黑碳气溶胶是大气中直接吸收太阳辐射最为重要的成分。研究黑碳在云中的活化效率不仅是决定其大气寿命从而影响直接加热效应的关键，也对于研究黑碳在云中引起的间接效应（通过改变云物理结构）和半直接效应（减少云的覆盖面积以及降低反射率）具有基础性的科学意义。但是黑碳在云中的活化效率至今还缺乏真实大气环境中的实际测量结果。本项目基于华北平原受人为污染源影响且经常有地形云经过的海坨山高山站点的测量，将在冷暖两季利用单颗粒黑碳光度计和扫描电迁移率粒径谱仪通过精细设计的交替进样口同时采集云中和云外的颗粒物，以此来计算黑碳和其他颗粒物在云中的活化效率；并结合实地云物理探头的测量来鉴定云相态，得出黑碳在冰云和暖云中不同的活化机理。本项目的实验结果将为黑碳的湿沉降及其和云的相互作用机制提供实验依据和模型参数，验证黑碳对于云微观物理性质和降水的影响，并为2022年冬奥会人工影响天气作业提供一定的科学参考依据。

Black carbon (BC) is the most important aerosol in absorbing solar radiation. The BC is mainly removed by wet deposition and its removal efficiency is largely determined by its scavenging efficiency in cloud and subsequent precipitation. It is thus important to determine its lifetime in the atmosphere which determines its direct radiative forcing effect but also the indirect effect (by modifying the cloud microphysics) and semi-direct effect (by reducing the cloud cover or decreasing the cloud albedo). However there are still lack of results about the cloud scavenging efficiency of BC in real world. This project will perform experiments at an alpine station - Haituo Mountain in the North China Plain where there is significant anthropogenic influence, and orographic cloud is frequently formed by air parcel lifting. This project will simultaneously measure the particle in-cloud and out-of-cloud by using a dedicated designed sampling system combined with the online measurements of single particle soot photometer and scanning mobility particle sizer in cold and warm seasons, to derive the scavenging efficiency of BC and other aerosols; also combine the in-situ measurements of cloud microphysics to investigate different activation mechanisms of BC in warm and ice cloud. This work will provide fundamental basis and modelling parameterization for the BC wet scavenging and its interaction with cloud, and identify the potential influence of BC on cloud microphysics and precipitation, also guiding the weather modification service for 2022 Beijing Winter Olympics and Paralympic Games.