Dust Emission Thresholds in Loess Soil Under Different Saltation Fluxes

Aviv Rubinstein,Meni Ben-Hur,Itzhak Katra

doi:10.3390/app10175949

Aviv Rubinstein, Meni Ben-Hur + Show 1 more

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https://doi.org/10.3390/app10175949

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Abstract

Soil-derived dust particles produced by aeolian (wind) processes have significant impacts on humans and the Earth’s systems. The soil particle size distribution is a major soil characteristic in dust emission models. Yet empirical information on the dependence of dust emission thresholds on soil particle size distribution is still lacking. The main goal of this study was to explore the dust emission threshold from semi-arid loess soil samples by a targeted wind-tunnel experiment. The results clearly show that the dust emission threshold is associated with the saltation threshold with no distinct direct aerodynamic lifting of the loose dust particle. The dust flux depends on the amount of the clay-silt fraction in the soil, the shear velocity, and the saltation flux under certain shear velocity. The study aimed to advance our understating of the dust emission processes, and to provide empirical information for parametrization in dust emission models and for management strategy of soils in preventing dust emission.

Highlights

The majority of aerosol mass in the atmosphere is related to soil-derived dust particles produced by aeolian processes [1]
Annual global dust emissions from soils into the atmosphere are estimated to be as high as 3000 million tons, including particulate matter (PM) that is less than 10 micrometers in diameter (PM10)
This study examined empirically the dust emission thresholds in loess soils with different content of sand-sized particles

Summary

Introduction

The majority of aerosol mass in the atmosphere is related to soil-derived dust particles produced by aeolian (wind) processes [1]. Other environmental impacts of atmospheric dust refer to the Earth’s global energy balance and climate sensitivity through radiative effects and climate feedbacks [1]. Considering these various important impacts of soil dust on the Earth system, it is critical to estimate accurately the dust emission. Models that estimate the dust emission from soils have been improved [5,6], still there is large disagreement between the empirical results and their estimated values by the models [1] These discrepancies are partly a result of our gap in understanding the threshold wind friction velocity needed to mobilize soil particles

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