风蚀事件中农田土壤PM10释放特征

地表风蚀导致的粉尘释放涉及全球变化研究的热点。自然条件下对粉尘释放的观测可以为风洞试验结果提供验证并为开发预测模型提供数据支撑与关键参数。本研究在河北坝上风蚀区，通过观测风蚀事件中农田近地表PM₁₀浓度、垂直通量与流失通量，以及风速和风沙流强度的变化，探讨农田风蚀过程中的粉尘释放特征。结果表明：地表风蚀释尘对近地表粉尘浓度的影响随高度增大而逐渐减弱，各高度的粉尘浓度变化趋势与摩阻风速、输沙率变化趋势相同；粉尘垂直通量和流失通量与摩阻风速呈幂函数关系，与输沙率呈线性关系；农田土壤跃移颗粒的轰击效率α数量级为10^-7m^-1。

Characteristics of PM10 emission from farmland during a wind erosion event

As the starting point of the dust cycle, dust emission caused by wind erosions is one of the hot issues related to global change. Observations of dust emission under natural conditions can provide validations for wind tunnel results and data support, as well as key parameters, for developing prediction models. To reveal the characteristics of dust emission from farmland in the process of soil wind erosion, this study conducted a field observation of PM₁₀ concentration, vertical flux and loss flux in the near surface layer in Bashang regions, Hebei province. Wind speed and sand transport were measured simultaneously. The results show that the effect of dust emission induced by local wind erosion on the dust concentration gradually decreases with increasing height above the ground. Dust concentration at different heights varied in the same trend with that of friction wind speed and sand transport rate in the process of wind erosion. Dust emission has a power function relationship with the friction velocity and a linear relationship with the sand transport rate. The bombardment efficiency of the cultivated soil is on the order of 10^-7 m^-1.