The influence of wind velocity on the size distributions of aerosols generated by the wind erosion of soils

Gillette, Dale A.; Blifford, I. H.; Fryrear, D. W.

doi:10.1029/jc079i027p04068

Cited by 258 publications

(164 citation statements)

References 7 publications

(4 reference statements)

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“…While both gross upward and downward fluxes in the PLAnET model are resolved separately, this does not happen when employing a gradient method, and the presence of depositional effects could affect the observed gradient. Following Gillette et al (1974Gillette et al ( , 1997, depositional effects for particles < 10 µm are significant only when the ratio between the deposition and friction velocity is greater than 0.1.The value of this ratio did not exceed the critical thresholds either in the 2008-2010 campaigns or in 2015. This guarantees the applicability of the gradient method for the observations at the Montfavet site made in sufficiently turbulent conditions.…”

Section: Discussionmentioning

confidence: 98%

Measurements and modeling of surface–atmosphere exchange of microorganisms in Mediterranean grassland

et al. 2017

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Abstract. Microbial aerosols (mainly composed of bacterial and fungal cells) may constitute up to 74 % of the total aerosol volume. These biological aerosols are not only relevant to the dispersion of pathogens, but they also have geochemical implications. Some bacteria and fungi may, in fact, serve as cloud condensation or ice nuclei, potentially affecting cloud formation and precipitation and are active at higher temperatures compared to their inorganic counterparts. Simulations of the impact of microbial aerosols on climate are still hindered by the lack of information regarding their emissions from ground sources. This present work tackles this knowledge gap by (i) applying a rigorous micrometeorological approach to the estimation of microbial net fluxes above a Mediterranean grassland and (ii) developing a deterministic model (the PLAnET model) to estimate these emissions on the basis of a few meteorological parameters that are easy to obtain. The grassland is characterized by an abundance of positive net microbial fluxes and the model proves to be a promising tool capable of capturing the day-to-day variability in microbial fluxes with a relatively small bias and sufficient accuracy. PLAnET is still in its infancy and will benefit from future campaigns extending the available training dataset as well as the inclusion of ever more complex and critical phenomena triggering the emission of microbial aerosol (such as rainfall). The model itself is also adaptable as an emission module for dispersion and chemical transport models, allowing further exploration of the impact of landcover-driven microbial aerosols on the atmosphere and climate.

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Section: Discussionmentioning

confidence: 98%

Measurements and modeling of surface–atmosphere exchange of microorganisms in Mediterranean grassland

et al. 2017

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“…Due to the high sensitivity of these analytical methods (a few micrograms per filter) they are recommended to determine mass concentration over short periods of erosion such as those used to measure vertical flux (typically 20 min) (Rajot et al, 2003;Gomes et al, 2003a). Particle number concentration can also be obtained by direct counting of particles on filters by coupling microscopy and image analysis (Gillette et al, 1974). This method requires counting a large number of particles to ensure optimal particle sampling on the filters, especially if automated image analysis is used.…”

Section: Suspended Sediment Samplersmentioning

confidence: 99%

“…Langham et al, 1938;Chepil and Woodruff, 1957;Gillette et al, 1974). For isokinetic sampling, the suction of the sampler is adjusted so the wind speed in the sampling orifice is the same as the ambient wind speed.…”

Section: Suspended Sediment Samplersmentioning

confidence: 99%

Measurement and data analysis methods for field‐scale wind erosion studies and model validation

Zobeck

Sterk

Funk

et al. 2003

Earth Surf Processes Landf

174

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Accurate and reliable methods of measuring windblown sediment are needed to confirm, validate, and improve erosion models, assess the intensity of aeolian processes and related damage, determine the source of pollutants, and for other applications. This paper outlines important principles to consider in conducting field-scale wind erosion studies and proposes strategies of field data collection for use in model validation and development. Detailed discussions include consideration of field characteristics, sediment sampling, and meteorological stations. The field shape used in field-scale wind erosion research is generally a matter of preference and in many studies may not have practical significance. Maintaining a clear nonerodible boundary is necessary to accurately determine erosion fetch distance. A field length of about 300 m may be needed in many situations to approach transport capacity for saltation flux in bare agricultural fields. Field surface conditions affect the wind profile and other processes such as sediment emission, transport, and deposition and soil erodibility. Knowledge of the temporal variation in surface conditions is necessary to understand aeolian processes. Temporal soil properties that impact aeolian processes include surface roughness, dry aggregate size distribution, dry aggregate stability, and crust characteristics. Use of a portable 2 tall anemometer tower should be considered to quantify variability of friction velocity and aerodynamic roughness caused by surface conditions in field-scale studies. The types of samplers used for sampling aeolian sediment will vary depending upon the type of sediment to be measured. The Big Spring Number Eight (BSNE) and Modified Wilson and Cooke (MWAC) samplers appear to be the most popular for field studies of saltation. Suspension flux may be measured with commercially available instruments after modifications are made to ensure isokinetic conditions at high wind speeds. Meteorological measurements should include wind speed and direction, air temperature, solar radiation, relative humidity, rain amount, soil temperature and moisture. Careful consideration of the climatic, sediment, and soil surface characteristics observed in future field-scale wind erosion studies will ensure maximum use of the data collected.

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“…Owing to theoretical considerations, micrometeorological parameters, such as the friction velocity, the roughness length and the evaporation, are very useful parameters to quantify wind erosion (e.g. Fryrear and Saleh, 1993;Gillette et al, 1974;Marticorena and Bergametti, 1995;Quiroga et al, 1998;Zobeck, 1991). The first two considerations allow for a description of the wind profile, and ultimately the prediction of wind erosion.…”

Section: Welsons (Wind Erosion and Losses Of Soil Nutrients In Semiarmentioning

confidence: 99%

Turbulent characteristics of a semiarid atmospheric surface layer from cup anemometers – effects of soil tillage treatment (Northern Spain)

2003

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Abstract. This paper deals with the characteristics of turbulent flow over two agricultural plots with various tillage treatments in a fallow, semiarid area (Central Aragon, Spain). The main dynamic characteristics of the Atmospheric Surface Layer (ASL) measured over the experimental site (friction velocity, roughness length, etc.), and energy budget, have been presented previously (Frangi and Richard, 2000). The current study is based on experimental measurements performed with cup anemometers located in the vicinity of the ground at 5 different levels (from 0.25 to 4 m) and sampled at 1 Hz. It reveals that the horizontal wind variance, the Eulerian integral scales, the frequency range of turbulence and the turbulent kinetic energy dissipation rate are affected by the surface roughness. In the vicinity of the ground surface, the horizontal wind variance logarithmically increases with height, directly in relation to the friction velocity and the roughness length scale. It was found that the time integral scale (and subsequently the length integral scale) increased with the surface roughness and decreased with the anemometer height. These variations imply some shifts in the meteorological spectral gap and some variations of the spectral peak length scale. The turbulent energy dissipation rate, affected by the soil roughness, shows a z-less stratification behaviour under stable conditions. In addition to the characterization of the studied ASL, this paper intends to show which turbulence characteristics, and under what conditions, are accessible through the cup anemometer.

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The influence of wind velocity on the size distributions of aerosols generated by the wind erosion of soils

Cited by 258 publications

References 7 publications

Measurements and modeling of surface–atmosphere exchange of microorganisms in Mediterranean grassland

Measurements and modeling of surface–atmosphere exchange of microorganisms in Mediterranean grassland

Measurement and data analysis methods for field‐scale wind erosion studies and model validation

Turbulent characteristics of a semiarid atmospheric surface layer from cup anemometers – effects of soil tillage treatment (Northern Spain)

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