Dust production and the release of iron oxides resulting from the aeolian abrasion of natural dune sands

Bullard, Joanna E.; White, Kevin

doi:10.1002/esp.1148

Cited by 54 publications

(46 citation statements)

References 32 publications

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“…An optimal fit to class 3b spectral distribution of single scattering albedo required ∼12% BC by volume, while class 3a required ∼15% BC and ∼13% hematite by volume. This very high hematite content effectively rules out an explanation for class 3a based on dust, particularly since dust emitted from the Channel Country arises from ablation of iron-poor clay soils leading to "white dust", in contrast to attrition of the iron-rich mantles on quartz grains in the dune fields that gives rise to "red dust" (Bullard and White, 2005).…”

Section: Classmentioning

confidence: 99%

Characterisation of episodic aerosol types over the Australian continent

Qin

Mitchell

2009

Atmos. Chem. Phys.

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Abstract. Classification of Australian continental aerosol types resulting from episodes of enhanced source activity, such as smoke plumes and dust outbreaks, is carried out via cluster analysis of optical properties obtained from inversion of sky radiance distributions at Australian aerosol ground stations using data obtained over the last decade. The cluster analysis distinguishes four significant classes, which are identified on the basis of their optical properties and provenance as determined by satellite imagery and backtrajectory analysis. The four classes are identified respectively as aged smoke, fresh smoke, coarse dust and a superabsorptive aerosol. While the first three classes show similarities with comparable aerosol types identified elsewhere, the super-absorptive aerosol has no obvious foreign prototype. The class identified as coarse dust shows a prominent depression in single scattering albedo in the blue spectral region due to absorption by hematite, which is shown to be more abundant in central Australian dust relative to the "dust belt"of the Northern Hemisphere. The super-absorptive class is distinctive in view of its very low single scattering albedo (∼0.7 at 500 nm) and variable enhanced absorption at 440 nm. The strong absorption by this aerosol requires a high black carbon content while the enhanced blue-band absorption may derive from organic compounds emitted during the burning of specific vegetation types. This aerosol exerts a positive radiative forcing at the top of atmosphere (TOA), with a large deposition of energy in the atmosphere per unit aerosol optical depth. This contrasts to the other three classes where the TOA forcing is negative. Optical properties of the four types will be used to improve the representation of Australian conCorrespondence to: R. M. Mitchell (ross.mitchell@csiro.au) tinental aerosol in climate models, and to enhance the accuracy of satellite-based aerosol retrievals over Australia.

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Section: Classmentioning

confidence: 99%

Characterisation of episodic aerosol types over the Australian continent

Qin

Mitchell

2009

Atmos. Chem. Phys.

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“…Dust is largely produced by the collisions between saltators-bouncing particles transported as bed load, themselves often weakly consolidated aggregates of soil-or between saltators and the surface, though in some special cases, emissions are possible without saltation [see Kjelgaard et al, 2004]. Additionally, mineral grains may have clay or oxide coatings that are accreted as soils form, abraded during transport, and released as dust, thus allowing deposits that nominally contain no fine particulates to be a source of aerosols [e.g., Bullard and White, 2005].…”

Section: How Do Soil Processes Influence Dust Production?mentioning

confidence: 99%

Dust: Small‐scale processes with global consequences

et al. 2011

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Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored.

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“…This is because sedimentary characteristics can be inherited from preceding phases of deposition and reworking, or even from parent sediments. The same applies to reddened dune sands, which have sometimes been assumed to indicate aeolian stability and humidity (see Gardner and Pye, 1981) or other aspects of dune landscape history (Bullard and White, 2005). Therefore aeolian attributes in a sediment do not necessarily indicate that aeolian processes were the last mechanism of deposition.…”

Section: Sedimentary Recordsmentioning

confidence: 99%