Pm10 emission flux in the tengger desert and mu us sand field, northern China, measured by PI-SWERL

Document Type

Article

Publication Date

6-15-2015

Publication Title

Kexue Tongbao Chinese Science Bulletin

Keywords

Dust emission, Friction velocity, PI-SWERL, PM10 flux, Tengger Desert

Abstract

The deserts and sand fields of northern China are important sources of dust in Asia. Quantitative estimations of dust emission flux in this region will contribute to the assessment of regional environmental air quality and its climatic impact. Previous evaluations of dust emission have largely been based on numerical simulations with few direct field measurements. In this study, we used the new portable in situ wind erosion laboratory (PI-SWERL) to measure the dust emission fluxes of several typical surface sediments (i.e., dunes, dry lakes, coppice dunes, and fluvial deposits) in the Tengger Desert and Mu Us sand field, from which the potential emission fluxes of the different soil/sediment types were derived. Our results showed that dust emissions could be characterized into four basic types, indicating the comprehensive effect of aerodynamic entrainment and sand saltation on dust emission. Furthermore, irrespective of whether the particles are clay or silt, supply should be considered when evaluating dust emission. It was found that PM10 emission flux varies with landform surface and increases with friction velocity (U*). When U* = 0.55 m/s, the PM10 emission flux of coppice dunes is greatest (0.70-10.23 mg/(m2 s)), followed by fluvial deposits (0.12-4.97 mg/(m2 s)); the fluxes of dry lakes and sand dunes are both low (<0.5 mg/(m2 s)). To understand the influence of surface crust on dust emission, we designed an experiment to investigate its effects. It was revealed that the PM10 emission flux of a crusted surface is several times or even dozens of times greater than without a crust; sand particles on a crusted surface also increase the PM10 emission flux by 1-2 orders of magnitude. The reliability and accuracy of our data were verified against the results of previous studies; some differences could be attributed to the effects of climate, soil, and topography. We demonstrate that PI-SWERL can be used to reflect differences in the emissions of different dust sources, which is of great significance with regard to the study of regional or even global dust emissions.

Volume

60

Issue

17

First Page

1621

Last Page

1630

ISSN

0023074X

E-ISSN

20959419

DOI

10.1360/N972014-01157

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