A model for predicting aeolian sand drift and dust entrainment on scales from paddock to region

Soil Research ◽  
1996 ◽  
Vol 34 (3) ◽  
pp. 309 ◽  
Author(s):  
YP Shao ◽  
MR Raupach ◽  
JF Leys
Keyword(s):  
Wind Erosion ◽  
Soil Surface ◽  
Experimental Results ◽  
Assessment Model ◽  
Natural State ◽  
Source Areas ◽  
Management Intervention ◽  
Physical Knowledge ◽  
Sand Drift ◽  
Dust Entrainment

This paper describes a Wind Erosion Assessment Model (WEAM) for the estimation of sand drift and dust entrainment in agricultural areas. Both the sand drift and dust entrainment parts of the model are physically based, utilising a combination of established and recent theoretical and experimental results. Key components of the model include the Owen equation for the saltation flux; the observed and theoretically predicted proportionality between saltation flux and dust entrainment by saltation bombardment; theoretical and experimental results on the amelioration of wind erosion by nonerodible roughness; and new experimental results on the suppression of erosion by surface moisture. The size distribution of the particles on the soil surface (in their natural state) is used as a primary parameter. The model is restricted to a description of the mobilisation of sand and dust in erosion source areas, and specifically excludes treatment of 2 groups of related processes: dust transport away from source areas and its ultimate deposition; and evolution of surface properties, by the wind erosion process itself, by other weathering processes, or by management intervention. The results of the model are compared with data from a portable wind erosion tunnel, and with direct wind erosion measurements at paddock scale. By offering a synthesis of available physical knowledge of sand drift and dust entrainment, the model also indicates key areas of uncertainty.

scholarly journals Potential threat of southern Moravia soils by wind erosion

2004 ◽  
Vol 52 (2) ◽  
pp. 33-42 ◽  
Author(s):  
Jana Dufková
Keyword(s):  
Wind Velocity ◽  
Wind Erosion ◽  
Linear Trend ◽  
Soil Surface ◽  
Potential Threat ◽  
Soil Humidity ◽  
Average Wind ◽  
Humidity Index ◽  
Southern Moravia ◽  
Average Wind Velocity

Wind erosion is caused by meteorological factors such as wind, precipitation and evaporation that influence the soil humidity. Erosive-climatological factor expresses wind and humidity conditions of particular landscape. This is an index of the influence of average soil surface humidity and average wind velocity on average soil erodibility by wind. On the basis of average wind velocity and Konček’s humidity index, the values of the erosive-climatological factor for three chosen areas of Czech republic (Telč-Kostelní Myslová, Znojmo-Kuchařovice and Brno-Tuřany), where the pro-cesses of wind erosion could exist, were evaluated. Thus, the change of the factor’s value during the period of 1961 – 2000 was studied. The linear trend for the region of Brno and Znojmo (dry areas) shows increasing threat of soils by wind erosion, the contrary situation is at the humid area (Telč). The results prove the influence of soil humidity on the erosive-climatological factor and hereby the influence on wind erosion spreadout.

scholarly journals Physical Crust Formation on Sandy Soils and Their Potential to Reduce Dust Emissions from Croplands

Land ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 503
Author(s):  
Heleen Vos ◽  
Wolfgang Fister ◽  
Frank Eckardt ◽  
Anthony Palmer ◽  
Nikolaus Kuhn
Keyword(s):  
Wind Erosion ◽  
Sandy Soils ◽  
Soil Surface ◽  
Free State ◽  
Cone Penetrometer ◽  
Crust Formation ◽  
Dust Emissions ◽  
Dust Flux ◽  
Dust Sources

The sandy croplands in the Free State have been identified as one of the main dust sources in South Africa. The aim of this study was to investigate the occurrence and strength of physical soil crusts on cropland soils in the Free State, to identify the rainfall required to form a stable crust, and to test their impact on dust emissions. Crust strength was measured using a fall cone penetrometer and a torvane, while laboratory rainfall simulations were used to form experimental crusts. Dust emissions were measured with a Portable In-Situ Wind Erosion Laboratory (PI-SWERL). The laboratory rainfall simulations showed that stable crusts could be formed by 15 mm of rainfall. The PI-SWERL experiments illustrated that the PM10 emission flux of such crusts is between 0.14% and 0.26% of that of a non-crusted Luvisol and Arenosol, respectively. The presence of abraders on the crust can increase the emissions up to 4% and 8% of the non-crusted dust flux. Overall, our study shows that crusts in the field are potentially strong enough to protect the soil surfaces against wind erosion during a phase of the cropping cycle when the soil surface is not protected by plants.

scholarly journals On-Site Water and Wind Erosion Experiments Reveal Relative Impact on Total Soil Erosion

Geosciences ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 478 ◽  
Author(s):  
Miriam Marzen ◽  
Thomas Iserloh ◽  
Wolfgang Fister ◽  
Manuel Seeger ◽  
Jesus Rodrigo-Comino ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Erosion ◽  
Wind Erosion ◽  
Soil Surface ◽  
Water Erosion ◽  
Relative Impact ◽  
Wheat Field ◽  
Total Soil ◽  
Potential Impact

The relative impact of water and wind on total erosion was investigated by means of an experimental-empirical study. Wind erosion and water erosion were measured at five different sites: (1) Mediterranean fallow, (2) Mediterranean orchard, (3) wheat field, (4) vineyard and (5) sand substrate. Mean erosion rates ranged from 1.55 to 618 g·m−2·h−1 for wind and from 0.09 to 133.90 g·m−2·h−1 for rain eroded material over all tested sites. Percentages (%) of eroded sediment for wind and rain, respectively, were found to be 2:98 on Mediterranean fallow, 11:89 on Mediterranean orchard, 3:97 on wheat field, 98:2 on vineyard and 99:1 on sand substrate. For the special case of soil surface crust destroyed by goat trampling, the measured values emphasize a strong potential impact of herding on total soil erosion. All sites produced erosion by wind and rain, and relations show that both erosive forces may have an impact on total soil erosion depending on site characteristics. The results indicate a strong need to focus on both wind and water erosion particularly concerning soils and substrates in vulnerable environments. Measured rates show a general potential erosion depending on recent developments of land use and climate change and may raise awareness of scientist, farmers and decision makers about potential impact of both erosive forces. Knowledge about exact relationship is key for an adapted land use management, which has great potential to mitigate degradation processes related to climate change.

Wind erosion of microplastics from soils: linking soil surface properties with microplastic flux

2020 ◽  
Author(s):  
Annie Ockelford ◽  
Joanna Bulalrd ◽  
Cheryl McKenna-Neuman ◽  
Patrick O'Brien
Keyword(s):  
Surface Roughness ◽  
Wind Tunnel ◽  
Wind Erosion ◽  
Soil Surface ◽  
Surface Characteristics ◽  
Test Material ◽  
Mineral Particle ◽  
Test Bed ◽  
Transport Pathway ◽  
Soil Surface Roughness

<p>Recent studies of soils in the Alps and Middle East indicate airborne transport of microplastics following wind erosion may be significant.  Where microplastics have been entrained by wind they show substantial enrichment ratios compared to mineral particle erosion.  Further, microplastic shape affects enrichment ratios with those for fibres greater than for microbeads which may reflect the lower density and asymmetric shape of microplastics compared to soil particles. This suggests that terrestrial to atmospheric transfer of microplastics could be a significant environmental transport pathway. However, currently we have very little understanding of how the properties, in particular the surface characteristics, of the sediment which they are being eroded from affects their entrainment potential.</p><p>This paper reports wind tunnel studies run to explore the impacts of soil surface characteristics on microplastic flux by wind erosion.  Experiments were performed in a boundary layer simulation wind tunnel with an open-loop suction design.  The tunnel has a working section of 12.5m x 0.7m x 0.76m and is housed in an environmental chamber which, for this study, was held constant at 20 <sup>o</sup>C and 20% RH. In experiments two types of low density microplastic (microbeads and fibres) were mixed into a poorly-sorted soil containing 13% organics.  The polyethylene microbeads had a size range of 212-250 microns and density of 1.2 g cm<sup>3</sup> and the polyester fibres were 5000 microns long and 500-1000 microns in width with a density of 1.38 g cm<sup>3</sup>.  Microplastics were mixed into the sediment in concentrations ranging from 40-1040 mg kg<sup>-1</sup>. For each experiment, test surfaces were prepared by filling a 1.0m x 0.35m x  0.025m metal tray with the given mixture of test material which was lowered into the wind tunnel such that it was flush with the tunnel floor and levelled. The wind tunnel was then switched on and run with increasing wind speeds using 0.25 m s<sup>-1</sup> increments until continuous saltation occurred.  Soil surface roughness was scanned prior to and after each experiment using a high resolution laser scanner (0.5mm resolution over the entire test section).  Transported soil and microplastic particles were captured in bulk using a 2 cm wide by 40 cm tall Guelph-Trent wedge trap that was positioned 2 m downwind of the test bed. </p><p>Discussion concentrates on linking the changes in soil surface topography to the magnitude of microplastic flux where data shows that there is a correlation between the development of the soil surfaces and overall microplastic flux.  Specifically, soil surface roughness is seen as a significant control on microplastic flux where it has a greater overall effect on microplastic fibre flux as compared to the microplastic beads.  The outcome of this research is pertinent to developing understanding surrounding the likely controls and hence propensity of microplastics to be entrained from soil by wind erosion.  </p>

On the Wind Erosion of Small Particles 1

1959 ◽  
Vol 40 (2) ◽  
pp. 73-77 ◽  
Author(s):  
Glenn R. Hilst ◽  
Paul W. Nickola
Keyword(s):  
Soil Conservation ◽  
Wind Erosion ◽  
Meteorological Factors ◽  
Particle Surface ◽  
Soil Surface ◽  
Small Particles

The importance of wind erosion with respect to soil conservation and to the spreading of noxious particles subsequent to deposit on a soil surface is indicated. The processes of wind erosion and transport are reviewed and are then illustrated by some measurements made at Hanford. Particle, surface, and meteorological factors which influence erosion by wind are listed and discussed briefly.

Atmospheric Quality Assessment Model Based on Immune Clonal Selection Algorithm

2011 ◽  
Vol 255-260 ◽  
pp. 3013-3017
Author(s):  
Li Min Wang ◽  
Xu Ming Han ◽  
Ming Li ◽  
Chi Jun Zhang ◽  
Yan Ting Zhang
Keyword(s):  
Quality Assessment ◽  
Growth Curve ◽  
Clonal Selection ◽  
Assessment Method ◽  
Experimental Results ◽  
Assessment Model ◽  
Clonal Selection Algorithm ◽  
Selection Algorithm ◽  
Intelligence Theory ◽  
Curve Index

The immune clonal selection algorithm is used to optimize the parameters in the formula of S growth curve index in the paper, thus we can obtain an assessment model for atmospheric comprehensive pollution that is suitable to the cases of multi-pollutants. Moreover the proposed assessment model is applied in the field of atmosphere assessment. Experimental results show that the assessment method proposed for atmosphere quality has many advantages such as pellucid principle, physical explication and correct assessment results etc. It is a new effective approach for intelligence theory and technology applied in the field of environment. Therefore it has great potential in the field of assessment the atmospheric quality.

scholarly journals Enhanced Assessment System to Improve The Efficiency of Current Generation Students

2019 ◽  
Vol 8 (6S) ◽  
pp. 579-581
Keyword(s):  
Assessment System ◽  
Learning System ◽  
Experimental Results ◽  
Assessment Model ◽  
Current Generation ◽  
Present Generation

Assessment leads to learning. The present generation students properly guided in their learning. The correct assessment improves the learning of the students. In the paper we present a new assessment model “E-Brahma” to assess the performance of the students in current academic scenario and it also enhance the learning system also. In this paper we propose an assessment algorithm. The experimental results show the efficiency of the proposed system.

Sign in / Sign up

Export Citation Format

Share Document