Quantitative Evaluation And Influencing Factors Of Surface Urban Heat Island (SUHI) In Chinese Urban Agglomerations Based On GEE

Since the reform and opening up,China experienced rapid urbanization.The urban heat island effect has become one of the major issues affecting the urban ecological environment.In recent years,the development of urban agglomerations in China has caused the problem of urban heat islands to become more prominent and seriously affect the ecological environment of the urban agglomeration areas in China.Conservation and sustainable development.Therefore,based on the GEE cloud platform,this paper uses MODIS surface temperature data to estimate the intensity of surface urban heat islands in China's urban agglomerations during the day,night,and throughout the year from 2003 to 2019,and analyzes the temporal and spatial characteristics of urban heat islands in China's urban agglomerations from 2003 to 2019.Sen+MK trend analysis method analyzes the change trend of urban agglomeration heat islands;through correlation analysis and regression analysis,respectively analyzes land cover change(LCC),vegetation index(Normalized Difference Vegetation Index,NDVI),and reference evapotranspiration.Correlation between development(Reference evapotranspiration,ET₀),air quality,DEM,population density,GDP,and surface urban heat island intensity changes;use the geographic detector model to analyze the main driving factors of urban heat islands,the interaction between driving factors and the indicating effect,The results show:(1)In the arid and semi-arid areas of the northwest,the intensity of heat islands in the northern slopes of the Tianshan Mountains,Lanxi,Hubao Eyu,Ningxia Yanhuang,Guanzhong,and Jinzhong is relatively high,and the intensity of urban heat islands at night is higher than that in the daytime;The urban heat island intensity of Beijing-Tianjin-Hebei,Chengdu-Chongqing,Pearl River Delta,and the middle reaches of the Yangtze River is relatively low.(2)From 2003 to 2019,the intensity of urban heat islands in China's urban agglomerations during the day was greater than that at night,and the intensity of heat islands during the day,night,and throughout the year showed a general downward trend,decreasing at a rate of-2.40%,-2.60%,and-2.50%,respectively.In addition,the spatial difference of the change trend is large.The areas of increased heat island intensity are mainly located in the eastern part of the Central Plains urban agglomeration,the northwestern part of the Chengdu-Chongqing and Liaozhong-south urban agglomerations,the central part of the Beijing-Tianjin-Hebei,Pearl River Delta,Guanzhong,and Jinzhong urban agglomerations,and the Yangtze River Delta urban agglomeration.North;the northern part of the Beijing-Tianjin-Hebei and Central Yunnan urban agglomerations,the southeast of the Yanhuang and Hubao Eyu urban agglomerations in Ningxia.(3)Reference evapotranspiration,population density,GDP,Nitrogen dioxide(NO₂),Ozone(O₃),Ultra Violet Aerosol Index(UVAI)and heat island intensity have a positive correlation,NDVI,DEM,Sulfur dioxide(SO₂),Carbon monoxide(CO),formaldehyde(HCHO)and heat island intensity have a negative correlation.(4)From the geographical detection results of urban heat island driving factors,the degree of influence of each driving factor on the heat island in descending order is NDVI>LC>UVAI>ET₀>O₃>CO>HCHO>DEM>NO₂>SO₂>POP>GDP.The explanatory power of vegetation,land cover type and ultraviolet aerosol are all above 30%,which is the main influencing factor of urban heat island.The explanatory power of NO₂,SO₂,population density and GDP are all below 10%,which has little impact on urban heat island.The driving factors have an interactive effect on the urban heat island,showing mutual enhancement and non-linear enhancement.There are no independent factors.The interaction of ozone and ultraviolet aerosol has the largest impact on the annual urban heat island,followed by Are vegetation and reference evapotranspiration,altitude and vegetation,land cover type and vegetation,land cover type and ultraviolet aerosol.The driving factors of urban heat island intensity are indicative.The vertical column density of ultraviolet aerosol on the ground is 2908.94×10^-4—2454.46×10^-4 mol/m²,the land cover type is bare land,and the vegetation index is 0—0.2.Reference evapotransp-iration When the diameter is 1328-1608 mm,the intensity of the urban heat island is higher.