Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM) phase images

Helas, G.

doi:10.5194/amt-1-1-2008

Cited by 7 publications

(7 citation statements)

References 40 publications

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“…More data sets are available from microscopy measurements, where the size range of atmospheric importance is covered by electron microscopy techniques like transmission and scanning electron microscopy (TEM/SEM). Atomic force microscopy (AFM) is also used, but limited to particles smaller than 1.5 µm in diameter (Gwaze et al, 2007;Chou et al, 2008;Helas and Andreae, 2008).…”

Section: Measuring Techniques To Determine Particle Shapementioning

confidence: 99%

Recent progress in understanding physical and chemical properties of African and Asian mineral dust

et al. 2011

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This paper presents a review of recently acquired knowledge on the physico-chemical properties of mineral dust from Africa and Asia based on data presented and discussed during the Third International Dust Workshop, held in Leipzig (Germany) in September 2008. Various regional field experiments have been conducted in the last few years, mostly close to source regions or after short-range transport. Although significant progress has been made in characterising the regional variability of dust properties close to source regions, in particular the mineralogy of iron and the description of particle shape and mixing state, difficulties remain in estimating the range of variability of those properties within one given source region. As consequence, the impact of these parameters on aerosol properties like optical properties, solubility, hygroscopicity, etc. – determining the dust impact on climate – is only partly understood. Long-term datasets in remote regions such as the dust source regions remain a major desideratum. Future work should also focus on the evolution of dust properties during transport. In particular, the prediction of the mineral dust size distribution at emission and their evolution during transport should be considered as a high-priority. From the methodological point of view, a critical assessment and standardisation of the experimental and analytical techniques is highly recommended. Techniques to characterize the internal state of mixing of dust particles, particularly with organic material, should be further developed

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Section: Measuring Techniques To Determine Particle Shapementioning

confidence: 99%

Recent progress in understanding physical and chemical properties of African and Asian mineral dust

et al. 2011

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“…More data sets are available from microscopy measurements, where the size range of atmospheric importance is covered by electron microscopy techniques like transmission and scanning electron microscopy (TEM/SEM). Atomic force microscopy (AFM) is also used, but limited to particles smaller than 1.5 µm in diameter (Chou et al, 2008;Gwaze et al, 2007;Helas and Andreae, 2008). The particle shape derived by microscopic techniques is usually derived from the two-dimensional outline of the particle.…”

Section: Measuring Techniques To Determine Particle Shapementioning

confidence: 99%

“…Surface roughness affects the scattering phase function especially for particles larger than the wavelength (Nousiainen and Muinonen, 2007 (Helas and Andreae, 2008) and airborne dust (Chou et al, 2008), but no systematic studies suitable for modelling purposes have been performed yet.…”

Section: Measuring Techniques To Determine Particle Shapementioning

confidence: 99%

Recent progress in understanding physical and chemical properties of mineral dust

Formenti¹,

Schuetz²,

Balkanski³

et al. 2010

Preprint

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This paper presents a review of recently acquired knowledge of the physico-chemical properties of mineral dust from Africa and Asia based on data and discussion during the Third International Dust Workshop, held in Leipzig (Germany) in September 2008. Various regional experiments have been conducted in the last few years, mostly close to source regions or after short-range transport. Significant progress has been made in characterising the mineralogy of iron and the description of particle shape close to source regions. We consider that future research should focus on the evolution of dust properties during transport. In particular, the prediction of the characteristics of the size distribution of mineral dust at emission and their dynamics evolution during transport should be considered as a high-priority. The presence of large airborne particles above 20 μm in diameter, suggested by various studies, has limited implication for radiation, but should be important for deposition-based studies such as those on ocean productivity. Modelling the uplifting and transport of such large particles will represent a new serious challenge for transport models. A critical assessment and standardisation of the experimental and analytical methods is recommended

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“…However, limited AFM analysis of dust particles by Chou et al (2008) revealed that particles were remarkably smooth (see Chou et al's Figure 8). Similarly, Helas and Andreae (2008) also found that Saharan dust particles were smooth; the surface roughness was not quantified in either case.…”

Section: Introductionmentioning

confidence: 91%

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

Woodward

Kostinski

China

et al. 2015

Aerosol Science and Technology

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Mineral dust particles in the atmosphere are often aspherical and their shape is important for a multitude of processes. Yet, measurements of the true shape in three dimensions are rare, even in a laboratory setting. Here, we employ atomic force microscopy to determine the 3D shape and surface roughness for two dusts commonly used in laboratory experiments, Arizona test dust (ATD) and kaolinite. Our major finding is that both are thin and remarkably smooth. An oblate spheroidal description is an excellent fit to these data. We use correlation analysis to further examine the surface properties of the dusts and find essentially no features at horizontal spatial scales between »10 and 100 nm. This surprising result is supported by the agreement between our specific surface area and BET surface area measurements. The thin, smooth, spheroidal approximation has many implications for physical processes in the atmosphere, including dust transport and radiative transfer.

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Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM) phase images

Cited by 7 publications

References 40 publications

Recent progress in understanding physical and chemical properties of African and Asian mineral dust

Recent progress in understanding physical and chemical properties of African and Asian mineral dust

Recent progress in understanding physical and chemical properties of mineral dust

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

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