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

Abstract

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.

Ecohydrology: Processes and Implications for Rangelands

“…One key advance in recent decades is recognition of the importance of wind-driven transport (aeolian) and its linkage with water erosion (Breshears et al 2003;Belnap et al 2011). Aeolian processes are much better understood now, thanks to improvements in measurement methods (Zobeck et al 2003)-including relative humidity near the soil surface (Ravi et al 2007a), the effects of vegetation patterns, and predictions of how vegetation structure influences horizontal sediment transport (Okin and Gillette 2001). Like water erosion, aeolian sediment transport is strongly influenced by the structure and arrangement of vegetation patches (Field et al 2012).…”

Aplicación De Un Modelo Matemático Para Predecir Y Reducción De La Erosión Eólica en Tierras Áridas No Protegidas

“…En los campos erosionables desprotegidos, la tasa de flujo del suelo es de cero en el borde de barlovento y aumenta con la distancia hasta alcanzar un valor máximo. Sin embargo, un campo con una longitud aproximada de 300 m podría necesitar en muchos casos aproximarse a la capacidad de transporte para la saltación de flujo en los campos de cultivo al descubierto (Zobeck et al, 2003). Por ello, esta investigación propone campos con longitudes diferentes (50, 100, 200, 300, 400 and 500 m) para evaluar la erosión eólica con la ayuda de las ecuaciones 15, 16, y 17.…”

“…On unprotected eroding fields, the rate of soil flow is zero on the windward edge and increases with distance until reaching a maximum value. However, a field length of about 300 m may be needed in many situations to approach transport capacity for saltation flux in bare agricultural fields (Zobeck et al, 2003). Therefore, this research is proposing fields with different lengths (50, 100, 200, 300, 400 and 500 m) to evaluate the wind erosion with the aid of equations.15, 16 and 17.…”

Fugitive Dust Emissions from Off-Road Vehicle Maneuvers on Military Training Lands

“…The opposite is true when the velocity within the sampler is higher than that of the moving air stream. Because of this phenomenon, passive sampling techniques are not usually considered adequate for accurately measuring suspended particle concentration in a moving air stream (Zobeck et al, 2003). Goossens and Offer (2000) suggested that efficiency loss due to non-isokinetic sampling conditions is the most important factor to consider when attempting to measure sediment flux.…”