scholarly journals Modeling the single and multiple scattering properties of soot-laden mineral dust aerosols

2017 ◽  
Vol 25 (24) ◽  
pp. A990 ◽  
Author(s):  
Guanglang Xu ◽  
Patrick G. Stegmann ◽  
Sarah D. Brooks ◽  
Ping Yang
Keyword(s):  
Multiple Scattering ◽  
Mineral Dust ◽  
Dust Aerosols ◽  
Mineral Dust Aerosols

scholarly journals Aethalometer multiple scattering correction C<sub>ref</sub> for mineral dust aerosols

2017 ◽  
Author(s):  
Claudia Di Biagio ◽  
Paola Formenti ◽  
Mathieu Cazaunau ◽  
Edouard Pangui ◽  
Nicholas Marchand ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Multiple Scattering ◽  
Mineral Dust ◽  
Single Scattering ◽  
Ambient Aerosols ◽  
Dust Aerosols ◽  
Scattering Coefficients ◽  
Scattering Correction ◽  
The Difference ◽  
Mineral Dust Aerosols

Abstract. In this study we provide a first estimate of the aethalometer multiple scattering correction Cref for mineral dust aerosols. The Cref at 450 and 660 nm was obtained from the direct comparison of aethalometer data (Magee Sci. AE31) with the absorption coefficient calculated as the difference between the extinction and scattering coefficients measured by a CAPS PMex and a nephelometer at 450 nm and the absorption coefficient from a MAAP (Multi-Angle Absorption Photometer) at 660 nm. Measurements were performed on seven dust aerosol samples generated in the laboratory by the mechanical shaking of natural parent soils issued from different source regions worldwide. The single scattering albedo (SSA) at 450 and 660 nm and the size distribution of the aerosols were also measured. Cref for mineral dust varies between 1.81 and 2.56 for a SSA of 0.85–0.96 at 450 nm and between 1.75 and 2.28 for a SSA of 0.98–0.99 at 660 nm. The calculated mean Cref for dust is 2.09 (± 0.22) at 450 nm and 1.92 (± 0.17) at 660 nm. With this new Cref the dust absorption coefficient by aethalometer is about 2 % (450 nm) and 11 % (660 nm) higher than that obtained by using Cref = 2.14, usually assumed in the literature. This difference induces up to 3 % change in the dust SSA. The Cref seems independent of the particle fine and coarse size fractions, and so the obtained Cref can be applied to dust both close to sources and following transport. Additional experiments performed with pure kaolinite mineral and polluted ambient aerosols indicate a Cref of 2.49 (± 0.02) and 2.32 (± 0.01) at 450 and 660 nm (SSA = 0.96–0.97) for kaolinite, and a Cref of 2.32 (± 0.36) at 450 nm and 2.32 (± 0.35) at 660 nm for pollution aerosols (SSA = 0.62–0.87 at 450 nm and 0.42–0.76 at 660 nm).

scholarly journals Aethalometer multiple scattering correction <i>C</i><sub>ref</sub> for mineral dust aerosols

2017 ◽  
Vol 10 (8) ◽  
pp. 2923-2939 ◽  
Author(s):  
Claudia Di Biagio ◽  
Paola Formenti ◽  
Mathieu Cazaunau ◽  
Edouard Pangui ◽  
Nicolas Marchand ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Multiple Scattering ◽  
Mineral Dust ◽  
Single Scattering ◽  
Empirical Constant ◽  
Particle Size Fractions ◽  
Dust Aerosols ◽  
Scattering Coefficients ◽  
Scattering Correction ◽  
Mineral Dust Aerosols

Abstract. In this study we provide a first estimate of the Aethalometer multiple scattering correction Cref for mineral dust aerosols. Cref is an empirical constant used to correct the aerosol absorption coefficient measurements for the multiple scattering artefact of the Aethalometer; i.e. the filter fibres on which aerosols are deposited scatter light and this is miscounted as absorption. The Cref at 450 and 660 nm was obtained from the direct comparison of Aethalometer data (Magee Sci. AE31) with (i) the absorption coefficient calculated as the difference between the extinction and scattering coefficients measured by a Cavity Attenuated Phase Shift Extinction analyser (CAPS PMex) and a nephelometer respectively at 450 nm and (ii) the absorption coefficient from a MAAP (Multi-Angle Absorption Photometer) at 660 nm. Measurements were performed on seven dust aerosol samples generated in the laboratory by the mechanical shaking of natural parent soils issued from different source regions worldwide. The single scattering albedo (SSA) at 450 and 660 nm and the size distribution of the aerosols were also measured. Cref for mineral dust varies between 1.81 and 2.56 for a SSA of 0.85–0.96 at 450 nm and between 1.75 and 2.28 for a SSA of 0.98–0.99 at 660 nm. The calculated mean for dust is 2.09 (±0.22) at 450 nm and 1.92 (±0.17) at 660 nm. With this new Cref the dust absorption coefficient by the Aethalometer is about 2 % (450 nm) and 11 % (660 nm) higher than that obtained by using Cref  =  2.14 at both 450 and 660 nm, as usually assumed in the literature. This difference induces a change of up to 3 % in the dust SSA at 660 nm. The Cref seems to be independent of the fine and coarse particle size fractions, and so the obtained Cref can be applied to dust both close to sources and following transport. Additional experiments performed with pure kaolinite minerals and polluted ambient aerosols indicate Cref of 2.49 (±0.02) and 2.32 (±0.01) at 450 and 660 nm (SSA  =  0.96–0.97) for kaolinite, and Cref of 2.32 (±0.36) at 450 nm and 2.32 (±0.35) at 660 nm for pollution aerosols (SSA  =  0.62–0.87 at 450 nm and 0.42–0.76 at 660 nm).

scholarly journals Modelling lidar-relevant optical properties of complex mineral dust aerosols

Tellus B ◽  
2011 ◽  
Vol 63 (4) ◽  
pp. 725-741 ◽  
Author(s):  
Josef Gasteiger ◽  
Matthias Wiegner ◽  
Silke Groß ◽  
Volker Freudenthaler ◽  
Carlos Toledano ◽  
...  
Keyword(s):  
Optical Properties ◽  
Mineral Dust ◽  
Dust Aerosols ◽  
Mineral Dust Aerosols

Properties and challenges of mineral dust aerosol modelling in the latest Earth System Models

2020 ◽  
Author(s):  
Ramiro Checa-Garcia ◽  
Yves Balkanski ◽  
Tommi Bergman ◽  
Ken Carslaw ◽  
Mohit Dalvi ◽  
...  
Keyword(s):  
Optical Depth ◽  
Mineral Dust ◽  
Regional Scale ◽  
Climate System ◽  
Deposition Flux ◽  
Dust Aerosols ◽  
Earth Systems ◽  
Imperfect Knowledge ◽  
Sahel Region ◽  
Mineral Dust Aerosols

&lt;p&gt;Mineral dust aerosols participate in the climate system and biogeochemistry processes due to its interactions with key components of Earth Systems: radiation, clouds, soil and chemical components. A central element to improve our understanding of mineral dust is through its modeling with Earth Systems Models where all these interactions are included. However, current simulations of dust variability exhibit important uncertainties and biases, which are model-dependent, whose cause is our imperfect knowledge about how to best represent the dust life cycle. For these reasons a continuous evaluation of the performance and properties of the different models compared against measurements is a crucial step to improve our knowledge of the dust cycle and its role in the climate system and biogeochemical cycles. Here we present an exhaustive evaluation of mineral dust aerosols in CRESCEND-ESMs over global, regional and local scales. We compare models against three networks of instruments for total dust deposition flux, yearly surface concentrations, and optical depths. Global and regional dust optical depths are compared with MODIS and MISR derived products. Specific analyses are done over the Sahel region where improved and compressive dust observational datasets are available. The results indicate that all the models capture the general properties of the global dust cycle, although the role of larger particles remains challenging. Differences are partially due to surface winds as nudged simulations improve the inter-model comparison and the performance in optical depth compared to MODIS. At the regional scale, there is an optical depth reasonable agreement over main source areas, but a joint inter-comparison including fluxes and concentration indicates larger differences. At the local scale, the uncertainties increase and current models are not able to reproduce together several observables at the same time.&lt;/p&gt;

A method to determine the effect of mineral dust aerosols on air quality

2009 ◽  
Vol 43 (34) ◽  
pp. 5463-5468 ◽  
Author(s):  
Eliezer Ganor ◽  
Amnon Stupp ◽  
Pinhas Alpert
Keyword(s):  
Air Quality ◽  
Mineral Dust ◽  
Dust Aerosols ◽  
Mineral Dust Aerosols
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