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DOI	10.1073/pnas.2006426117
	The role of turbulent fluctuations in aerosol activation and cloud formation
	Prabhakaran P.; Shawon A.S.Md.; Kinney G.; Thomas S.; Cantrell W.; Shaw R.A.
发表日期	2020
ISSN	0027-8424
起始页码	16831
结束页码	16838
卷号	117 期号:29
英文摘要	Aerosol indirect effects are one of the leading contributors to cloud radiative properties relevant to climate. Aerosol particles become cloud droplets when the ambient relative humidity (saturation ratio) exceeds a critical value, which depends on the particle size and chemical composition. In the traditional formulation of this problem, only average, uniform saturation ratios are considered. Using experiments and theory, we examine the effects of fluctuations, produced by turbulence. Our measurements, from a multiphase, turbulent cloud chamber, show a clear transition from a regime in which the mean saturation ratio dominates to one in which the fluctuations determine cloud properties. The laboratory measurements demonstrate cloud formation in mean-subsaturated conditions (i.e., relative humidity <100%) in the fluctuation-dominant activation regime. The theoretical framework developed to interpret these measurements predicts a transition from a mean- to a fluctuation-dominated regime, based on the relative values of the mean and standard deviation of the environmental saturation ratio and the critical saturation ratio at which aerosol particles activate or become droplets. The theory is similar to the concept of stochastic condensation and can be used in the context of the atmosphere to explore the conditions under which droplet activation is driven by fluctuations as opposed to mean supersaturation. It provides a basis for future development of cloud droplet activation parameterizations that go beyond the internally homogeneous parcel calculations that have been used in the past. © 2020 National Academy of Sciences. All rights reserved.
英文关键词	Aerosol activation; Aerosol indirect effects; Cloud droplet growth; Stochastic condensation; Turbulence-cloud interactions
语种	英语
scopus关键词	aerosol; article; atmosphere; calculation; conceptual framework; humidity; stochastic model
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160884
作者单位	Prabhakaran, P., Department of Physics, Michigan Technological University, Houghton, MI 49931, United States; Shawon, A.S.Md., Department of Physics, Michigan Technological University, Houghton, MI 49931, United States; Kinney, G., Department of Physics, Michigan Technological University, Houghton, MI 49931, United States; Thomas, S., Department of Physics, Michigan Technological University, Houghton, MI 49931, United States; Cantrell, W., Department of Physics, Michigan Technological University, Houghton, MI 49931, United States; Shaw, R.A., Department of Physics, Michigan Technological University, Houghton, MI 49931, United States
推荐引用方式 GB/T 7714	Prabhakaran P.,Shawon A.S.Md.,Kinney G.,et al. The role of turbulent fluctuations in aerosol activation and cloud formation[J],2020,117(29).
APA	Prabhakaran P.,Shawon A.S.Md.,Kinney G.,Thomas S.,Cantrell W.,&Shaw R.A..(2020).The role of turbulent fluctuations in aerosol activation and cloud formation.Proceedings of the National Academy of Sciences of the United States of America,117(29).
MLA	Prabhakaran P.,et al."The role of turbulent fluctuations in aerosol activation and cloud formation".Proceedings of the National Academy of Sciences of the United States of America 117.29(2020).