Study On Spatial Characteristics Of Rail Transit Site Area From The Perspective Of Urban Heat Island

Rail transit has the advantages of large traffic volume,fast speed,small land occupation and environmental protection.It is favored by big cities with heavy traffic pressure and land resource shortage.In recent years,the construction of rail transit in major cities in China has entered a period of rapid development.Rail transit station is a node that connects the transportation network and the external urban space,and its status is very important.There are few studies on the spatial characteristics of the site area,and the research on the physical environment of the site area is rare.This paper takes the Wuhan rail transit station as the research object and uses the combination of empirical research and simulation research to analyze the thermal environment problems in the rail transit station area,and proposes relevant improvement suggestions.Firstly,the remote sensing image and ENVI software are used to retrieve the heat island effect characteristics of 54 stations in Wuhan Rail Transit Line 2 and Line 4,The heat island effect problem of rail transit stations is analyzed from the status quo of heat island effect in site area,time change of heat island effect and spatial change of heat island effect.Spatial characteristics such as land use characteristics,floor area ratio,building density,building height,and vegetation coverage of 54 site areas are obtained from field research,GIS data,and Google satellite image data.Multi-factor correlation analysis are used to analyze the correlation between the heat island intensity and the spatial characteristics of the site.It is found that there is a certain correlation between the proportion of municipal transportation land,the proportion of unused land,building density,vegetation coverage and the heat island intensity index of the site area.Multivariate regression analysis is performed on the correlation index to quantify the degree of influence of the indicator.According to the spatial characteristics of the site and the existing site type division method,and 54 sites are classified.16 site sample cases are selected to simulate the thermal environment conditions of typical summer weather days in the site area by the thermal environment simulation software Envi-met.Research on the spatial characteristics,thermal environment characteristics and impact mechanisms of various types of stations are conducted,and the spatial and thermal environmental problems of various types of sites are analyzed.Finally,the concrete measures to improve the thermal environment problem in the site area are summarized from the aspects of road design,architectural design and landscape design,and the typical site is selected to verify the optimization strategy.