| Urbanization construction is an important foundation for promoting comprehensive social governance and improving people’s quality of life,but the resulting heat island effect has become a global ecological and environmental problem in the urban thermal environment that cannot be ignored,and has become a constraining factor in the current urbanization construction.The green areas and water bodies in cities play an active role in improving the urban thermal environment.Therefore,it is important to optimize the spatial structure of cities and the spatial layout of green areas and water bodies to improve the urban thermal environment.Fuzhou is a typical coastal city.Under the promotion of Fuzhou’s"3820"strategy,the construction of urban buildings and the expansion of construction areas have greatly changed the spatial structure of the city,and the urban green areas,under the mutual influence of subtropical high pressure in summer,have made the"thermal environment"of Fuzhou city"This paper takes the main urban area of Fuzhou as the study area.The paper takes the main urban area of Fuzhou city as the research object,based on Landsat inversion of surface temperature,combines multi-source data to extract the important influencing elements of urban vertical structure and horizontal structure that affect the thermal environment,and analyzes the influence mechanism of urban spatial structure on the thermal environment,constructs a composite corridor to mitigate the effect of thermal environment;reveals the mitigation law of urban park green space and water bodies on the thermal environment,and determines the park The spatial demand deployment points of green areas and water bodies are revealed,and the thermal environment characteristic partition of the spatial structure is divided by neighborhoods.The main conclusions of the study are as follows.(1)The spatial distribution of surface temperature in Fuzhou is significantly autocorrelated,and the global autocorrelation Moran’s I reaches 0.620,and there is significant clustering of surface temperature.The high-temperature thermal environment in Fuzhou City accounts for55.23%of the main urban area,of which 31.23%is sub-moderate temperature,15.75%is moderate temperature,6.39%is sub-high temperature,1.52%is high temperature,and 0.34%is super-high temperature.The super-high temperature and high temperature areas were mainly distributed in the district of Changshan and Jinan,and these two urban areas accounted for 92.01%of the total high temperature thermal environment area in the study area.(2)Building height,high building rate,average building height standard deviation,sky visibility rate,windward area density and green view rate ratio were extracted as the main vertical spatial structure impact indicators of the thermal environment in Fuzhou.In contrast,the building distribution in Changshan District and Jin’an District is relatively small,but the green view rate is the lowest among the four urban areas because Jin’an District has a more intensive industrial industrial park.Building height,high building rate,average building height standard deviation,sky visibility rate,windward area density,and green view rate are negatively correlated with surface temperature.(3)Impervious surface,normalized water body index,normalized vegetation index,surface albedo,topographic elevation and land use type were extracted as the main horizontal spatial structure influencing indicators of thermal environment in Fuzhou.Among the land use types,forest land,building land,water bodies,cultivated land and grassland were significantly correlated with the surface temperature in Fuzhou.(4)The study used a spatial lag regression model as the optimal model,and the R~2 of the model fit reached 0.76.The results indicated that building height,standard deviation of mean building height,windward area density,normalized vegetation index,percentage of forest land,percentage of water bodies and topography were important variables in reducing surface temperature.Sky visibility,impermeable surface,and building occupancy were positively correlated with surface temperature,with Building occupancy being an important influencing element leading to higher temperature.(5)With the morphological spatial pattern analysis method,ecological source points are identified and 20 cooling core areas are extracted;the entropy weight method is used to assign weights to important indicators affecting the spatial structure of thermal environment and construct resistance surfaces;48 corridors are extracted with the minimum cumulative resistance model and gravity model,which constitute the main optimized composite corridors.(6)Among the 56 parks and green areas in the main urban area of Fuzhou for cooling benefits,the park area and park perimeter are better for improving the cooling distance of parks,with the fitting R~2 of 0.556 and0.526,respectively;the park with the largest cooling effect distance is Wushan Park,and the park with the largest cooling amplitude and cooling gradient is Gao Gai Mountain Park;the optimal cooling area of urban parks is 1.14hm~2;the cooling distance of water bodies,the The cooling distance,cooling magnitude and cooling gradient of water bodies have a significant positive correlation,and the area and shape of water bodies have a certain effect on reducing the temperature of the surrounding environment.The optimal cooling area of the water body is 0.88hm~2.The cooling demand points of 10 urban parks and water bodies were selected by cluster analysis method.(7)Based on the intrinsic relationship between thermal environment and spatial structure influencing elements,7 types of spatial feature areas were classified based on clustering characteristics:the number of feature areas 1 to 7 were 508,475,377,350 141,110,and 21 for the 7th feature area,the 1st and 4th feature areas were significantly higher than the average surface temperature of the study area,accounting for 44.25%of the total number of the entire feature areas The 6th and 7th feature areas are the main core areas of Fuzhou City.(8)The study identifies the main thermal environment impact elements and constructs nine important composite corridors for cooling and seven general composite corridors.Combined with the cooling benefits of park green areas and water bodies new cooling demand points,including one in Gulou District,one in Taijiang District,three in Jinan District and five in Cangshan District.Finally,the main factors affecting the thermal environment are divided into characteristic areas,and the comprehensive optimization suggestions are put forward according to the different characteristics of each urban area. |
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