亚微米气溶胶吸收特性粒径分布的多波长观测研究

Aerosol absorptive property is one of important factors that influence aerosol radiation effects. Black carbon (BC), brown carbon (BrC) and dust are light absorbing in the visible and near-ultraviolet range. Light absorbing aerosols have various emission sources. Their chemical composition and physical properties constantly change through the atmospheric aging processes, resulting in a change in aerosol optical properties. Despite of numerous observational studies on aerosol optical and chemical properties, multi-wavelength observations of size-resolved aerosol light absorption are currently still scarce. . This project intends to measure the size distribution of light absorption of aerosols under conditions of regional air pollution and biomass burning. The contribution of absorption by BC and BrC will be attributed and their size dependence will be investigated. Mixing state of light-absorbing and non-absorbing aerosols will be analyzed based on the optical measurements. What’s more, equivalent complex refractive index will be inferred. Such measurement methodology and observation-based analysis will enhance our understanding in emission sources, aging processes, and optical properties of light absorbing aerosols, as well as their impacts on climate and environment.

气溶胶的吸收特性是影响气溶胶辐射效应的重要因素之一。在可见光和近紫外范围内，黑碳、棕色碳和沙尘都具有光吸收性。吸收性气溶胶来源广泛，老化过程又不断改变着气溶胶的化学组成和物理性质，从而改变着气溶胶的光学特性。虽然目前已有不少关于气溶胶光学及化学性质的观测研究，但是仍然缺乏分粒径的气溶胶光学吸收特性的多波长观测研究。. 本项目计划在区域性污染及生物质燃烧两种情形下，观测多波长下气溶胶吸收特性随粒径的变化。研究黑碳和棕色碳对气溶胶吸收特性的贡献及其对波长和粒径的依赖关系。基于气溶胶光学观测分析气溶胶混合状态，并计算等效复折射指数。项目的观测方法和研究结果能为研究吸收性气溶胶的来源、老化过程、光学性质及其对气候和环境的影响提供有力的观测依据。

气溶胶吸收特性是影响气溶胶辐射效应的重要因素。气溶胶吸收特性的多波长粒径分布是重要的气溶胶光学信息，但目前尚缺乏相关观测研究。.本项目通过硬件优化和测量流程的设计，实现了粒径分辨的气溶胶数浓度、云凝结核数浓度和等效黑碳质量浓度的同时测量，并通过优化数据反演算法可最终获取吸收性气溶胶粒径分布及不同混合状态下的黑碳质量浓度粒径分布。.基于测量方法在不同地区不同季节开展了大量外场观测，获取了吸收性气溶胶粒径分布的时空分布特征。通过不同源排放地区和减排条件下的对比研究，探讨了源排放对吸收性气溶胶粒径分布特征的影响，并探讨了老化过程中吸收性气溶胶粒径分布的演变特征。同时，还基于敏感性试验研究了吸收性气溶胶粒径分布对气溶胶光学性质的影响。.本项目获取的宝贵观测数据有助于增进我们对于气溶胶吸收特性和气溶胶老化过程的认识，也为气溶胶直接辐射效应及环境过程研究提供了有力的观测支撑。.