Temporal And Spatial Characteristics Of Urban Surface Temperature And Landscape Regulation In China

Since the reform and opening up,China’s urbanization process has accelerated,accompanied by more and more serious urban thermal environmental problems,which seriously endanger the health of urban residents and the sustainable development of cities.Clarifying the spatial and temporal pattern and influencing factors of urban thermal environment in China,and quantifying the specific controllable range of LST could provide references and policy planning inspiration for urban cooling strategies.The paper takes 32 megacities in China as the research objects.Based on surface temperature,land use/cover change(LUCC),vegetation cover,meteorological station monitoring data and other auxiliary data(such as night light data and socioeconomic statistics),Using correlation analysis,stepwise regression analysis,relative importance analysis methods,etc.,to quantitatively study the temporal and spatial characteristics of four seasons,months,and day and night LST at the global,regional and urban scales in China,and analyze the temporal and spatial evolution of urban thermal environment,influencing factors and responses to landscape patterns.The main research conclusions are as follows:(1)The spatial and temporal distribution of LST in 32 cities is quite different.The LST of cities in East China and Central and South China is higher than 32℃ in summer and higher than 10℃ in winter.In northern cities,the LST in summer is between 2632℃,and the LST in winter is between-10-3℃.The seasonal variability of surface LST in cities in Northeast China reached 40℃,while that in cities in Southwest China was less than 15℃.(2)From the perspective of driving sources,LST changes mainly depend on climate and landscape factors rather than economic factors,and have obvious seasonal characteristics.Further analysis shows that the daytime LST changes are mainly affected by EVI,while nighttime LST is mainly affected by RHU.Among the landscape factors,water_ED and urban_SHAPE MN have the most significant impact on LST changes.(3)From the perspective of landscape pattern,there are differences in the relative importance of different landscape components to the seasonal changes of LST.In urban management,the seasonal effects of urban underlying surfaces should be fully considered to adapt to changes in urban climate.In summer,the dispersion degree of water body,edge density and the area,shape and dominance of vegetation dominate the LST change;the area and dominance of vegetation dominate the LST change at night.In winter,the dominance,mean patch area and edge density of daytime water landscape dominated LST changes;the dominance,mean patch area and edge density of nighttime buildings and water landscape dominated LST changes.(4)The regulation ability of LST on building patches shows strong temporal and regional variation characteristics.The regulation range of all cities is between 0-13℃,the western cities are between 8-13℃,and the eastern cities are between 0-4℃.Cities located in cold and dry regions have more room for regulation than those in hot and humid regions because of relative humidity,precipitation,evaporation,and vegetation cover.(5)Reasonable urban landscape management helps to alleviate the urban thermal environment to achieve a cool city.In landscape design,the density and aggregation degree of vegetation patches in green space should be reduced,the edge rate and shape complexity of green space should be appropriately increased,large water bodies should be set up as much as possible,and the meandering degree of water shoreline should be increased.Small-scale,edge-contoured complex urban architectural landscapes.The results show that the change of LST in China has obvious regional characteristics.This study can provide a reference for the study of large-scale seasonal urban thermal environment,and can provide a reference for country to formulate reasonable urban planning policies.This study discusses the controllable range of LST based on building patches and the specific measures to reduce LST by landscaping.At present,this research belongs to a new idea,and the research results can provide relevant theoretical reference for scientific researchers,urban planning and design practitioners,and environmental protection policies.