利用南京市1989年TM和2001年、2010年ETM+卫星遥感数据,提取了3个时期的归一化植被指数(normalized difference vegetation index,NDVI)、改进的归一化水体指数(modified normalized difference water index,MNDWI)、归一化建筑指数(normalized difference build-up index,NDBI)和归一化不透水面指数(normalized difference impervious surface index,NDISI)等地表参数;利用热红外波段遥感数据反演地表温度,并从时间维对比分析了3个时期各个参数的变化和产生的原因;利用回归分析方法探讨了上述地表参数变化与城市地表温度之间的关系,即地表温度与NDISI和NDBI呈正相关,与NDVI呈负相关。进一步分析表明,南京市最近20 a来不透水面和建筑面积大幅增大,植被覆盖范围减少,城市热岛效应加剧,不透水面、建筑指数与地表温度的变化趋势和城市扩张趋势一致。该研究成果对于揭示南京市热岛效应、优化土地配置和推进生态城市建设具有一定的参考意义。
In this paper, ground surface parameters such as normalized difference vegetation index ( NDVI ) , modified normalized difference water index ( MNDWI ) , normalized difference build - up index ( NDBI ) and normalized difference impervious surface index (NDISI) were extracted from TM (1989) and ETM+(2001,2010) images of Nanjing, and land surface temperature was retrieved from thermal infrared image so as to make a comparative analysis of factors responsible for the variation of each parameter at the temporal and spatial level. The authors also analyzed the correlations between ground surface parameters and land surface temperatures. The results of the experiments show that land surface temperature is positively correlated with NDISI and NDBI but negatively correlated with NDVI. Further analysis shows that NDISI, NDBI of Nanjing City have been significantly increased, vegetation coverage decreased and the urban heat island effect exacerbated in the past 20 years, and these trends are in