气候变化领域集成服务门户(CCPortal): Complex refractive indices and single-scattering albedo of global dust aerosols in the shortwave spectrum and relationship to size and iron content

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DOI	10.5194/acp-19-15503-2019
	Complex refractive indices and single-scattering albedo of global dust aerosols in the shortwave spectrum and relationship to size and iron content
	Di Biagio C.; Formenti P.; Balkanski Y.; Caponi L.; Cazaunau M.; Pangui E.; Journet E.; Nowak S.; Andreae M.O.; Kandler K.; Saeed T.; Piketh S.; Seibert D.; Williams E.; Doussin J.-F.
发表日期	2019
ISSN	16807316
起始页码	15503
结束页码	15531
卷号	19 期号:24
英文摘要	The optical properties of airborne mineral dust depend on its mineralogy, size distribution, and shape, and they might vary between different source regions. To date, large differences in refractive index values found in the literature have not been fully explained. In this paper we present a new dataset of complex refractive indices (m D n-ik) and single-scattering albedos (SSAs) for 19 mineral dust aerosols over the 370-950 nm range in dry conditions. Dust aerosols were generated from natural parent soils from eight source regions (northern Africa, Sahel, Middle East, eastern Asia, North and South America, southern Africa, and Australia). They were selected to represent the global-scale variability of the dust mineralogy. Dust was resuspended into a 4.2 m3 smog chamber where its spectral shortwave scattering (ßsca) and absorption (ßabs) coefficients, number size distribution, and bulk composition were measured. The complex refractive index was estimated by Mie calculations combining optical and size data, while the spectral SSA was directly retrieved from ßsca and ßabs measurements. Dust is assumed to be spherical in the whole data treatment, which introduces a potential source of uncertainty. Our results show that the imaginary part of the refractive index (k) and the SSA vary widely from sample to sample, with values for k in the range 0.0011 to 0.0088 at 370 nm, 0.0006 to 0.0048 at 520 nm, and 0.0003 to 0.0021 at 950 nm, as well as values for SSA in the range 0.70 to 0.96 at 370 nm, 0.85 to 0.98 at 520 nm, and 0.95 to 0.99 at 950 nm. In contrast, the real part of the refractive index (n) is mostly source (and wavelength) independent, with an average value between 1.48 and 1.55. The sample-to-sample variability in our dataset of k and SSA is mostly related to differences in the dust iron content. In particular, a wavelength-dependent linear relationship is found between the magnitude of k and SSA and the mass concentrations of both iron oxide and total elemental iron, with iron oxide better correlated than total elemental iron with both k and SSA. The value of k was found to be independent of size. When the iron oxide content exceeds 3 %, the SSA linearly decreases with an increasing fraction of coarse particles at short wavelengths (< 600 nm). Compared to the literature, our values for the real part of the refractive index and SSA are in line with past results, while we found lower values of k compared to most of the literature values currently used in climate models. We recommend that source-dependent values of the SW spectral refractive index and SSA be used in models and remote sensing retrievals instead of generic values. In particular, the close relationships found between k or SSA and the iron content in dust enable the establishment of predictive rules for spectrally resolved SW absorption based on particle composition. © 2019 Author(s).
语种	英语
scopus关键词	aerosol; albedo; dust; iron; refractive index; scattering; spectrum; Australia; Far East; Middle East; North Africa; North America; Sahel [Sub-Saharan Africa]; South Africa; South America
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/143956
作者单位	LISA, UMR CNRS 7583, Université Paris-Est-Créteil, Université de Paris, Institut Pierre Simon Laplace (IPSL), Créteil, France; Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ UP Saclay, Gif sur Yvette, 91191, France; PM_TEN Srl, Piazza della Vittoria 7/14, Genoa, 16121, Italy; Plateforme RX UFR de Chimie, Université Paris Diderot, Paris, France; Max Planck Institute for Chemistry, P.O. Box 3060, Mainz, 55020, Germany; Geology and Geophysics Department, King Saud University, Riyadh, Saudi Arabia; Institut für Angewandte Geowissenschaften, Technische Universität Darmstadt, Schnittspahnstr. 9, Darmstadt, 64287, Germany; Science Department, College of Basic Education, Public Authority for Applied Education and Training, Al-Ardeya, Kuwait; Climatology Research Group, Unit for Environmental Science and Management, North-West University, Potchefstroom, South Africa; Walden University, Minneapolis, MN, United States; Parsons Laboratory, Massachusetts Institute of Technology, Cambridge, MA,...
推荐引用方式 GB/T 7714	Di Biagio C.,Formenti P.,Balkanski Y.,et al. Complex refractive indices and single-scattering albedo of global dust aerosols in the shortwave spectrum and relationship to size and iron content[J],2019,19(24).
APA	Di Biagio C..,Formenti P..,Balkanski Y..,Caponi L..,Cazaunau M..,...&Doussin J.-F..(2019).Complex refractive indices and single-scattering albedo of global dust aerosols in the shortwave spectrum and relationship to size and iron content.Atmospheric Chemistry and Physics,19(24).
MLA	Di Biagio C.,et al."Complex refractive indices and single-scattering albedo of global dust aerosols in the shortwave spectrum and relationship to size and iron content".Atmospheric Chemistry and Physics 19.24(2019).