Research On Thermal Environment And Quantitative Mitigation Of Small And Medium-Sized Cities Based On Remote Sensing And GIS

With the rapid development of economy,the thermal environment problem has drawn increasing attention due to its potential detrimental effects on human daily life and even the dynamic equilibrium of global climate.In this context,many researches on this issue have been conducted.However,these studies regarding on thermal environment effect were mostly concentrated in large cities with developed economy,dense population and high-level industry.Less researches have been done for the small and middle-sized cities.Moreover,these studies usually focused on investigating mechanism of thermal environmental impact and causes,while relieving measures were ignored.Therefore,this study is devoted to investigating the thermal environment effect of small and medium-sized cities with land use.Results are expected to provide some valuable information for the control measures for high temperature area.Taking the main urban area of Tongxiang City as the research area,this study applied atmospheric correction method to invert the land surface temperature(LST)according to Landsat-8 TIRS data on August 21,2019.And the spatial characteristics and differences of LST in the study area were analyzed.The relationship between the LST and the proportion of land use type in different regions were explored,the multiple linear regression equation was constructed after correlation analysis between LST and land use data.On the basis of the equation,taking a high temperature area as the research object,this thesis proposed several relieving means to improve the thermal environment management and predicted the average surface temperature.The main conclusions are as following:(1)The inversion results obtained by Landsat-8 image indicated that there was a significant difference of temperature besides the boundary of the built-up area.The boundary between higher temperature area and lower temperature area basically coincided with the boundary of built-up area.The average surface temperature within the boundary of built-up area was 32.16?,while the average surface temperature outside was 29.54?.The difference of temperature between the two area reached 2.62?,it was clear that there was a thermal environment effect in the study area.As a reserve force for regional development,the thermal environment effect of small and medium-sized cities should be concern.(2)Multiple linear regression analysis between LST data and land use data was conducted,and the regression model was LST=31.143-0.030 × cultivated land proportion-0.026 × green space proportion + 0.025 × industrial and mining proportion + 0.012 × other construction proportion-0.031 × water area proportion.Among them,land used for industrial and mining,other construction were positively correlated with LST,while farmland,green land and water area are negatively correlated with LST.According to the regression coefficient,industrial and mining construction has the greatest impact on the rise of land surface temperature,and the relieving effect of water area is the best.(3)After an in-depth analysis of some typical sampling areas in the research area with the combination of high-resolution remote sensing image and POI data,the results revealed that urban thermal environment problems are not only related to land use types,but also affected by multiple factors such as land use pattern and scale.In order to explore the relieving measures of urban thermal anomalies,a high temperature block was selected from the research area,and two thermal relieving means were proposed based on the land use status and functional positioning of the block.Using regression model for simulation and calculation of relieving means,it is found that these measures could cool the average land surface temperature of the test area by 1.06?,which has a relatively significant cooling effect.The research results of this thesis can provide reference for the study of thermal environment in small and medium-sized cities.The relieving measures proposed in this research maybe provide some useful suggestions and ideas for the mitigation of thermal abnormal blocks.