The role of fluctuations of vertical and horizontal wind and particle concentration in the deposition of dust suspended by wind
作者:
Dale A. Gillette,
William M. Porch,
期刊:
Journal of Geophysical Research: Oceans
(WILEY Available online 1978)
卷期:
Volume 83,
issue C1
页码: 409-414
ISSN:0148-0227
年代: 1978
DOI:10.1029/JC083iC01p00409
数据来源: WILEY
摘要:
Fluctuating quantities of vertical wind speed, horizontal wind speed, and concentration of particles with radii between 0.5 and 3 μm were observed for dusty air generated by wind erosion of soil a short distance upwind of the sensors. Probability distributions for the fluctuating quantities showed a form that was explained by a strong correlation of particle concentration with wind speed, momentum flux downward, and particle flux downward. A distribution showing percentage of the particle flux indicated that the most effective fluctuation scales were within 1–3 standard deviations of the means. The distribution showed that much of the flux was counter to the gradient in a rather inefficient turbulent mixing process. Observations that a large contribution to total particle flux occurs at horizontal wind speeds as high as 3 standard deviations above the mean would indicate that wind tunnel tests with a distribution of horizontal wind speeds narrower than distributions of natural winds may give significantly different suspension results for wind erosion studies. The authors interpret the strong correlation of horizontal wind speed and particle concentration to show a very fast response of small particle input by ‘sandblasting’ (disaggregation of small particles from larger particles and splashing of loose small particles from the surface). This sandblasting is driven by saltation of larger sand grains, a process which is highly responsive to
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