气候变化领域集成服务门户(CCPortal): Aitken mode particles as CCN in aerosol- And updraft-sensitive regimes of cloud droplet formation

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DOI	10.5194/acp-21-11723-2021
	Aitken mode particles as CCN in aerosol- And updraft-sensitive regimes of cloud droplet formation
	Pöhlker M.L.; Zhang M.; Campos Braga R.; Krüger O.O.; Pöschl U.; Ervens B.
发表日期	2021
ISSN	1680-7316
起始页码	11723
结束页码	11740
卷号	21 期号:15
英文摘要	The high variability of aerosol particle concentrations, sizes and chemical composition makes their description challenging in atmospheric models. Aerosol-cloud interaction studies are usually focused on the activation of accumulation mode particles as cloud condensation nuclei (CCN). However, under specific conditions Aitken mode particles can also contribute to the number concentration of cloud droplets (Nd), leading to large uncertainties in predicted cloud properties on a global scale. We perform sensitivity studies with an adiabatic cloud parcel model to constrain conditions under which Aitken mode particles contribute to Nd. The simulations cover wide ranges of aerosol properties, such as total particle number concentration, hygroscopicity (κ) and mode diameters for accumulation and Aitken mode particles. Building upon the previously suggested concept of updraft (w)- and aerosol-limited regimes of cloud droplet formation, we show that activation of Aitken mode particles does not occur in w-limited regimes of accumulation mode particles. The transitional range between the regimes is broadened when Aitken mode particles contribute to Nd, as aerosol limitation requires much higher w than for aerosol size distributions with accumulation mode particles only. In the transitional regime, Nd is similarly dependent on w and κ. Therefore, we analyze the sensitivity of Nd to κ, ζ(κ), as a function of w to identify the value combinations above which Aitken mode particles can affect Nd. As ζ(κ) shows a minimum when the smallest activated particle size is in the range of the "Hoppel minimum"(0.06g μmg ≤g Dming ≤0.08g μm), the corresponding (w-κ) pairs can be considered a threshold level above which Aitken mode particles have significant impact on Nd. This threshold is largely determined by the number concentration of accumulation mode particles and by the Aitken mode diameter. Our analysis of these thresholds results in a simple parametric framework and criterion to identify aerosol and updraft conditions under which Aitken mode particles are expected to affect aerosol-cloud interactions. Our results confirm that Aitken mode particles likely do not contribute to Nd in polluted air masses (urban, biomass burning) at moderate updraft velocities (w≤3g mg s-1) but may be important in deep convective clouds. Under clean conditions, such as in the Amazon, the Arctic and remote ocean regions, hygroscopic Aitken mode particles can act as CCN at updrafts of w<1g mg s-1. © Author(s) 2021.
语种	英语
scopus关键词	aerosol; aerosol composition; Aitken nucleus; atmospheric modeling; cloud condensation nucleus; cloud droplet; concentration (composition); formation mechanism; particle size; updraft
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246679
作者单位	Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, 55128, Germany; Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, Clermont-Ferrand, 63000, France
推荐引用方式 GB/T 7714	Pöhlker M.L.,Zhang M.,Campos Braga R.,et al. Aitken mode particles as CCN in aerosol- And updraft-sensitive regimes of cloud droplet formation[J],2021,21(15).
APA	Pöhlker M.L.,Zhang M.,Campos Braga R.,Krüger O.O.,Pöschl U.,&Ervens B..(2021).Aitken mode particles as CCN in aerosol- And updraft-sensitive regimes of cloud droplet formation.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(15).
MLA	Pöhlker M.L.,et al."Aitken mode particles as CCN in aerosol- And updraft-sensitive regimes of cloud droplet formation".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.15(2021).