【作者】 覃志豪； 李文娟； 徐斌； 张万昌；

【Author】 QIN Zhi hao 1,2 , LI Wen jian 2, XU Bin 2, ZHANG Wang chang 1 (1. International Institute of Earth System Science, Nanjing University , Nanjing 210093, China; 2. Institute of Agricaltural Resources and Regional Planning, Chinese Academy of Agricultural Sciences , Beijing 100081, China)

【机构】 南京大学国际地球系统科学研究所； 中国农业科学院农业资源区划研究所农业部资源遥感和数字农业重点开放实验室；

【摘要】 地表温度是地球资源环境动态分析的重要指标。从热红外遥感数据中反演地表温度通常需要地表比辐射率为已知。因此,地表比辐射率的估计是地表温度遥感反演的关键。陆地卫星Landsat TM有一个热波段(TM6),可以用来反演地表温度。目前共有3种算法可以用来从TM6波段数据中反演地表温度:大气校正法、单窗算法和单通道算法。这3种算法都需要TM6波段范围内的地表发射率来作为地表温度反演的参数。首先简介这3 种反演算法,然后重点探讨TM6的地表发射率估计方法。TM6的星下空间分辨率为120 m。在这一尺度上,大多数情况下天然地表的构成可以看成是由水面、植被和裸土三种基本类型构成。城镇像元也可看成是由建筑表面和绿化植物构成。根据这几种地表类型的地表发射率相对较稳定的特性,提出了用TM数据的可见光波段来进行TM6像元的地表发射率的估计。TM3和TM4波段可以用来确定植被叶冠在像元尺度上的覆盖度。通过这一覆盖度,就可以构建混合像元的地表热辐射构成方程,以便进行地表发射率的简单估计,从而为TM6 热波段数据在农业和资源环境监测中的广泛应用,提供技术支撑。最后,用这一方法来进行华北平原山东省陵县地区的地表发射率估计和地表温度反演。分析表明,这一方法能获得较合理的地表温度反演结果。更多还原

【Abstract】 Land surface emissivity is an essential parameter for retrieving land surface temperature from thermal infrared remote sensing data. Landsat thematic mapper(TM) has a thermal band(TM6), and this band can be used for retrieving land surface temperature(LST). Up to now, three methods have been developed for retrieving LST from TM6 data, they are atmospheric correction method, mono window algorithm and single channel algorithm, and they all need the land surface emissivity as the parameter for LST retrieval. The spatial resolution of TM6 is 120 m under nadir, the pixels of TM6 on this scale for most natural surfaces can be viewed as composed of 3 land cover patterns: vegetation, bare soil and water, and those for urban areas can be viewed as composed of building surface and vegetation. The emissivities of these landsat cover patterns are relatively stalbe, so Landsat TM visible band data can be used to estimate the land surface emissivity. The composition ratio of vegetation and bare soil or building surface on pixel scale can be estimated using TM3 and TM4 band data, and the land surface emissivity of TM6 pixel can be estimated by using the land surface thermal radiation equation of composed pixel and the known enissivities of land cover patterns, which will provide scientific basis for applying TM6 band data in the agricultural and resource environment monitoring. Finally, the method is used for the land surface emissivity estimation and the LST retrieval in the Lingxian area of North China Plain, and it is shown from the analysis results that reasonble LST retrieval results can be obtained by using this method.更多还原