北京市主城区不透水面时空演变及其热环境效应研究

城市不透水面是表征城市化进程的重要指标,开展城市不透水面研究对生态环境监测及城市建设规划具有重要意义.以北京市主城区为研究区,基于Landsat影像采用支持向量机(SVM)和线性光谱混合分解模型(LSMM)相结合的方法提取研究区2002年、2009年和2017年三期不透水面;同时采用辐射传输方程法反演研究区地表温度,分...

Spatiotemporal evolution and thermal environmental effects of impervious surfaces in the main urban area of Beijing

The impervious surface of a city is an important indicator to characterize the process of urbanization.The research on imperviousness of the city is of great significance for ecological environment monitoring and urban construction planning.The main urban area of Beijing was taken as the research area.Based on Landsat image,the impervious surface was extracted from the research area in 2002,2009 and 2017 by combining support vector machine(SVM)and linear spectral hybrid decomposition model(LSMM).At the same time,the radiative transfer equation method was used to invert the surface temperature of the study area,the spatial and temporal pattern evolution of impervious surface in the main urban area of Beijing and its correlation with the urban thermal environment were analyzed.The proportion of impervious surface area in the Dongcheng District and Xicheng District areas was the highest,and the growth rate and intensity of impervious surface in Chaoyang District and Haidian District were relatively large.The impervious surface of the main urban area of Beijing showed a radial expansion trend and the growth was concentrated outside the Fourth Ring Road,the area with high coverage of impervious surface increased continuously.In recent 15 years,the surface temperature of the study area has been rising continuously,the heat island effect has been intensified,and the spatial distribution of the high value area of the surface temperature is consistent with that of the urban construction area.The spatial pattern of impervious surface was highly correlated with the thermal environment,the patch density and fragmentation of impervious surface were negatively correlated with the surface temperature,and the proportion of patches in the landscape and the maximum patch index were positively correlated with the surface temperature,the surface temperature could be controlled by reasonably controlling relevant landscape indexes and optimizing the spatial pattern of impervious surface.On this basis,some suggestions are put forward to alleviate the urban heat island effect:adding land use types such as trees and grass;dividing the impervious surface into many small patches to reduce the distribution of large areas of impervious surface;using permeable materials,etc.