Study On The Impact Of Urban Spatial Form On Thermal Environment Effect

In the process of urban development,the scale of the city is expanding constantly.There are many problems in the city,such as extreme climate,urban thermal environment effect,haze pollution and so on.How to strengthen the ventilation of cities and urban agglomerations and alleviate the urban thermal environment effect is particularly important.Based on the remote sensing,building and water data of typical urban agglomerations in the Yangtze River Delta(including Shanghai,Changzhou,Jiaxing,Nantong,Suzhou and Wuxi),and combined with single window algorithm,correlation analysis and spatial superposition analysis,this paper studies the spatial differentiation characteristics of building space,blue space,green space and surface temperature,surface temperature and windward index.The correlations between number and vegetation coverage,and the construction of urban potential ventilation corridors by multi-factors,draw some conclusions as follows:(1)The spatial distribution of building coverage,average building height and frontal area index is consistent with the building distribution,which can be divided into two situations: one is that the building coverage(average building height,frontal area index)of the center(or central city)of the building complex is higher,the building coverage around(or the edge of the central city)and scattered around the building group(average building coverage is higher).The degree and frontal area index are lower;the second is that the coverage rate of central buildings(average building height,frontal area index)is higher,while the coverage rate of scattered buildings(average building height,frontal area index)is lower.(2)The water body is mainly composed of Taihu Lake,Yangtze River and Gehu Lake,which account for 76.88% of the total water area.0-1 km2,the largest amount of water area,but only 2.63% of the total water area.The longest length of water body is the Yangtze River,followed by Taihu Lake.10-50 km is the most abundant water body,reaching 49.31%.(3)Distribution of vegetation coverage: In April and May,vegetation coverage was mainly low,medium and low coverage,and a small amount of bare land andwater,as well as high coverage;in July and August,vegetation coverage was mainly medium and low coverage,medium and high coverage,and a small amount of bare land and water and low coverage.(4)Distribution of land surface temperature: The distribution of land surface temperature is consistent with that of buildings.The land surface temperature gradually decreases from the center of the building complex to the surrounding areas,and the land surface temperature of green space and water body is lower.The land surface temperature mainly distributes in April at 304-314 K,in May at 208-314 K,in July at 310-314 K,and in August at 308-214 K.(5)The positive correlation between the surface temperature and the frontal area index is lower,which can explain to some extent that the higher the frontal area index is,the higher the surface temperature is.Relevant effects: Jiaxing > Suzhou >Changzhou > Wuxi > Nantong > Shanghai.The negative correlation between surface temperature and vegetation coverage is relatively low,which can explain to some extent that the higher the vegetation coverage,the lower the surface temperature.There was a moderate correlation between them in some cities(Nantong in May and June,Changzhou in July).Relevant effects: Nantong > Changzhou > Jiaxing >Wuxi > Suzhou > Shanghai.(6)Potential ventilation corridors in cities are mainly composed of urban building spaces,green spaces and water bodies.The ventilation capacity is different in different months,July and August have stronger ventilation capacity.The number of plots with grades 1-2(scores)and 4-5(scores)is less,and the ventilation capacity is concentrated in grades 2-3(scores)and 3-4(scores).