Distribution Of Impervious Surface Area And Thermal Environment Pattern Based On Urban Partition And Hot Spot Analysis

It is a typical process in the human-land system that the Land-Use and Land-Cover changed(LUCC)by the urbanization process.The change of urban landscape pattern has a significant impact on the urban ecological environment.Therefore,the research on the correlation between the spatial and temporal distribution of impervious surface area(ISA)and the distribution of thermal environment landscape pattern is of great significance to the construction of urban ecological environment.In this paper,according to the urban spatial structure planning and the difference of regional urbanization development,the study area was divided into three circular sites of different stages of urbanization,and on this basis,circular sites divided into eight different directions,thus producing a total of 24 spatial sectors.From the perspective of the degree of urbanization,the landscape ecology and spatial autocorrelation theory were used to explore the influence mechanism of the spatial and temporal changes of ISA on the spatial and temporal distribution of urban thermal environment,which provided new ideas for the optimization of urban thermal environment.It provides a theoretical basis for reducing the destruction of urban ecological environment by human activities during urbanization.Through the analysis of the temporal distribution characteristics of ISA landscape pattern,it was found that the distribution of the ISA landscape pattern is more reasonable with the change of time phase.In the inner circular site,except for the WNW and NNW directions,the other 6-direction ISA had a significant increase,and the area of ESE in the middle and outer circular site was the largest.The same level of ISA coverage plaques generally showed fragmentation distribution,and different levels of plaques showed a landscape pattern of mutual penetration distribution.Through the analysis of the temporal and spatial changes of urban thermal environment,it was found that the area ratio of the UHI plaque in each circular site increased with the change of time phase,and the plaque in the sub-high temperature region gradually shifted to high temperature and extremely high temperature.In the inner circular site,the UHI patches in the SSE,WSW,and NNW directions were relatively large;in the middle circular site,the coverage of the UHI patches in the SSW direction was the widest;in the outer circular site,the UHI effect was most obvious in the ESE direction.Based on the zoning idea of urban spatial structure,after considering the three factors of LST,urban development degree and hot spot aggregation degree,the thermal environment of the study area was preliminarily evaluated.In the inner circular site,the thermal environment in the NNW,SSW and SSE areas was in urgent need of optimization;in the middle circular site,the ESE,SSW and WSW directions,the optimization of the regional thermal environment was first considered;in the outer circular site,the optimization priority was highest in the ESE direction.