基于辐射模拟反演ETM+数据宽波段反照率  

Calculation of ETM+ Broadband Albedos by Radiative Simulations

作　　者：阿布都瓦斯提.吾拉木 秦其明[1] 

机构地区：[1]北京大学遥感与GIS研究所

出　　处：《北京大学学报（自然科学版）》2007年第4期474-483,共10页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家重点基础研究发展规划(G2000077900);国家高技术发展计划(2001AA135110)资助项目

摘　　要：利用增强的专题制图仪＋（Enhanced Thematic Mapper Plus,ETM＋）数据,先针对各种下垫面反射率特征不同,对地物类型进行分类,以便减少邻近效应和模拟传感器未包含的谱段数据。借助卫星同步观测的气象数据,通过6S（Second Simulation of Satellite Signal inthe Solar Spectrum）模型对ETM＋可见光、近红外6个波段数据进行了大气纠正。以ETM＋可见光和近红外波段波谱范围为单位谱段,将整个短波波段（0.3-4μm）分为13个光谱域,利用ASTER光谱数据库和实测地表反射率数据,6S模拟获取各ETM＋观测波段和未观测波段地表入射光通量密度和反射光通量密度,计算每一个光谱域入射能量占整个短波入射能量中的权重,并反演地表窄波段反照率。然后,各波段能量权重作为转换参数,实现窄波段反照率向宽波段反照率的转换。结果表明,模型反演和卫星同步观测的实测地表反照率之间最大相对误差17.9%,作者提出的方法可行。Surface broadband albedo is calculated from Enhanced Thematic Mapper Plus （ETM ＋ ） data using 6S （Second Simulation of Satellite Signal in the Solar Spectrum） simulations. First, land cover of study area is classified into three ciasses as vegetation, bare soil and water as to. surface features so that it is possible to simulate the spectral data not available from ETM ＋ sensor as well as to reduce both the adjacency and angular effects. Then, The whole shortwave region（0.3-4μm） is divided into 13 spectral bands following by the bandwidth of ETM ＋ . ETM ＋ data has only six bands could be used to calculate broadband albedo. To remedy the spectral deficiency, the radiances in the wavelengths not included in ETM ＋ sensor are simulated by 6S using field measured reflectance and ASTER spectral library. Next, illuminated and reflected spectral irradiances at the surface are calculated for per band to estimate the spectral albedo and band weights. The spectral albedos are calculated as the ratio of spectral reflected to incident irradiance. Finally, broadband albedos in 0.3-0.7, 0.7-4, 0.3-4μm ranges are estimated and validated using isochronous field measurement data obtained in Shunyi District of Beljing. Comparisons of satellite estimated and field observed albedos demonstrat high accordance with maximum relative error of 17.9% .

关 键 词：6S模型 大气纠正 反照率 辐射模拟 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置] TP701[自动化与计算机技术—控制科学与工程]