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DOI	10.5194/acp-19-2917-2019
	Accounting for the effects of nonideal minor structures on the optical properties of black carbon aerosols
	Teng S.; Liu C.; Schnaiter M.; Chakrabarty R.K.; Liu F.
发表日期	2019
ISSN	16807316
起始页码	2917
结束页码	2931
卷号	19 期号:5
英文摘要	Black carbon (BC) aerosol is the strongest sunlight-absorbing aerosol, and its optical properties are fundamental to radiative forcing estimations and retrievals of its size and concentration. BC particles exist as aggregate structures with small monomers and are widely represented by the idealized fractal aggregate model. In reality, BC particles possess complex and nonideal minor structures besides the overall aggregate structure, altering their optical properties in unforeseen ways. This study introduces the parameter "volume variation" to quantify and unify different minor structures and develops an empirical relationship to account for their effects on BC optical properties from those of ideal aggregates. Minor structures considered are as follows: The polydispersity of monomer size, the irregularity and coating of the individual monomer, and necking and overlapping among monomers. The discrete dipole approximation is used to calculate the optical properties of aggregates with these minor structures. Minor structures result in scattering cross-section enhancement slightly more than that of absorption cross section, and their effects on the angle-dependent phase matrix as well as asymmetry factor are negligible. As expected, the effects become weaker with the increase in wavelength. Our results suggest that a correction ratio of 1.05 is necessary to account for the mass or volume normalized absorption and scattering of nonideal aggregates in comparison to ideal ones, which also applies to aggregates with multiple minor structures. In other words, the effects of minor structures are mainly contributed by their influence on particle volume/mass that cannot be ignored, and a relative difference of approximately 5% is noticed after removing the volume effects. Thus, accurate knowledge and evaluation of BC volume/mass are more important than those of the minor structures themselves. Most importantly, the simulations of optical properties of nonideal aggregates are greatly simplified by applying the empirical relationship because they can be directly obtained from those of the corresponding ideal aggregates, a volume/mass difference parameter, and the correction factor, i.e., 1.05, not the detailed minor structure information. We expect this convenient treatment to find wide applications for the accounting for the effects of nonideal minor structures on BC optical properties. © 2019 Author(s).
语种	英语
scopus关键词	aerosol composition; aerosol property; black carbon; concentration (composition); optical property; particle size; radiative forcing
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/144589
作者单位	Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Key Laboratory for Aerosol-Cloud-Precipitation, China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Karlsruhe, 76021, Germany; Center for Aerosol Science and Engineering, Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, United States; Black Carbon Metrology, Measurement Science and Standards, National Research Council, Ottawa, ON K1A0R6, Canada
推荐引用方式 GB/T 7714	Teng S.,Liu C.,Schnaiter M.,et al. Accounting for the effects of nonideal minor structures on the optical properties of black carbon aerosols[J],2019,19(5).
APA	Teng S.,Liu C.,Schnaiter M.,Chakrabarty R.K.,&Liu F..(2019).Accounting for the effects of nonideal minor structures on the optical properties of black carbon aerosols.Atmospheric Chemistry and Physics,19(5).
MLA	Teng S.,et al."Accounting for the effects of nonideal minor structures on the optical properties of black carbon aerosols".Atmospheric Chemistry and Physics 19.5(2019).