The study presents a climatology of aerosol composition concentrations obtained by a recently developed algorithm approach, namely the Generalized Retrieval of Atmosphere and Surface Properties (GRASP)/Component. It is applied to the whole archive of observations from the POLarization and Directionality of the Earth's Reflectances (POLDER-3). The conceptual specifics of the GRASP/Component approach is in the direct retrieval of aerosol speciation (component fraction) without intermediate retrievals of aerosol optical characteristics. Although a global validation of the derived aerosol component product is challenging, the results obtained are in line with general knowledge about aerosol types in different regions. In addition, we compare the GRASP-derived black carbon (BC) and dust components with those of the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) product. Quite a reasonable general agreement was found between the spatial and temporal distribution of the species provided by GRASP and MERRA-2. The differences, however, appeared in regions known for strong biomass burning and dust emissions; the reasons for the discrepancies are discussed. The other derived components, such as concentrations of absorbing (BC, brown carbon (BrC), iron-oxide content in mineral dust) and scattering (ammonium sulfate and nitrate, organic carbon, non-absorbing dust) aerosols, represent scarce but imperative information for validation and potential adjustment of chemical transport models. The aerosol optical properties (e.g., aerosol optical depth (AOD), Ångström exponent (AE), single-scattering albedo (SSA), fine- and coarse-mode aerosol optical depth (AODF AND AODC)) derived from GRASP/Component were found to agree well with the Aerosol Robotic Network (AERONET) ground reference data, and were fully consistent with the previous GRASP Optimized, High Precision (HP) and Models retrieval versions applied to POLDER-3 data. Thus, the presented extensive climatology product provides an opportunity for understanding variabilities and trends in global and regional distributions of aerosol species. The climatology of the aerosol components obtained in addition to the aerosol optical properties provides additional valuable, qualitatively new insight about aerosol distributions and, therefore, demonstrates advantages of multi-angular polarimetric (MAP) satellite observations as the next frontier for aerosol inversion from advanced satellite observations. The extensive satellite-based aerosol component dataset is expected to be useful for improving global aerosol emissions and component-resolved radiative forcing estimations. The GRASP/Component products are publicly available (https://www.grasp-open.com/products/, last access: 15 March 2022) and the dataset used in the current study is registered under https://doi.org/10.5281/zenodo.6395384 (Li et al., 2022b).

中文翻译：

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使用 GRASP 算法从多角偏振 POLDER-3 观测得出的气溶胶成分浓度的气候学

该研究提出了通过最近开发的算法方法获得的气溶胶成分浓度的气候学，即大气和表面特性的广义检索 (GRASP)/组分。它适用于地球反射率的极化和方向性 (POLDER-3) 的整个观测档案。GRASP/组分方法的概念细节是直接检索气溶胶形态（组分分数），而无需中间检索气溶胶光学特性。尽管衍生气溶胶成分产品的全球验证具有挑战性，但获得的结果与不同地区气溶胶类型的一般知识一致。此外，我们将 GRASP 衍生的黑碳 (BC) 和粉尘成分与研究和应用的现代回顾分析第 2 版 (MERRA-2) 产品进行比较。在 GRASP 和 MERRA-2 提供的物种的空间和时间分布之间发现了相当合理的普遍一致性。然而，差异出现在以强烈的生物质燃烧和粉尘排放而闻名的地区。讨论了差异的原因。其他衍生成分，例如吸收（BC、棕碳 (BrC)、矿物粉尘中的氧化铁含量）和散射（硫酸铵和硝酸铵、有机碳、非吸收粉尘）气溶胶的浓度，代表了稀缺但必不可少的信息用于化学传输模型的验证和潜在调整。气溶胶光学特性（例如，发现源自 GRASP/Component 的气溶胶光学深度 (AOD)、Ångström 指数 (AE)、单散射反照率 (SSA)、精细和粗模式气溶胶光学深度 (AODF 和 AODC)) 与 Aerosol Robotic 非常吻合Network (AERONET) 地面参考数据，并且与之前应用于 POLDER-3 数据的 GRASP 优化、高精度 (HP) 和模型检索版本完全一致。因此，所提出的广泛的气候学产品为了解气溶胶物种全球和区域分布的变异性和趋势提供了机会。除了气溶胶光学特性之外，获得的气溶胶成分的气候学提供了关于气溶胶分布的额外有价值的、定性的新见解，因此，展示了多角极化（MAP）卫星观测作为先进卫星观测气溶胶反演的下一个前沿的优势。广泛的基于卫星的气溶胶成分数据集预计将有助于改进全球气溶胶排放和成分分辨的辐射强迫估计。GRASP/组件产品是公开可用的（https://www.grasp-open.com/products/，最后访问时间：2022 年 3 月 15 日），当前研究中使用的数据集在 https://doi.org/10.5281/zenodo.6395384 下注册（Li et al ., 2022b)。