Characterization of Dust Particles’ 3D Shape and Roughness with Nanometer Resolution

Woodward, Xinxin; Kostinski, A. B.; China, Swarup; Mazzoleni, Cláudio; Cantrell, Will

doi:10.1080/02786826.2015.1017550

Cited by 17 publications

(14 citation statements)

References 44 publications

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“…Although the AR of North African dust might thus be larger than that of Asian dust (p value = 0.001 from Student's t test), this regional difference is 10.1029/2019GL086592 In the legend, the numbers in parentheses denote the numbers of analyzed individual dust particles. Chou et al (2008) and Woodward et al (2015) have two numbers with the first one denoting the number of analyzed dust particles for AR and the second one for HWR. In (c) and (e), Chou et al (2008) is not used in regressions due to the insignificant number of analyzed particles for HWR.…”

Section: Measurement Compilation Of Dust Shape Descriptorsmentioning

confidence: 99%

“…In (d) and (f), the errors of African dust are not shown due to only one measurement of HWR (Jeong et al, 2016). Results of measurements of processed or artificial dust (Matsuki et al, 2010;Sakai et al, 2010;Woodward et al, 2015) are shown for completeness, but because their representativeness to real mineral dust aerosols is unclear, these studies are not used in the groupings in (b), (d), and (f) or in regressions in (a), (c), and (e).…”

Section: Measurement Compilation Of Dust Shape Descriptorsmentioning

confidence: 99%

See 1 more Smart Citation

Climate Models and Remote Sensing Retrievals Neglect Substantial Desert Dust Asphericity

Huang

Kok

Kandler³

et al. 2020

Geophysical Research Letters

109

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Climate models and remote sensing retrievals generally assume that dust aerosols are spherical or spheroidal. However, measurements show that dust aerosols deviate substantially from spherical and spheroidal shapes, as ratios of particle length to width (the aspect ratio) and height to width (height‐to‐width ratio) deviate substantially from unity. Here, we quantify dust asphericity by compiling dozens of measurements of aspect ratio and height‐to‐width ratio across the globe. We find that the length is on average 5 times larger than the height and that climate models and remote sensing retrievals underestimate this asphericity by a factor of ~3–5. Compiled measurements further suggest that North African dust becomes more aspherical during transport, whereas Asian dust might become less aspherical. We obtain globally‐averaged shape distributions, from which we find that accounting for dust asphericity increases gravitational settling lifetime by ~20%. This increased lifetime helps explain the underestimation of coarse dust transport by models.

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Section: Measurement Compilation Of Dust Shape Descriptorsmentioning

confidence: 99%

Section: Measurement Compilation Of Dust Shape Descriptorsmentioning

confidence: 99%

Climate Models and Remote Sensing Retrievals Neglect Substantial Desert Dust Asphericity

Huang

Kok

Kandler³

et al. 2020

Geophysical Research Letters

109

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“…For example, derivation of the true three-dimensional shape requires application of atomic force microscopy (e.g. Chou et al, 2008;Woodward et al, 2015), or stereogrammetry from electron microscope images (Lindqvist et al, 2014). Internal structures can be analyzed, e.g., by slicing open dust particles with a focused ion beam, as done by Jeong and Nousiainen (2014).…”

Section: Introductionmentioning

confidence: 99%

Effects of dust particle internal structure on light scattering

2015

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Abstract. There is a large variety of internal structures inside atmospheric dust particles, making them inherently inhomogeneous. Such structures may have a large effect on ground-level and atmospheric radiation. So far, dust particle internal structures and their effect on the light scattering properties have proved to be hard to quantify, in part due to challenges in obtaining information about these structures. Recently, internal structures of individual dust particles were revealed through focused ion beam milling and analyzed. Here, we perform a sensitivity study to evaluate the optical impacts of some of the typical internal structures revealed. To obtain suitable model particles, the first step is to generate inhomogeneous particles with varying internal structures by using an algorithm that is based on three-dimensional Voronoi tessellation. The parameters for the particle generation are obtained from studies of real-world Asian dust particles. The second step is to generate homogeneous versions of the generated particles by using an effective-medium approximation, for comparison. Third, light scattering by both versions of these particles is simulated with discrete dipole approximation code. This allows us to see how different internal structures affect light scattering, and how important it is to account for these structures explicitly. Further, this allows us to estimate the potential inaccuracies caused by using only homogeneous model particles for atmospheric studies and remote-sensing measurements. The results show that the effects vary greatly between different kinds of internal structures and single-scattering quantity considered, but for most structure types the effects are overall notable. Most significantly, hematite inclusions in particles impact light scattering heavily. Furthermore, internal pores and hematite-rich coating both affect some form of light scattering noticeably. Based on this work, it seems that it is exceedingly important that the effects of dust particle internal structures on light scattering are accounted for in a wide variety of applications.

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“…These observations are consistent with previously reported values. 71,[74][75][76] The IN-ESEM platform provides the capability to identify the location of ice nucleation events within individual particles and is capable of capturing early stages of ice formation and its dynamic evolution. Fig.…”

Section: Isothermal Ice Nucleation Experimentsmentioning

confidence: 99%

Direct observation of ice nucleation events on individual atmospheric particles

Wang

Knopf

China

et al. 2016

Phys. Chem. Chem. Phys.

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The work presents microscopic observations of heterogeneous ice nucleation from experiments conducted inside an environmental scanning electron microscope. Observations of ice formation on kaolinite particles demonstrate that ice preferentially nucleates at the edges of the stacked platelets, rather than on the basal planes. This platform is applied for directly detecting and tracking ice nucleating particles in ambient aerosol samples and is complemented by micro-spectroscopic chemical imaging. This technique opens a path to new physical chemistry studies of ice formation in atmospheric science, cryobiology, and material science.www.rsc.org/pccp Heterogeneous ice nucleation is a physical chemistry process of critical relevance to a range of topics in the fundamental and applied sciences and technologies. Heterogeneous ice nucleation remains insufficiently understood, partially due to the lack of experimental methods capable of obtaining in situ microscopic details of ice formation over nucleating substrates or particles. We present microscopic observations of ice nucleation events on kaolinite particles at the nanoscale and demonstrate the capability of direct tracking and micro-spectroscopic characterization of individual ice nucleating particles (INPs) in an authentic atmospheric sample. This approach utilizes a custom-built ice nucleation cell, interfaced with an Environmental Scanning Electron Microscope (IN-ESEM platform) operated at temperatures and relative humidities relevant for heterogeneous ice nucleation. The IN-ESEM platform allows dynamic observations of individual ice formation events over particles in isobaric and isothermal experiments. Isothermal experiments on individual kaolinite particles demonstrate that ice crystals preferably nucleate at the edges of the stacked kaolinite platelets, rather than on their basal planes.These experimental observations of the location of ice nucleation provide direct information for further theoretical chemistry predictions of ice formation on kaolinite.

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Characterization of Dust Particles’ 3D Shape and Roughness with Nanometer Resolution

Cited by 17 publications

References 44 publications

Climate Models and Remote Sensing Retrievals Neglect Substantial Desert Dust Asphericity

Climate Models and Remote Sensing Retrievals Neglect Substantial Desert Dust Asphericity

Effects of dust particle internal structure on light scattering

Direct observation of ice nucleation events on individual atmospheric particles

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