Atmospheric nucleation: highlights of the EUCAARI project and future directions
Atmospheric nucleation: highlights of the EUCAARI project and future directions
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DOI：
10.5194/acp-10-10829-2010
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发表时间：
2010-01-01
影响因子：
6.3
通讯作者：
Kulmala, M.
中科院分区：
文献类型：
--
作者：
Kerminen, V. -M.;Petaja, T.;Kulmala, M.
在EUCAARI项目内（欧洲气溶胶云气候和空气质量相互作用综合项目），通过（i）开发和测试新的空气离子和团簇光谱仪，（ii）在实验室中进行硫酸盐和有机系统的均匀成核实验，（iii）在野外条件下研究大气成核机制，以及（iv）应用新的理论和建模工具进行数据解释和制定参数。目前的文件提供了一个合成所获得的结果，并确定了剩余的主要知识差距有关的大气成核。该项目最重要的技术成就是开发了用于测量3纳米以下颗粒群的新仪器，沿着这些仪器在实验室和现场的广泛应用。EUCAARI期间获得的所有结果表明，硫酸在大气成核中起着核心作用。然而，也需要蒸汽以外的硫酸来解释成核和随后的增长过程，至少在大陆边界层。在这方面，候选蒸汽是一些有机化合物、氨，特别是胺。我们的现场和实验室数据都表明，成核速率与成核蒸汽浓度的一次或二次幂成比例。这与早期的几个现场观测结果一致，但与经典的热力学成核理论形成鲜明对比。2-nm粒子的平均形成速率被发现变化几乎两个数量级之间的不同EUCAARI网站，而带电的2-nm粒子的形成速率变化很小的网站之间。总的来说，我们的观测结果表明，频繁的，但温和的，离子诱导的成核通常超过了更强的中性成核事件在大陆低对流层。EUCAARI成核研究的最具体成果是基于现场观测的新的半经验成核率参数化，沿着更新的气溶胶形成参数化。
Within the project EUCAARI (European Integrated project on Aerosol Cloud Climate and Air Quality interactions), atmospheric nucleation was studied by (i) developing and testing new air ion and cluster spectrometers, (ii) conducting homogeneous nucleation experiments for sulphate and organic systems in the laboratory, (iii) investigating atmospheric nucleation mechanism under field conditions, and (iv) applying new theoretical and modelling tools for data interpretation and development of parameterisations. The current paper provides a synthesis of the obtained results and identifies the remaining major knowledge gaps related to atmospheric nucleation. The most important technical achievement of the project was the development of new instruments for measuring sub-3 nm particle populations, along with the extensive application of these instruments in both the laboratory and the field. All the results obtained during EUCAARI indicate that sulphuric acid plays a central role in atmospheric nucleation. However, also vapours other than sulphuric acid are needed to explain the nucleation and the subsequent growth processes, at least in continental boundary layers. Candidate vapours in this respect are some organic compounds, ammonia, and especially amines. Both our field and laboratory data demonstrate that the nucleation rate scales to the first or second power of the nucleating vapour concentration(s). This agrees with the few earlier field observations, but is in stark contrast with classical thermodynamic nucleation theories. The average formation rates of 2-nm particles were found to vary by almost two orders of magnitude between the different EUCAARI sites, whereas the formation rates of charged 2-nm particles varied very little between the sites. Overall, our observations are indicative of frequent, yet moderate, ion-induced nucleation usually outweighed by much stronger neutral nucleation events in the continental lower troposphere. The most concrete outcome of the EUCAARI nucleation studies are the new semi-empirical nucleation rate parameterizations based on field observations, along with updated aerosol formation parameterizations.