Research On The Spatial Heterogeneity And Influence Factors Of The Urban Thermal Environment

In the process of urban development,changes in the urban thermal environment are coming along with economic growth and population growth.Therefore,understanding the spatial heterogeneity distribution of urban thermal environment and its influencing factors,and adjusting the structural characteristics of relevant factors to alleviate the urban heat island effect are significant for promoting sustainable urban development.The single-window algorithm was used to extract the surface temperature of the study area.According to the correlation between NDVI and NDBI and LST,green plaques were selected as surface factors with cooling effect,and building plaques were used as surface factors with warming effect for feature analysis.The conclusions of this study are as follows:(1)The heat island phenomenon in the study area is obvious.The ratio of the plaque area in the middle temperature zone,the sub-high temperature zone,the high temperature zone and the ultra-high temperature zone is about 75%,and the low temperature zone accounts for only 25%.The high temperature center is mostly distributed in the southeast of the study area.The temperature in the center of the city is relatively high and the low temperature area is less,but the high temperature area without aggregation appears.Large areas of low temperature centers appear in the northwest and northeast corners of the study area.Based on the temperature statistics of each loop,it is found that the middle temperature zone accounts for the highest proportion in each loop area.Special high temperature areas account for the least.The ratio of the ultra-high temperature zone and the low temperature zone of the five rings is higher than other loops.(2)The relationship between temperature and NDVI and vegetation coverage of the two east-south sections is negatively correlated.When the vegetation coverage increases by 0.1,the temperature will drop by 0.87 °C;the relationship between temperature and NDBI and impervious surface ratio is positive.Correlation,the temperature of the impervious surface increases by 0.19 °C for every 0.1 increase.(3)The green plaques were used as the cooling factor to study,and 30 park green spaces were selected as the key research objects.The plaque area in the plaque morphological characteristics index showed a significant negative correlation with the internal temperature of the plaque.The landscape type in the green plaque has a certain influence on the internal temperature of the plaque,and the temperate minimum temperature gradually decreases with the increase of green space and water area.The difference in the layout and structure of the surrounding construction land makes the cooling effect around the green plaque appear different with the distance.The variation curves are logarithmic,parabolic and uniform.(4)Taking the building as a heating factor,the building coverage and temperature in the grid are positively correlated under the 900m×900m large-scale grid analysis,and there is no obvious correlation between other building parameters.In the 30 m buffer outside the green patch,the correlation between building coverage and temperature gradually increases with distance.Comparing the different scales,it is known that the small-scale construction coverage control has a greater impact on temperature.