城市不透水面与地表温度定量关系的遥感分析

作为城市下垫面的最主要组成部分，城市不透水面是引发城市热岛效应的主要因素，但目前不透水面与地表温度之间的定量关系仍不明确，不同研究的结论也不尽相同。选取了上海、广州、北京、长沙、兰州、福州等6个代表我国不同区域的城市作为研究区来进一步研究城市不透水面与城市热环境的定量关系。采用Landsat ETM+影像和线性光谱混合分析法提取出各个研究区的不透水面，利用热红外波段反演出各研究区的地表温度，采用多种回归模型和大样本量对二者之间的相关关系进行定量分析；在此基础上讨论了不透水面对城市热环境的影响机制。结果表明：不透水面与地表温度呈明显的正相关关系，并且以指数函数为最佳拟合模型，回归方程的相关系数均为0.750以上，最高可达0.954 1；高不透水面盖度地区的升温幅度更大，比低不透水面盖度地区高出0.600~1.700 ℃，其原因主要是高不透水面盖度地区的植被覆盖率低，蒸腾蒸发作用小。

Quantitative Relationship Between Impervious Surface and Land Surface Temperature Based on Remote Sensing Technology

As the most important component of the urban surface, impervious surface has been recognized as a main indicator of urban heat island effect. However, the quantitative relationship between impervious surface area (ISA) and land surface temperature (LST) is still unclear as different studies achieved different results. Therefore, the present paper selected six cities from different geographical regions of China to further investigate the quantitative relationship between ISA and LST. The cities involved are Shanghai, Guangzhou, Beijing, Changsha, Lanzhou and Fuzhou. The ISAs of the six cities were derived from Landsat ETM+ images by using linear spectral mixture analysis and the LSTs of the cities were retrieved from the thermal infrared band of the images. Multivariate regression analysis with a large amount of samples was implemented to examine quantitative relationship between ISA and LST. Results showed that the ISAs of the six cities were all positively correlated to the LST, but with an exponential relationship being the best fit model. The correlation coefficients of the exponential relationship were above 0.750 0 and could be up to 0.954 1. This suggested that the area with high percent ISA could accelerate LST rise and the temperature rise was higher than 0.600 to 1.700 ℃ compared to the area with low percent ISA. The weaker transpiration evaporation and lower vegetation cover are the main factors contributing to the higher LST rise in the high percent ISA area.