TY - JOUR
T1 - A comparison of Lagrangian model estimates to light detection and ranging (LIDAR) measurements of dust plumes from field tilling
AU - Wang, Junming
AU - Hiscox, April L.
AU - Miller, David R.
AU - Meyer, Thomas H.
AU - Sammis, Ted W.
N1 - Funding Information:
This project was supported by National Research Initiative Competitive grants 2007-55112-17849 and 2004-35112-14230 from the U.S. Department of Agriculture Cooperative State Research, Education, and Extension Service Air Quality Program. It was also supported by the University of Connecticut Storrs Agricultural Experiment Station and the New Mexico State University Agricultural Experiment Station. The authors are grateful to the staff at the Agricultural Experiment Station at New Mexico State University for their generous cooperation during the field experiments. The authors thank Dr. Jinfa Zhang at the Department of Plant and Environment Sciences, New Mexico State University, for allowing us use his cotton field for the experiments.
PY - 2009/11
Y1 - 2009/11
N2 - A Lagrangian particle model has been adapted to examine human exposures to particulate matter ≤ 10 μm (PM10) in agricultural settings. This paper reports the performance of the model in comparison to extensive measurements by elastic LIDAR (light detection and ranging). For the first time, the LIDAR measurements allowed spatially distributed and time dynamic measurements to be used to test the predictions of a field-scale model. The model outputs, which are three-dimensional concentration distribution maps from an agricultural disking operation, were compared with the LIDAR-scanned images. The peak cross-correlation coefficient and the offset distance of the measured and simulated plumes were used to quantify both the intensity and location accuracy. The appropriate time averaging and changes in accuracy with height of the plume were examined. Inputs of friction velocity, Monin-Obukhov length, and wind direction (1 sec) were measured with a three-axis sonic anemometer at a single point in the field (at 1.5-m height). The Lagrangian model of Wang et al. predicted the near-field concentrations of dust plumes emitted from a field disking operation with an overall accuracy of approximately 0.67 at 3-m height. Its average offset distance when compared with LIDAR measurements was approximately 38 m, which was 6% of the average plume moving distance during the simulation periods. The model is driven by weather measurements, and its near-field accuracy is highest when input time averages approach the turbulent flow time scale (3-70 sec). The model accuracy decreases with height because of smoothing and errors in the input wind field, which is modeled rather than measured at heights greater than the measurement anemometer. The wind steadiness parameter (S) can be used to quantify the combined effects of wind speed and direction on model accuracy.
AB - A Lagrangian particle model has been adapted to examine human exposures to particulate matter ≤ 10 μm (PM10) in agricultural settings. This paper reports the performance of the model in comparison to extensive measurements by elastic LIDAR (light detection and ranging). For the first time, the LIDAR measurements allowed spatially distributed and time dynamic measurements to be used to test the predictions of a field-scale model. The model outputs, which are three-dimensional concentration distribution maps from an agricultural disking operation, were compared with the LIDAR-scanned images. The peak cross-correlation coefficient and the offset distance of the measured and simulated plumes were used to quantify both the intensity and location accuracy. The appropriate time averaging and changes in accuracy with height of the plume were examined. Inputs of friction velocity, Monin-Obukhov length, and wind direction (1 sec) were measured with a three-axis sonic anemometer at a single point in the field (at 1.5-m height). The Lagrangian model of Wang et al. predicted the near-field concentrations of dust plumes emitted from a field disking operation with an overall accuracy of approximately 0.67 at 3-m height. Its average offset distance when compared with LIDAR measurements was approximately 38 m, which was 6% of the average plume moving distance during the simulation periods. The model is driven by weather measurements, and its near-field accuracy is highest when input time averages approach the turbulent flow time scale (3-70 sec). The model accuracy decreases with height because of smoothing and errors in the input wind field, which is modeled rather than measured at heights greater than the measurement anemometer. The wind steadiness parameter (S) can be used to quantify the combined effects of wind speed and direction on model accuracy.
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U2 - 10.3155/1047-3289.59.11.1370
DO - 10.3155/1047-3289.59.11.1370
M3 - Article
C2 - 19947118
AN - SCOPUS:73349133010
SN - 1096-2247
VL - 59
SP - 1370
EP - 1378
JO - Journal of the Air and Waste Management Association
JF - Journal of the Air and Waste Management Association
IS - 11
ER -