scholarly journals The implications for dust emission modeling of spatial and vertical variations in horizontal dust flux and particle size in the Bodélé Depression, Northern Chad

2008 ◽  
Vol 113 (D4) ◽  
Author(s):  
Adrian Chappell ◽  
Andrew Warren ◽  
Alice O'Donoghue ◽  
Andrea Robinson ◽  
Andrew Thomas ◽  
...  
Keyword(s):  
Particle Size ◽  
Dust Emission ◽  
Dust Flux ◽  
Vertical Variations ◽  
Emission Modeling ◽  
Bodele Depression ◽  
Horizontal Dust Flux

Experimental Study the Affection of the Dust Emission on Sand Stockpile by the Height of Windbreak Wall and Wind Speed

2014 ◽  
Vol 989-994 ◽  
pp. 823-826
Author(s):  
Ze Qin Liu ◽  
Li Ying Ma ◽  
Xin Yu Zhao
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Wind Speed ◽  
Experimental Testing ◽  
Dust Emission ◽  
Engineering Application ◽  
Local Wind ◽  
Practical Engineering ◽  
Working Principle ◽  
Natural Wind

Based on the perspective of saving investment and reducing dust emission, the method of experimental study and the working principle of windbreak wall were adopted in this paper to explore the affection of the dust emission on sand stockpile by the height of windbreak wall and natural wind speed. According to the experimental testing, the data processing and analysis by the origin software, the studied results indicated that, the dust emission of the same particle size of powder (sand) increased with increasing the wind speed, the dust emission of the same particle size and the same wind speed of powder reduced with increasing the height of the windbreak wall., When the height of windbreak wall is 5/6 times of the height of the stockpile for a certain height of the bulk stockpile, the dual purposes of the minimum dust emission of bulk stockpile and saving investment could be gained. In the practical engineering application, the height of the windbreak wall should be chosen according to the actual situation (the density of the stockpile, particle size as well as the local wind speed).

scholarly journals Testing the performance of state-of-the-art dust emission schemes using DO4Models field data

2015 ◽  
Vol 8 (2) ◽  
pp. 341-362 ◽  
Author(s):  
K. Haustein ◽  
R. Washington ◽  
J. King ◽  
G. Wiggs ◽  
D. S. G. Thomas ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Field Data ◽  
Dust Emission ◽  
Shear Velocity ◽  
Box Model ◽  
Wind Speeds ◽  
Dust Flux ◽  
Dry Lake ◽  
Order Of Magnitude ◽  
Emission Threshold

Abstract. Within the framework of the Dust Observations for Models (DO4Models) project, the performance of three commonly used dust emission schemes is investigated in this paper using a box model environment. We constrain the model with field data (surface and dust particle properties as well as meteorological parameters) obtained from a dry lake bed with a crusted surface in Botswana during a 3 month period in 2011. Our box model results suggest that all schemes fail to reproduce the observed horizontal dust flux. They overestimate the magnitude of the flux by several orders of magnitude. The discrepancy is much smaller for the vertical dust emission flux, albeit still overestimated by up to an order of magnitude. The key parameter for this mismatch is the surface crusting which limits the availability of erosive material, even at higher wind speeds. The second-most important parameter is the soil size distribution. Direct dust entrainment was inferred to be important for several dust events, which explains the smaller gap between modelled and measured vertical dust fluxes. We conclude that both features, crusted surfaces and direct entrainment, need to be incorporated into dust emission schemes in order to represent the entire spectra of source processes. We also conclude that soil moisture exerts a key control on the threshold shear velocity and hence the emission threshold of dust in the model. In the field, the state of the crust is the controlling mechanism for dust emission. Although the crust is related to the soil moisture content to some extent, we are not as yet able to deduce a robust correlation between state of crust and soil moisture.

scholarly journals Quantifying particle size and turbulent scale dependence of dust flux in the Sahara using aircraft measurements

2014 ◽  
Vol 119 (12) ◽  
pp. 7577-7598 ◽  
Author(s):  
Philip D. Rosenberg ◽  
Douglas J. Parker ◽  
Claire L. Ryder ◽  
John H. Marsham ◽  
Luis Garcia-Carreras ◽  
...  
Keyword(s):  
Particle Size ◽  
Scale Dependence ◽  
Aircraft Measurements ◽  
Dust Flux

scholarly journals ESTIMATION OF VERTICAL DUST EMISSION FLUX AT A SITE IN THE MONGOLIAN GOBI DURING A DUST STORM PERIOD

2018 ◽  
pp. 25-40
Author(s):  
Jugder D
Keyword(s):  
Soil Moisture ◽  
Wind Speed ◽  
Dust Storm ◽  
Friction Velocity ◽  
Sonic Anemometer ◽  
Dust Emission ◽  
Ground Level ◽  
Gobi Desert ◽  
Moisture Sensor ◽  
Dust Flux

A meteorological and dust monitoring tower with 20 m height set up at a Nomgon site in Umnugobi Aimag in the Mongolian Gobi in 2010. The Nomgon monitoring tower equipped with wind speed sensors at 2, 4, 10 and 20 m height above the ground level (AGL), a wind direction sensor at 10 m height, a sonic anemometer to measure turbulent momentum flux at 8 m height and a soil moisture sensor at 5 cm depth. We had a purpose to measure dust concentration of PM10 at two levels using Dust-Trak instruments during an intensive observation period (IOP) of a dust event in spring. A dust storm was expected in the Mongolian Gobi from 30 April to 1 May 2016 and two Dust-Traks were set at 0.9 and 2.95 m heights in the tower during this IOP for measuring PM10. Wind data at 2 and 10 m height, three wind components at 8 m height by a sonic anemometer, soil moisture (volumetric water content) data in 5 cm depth and dust concentrations of PM10 at two levels are used in this study. These data from the sensors and instruments in the tower were used for estimation friction velocity and vertical dust flux at the Nomgon site. In association with a surface cyclone, its frontal system and a trough aloft, the expected dust storm occurred in the Mongolian Gobi during the IOP period. Dust concentrations of PM10 increased during the dust storm period due to raised wind speed in the dry conditions of air and soil. The present study aimed to estimate friction velocity (u*) and vertical dust flux (F) around Nomgon site in the Mongolian Gobi desert during the dust storm period. The estimation results were presented in this paper.

scholarly journals A Global Analysis of Dust Diurnal Variability Using CATS Observations

2020 ◽  
Author(s):  
Yan Yu ◽  
Olga V. Kalashnikova ◽  
Michael J. Garay ◽  
Huikyo Lee ◽  
Myungje Choi ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
Global Analysis ◽  
Space Station ◽  
Dust Emission ◽  
Analytical Framework ◽  
Diurnal Variability ◽  
Diurnal Cycles ◽  
Dust Sources ◽  
Dust Loading ◽  
Bodele Depression

Abstract. The current study investigates the diurnal cycle of dust loading across the global tropics, sub-tropics, and mid-latitudes by analyzing aerosol extinction and typing profiles observed by the Cloud–Aerosol Transport System (CATS) lidar aboard the International Space Station. According to the comparison with ground-based and other satellite observations, CATS aerosol and dust loading observations exhibits reasonable quality but significant day–night inconsistency. To account for this day–night inconsistency in CATS data quality, the diurnal variability in dust characteristics are currently examined separately for daytime and nighttime periods. Based on an analysis of variance analytical framework, pronounced diurnal variations in dust loading are generally uncovered during daytime periods and over terrestrial areas. The current study identifies statistically significant diurnal variability in dust loading over key dust sources, including the Bodélé Depression, the West African El Djouf, Rub-al Khali Desert, and western and southern North America, confirming the previous observation-based findings regarding the diurnal cycle of dust emission and underlying meteorological processes in these regions. Significant seasonal dust diurnal variability is identified over the Iraqi and Thar deserts. The identified significant diurnal cycles in dust loading over the rainforests in Amazon and tropical southern Africa are hypothesized to be driven by enhanced dust emission due to wildfires.

A Discussion on recent research in air pollution - Developments in air pollution measurement

1969 ◽  
Vol 265 (1161) ◽  
pp. 143-151 ◽  
Keyword(s):  
Air Pollution ◽  
Particle Size ◽  
High Speed ◽  
Dust Emission ◽  
Dust Concentration ◽  
Full Effect ◽  
Pollution Measurement ◽  
Averaging Time ◽  
Time Required ◽  
Dust Monitor

The behaviour of plumes from tall chimneys is now fairly well understood. To achieve this understanding it has been necessary to develop high speed recording devices for sulphur dioxide concentration and plume height and to use recorders of atmospheric turbulence and temperature profile at heights up to some hundreds of metres. Instruments for pollution control, in particular the control of dust, have a different requirement. They must be simple; and in addition must measure meaningful functions of the basic variables rather than a single variable. A dust gauge has been developed which measures in the field a function of dust concentration, dust velocity and particle size, and is also dependent on wind direction. The function is considered to represent the ‘ nuisance value ’ of the dust emission. A dust monitor has been developed which measures, before emission, the same function of the dust variables, and can be used for emission control. It supplements the smoke meter type of instrument which measures a different function of dust concentration and particle size. The zero stability of both instrument types has been studied and improved. The averaging time of a measurement is an important conception both in the investigation and the control of pollution. In monitoring instruments it must be related to the | integrating time ’ of each type of complaint. This is the time required for a pollutant to produce its full effect from an arbitrary starting time.

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