of the simulation method for deriving the dynamic changes of quantitative analysis factors.Finally,on the basis of the above quantitative analysis,different schemes of parkland design was proposed and the change rule of quantitative analysis factors under such schemes were simulated by using ENVI-MET.Further,the improved strategy of parkland was proposed.The innovation of this paper is as follows:(1)the influence of parkland on microclimate and PM2.5 diffusion was studied by methods combined with field measurement and numerical simulation.(2)Quantitative analysis of the microclimate and PM2.5 diffusion in three parks during the plant growth period(spring,summer and winter)provided a relatively complete technical method and workflow for the quantitative evaluation of the ecological and microclimate of urban parks.(3)Quantitative simulation analysis was carried out for evaluating the impact on the microclimate and PM2.5 by designing different schemes based on parkland layout,parkland type and tree height characteristics.The optimal strategy of parkland was purposed for the purpose of improving microclimate and retarding PM2.5 diffusion effects.