巴丹吉林沙漠风沙流输沙沙粒形貌特征分析

Analysis of Sand Shape Characteristics from the Wind-Sand Flows in Badanjilin Desert

为了解风沙流输沙沙粒微观形貌特征,本文利用尼康公司SMZ1500体视显微镜和DT2000图像分析软件对巴丹吉林沙漠拐子湖沙尘暴天气过程中所采集的梯度沙样粒形进行分析,结果显示粒径大于0.3 mm的沙粒表面磨蚀作用明显,尤其是透明度差的沙粒磨蚀更为显著,沙粒圆度值分布在0.8～1.0之间,沙粒圆度集中在0.8～0.9之间,磨圆较好,表面光滑。粒径在0.15～0.3 mm之间的沙粒的表面磨蚀作用相对较弱,棱角明显增多,沙粒形状渐趋复杂;圆度值仍然分布于0.8～1.0之间,不过较多地集中在0.8～0.9之间。粒径在0.074～0.15 mm间的沙粒表面磨蚀作用更弱,棱角更多、更明显,沙粒圆度值分布在0.6～1.0之间,跨度变大,说明沙粒的形状更多样化,以50 cm高度上所取沙样最明显。沙粒圆度、磨圆度的研究及分析对本区沙尘源的确定具有一定的参考意义。

In order to understand the shape features of sand from sand-wind flow, using NIKONSMZ1500 and DT2000 image analysis software the shape of sand from the sand storm at the region of Guaizi Lake in the Badain Jaran desert was analyzed in the paper. The results indicate that sand surfaces with the diameter over 0.3mm were obviously eroded especially for the sands with poor transparency. The roundness value was between 0.8mm and 1.0mm, and the value was concentrated between 0.8ram and 0.9ram. On the contrary, the sands with the diameter between 0.15mm and 0.3 mm were weaker in abrasive action,with more obvious surface edges and corners, and more complicated sand shapes. The roundness value distributed between 0.8 and 1.0 concentrating in the range of 0.8-0.9. The sands, whose diameter were between 0.074 mm and 0.15ram, were weakest in abrasive action, with more obvious surface edges. The rather large span of sand roundness value between 0.6 and 1.0 illustrated the sand shape was more diversified, especially obvious for the samples at the 50em height. The research on circular degree and grinding roundness of sands provided certain reference significance for determining the dust source area.