Urban Thermal Environment Effect And Its Driving Factors In Kashgar City Based On RS

Since the 21 st century,my country's urbanization has developed rapidly.With the advancement of reforms and economic development,by the end of 2020,my country's urbanization rate has reached 63.89%.Xinjiang is a must pass through the ancient Silk Road and the core area of the "Silk Road Economic Belt".With the advancement of the “One Belt,One Road”initiative and economic development,the role of Xinjiang's cities and towns has become increasingly prominent.However,the process of urbanization will also bring some negative effects.The influx of a large number of rural people into the city has brought about an increasingly serious problem of "urban disease".On the other hand,in the process of continuous urban expansion,a large number of natural coverings such as green land have been replaced by artificial ground such as cement and asphalt,which has artificially destroyed the city.ecosystem.The underlying surface structure has undergone major changes,causing the surface temperature to rise,leading to varying degrees of urban thermal environmental effects,which seriously affects the sustainable development of the city and all aspects of people's production and life,ranging from the physical and mental health and physical comfort of urban residents to large Changes in the city's climate.Scholars at home and abroad have conducted a lot of research on this,but most of them are concentrated in the economically developed and densely populated subtropical and tropical large and medium urban areas,small cities and arid zone oasis cities are still lacking.The research is based on the Landsat series data and land cover data,using multiple linear regression models,landscape analysis,spatial autocorrelation models,geographic detectors and other linear fitting and multiple spatial analysis methods.During 1998-2008,Kashgar City,Kashgar Region,Xinjiang Based on the analysis of urban expansion,the dynamic changes of the thermal environment and the spatial evolution of the thermal landscape are further analyzed.Finally,the multiple linear regression geo-detector model is used to detect the change factors of the surface thermal environment.The main research results and conclusions are as follows:(1)With the rapid development of urbanization in Kashgar,the land use has changed drastically,and a large number of artificial underlying surfaces have replaced the natural covered surface.The temperature was divided into 7 grades of low temperature,lower temperature,submiddle temperature,middle temperature,higher temperature,high temperature and higher temperature by the mean-standard deviation method.The analysis found that: on the spatial scale,the middle-temperature area and the higher-temperature area are distributed in the urban built-up area,the low-temperature and low-temperature areas are dotted in the periphery of the built-up area,and the high-temperature and ultra-high temperature areas are distributed in the bare area in the north of the urban area.location.On the time scale,with the continuous development of the region,the mid-temperature region gradually took the dominant position.By 2018,the area of the warm region was 161.89 km~2,accounting for 29.45%;due to the coexistence of the encroachment of cultivated land,the expansion of towns and afforestation,the area of the low-temperature region increased.4.58%,the bare land has been effectively improved,and the area of high temperature and ultra-high temperature areas has been reduced by 20.41 km~2.(2)The distribution of the mid-temperature area is highly consistent with the artificial impervious surface range.There are obvious cold corridor effects near the waters of the Kizi River in the south of the main urban area,the Tuman River in the north,and Donghu Park in the center of the city,as well as near the wetlands of People's Park and Dongcheng Park.The dominance of mesophilic patches was prominent,with an area nearly 2-fold increase and a 3.66 increase in the degree of aggregation index.The advantages of mesophilic plaques are prominent.The proportion of low temperature patches in the landscape area increased by 1.93,and the landscape shape index increased by nearly three times,and the patch dispersion phenomenon was serious.The Shannon evenness index tends to 1,and the landscape shape index changes significantly.The regional thermal landscape pattern gradually changed from single to fragmented,and the overall landscape heterogeneity was increased.(3)While construction land is gradually encroaching on cultivated land and green space,the mid-temperature area continues to increase.As the local government has established projects such as "Garden City" and "Blue Sky Project" in recent years,the area of woodland near Pahatikri Township in the south of the urban area has increased since 2008,resulting in the weakening of the thermal field in the small area and being reduced to a certain extent.Spatial transfer matrix analysis found that from 1998 to 2008,the lower temperature was the thermal landscape area with the largest transfer out area,reflecting the phenomenon that the area of lower temperature decreased and the area of sub-medium temperature and middle temperature increased.The midtemperature area was the thermal field area with the largest transfer area from 2008 to 2018,reflecting the rapid expansion of the mid-temperature area and the shrinking of other thermal fields.(4)The center of gravity shift in the low temperature region is the most obvious,and it shifts in the northeast-northwest direction successively,and the spatial range varies greatly.The spatial differentiation process of surface thermal landscape is dominated by IBI and land use type in Kashgar City.The explanatory power values of IBI in 1998,2008 and 2018 are 0.878,0.746 and0.808,respectively,followed by vegetation coverage and land use type.However,as the intensity of human activities increases,the modes of human disturbance become more complex and diverse.The contribution rate of the altitude factor,which represents natural factors,to the spatial differentiation of thermal landscapes gradually decreases,while the explanatory power of land use/cover changes to it.phase-by-phase enhancements.