传统的大气校正方法原理比较复杂,而且有些参数特别是实时的大气剖面资料难以获取。本文利用DEM对TM 影像进行地形校正后,用简便而又实用的方法对TM影像进行了大气校正,较精确地反演出黑河流域河西走廊中段对应于Landsat TM 1~5 和7波段的地表反射率。在此基础上,通过不同波段地表反射率的组合,获得了地表反照率。通过与实地观测数据对比分析,表明对于植被覆盖区用TM 2,4,7波段组合结果较好,而在非植被覆盖区用TM 1~5,7这6 个波段组合结果更佳。
Traditional atmospheric correction methods are complicated in theory, difficult in practice owning to some parameters, especially field real-time atmospheric profile data, are seldom available.This study presents an easy, fast approach that takes the best use of DEM in association with the application of an atmospheric correction model to obtain the surface reflectance from Landsat TM imaginary over the Heihe River Basin.Based on surface reflectance imaginaries for TM Band 1-5 and 7, different band integration approaches were attempted to obtain the total continuous spectral albedo over the study site for comparing with the field observed ones.It was found that for vegetated area the TM band 2, 4, 7 integration approach performs better, while for non-vegetation area band integration using TM 1-5 and 7 bands data is more reliable.
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