| With the rapid development of society and economy,the development of a single city will be limited by geographical space to a certain extent.Therefore,the concept of joint development of urban agglomerations is born.Alleviating the environmental problems brought about by the development of urban agglomerations has become the focus of current research.This study starts from the surface thermal environment,takes the Chengdu-Chongqing economic circle as the research object,and uses most of the remote sensing data as the data source.The spatial distribution,evolution law and the action mechanism of influencing factors of the thermal environment on the surface of the enclosure are analyzed.Based on the circuit theory model,the heat flow corridor of the surface thermal environment in the study area is constructed.On this basis,taking the heat flow corridor in 2020 as an example,the spatial pattern of the surface thermal environment in the Chengdu-Chongqing economic circle in 2020 is constructed.The coefficient of heat source area-corridor length identifies the "sensitive corridor" and proposes a thermal environment spatial pattern optimization strategy for it.The main conclusions of this paper are as follows:(1)Based on the mean standard deviation method and the MODIS surface temperature data,this paper divides the surface thermal environment grades into five categories:low temperature area,sub-low temperature area,medium temperature area,sub-high temperature area and high temperature area.Combined with spatial statistical analysis method,the area composition and spatial distribution of each thermal environment level in 2000,2005,2010,2015,and 2020,as well as the evolution law of different levels of regions in time and space,were obtained.The medium-temperaturc zone has the largest spatial distribution of the environment.From 2000 to 2020,its spatial area is 97507.38km~2,823 18.62km~2,74200.11km~2,92296.74km~2,89254.21km~2,and its space proportion is 52.71%,44.50%,40.11%,49.89%respectively,48.25%,showing a trend of first decreasing and then increasing.The area of the area where the surface thermal environment grade is high temperature area increased from 11455.06km~2 in 2000 to 18240.66km~2 in 2020,and its area increased by 6785.60km~2.For the case where there is no significant increase across grades in the time series between each grade of the surface thermal environment,the change rule is that the proportion of adjacent grade transformation is much larger than that of cross grade transformation,and there is no mutual transformation between the two extreme grades.(2)From 2000 to 2020,the influence factors of the surface thermal environment of the Shuangcheng Economic Circle in the Chengdu-Chongqing area were correlated with the thermal environment,and the R2 of the influence factors over the years were all greater than 0.6,indicating a good correlation.The factors that show positive correlation are nighttime light,annual average temperature,and annual average rainfall.Among them,the annual average temperature factor has the greatest correlation over the years,and its correlation coefficients are 0.418706,0.56.230,0.485290,0.123370,and 0.473223,respectively.The factors with negative correlation are vegetation cover,altitude and slope,and the factor with the largest negative correlation is the altitude factor,and the correlation coefficients are-0.474190,-0.302610,0.234913,-0.86889,-0.25556,respectively.Overall,the annual mean temperature and altitude have the greatest correlation with the surface thermal environment.Using the geographic detector model to analyze the mechanism of the effect of factors and the surface thermal environment,the degree of effect is shown by its single factor q value and the q value of multifactor interaction,and the results of the past years are analyzed,and the overall situation is q(annual average temperature)>q(altitude)>q(slope)>q(vegetation cover)>q(average annual rainfall)>q(lights at night).The factors are not simply superimposed,but there is a relationship of linear enhancement or nonlinear enhancement,through which a synergy and nonlinear synergy can be achieved.(3)Combined with the classification of surface thermal environment,the area with high temperature area was proposed as the heat source of this study.Finally,the number of heat source patches in the surface thermal environment in 2000,2005,2010,2015,and 2020 was obtained through screening.There are 27 blocks,26 blocks,30 blocks,24 blocks,and 28 blocks,and the total heat source area is 6525.11km~2,9546.29km~2,13101.71km~2,6437.11km~2,12496.41km~2 respectively.By analyzing the effect of influencing factors,combined with the coefficient of variation method,the calendar year was constructed.The comprehensive thermal resistance surface of the surface thermal environment of the Shuangcheng Economic Circle in the Chengdu-Chongqing area is based on the identification of the above heat sources and the construction of the resistance surface,and the circuit theory model is used to construct the surface thermal environment heat utilization corridor over the years,and identify the key thermal corridors in the study area in 2000.60 corridors with a total length of 3050.60km;63 key hot corridors in 2005 with a total corridor length of 3412.84km;68 key corridors in 2010 with a total corridor length of 2581.29km;key hot corridors in 2015 There are 60 corridors with a total length of 3638.43km;in 2020,there are 60 key corridors with a total length of 2581.25km.Finally,the thermal environment spatial pattern of the study area in 2020 is constructed,and the surface thermal environment spatial layout of "one circle,one belt,three centers" is proposed.(4)Regarding the constructed surface thermal environment pattern of the ChengduChongqing economic circle,starting from the stability of the corridor,the stability of the pattern is analyzed.There are 31 sensitive corridors,accounting for 51.67%of the total number of corridors,with a total length of 2207.69km.;There are 12 stable corridors,accounting for 20.00%of the total number of corridors,and their total length is 284.27km;17 should be styled corridors,accounting for 28.33%of the total number of corridors,and their total length is 89.28km.And put forward optimization strategies for "sensitive corridors",which are divided into two construction strategies:dredging type and "blocking type". |
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