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What's the Real Role of Iron-oxides in the Optical Properties of Dust Aerosols? : Volume 15, Issue 4 (26/02/2015)

By L. Zhang, X.

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Book Id: WPLBN0003997158
Format Type: PDF Article :
File Size: Pages 44
Reproduction Date: 2015

Title: What's the Real Role of Iron-oxides in the Optical Properties of Dust Aerosols? : Volume 15, Issue 4 (26/02/2015)  
Author: L. Zhang, X.
Volume: Vol. 15, Issue 4
Language: English
Subject: Science, Atmospheric, Chemistry
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
2015
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

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Xu, T. L., Zhang, C. L., Zhang, X. L., Zhou, Q. Q., & Wu, G. J. (2015). What's the Real Role of Iron-oxides in the Optical Properties of Dust Aerosols? : Volume 15, Issue 4 (26/02/2015). Retrieved from http://worldlibrary.net/


Description
Description: Key laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China. Iron oxides compounds constitute an important component of mineral dust aerosol. Several previous studies have shown that these minerals are strong absorbers at visible wavelengths and thus that they play a critical role in the overall climate forcing caused by dust aerosol. When compiling a database of complex refractive indices of possible mineral species of iron-oxides to study their optical properties, we found that uniformly continuous optical constants for a single type of iron-oxides in the wavelength range between 0.2 and 50 μm is very scarce and that the use of hematite to represent all molecular or mineral iron-oxides types is a popular hypothesis. However, the crucial problem is that three continuous datasets for complex refractive indices of hematite are employed in climate models, but there are significant differences between them. Thus, the real role of iron-oxides in the optical properties of dust aerosols becomes a key scientific question, and we address this problem by considering different refractive indices, size distributions, and more logical weight fractions and mixing states of hematite. Based on the microscopic observations, a semi-external mixture that employs an external mixture between Fe-aggregates and other minerals and partly internal mixing between iron-oxides and aluminosilicate particles is advised as the optimal approximation. The simulations demonstrate that hematite with a spectral refractive indices from Longtin et al. (1988) shows approximately equal absorbing capacity to the mineral illite over the whole wavelength region from 0.55 to 2.5 μm, and only enhances the optical absorption of aerosol mixture at λ < 0.55 μm. Using the dataset from Querry (1985) may overestimate the optical absorption of hematite at both visible and near-infrared wavelengths. More laboratory measurements of the refractive index of iron-oxides, especially for hematite and goethite in the visible spectrum, should therefore be taken into account when assessing the effect of mineral dust on climate forcing.

Summary
What's the real role of iron-oxides in the optical properties of dust aerosols?

Excerpt
Alfaro, S., Lafon, S., Rajot, J., Formenti, P., Gaudichet, A., and Maille, M.: Iron oxides and light absorption by pure desert dust: an experimental study, J. Geophys. Res.-Atmos., 109, D08208, doi:10.1029/2003JD004374, 2004.; Anderson, B. and Jenne, E.: Free-iron and-manganese oxide content of reference clays, Soil Sci., 109, 163–169, 1970.; Angel, B. and Vincent, W.: Associated with the surface of kaolins, Clay Clay Miner., 26, 263–272, 1978.; Arimoto, R., Balsam, W., and Schloesslin, C.: Visible spectroscopy of aerosol particles collected on filters: iron-oxide minerals, Atmos. Environ., 36, 89–96, 2002.; Arimoto, R., Ray, B., Lewis, N., Tomza, U., and Duce, R.: Mass–particle size distributions of atmospheric dust and the dry deposition of dust to the remote ocean, J. Geophys. Res.-Atmos., 102, 15867–15874, 1997.; Balkanski, Y., Schulz, M., Claquin, T., and Guibert, S.: Reevaluation of Mineral aerosol radiative forcings suggests a better agreement with satellite and AERONET data, Atmos. Chem. Phys., 7, 81–95, doi:10.5194/acp-7-81-2007, 2007.; Balsam, W., Ji, J., Renock, D., Deaton, B. C., and Williams, E.: Determining hematite content from NUV/Vis/NIR spectra: limits of detection, Am. Mineral., 99, 2280–2291, 2014.; Baltrusaitis, J., Cwiertny, D. M., and Grassian, V. H.: Adsorption of sulfur dioxide on hematite and goethite particle surfaces, Phys. Chem. Chem. Phys., 9, 5542–5554, 2007.; Bedidi, A. and Cervelle, B.: Light scattering by spherical particles with hematite and goethitelike optical properties: effect of water impregnation, J. Geophys. Res.-Sol. Ea., 98, 11941–11952, 1993.; Bernabé, J., Carretero, M., and Galán, E.: Mineralogy and origin of atmospheric particles in the industrial area of Huelva (SW Spain), Atmos. Environ., 39, 6777–6789, 2005.; Bohren, C. F. and Huffman, D. R.: Absorption and Scattering of Light by Small Particles, John Wiley and Sons, New York, 1998.; Chiapello, I., Bergametti, G., Chatenet, B., Bousquet, P., Dulac, F., and Soares, E. S.: Origins of African dust transported over the northeastern tropical Atlantic, J. Geophys. Res.-Atmos., 102, 13701–13709, 1997.; Chou, C., Formenti, P., Maille, M., Ausset, P., Helas, G., Harrison, M., and Osborne, S.: Size distribution, shape, and composition of mineral dust aerosols collected during the African monsoon multidisciplinary analysis special observation period 0: dust and biomass – burning experiment field campaign in Niger, January 2006, J. Geophys. Res.-Atmos., 113, D00C10, doi:10.1029/2008JD009897, 2008.; Chyýlek, P., Srivastava, V., Pinnick, R. G., and Wang, R.: Scattering of electromagnetic waves by composite spherical particles: experiment and effective medium approximations, Appl. Optics, 27, 2396–2404, 1988.; Cornell, R. M. and Schwertmann, U.: The Iron Oxides: Structure, Properties, Reactions, Occurrences and Uses, John Wiley and Sons, New York, 2006.; Dang, C. and Hegg, D. A.: Quantifying light absorption by organic carbon in western North American snow by serial chemical extractions, J. Geophys. Res.-Atmos., 119, 10247–210261, 2014.; Dave, J. and Center, I. P. A. S.: Subroutines for Computing the Parameters of the Electromagnetic Radiation Scattered by a Sphere, IBM Scientific Center, Palo Alto, California, 1968.; Deboudt, K., Gloter, A., Mussi, A., and Flament, P.: Red–speciation and mixing state of iron in individual African dust particles, J. Geophys. Res.-Atmos., 117, D12307, doi:10.1029/2011JD017298, 2012.; Derimian, Y., Karnieli, A., Kaufman, Y. J., Andreae, M. O., Andreae, T. W., Dubovik, O., Maenhaut, W., and Koren, I.: The role of iron and black carbon in aerosol light absorption, Atmos. Chem. Phys., 8, 3623–3637, doi:10.5194

 

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