Big Spring Number Eight Samplers Research Articles

Estimation of sampling efficiency of the Big Spring Number Eight (BSNE) sampler at different heights based on sand particle size in the Taklimakan Desert

The Big Spring Number Eight (BSNE) sampler is an important and widely used instrument in studies of aeolian sand transport. Its sampling efficiency is an important parameter and varies with particle size. However, little is known about the variations in sampling efficiency caused by the differences in particle size with height. The variations in particle size with height from 10 to 200 cm were obtained from a field experiment at four sites in the Taklimakan Desert from May 2010 to April 2011. The variation in the sampling efficiency of the BSNE sampler with particle size was estimated based on previous studies and a wind tunnel experiment. It was found that the average particle size decreased with height above ground from 10 to 200 cm at three experimental sites, while at the other site it decreased from 10 to 15 cm and then slightly increased. The percentage distribution of particle sizes with height was similar for sizes below 63 μm and between 125 and 200 μm at all experimental sites, but there were differences in the percentage of size classes between 63 and 125 μm and above 200 μm. The sampling efficiencies ranged from 66.27 to 58.98%, 64.97 to 57.47%, 56.04 to 52.76%, and 72.07 to 58.9% at the four sites, respectively, with an average of 64.84 to 57.03% at heights from 10 to 200 cm. After correcting for sampling efficiency, the amount of aeolian sand that passed through a section of 100 cm (width) × 200 cm (height) increased by 44.5, 52.1, 78.8, and 26.4% at the four sites, respectively, with an average of 50.5%. These results indicate that the sampling efficiency of the device needs to be considered when making observations across a gradient of particle sizes.

Field and laboratory comparison of PM10 instruments in high winds

Abstract Instruments capable of measuring PM10 (particulate matter ≤10 µm in aerodynamic diameter) concentrations may vary in performance as a result of different technologies utilized in measuring PM10. Therefore, the performance of five instruments capable of measuring PM10 concentrations above eroding soil surfaces was tested during high wind events at field sites in the Columbia Plateau and inside a wind tunnel. Comparisons among the Big Spring Number Eight (BSNE) sampler, DustTrak monitor, E-sampler, High-Volume sampler, and Tapered Element Oscillating Microbalance (TEOM) monitor were made at field sites during nine wind erosion events and inside a wind tunnel at two wind speeds (7 and 12 m s−1) and two ambient PM10 concentrations (2 and 50 mg m−3). PM10 concentrations were similar for the High-Volume sampler and TEOM monitor as well as for the BSNE samplers and DustTrak monitors but higher for the High-Volume sampler and TEOM monitor than the E-sampler during field erosion events. Based upon wind tunnel experiments, the TEOM monitor measured the highest PM10 concentration while the DustTrak monitor typically measured the lowest PM10 concentration as compared with other instruments. In addition, PM10 concentration appeared to lower for all instruments at a wind speed of 12 as compared with 7 m s−1 inside the wind tunnel. Differences in the performance of instruments in measuring PM10 concentration poses risks in comparing PM10 concentration among different instrument types or using multiple instrument types to jointly measure concentrations in the field or laboratory or even the same instrument type subject to different wind speeds.

Quantification of wind erosion from some arid soils in Jordan under two different management practices

Jordan’s national food security is challenged by many threats such as soil erosion and desertification. Unfortunately, Jordan lacks field data that can strengthen efforts in reducing erosion and therefore combating desertification necessary to enable sustainable decision making. This study aimed to investigate the effect of passing sheep on soil wind erosion and to quantify windblown soil mass in arid soils. The field was divided into two sites; the first site was subject to disturbance through passage of about 40 sheep biweekly, while the other site was kept undisturbed. Two Big Spring Number Eight (BSNE) sediment catcher traps were installed on each site. Two mass flux models were tested for calculating mass transport rates. The total horizontal flux is obtained by integrating the airborne particles collected by the BSNE sampler. Soil analyses showed no significant differences in all measured properties, ensuring that soil inherent erodibility is similar. Both models were significantly effective (P < 0.001) in predicting airborne sediment loads as indicated by their high associated R2 and low root-mean-square error (RMSE). The results also showed that trapped airborne dust decreases with height, where maximum fluxes were generally at lowest height, indicating that saltation is the dominant transport mode. Average erosion from the disturbed site is almost double the undisturbed site, (6.6 and 3.9 t/ha, respectively). The suggested management plan is to set the area aside as a land reserve or at least performing better grazing management, which will insure lower disturbance of surface soil, result in better plant recover rate leading to stronger soil cover, and allow soil aggregates to develop and be more stable.

Experimental Evaluation of Relative Efficiency of MWAC, MDCO, CDSC, and CDS Aeolian Dust Traps

Quantitative measurement of aeolian dust may help properly monitor and control the wind erosion. The aim of this study was to evaluate the efficiencies of four aeolian dust samplers including the modified Wilson and Cooke sampler (MWAC), cyclone dust sampler with cone (CDSC), cyclone dust sampler (CDS), and marble dust collector (MDCO) in comparison with the big spring number eight sampler (BSNE) in different velocity rates and particles sizes. For this purpose, MWAC, MDCO, BSNE were simulated and CDSC and CDS were designed and constructed. The relative efficiencies of the CDSC, CDS, MWAC, and MDCO were evaluated for the 80, 137, 260 micron diameter particle sizes (D50) in 2-7 ms -1 velocity by wind tunnel. The results showed that relative efficiency of CDSC is higher than CDS, MWAC, and MDCO as a consequence of the wind speed. CDSC and CDS relative efficiencies varied in relation to wind velocity, but MWAC, MDCO relative efficiencies remained constant. Also, CDSC, CDS, MWAC, MDCO relative efficiencies varied from 0.8, 0.48, 2.18, 0.58 times by increasing the particle size diameters from 80 to 260 micrometers, respectively.

A field experiment on dust emission by wind erosion in the Taklimakan Desert

Dust emission by wind erosion in surface is a serious problem in many arid regions around the world, and it is harmful to the ecological environment, human health, and social economy. To monitor the characteristics of saltation activity and to calculate the threshold wind velocity and sediment discharge under field conditions have significance on the research of dust emission by wind erosion. Therefore, a field experiment was conducted over the flat sand in the hinterland of the Taklimakan Desert. One sampling system was installed on the flat sand surface at Tazhong, consisting of a meteorological tower with a height of 2 m, a piezoelectric saltation sensor (Sensit), and a Big Spring Number Eight (BSNE) sampler station. Occurrence of saltation activity was recorded every second using the Sensit. Each BSNE station consisted of five BSNE samplers with the lowest sampler at 0.05 m and the highest sampler at 1.0 m above the soil surface. Sediment was collected from the samplers every 24 h. It is found that saltation activity was detected for only 21.5% of the hours measured, and the longest period of saltation activity occurring continuously was not longer than 5 min under the field conditions. The threshold wind velocity was variable, its minimum value was 4.9 m s−1, the maximum value was 9.2 m s−1, and the average value was 7.0 m s−1. The threshold wind velocity presented a positive linear increase during the measurement period. The observation site had a sediment discharge of 82.1 kg m−1 over a period of 24 h. Based on hourly saltation counts, hourly sediment discharge was estimated. Overall, there was no obvious linear or other functional relationship between the hourly sediment discharge and wind velocity. The results show that the changes of sediment discharge do not quite depend on wind velocity.

Technical Note: Aeolian Materials Sampler for Measuring Surface Flux of Soil Nitrogen and Carbon During Wind Erosion Events in the Sahel, West Africa

In the Sahel, determining the effects of wind erosion on soil fertility and soil carbon balance is crucial for achieving sustainable agriculture and for carbon sequestration, respectively. We designed the Aeolian Materials Sampler (AMS) to measure the surface flux of soil nitrogen and carbon, which limit crop production as well as water in the Sahel. The AMS should not be used alone, but with the Big Spring Number Eight (BSNE) sampler, which is a quasi-isokinetic sampler. We examined the performance of the AMS in estimating the surface flux of soil nitrogen and carbon by conducting wind-tunnel and field experiments. In the former experiment, we measured the trapping efficiency of the AMS for nitrogen and carbon content in coarse organic matter (COM) and soil particles. We observed that the AMS allows estimation of the surface flux of soil nitrogen and carbon associated with the movement of COM and soil particles; wind data and empirical equations were used for the estimation. In the field experiment, we assessed the contribution of the inherent error of the AMS to the total measurement error and found that the inherent error was negligible and did not increase the total measurement error in the estimation of the surface flux of soil nitrogen and carbon. Therefore, we concluded that the combination of the AMS and the BSNE sampler could be effectively used to evaluate the effects of wind erosion on soil fertility and soil carbon balance in the Sahel.

Sediment Catcher to Trap Coarse Organic Matter and Soil Particles Transported by Wind

Wind can erode fertile topsoil and reduce soil fertility. Evaluating the effect of wind erosion on soil fertility is crucial to achieve sustainable agriculture in areas suffering from desertification caused by wind erosion. To estimate soil loss and associated soil nutrient loss by wind erosion, flux of coarse organic matter (COM) (defined here as free organic debris larger than 200 µm) and soil particles (defined as the other soil components) must be measured separately. This is because their modes of transport are different, and COM plays a prominent role in soil nutrient dynamics in some semiarid zones where COM accounts for a large percentage of the total soil carbon. Because the Big Spring Number Eight (BSNE) sampler can trap both COM and soil particles 0.05 m above the surface, we designed a sediment catcher, the Aeolian Materials Sampler (AMS), to trap these components below 0.05 m. This device can be manufactured easily at low cost. AMS performance was tested by wind tunnel experiments over a range of wind velocities typically observed in erosive storms and with six incident wind angles because the AMS is a buried-type sampler that is unable to rotate toward the wind. The trapping efficiency of the AMS for COM and soil particles was not 100%, but it can be calibrated easily using wind data. Therefore, we can estimate the mass flux of COM and soil particles and evaluate the effect of wind erosion on soil fertility using the AMS with the BSNE sampler.

Influence of vegetation cover and crust type on wind-blown sediment in a semi-arid climate

This study determined the influence differing soil surface textures and vegetative covers have on the magnitude of wind erosion in a semi-arid environment. The study was conducted from March 2000 through late April 2000 on the Jornada Experimental Range approximately 37 km north of Las Cruces, New Mexico. Big Spring Number Eight (BSNE) samplers placed at nine locations, collected particulates in suspension and saltation at heights of 5, 10, 20, 50, and 100 cm from the following surfaces: loose sand, thick silty physical crust, flaky physical crust, weak desert pavement, and a forb/grass ground cover. BSNE samplers collected the largest amounts of sediment were collected in areas of loose sand and at sites directly downwind from loose sand than sites containing heavy crusting, gravel, or a forb/grass cover. Differences between sites with gravel surfaces and those with forb/grass cover were insignificant. These results quantify the importance of surface cover as an agent towards reducing the extent of wind erosion on semi-arid landscapes.

Wind erosion from military training lands in the Mojave Desert, California, U.S.A.

Military training activities reduce vegetation cover, disturb crusts, and degrade soil aggregates, making the land more vulnerable to wind erosion. The objective of this study was to quantify wind erosion rates for typical conditions at the Marine Corps Air Ground Combat Center, Twentynine Palms, CA, U.S.A. Five Big Spring Number Eight (BSNE) sampler stations were installed at each of five sites. Each BSNE station consisted of five BSNE samplers with the lowest sampler at 0·05 m and the highest sampler at 1·0 m above the soil surface. Once a month, sediment was collected from the samplers for analysis. Occurrence of saltating soil aggregates was recorded every hour using Sensits, one at each site. The site with the most erosion had a sediment discharge of 311 kg m −1 over a period of 17 months. Other sites eroded much less because of significant rock cover or the presence of a crust. Hourly sediment discharge was estimated combining hourly Sensit count and monthly sediment discharge measured using BSNE samplers. More simultaneously measured data are needed to better characterize the relationship between these two and reconstruct a detailed time-series of wind erosion. This measured time-series can then be used for comparison with simulation results from process-based wind erosion models such as the Wind Erosion Prediction System (WEPS), once it has been adapted to the unique aspects of military lands.

Wind tunnel and field calibration of six aeolian dust samplers

The efficiency of six aeolian dust samplers was tested via wind tunnel experiments and field measurements. In the wind tunnel, four samplers designed to measure the horizontal dust flux and one sampler designed to measure the vertical dust flux (in the downward direction, i.e., deposition) were calibrated against an isokinetic reference sampler. The horizontal dust flux samplers were: the big spring number eight sampler (BSNE), the modified Wilson and Cooke sampler (MWAC), the suspended sediment trap (SUSTRA), and the wedge dust flux gauge (WDFG). Vertical deposition flux was measured using a marble dust collector (MDCO). A modified Sartorius SM 16711 dust sampler with adjustable flow rate (SARTORIUS) was used as isokinetic reference sampler. In the field experiments, the WDFG was replaced by a Sierra ultra high volume dust sampler (SIERRA). Wind tunnel calibrations were carried out at five wind velocities ranging from 1 to 5 m s −1. Field calibrations were conducted during seven periods of two weeks each. The most efficient samplers are the MWAC and the SIERRA, followed by the BSNE and the SUSTRA. The WDFG is more effective than the BSNE at velocities below 3 m s −1, but its efficiency drops quickly at higher wind speeds. The most recommendable sampler for field measurements is the BSNE, because its efficiency varies only very slightly with wind speed. In the absence of horizontal flux samplers, the MDCO collector can be used as an alternative to assess horizontal dust flux and airborne dust concentration provided the appropriate calibrations are made.