兰州市城市绿地系统热消减功能的研究

Study on Heat Reduction Function of Urban Green Space System in Lanzhou City

随着中国城市面貌变化愈来愈大,城市热岛作用也愈来愈强,城市生态系统中的蓝绿空间可以对城市地表温度进行调控,缓解或改变城市热条件。本文基于2020年7月的Landsat-8OLI/TIRS遥感影像,采用大气校正法反演兰州市建成区地表温度,结合2020年全国土地利用数据、景观格局指数数据。使用ArcGis软件空间分析以及相关性分析等方法分析蓝绿生态斑块平均地表温度,研究生态斑块的降温效益。结果表明:(1)兰州市建成区生态斑块的热消减量为0.007~7.060℃,绿地和水体斑块中降温幅度最大的为公园绿地和河渠,分别为1.93、7.06℃,降温距离均为100 m;(2)不同土地利用类型与降温效益有一定相关性,其中相关性较强的为公园绿地、有林地、河渠;(3)景观格局指数能影响生态斑块的降温效益,面积、周长与地表温度相关性最大,边缘面积比和分维数相对影响较小。

In recent years,with the change of urban landscape in China,the role of urban heat island has become more and more intense.The blue-green space in urban ecosystem can regulate urban surface temperature and alleviate or change urban heat conditions.Based on Landsat-8OLI/TIRS remote sensing images in July 2020,this paper uses atmospheric correction method to retrieve land surface temperature in built-up areas of Lanzhou City,combined with national land use data and landscape pattern index data in 2020.ArcGis software spatial analysis and correlation analysis were used to analyze the average surface temperature of blue-green ecological patches,and the cooling benefit of ecological patches was studied.The results showed that:(1)The heat loss of ecological patches in built-up areas of Lanzhou ranged from 0.007℃ to 7.06℃.Among green patches and water patches,park green patches and river channels had the largest cooling ranges of 1.93℃ and 7.06℃,respectively,with cooling distances of 100m.(2)Different land use types have a certain correlation with cooling efficiency,among which the strong correlation is park green space,forest land and river channel.(3)Landscape pattern index can affect the cooling efficiency of ecological patches,in which the area and perimeter have the greatest correlation with surface temperature,while the marginal area ratio and fractal dimension have little effect.