Parameterization of surface polarized reflectance derived from POLDER spaceborne measurements
Parameterization of surface polarized reflectance derived from POLDER spaceborne measurements
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DOI：
10.1109/36.763292
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发表时间：
1999-05
期刊：
影响因子：
--
通讯作者：
F. Nadal;F. Bréon
中科院分区：
文献类型：
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作者：
F. Nadal;F. Bréon
两个月的星载极化测量被用来产生经验表面双向极化分布函数(BPDF)。根据地表分类和植被指数定义了11个地表类别。在每一类中，表面偏振反射率都比较均匀。表面偏振反射率是高度各向异性的，在接近后向散射方向的0和前向散射方向的几个百分比之间变化。对于给定的观测几何形状，被归类为“沙漠”的像素上的偏振大约是植被表面上的两倍。具有两个参数的经验函数对估计的表面偏振反射率进行了拟合，其残差约为10/sup-3/以反射为单位。对大气贡献特征较好的特定太阳光度计站点上的大气层顶部(TOA)偏振反射率的分析证实了10/sup-3/的估计精度。
Two months of spaceborne POLDER polarization measurements have been used to generate empirical surface bidirectional polarization distribution functions (BPDFs). Eleven surface classes have been defined based on a surface classification and a vegetation index. Within each class, the surface polarized reflectance was found rather homogeneous. The surface polarized reflectance is highly anisotropic and varies between 0 close to the backscattering direction, and a few percent in the forward scattering direction. For a given observation geometry, the polarization is about twice as large over the pixels classified as "desert" than over vegetated surfaces. An empirical function with two parameters fits the estimated surface polarized reflectance with a residue on the order of 10/sup -3/ in reflectance units. An analysis of top-of-the-atmosphere (TOA) polarized reflectance over specific sunphotometer sites where the atmospheric contribution is well characterized confirms the estimated accuracy of 10/sup -3/.