干涸尾闾湖盆区泥漠地表磨蚀释尘特征

沙粒的表面磨蚀效应是地表产尘、释尘的重要机制，针对干湖盆泥漠地表开展磨蚀释尘实验研究，对理解干湖盆地表风蚀过程及盐碱尘暴形成机理具有重要意义。对采自西居延海干涸湖盆泥漠地表土样进行室内磨蚀模拟实验，研究了不同粒级（细、中、粗）沙粒不同落沙角度（30°，45°，60°）的磨蚀效应。结果表明：（1）泥漠地表磨蚀实验中能够产生明显释尘效应的沙粒粒级阈值为中沙（0.25 mm<M_d<0.50 mm）；（2）磨蚀粒径粒级相同时，磨蚀角度会对泥漠地表磨蚀释尘速率产生影响，磨蚀量的角度排序为60°>30°>45°，但同一粒级3种角度下的磨蚀释尘率差异不显著。（3）磨蚀角度为45°时，计算了泥漠地表的质量磨蚀率与能量磨蚀率，其中中沙为0.04 g·kg^-1、0.43 g·J^-1，粗沙为0.08 g·kg^-1、0.74 g·J^-1，极粗沙为0.26 g·kg^-1、2.54 g·J^-1；在磨蚀沙粒粒级倍增而磨蚀角度不变情况下，泥漠地表磨蚀释尘率与能量磨蚀率未发生正比例线性增长变化。

The surface abrasion and dust emission of mud desert in dry rump lake basin

The bombardment effect of saltating sand particles on the erodible surface is an important mechanism of dust release. It is of great significance to study the aeolian abrasion process and dust release mechanism on the surface of dry lake bed to mitigate the hazards of saline-alkali dust storm. In this paper， samples from mud desert surface of dry lakebed in the West Juyan Lake were collected to conduct laboratory abrasion experiments to study the abrasion effect of sand grains at different impacting angles（30°， 45°， 60°）. The results show that： （1） The threshold sand size of erosion and dust release on mud desert surface is medium （0.25 mm<M_d<0.50 mm）. （2） When the abrasive particle size is the same， the impacting angle exerts effects on the dust release rate of mud desert surface， and the ranking order from higher dust release rate is 60°>30°>45°， but the difference of the dust release rate is not significant under such conditions. （3） When the impacting angle is 45°， the mass erosion rate and energy erosion rate of medium sand， coarse sand and extremely coarse sand on mud desert surface are 0.04 g·kg^-1 and 0.43 g·J^-1， 0.08 g·kg^-1 and 0.74 g·J^-1， 0.26 g·kg^-1 and 2.54 g·J^-1， respectively. When the grain size of sand abrader double increases while remaining the impacting angle， there is no proportional linear change in growth between the dust release rate and energy abrasion rate.