Study On Numerical Simulation Of "Cold Island Effect" Of Urban Green Space In Hot-Summer And Cold-Winter Zone

Urban green space not only has the social function of beautifying urban space and providing activity space,but also has the ecological function of influencing spatial microclimate.Compared with the "heat island effect" produced by urban construction,the micro-climate effect caused by green space is called the "cold island effect" of green space.The "cold island effect" of urban green space can affect green space and surrounding space,which will change under the influence of environmental factors.Understanding the characteristics and changing rules of the "cold island effect" of green space under the influence of relevant factors is of great practical significance for utilizing urban green space to adjust the urban microclimate environment and improve the urban spatial microclimate environment.In this paper,the "cold island effect" of urban green space is taken as the research object.Firstly,through the literature study,the characteristics of "cold island effect" of green space are affected by the changes of solar radiation,wind environment and architectural factors.Secondly,on the basis of factor induction,using numerical simulation software ENVI-met,we simulate the "cold island effect" of urban arbor green space in hot summer and cold winter area under static wind state,and explore the influence of solar radiation on the "cold island effect" of green space.By simulating the change of wind speed direction and building factors,we explore the wind environment and other rings with building factors as the main factors.The influence of environmental factors on "cold island effect" of green space.Through the outdoor microclimate evaluation index of temperature,humidity,wind speed and PMV comfort index,the change rule of "cold island effect" of green space was analyzed and evaluated.Through the analysis of simulation results,the following series of conclusions are drawn: 1.The "cold island" of green space dominated by trees has certain influence on the temperature,humidity,wind and other meteorological factors of green space and its surrounding space;2.The characteristics and changes of "cold island effect" of urban green space are seasonal and temporal under the influence of changes in solar radiation;3.The "cold island effect" of green space.The influence of Ying on the microclimate of green space and surrounding space is twofold.The characteristics and changes of "cold island effect" of green space have certain practical value in the design and layout of green space and its surrounding space,even in urban space planning and design.4.The characteristics and changes of "cold island effect" of green space are influenced by wind environment factors.A certain wind speed can enhance the intensity of "cold island effect" of urban green space in summer.The migration characteristics of "cold island" in green space are influenced by wind direction.5.The characteristics and changes of "cold island effect" of green space are influenced by the surrounding building factors,and the degree of influence will change with the changes of solar radiation environment and wind environment.