大气黑碳气溶胶影响空气质量及能见度，对太阳辐射有强烈吸收效应，因此对区域及全球气候也有重要影响。黑碳气溶胶在老化过程中会被各类污染物包覆，且包覆物的理化特性如浓度（包覆厚度）、组成及混合状态等，对于黑碳气溶胶的吸光能力有着很大影响，但一般模型中对此处理过于简单，存在较大不足。本项目拟以Aerodyne 黑碳气溶胶质谱仪（SP-AMS）为核心，结合系列在线仪器对我国典型大气环境（城区、背景点、偏远地区）冬夏两季黑碳及其包覆物的理化特性及吸光性质进行高时间分辨率观测。SP-AMS技术具有选择性检测仅含黑碳的气溶胶粒子，并同时检测包覆物化学组成的独特优势；高时间和化学分辨率的数据也有助于解析包覆物的来源、贡献及大气演化过程。本项目将阐明典型大气条件-黑碳包覆物理化特性-吸光增强之间的定量关系，进行参数化并建立相应的黑碳吸光增强计算方法，为气候模型中对黑碳辐射强迫效应的准确模拟提供实测依据。

Atmospheric black carbon (BC) particles can significantly impact air quality and visibility, strongly absorbs lights, thus has great influences on the regional and global climate. Once emitted into the atmosphere, BC particles can be coated by various pollutants during its aging process, and the properties of such coating including concentration (coating thickness), composition and mixing state, etc., will significantly affect light-absorption ability of the BC-containing aerosols. Nevertheless, climate models don’t considerably include this effect. In this project, we aim to utilize the Aerodyne Soot Particle-Aerosol Mass spectrometer (SP-AMS), in combination with a suite of online instruments, to measure the physicochemical and optical properties of BC and its associated coating species, under representative atmospheric environments in China (urban areas, background site and remote regions). The SP-AMS technique is unique as it can selectively measure the rBC-containing particles only, and can simultaneously obtain chemical information of the coating species; Highly time- and chemically resolved data is also powerful to elucidate sources, mass contributions and atmospheric aging processes of the coatings. This project will parameterize the interplay among typical atmospheric conditions, physical and chemical properties of BC coatings, and the light absorption, and establish the corresponding algorithm for light absorption calculations, thus provide basis for the accurate simulation of the radiative forcing effects due to black carbon in climate models.