城市热场与绿地景观相关性定量分析

A QUANTITATIVE STUDY OF THE RELATIONSHIP BETWEEN URBAN VEGETATION AND URBAN HEAT ISLAND

首先,利用南京市Landsat7 TM6波段高增益图像亮度值和地面温度之间的关系进行定量分析,得出南京市温度分布图;然后,利用NDVI值和实地调绘,根据绿地密度和绿量的不同,将绿地分为密林、疏林和草本植物等类型,并对非植被地物进行分层分类;最后,对各类地物与地面温度场进行相关性分析,并就影响这一相关性的重要因素之一———景观破碎度,解释和分析了该相关性。结果表明,由于各类绿地的破碎程度不同,对地面温度的影响能力也有很大不同。

With the rapid urbanization, problems caused by heat -island effect have become more and more serious. It is necessary to make rapid and effective monitoring of the distribution of heat islands in cities. In this paper, the Landsat7 ETM^＋ image of Nanjing was investigated as an example. A correlation model was built between ground temperature and image brightness of TM6, and in this way, the distribution of temperatures in Nanjing was obtained. The urban vegetation can be classified into forest, interspersed tree and herbaceous plant based on the NDVI value. At the same time, the other ground objects can be classified by supervised classification. In addition, the authors probed into the correlation coefficient between the ground covers and the temperature distribution from the angle of fragmentation degree. It can be concluded that different fragmentation degrees of urban greening exert different effects on the temperature of ground surface.