城市广场不同空间尺度下空气温湿度与环境因子的相关性

Correlation between Air Temperature and Humidity and Environmental Factors at Urban Squares on Different Spatial Scales

探究空气温湿度与环境影响因子间的空间尺度相关关系,界定关键影响尺度范围,可为合理规划城市公共开敞活动空间建成环境提供科学的理论依据。选择武汉市8块城市广场下垫面作为研究对象,分析夏季空气温湿度值、广场-行道树温湿度差值、日较差值与测试点周边25~3000 m缓冲区内地表温度、硬质下垫面面积、绿地面积、归一化植被指数、交通道路长度和人口密度变量间的相关关系。结果表明:1)气温与测试点周边50 m缓冲区地表温度变量相关性最显著;相对湿度与测试点周边100 m缓冲区内绿地面积变量和硬质下垫面面积变量、250 m缓冲区NDVI变量、500 m缓冲区地表温度变量相关性最显著。2)广场-行道树温度、相对湿度差值分别与测试点周边2000 m、3000 m缓冲区内绿地面积变量最显著相关。3)温度、相对湿度日较差分别与测试点周边500 m、1000 m缓冲区内交通道路长度变量最显著相关。由此可见,夏季城市广场空气温湿度与周边环境因子存在明显的尺度效应,增加广场建成环境周边绿地面积、减少硬质下垫面面积、提高NDVI、减少交通道路长度可有效改善城市开敞空间的温湿效应。

Exploring the correlation on spatial scale between air temperature&humidity and environmental factors to obtain the key influencing scales will provide a science-based theoretical basis for the rational planning of the built environment in urban public open space.The study selects 8 urban squares in Wuhan City as the research objects,to analyze the correlations between air temperature and humidity,the gap of air temperature and humidity between square and street trees and daily range of air temperature and humidity in summer and environmental factors of land surface temperature,hard underlying area,green area,NDVI,road length and population density in the buffer area within 25~3000 m surrounding the test points.The results show:1)Air temperature at squares is most significantly correlated with the land surface temperature of buffer area within 50 m from the test points;the correlations between relative humidity at squares and green area variable and hard underlying area within 100 m buffer,NDVI variable within 250 m buffer,land surface temperature within 500 m buffer are the most significant;2)The gap of air temperature and relative humidity between square and street trees is the most significantly correlated with the variable of green area in the buffer area within 2000 m and 3000 m from the test points respectively;and 3)The daily range of air temperature and relative humidity has the most significant correlation with the variable of road length in the buffer area within 500 m and 1000 m from the test points.It is concluded that there are obvious scale effects between air temperature and humidity at urban square and the surrounding environmental factors in summer,and increasing green space area in the surroundings of built environment of squares,decreasing the hard underlying area,improving NDVI and shortening road length could effectively improve the temperature and humidity effects of urban open spaces.