Abstract. The Hybrid End-To-End Aerosol Classification (HETEAC) model for the Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission is introduced. The model serves as the common baseline for development, evaluation, and implementation of EarthCARE algorithms. It guarantees the consistency of different aerosol products from the multi-instrument platform and facilitates the conform specification of broad-band optical properties needed for EarthCARE radiative closure assessments. While the hybrid approach ensures that the theoretical description of aerosol microphysical properties is consistent with the optical properties of the measured aerosol types, the end-to-end model permits the uniform representation of aerosol types in terms of microphysical, optical, and radiative properties. Four basic aerosol components with prescribed microphysical properties are used to compose various natural and anthropogenic aerosols of the troposphere. The components contain weakly and strongly absorbing fine-mode as well as spherical and non-spherical coarse-mode particles and thus are representative for pollution, smoke, sea salt, and dust, respectively. Their microphysical properties are selected such that a good coverage of the observational phase space of intensive, i.e., concentration-independent, optical aerosol properties derived from EarthCARE measurements is obtained. Mixing rules to calculate optical and radiative properties of any aerosol blend composed of the four basic components are provided. Applications of HETEAC in the generation of test scenes, the development of retrieval algorithms for stand-alone and synergistic aerosol products from EarthCARE's Atmospheric Lidar (ATLID) and Multi-Spectral Imager (MSI), as well as for radiative closure assessments are discussed. In the end, conclusions for future development work are drawn.

中文翻译：

---

HETEAC——EarthCARE 的混合端到端气溶胶分类模型

摘要。引入了用于地球云、气溶胶和辐射探测器 (EarthCARE) 任务的混合端到端气溶胶分类 (HETEAC) 模型。该模型作为 EarthCARE 算法的开发、评估和实施的共同基线。它保证了来自多仪器平台的不同气溶胶产品的一致性，并有助于符合 EarthCARE 辐射闭合评估所需的宽带光学特性规范。虽然混合方法确保气溶胶微物理特性的理论描述与测量的气溶胶类型的光学特性一致，但端到端模型允许气溶胶类型在微物理、光学和辐射特性方面的统一表示。具有规定微观物理特性的四种基本气溶胶成分用于构成对流层的各种自然和人为气溶胶。这些成分包含弱和强吸收的精细模式以及球形和非球形粗模式粒子，因此分别代表污染、烟雾、海盐和灰尘。选择它们的微物理特性，以便获得对从 EarthCARE 测量得出的密集（即与浓度无关）光学气溶胶特性的观测相空间的良好覆盖。提供了计算由四种基本成分组成的任何气溶胶混合物的光学和辐射特性的混合规则。HETEAC在测试场景生成中的应用，讨论了 EarthCARE 的大气激光雷达 (ATLID) 和多光谱成像仪 (MSI) 的独立和协同气溶胶产品的检索算法的开发，以及辐射闭合评估。最后对今后的开发工作进行了总结。