Polarized signal has been proven to be sensitive to the aerosol optical depth and aerosol microphysical parameters. However, in most current applications, the directions of polarization, which are expressed by the sign of polarization, have long been regarded as minor factor. In most remote sensing retrievals, the absolute values of negative polarizations are considered. Therefore, whether this neglection will introduce uncertainty in remote sensing has not been investigated. In this study, TOA polarized reflectances are calculated with the measured surface (with sign) and modeled (without sign) polarized reflectance to obtain the TOA polarized reflectance dataset. Our results suggest that 7% of the surface measured polarized reflectance is negative, while after the vector radiative transfer calculation, this proportion increases to 20–50%. Although correlations between absolute values of measured and modeled data are high (>0.99), when including the effects of the sign, the correlations will decrease to less than 0.5 or even 0.2, and RMSE will increase 10 times. These discrepancies will introduce a lot of uncertainty in polarized remote sensing retrieval when mixed pixels with opposite polarizations for subpixels occur. Furthermore, the same polarization for different objects is another problem when there are both negative and positive polarizations. Our study is particularly important for future applications of polarized signals to obtain accurate and reliable results.

偏振信号已被证明对气溶胶光学深度和气溶胶微物理参数敏感。然而，在大多数当前应用中，由极化符号表示的极化方向长期以来一直被视为次要因素。在大多数遥感检索中，都会考虑负极化的绝对值。因此，尚未研究这种忽略是否会在遥感中引入不确定性。在这项研究中，TOA偏振反射率是使用被测表面（带符号）计算出来的，并建模（没有符号）偏振反射率以获得TOA偏振反射率数据集。我们的结果表明，被测表面的7％偏振反射率为负，而在矢量辐射传输计算之后，该比例增加到20–50％。尽管测量数据和建模数据的绝对值之间的相关性很高（> 0.99），但是当包括符号的影响时，相关性将减小到小于0.5甚至0.2，RMSE将增加10倍。当子像素具有相反极化的混合像素出现时，这些差异将在极化遥感检索中引入很多不确定性。此外，当同时存在负极化和正极化时，针对不同对象的相同极化是另一个问题。我们的研究对于极化信号的未来应用以获得准确和可靠的结果特别重要。RMSE将增加10倍。当子像素具有相反极化的混合像素出现时，这些差异将在极化遥感检索中引入很多不确定性。此外，当同时存在负极化和正极化时，针对不同对象的相同极化是另一个问题。我们的研究对于极化信号的未来应用以获得准确和可靠的结果特别重要。RMSE将增加10倍。当子像素具有相反极化的混合像素出现时，这些差异将在极化遥感检索中引入很多不确定性。此外，当同时存在负极化和正极化时，针对不同对象的相同极化是另一个问题。我们的研究对于极化信号的未来应用以获得准确和可靠的结果特别重要。