A study on the propagation of surface polarization errors to the top of atmosphere. (1st March 2021)

• Record Type: Journal Article
• Authors: Chen, Wei; Zhu, Yujiao; Zhao, Haimeng; Tian, Huimin; Peltoniemi, Jouni; Yang, Bin
• Is Part Of: Atmospheric environment. Volume 248(2021)
• Publication Date: 2021-03-01
• Subjects: Polarized remote sensing -- Polarization -- Statistical aggregating -- Bidirectional polarized distribution function; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2021.118240
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: Light scattered by the surface–atmosphere system is partially polarized and provides useful information about aerosols and the underlying surface as polarized signals are sensitive to angular information about aerosols. To fully utilize this information, separating polarization signals of the atmosphere and surface by using the bidirectional polarized distribution function (BPDF) is necessary. However, although several BPDF models have been developed, the effects of the uncertainties of these models on the top-of-the-atmosphere (TOA) have not been fully investigated. In this study, we utilize the newly released POLarization and Directionality of the Earth's Reflectances (POLDER) dataset as a measured surface polarized reflectance dataset to parameterize the six currently used BPDF models. The measured and modeled surface polarized reflectances are used as inputs to vector radiative transfer models by statistical aggregating schemes considering all possible POLDER geometries. The root mean square errors between the measured and modeled polarized reflectances at the TOA decreased to 60–75% of the root mean square errors between the measured and modeled polarized reflectances at the surface and further decreased to a relatively low level (20%–30%) when the aerosol optical depth (AOD) increased. The BPDF uncertainty mainly affects the aerosol property retrievals mainly at low aerosol loadings. However, the accuracy of the surface BPDF required to obtain a sufficiently accurate retrieval at small AODs is still unknown. This study provides further insights that are valuable for understanding the coupling effect of the surface and atmosphere and important methods and information for retrieval of aerosol properties. Highlights: A statistical aggregating method was proposed to evaluate surface's disturbance on TOA Polarization. Different BPDF's accuracies are presented. BPDF's uncertainty will mainly affect aerosol type retrieval for low aerosol loading conditions.