Study On Summer Spatial Thermal Environment Based On Urban Spatial Forms In Chongqing City

With the rapid development of urbanization in China,the agglomeration of highlevel and high-density buildings has led to the drawbacks of urbanization,such as the reduction of environmental quality,the serious heat island effect and the aggravation of low-altitude pollution.These urban problems not only hinder the construction and sustainable development of urban human settlements environment,but also reduce the comprehensive social,economic and ecological benefits brought by urbanization.As the density and height of buildings increase,the geometric and surface thermal properties of street valleys become complex and changeable,the microclimate becomes more complex,and the urban thermal environment problems become increasingly prominent,which seriously affects people's daily production and life.In this study,the characteristics of summer thermal environment in Yuzhong District of Chongqing were analyzed by combining field test and statistical analysis.At the same time,the relationship between spatial morphology and summer thermal environment in Yuzhong District of Chongqing was analyzed,and the fitting relationship between thermal environment and spatial index in Chongqing was obtained.At last,the SVF databases of 29 provincial capitals were established,and the relationship between spatial indicators and urban planning and management was studied.The conclusions are as follows:Firstly,through the data of meteorological stations,it is found that in the summer of 2018,the number of hot days in August is the largest,and the air temperature in the middle and late July is the highest.The change trend of relative humidity and air temperature in urban area is opposite.The average wind speed of the four stations in the main city is low,and most of them are in Level 2,that is,the level of light breeze.The THW Index is higher than the air temperature in summer,which is a typical hot and humid summer weather.Combining with the flow test results,it is found that the urban thermal environment in Chongqing is obviously affected by the urban spatial morphology,and the heat island centers are numerous and strong.Secondly,the statistical analysis of spatial indicators and thermal environment in Yuzhong District of Chongqing finds that SVF is better than building density in terms of the correlation with surface temperature,and the impact trend of spatial indicators on urban thermal environment is different in the morning and afternoon,which is closely related to local climatic conditions.From the best impact range of spatial indicators,green space > water quantity > SVF or building density.Furthermore,the SVF databases of 29 urban centers in China are obtained through large data analysis.Statistical analysis shows that the SVF values obtained from large data have local urban characteristics(economy,population).From the statistical analysis results of this paper,we can preliminarily know the spatial utilization of urban environment.To sum up,the study of spatial indicators will help to have a more comprehensive and in-depth understanding of urban thermal environment and climate-related issues,and help urban environmental planning,construction and improvement.