城市地表温度反演及其与下垫面定量关系分析——以西安市为例

Analysis on the Urban Land Surface Temperature Inversion and Its Quantitative Relationship with Underlying Surface——Taking Xi'an City as a case

城市地理与气象条件、人为因素共同决定了当今城市的热岛现象,其中后者的影响更为重要,而下垫面又是主要的人为因素之一。本文以西安市为研究区域,利用2014年的landsat8数据,反演出地表温度、植被和不透水面等信息,对城市热岛效应与下垫面关系进行定量分析,结果表明:作为下垫面重要表征组分的植被、不透水面与地表温度有着密切的关系,其中植被指数与地表温度之间的相关系数为-0.912,呈负相关关系;而不透水面指数与地表温度之间的相关系数是0.747,呈正相关关系;此外,还对地表温度、植被指数和不透水面指数进行了多元回归分析。由此说明,植被对城市热岛效应的改善起到积极的作用,而不透水面会增加地表温度,从而加剧热岛效应,因此可根据植被、不透水面这两大因子对城市生态环境进行评估,从而制定相应的生态决策。

Urban geographical and meteorological conditions and human factors jointly determines the current urban heat island phenomenon. The more important effect comes from human factors, however the underlying surface is one of the main human factors. This research took Xi＇an City, provincial capital of Shanxi China as research area and applied the 2014landsat8 data to extract land surface temperature, vegetation and impervious surface information and analyzed the quantitative relationship between urban heat island effect and vegetation, underlying surface. The results showed that vegetation and impervious surface which were important components of underlying surface had close relations with land surface temperature. The correlation coefficient between vegetation index and land surface temperature was negative 0.912,and the correlation coefficient between the land surface temperature and impervious surface index was 0.747. In addition, the land surface temperature, vegetation index and impervious surface index had been carried on a multiple regression analysis.Above research indicated that vegetation played a positive role in the improvement of the urban heat island effect, while impervious surface increased the land surface temperature to aggravate the heat island effect. So on the basis of vegetation and impervious surface, the urban ecological environment could be evaluated, and the corresponding ecological decisions could be made.