Quantifying the reflectance anisotropy effect on albedo retrieval from remotely sensed observations using archetypal BRDFs
Quantifying the reflectance anisotropy effect on albedo retrieval from remotely sensed observations using archetypal BRDFs
复制标题
使用原型 BRDF 量化反射率各向异性对遥感观测反照率反演的影响
DOI：
10.3390/rs10101628
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发表时间：
2018
期刊：
影响因子：
5
通讯作者：
Cui Tiejun
中科院分区：
文献类型：
--
作者：
Zhang Hu;Jiao Ziti;Chen Lei;Dong Yadong;Zhang Xiaoning;Lian Yi;Qian Da;Cui Tiejun
使用中分辨率成像光谱仪（MODIS）双向反射分布函数（BRDFs）产品和原型BRDFs，反射率各向异性的效果进行了评估。基于各向异性平坦指数（AFX）和时间序列MODIS BRDF，在h11 v03瓦片上建立了短波原型BRDF，并进行了验证。为了生成表面反射率，基于最小二乘法，使用原型BRDF来拟合模拟反射率。反照率也是基于最小均方根误差（RMSE）方法或归一化差异植被指数（NDVI）的BRDF知识的基础上检索。这些反射率与MODIS反射率之间的差异被用来量化反射率各向异性效应。2009年第185天h11 v03瓦片上的反射波是从单向反射和第三原型BRDF中检索的。结果表明，六个原型的BRDF是足够的代表反射率各向异性的估计。对于本研究中所使用的数据，反射率各向异性引起的相对不确定性可以达到7.4%，16.2%和20.2%，充分，不充分的多角度和单方向的观测。中间原型BRDFs可以用来提高不充分或单一观测的反演精度，相对不确定度范围为8- 15%。
The reflectance anisotropy effect on albedo retrieval was evaluated using the Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution functions (BRDFs) product, and archetypal BRDFs. Shortwave-band archetypal BRDFs were established, and validated, based on the Anisotropy Flat indeX (AFX) and time series MODIS BRDF over tile h11v03. To generate surface albedo, archetypal BRDFs were used to fit simulated reflectance, based on the least squares method. Albedo was also retrieved based on the least root-mean-square-error (RMSE) method or normalized difference vegetation index (NDVI) based prior BRDF knowledge. The difference between those albedos and the MODIS albedo was used to quantify the reflectance anisotropy effect. The albedo over tile h11v03 for day 185 in 2009 was retrieved from single directional reflectance and the third archetypal BRDF. The results show that six archetypal BRDFs are sufficient to represent the reflectance anisotropy for albedo estimation. For the data used in this study, the relative uncertainty caused by reflectance anisotropy can reach up to 7.4%, 16.2%, and 20.2% for sufficient, insufficient multi-angular and single directional observations. The intermediate archetypal BRDFs may be used to improve the albedo retrieval accuracy from insufficient or single observations with a relative uncertainty range of 8–15%.