固定沙丘风蚀坑不同部位风速特征

Wind Speed Character in Different Parts of Blowout in Fixed Dunes

固定沙丘活化形成的风蚀坑呈现出斑点状流沙分布,其直接的后果就是扩展为流动沙丘,导致沙地面积扩展。本文采用HOBO风速/风向自动记录仪测定了浑善达克沙地固定沙丘风蚀坑内不同部位不同高度的风速变化。结果表明,风沿着纵轴方向进入风蚀坑后,沿着坡向向上逐渐增加且高于对照(CK)位置,并且风蚀坑内50 cm以下高度范围内风速变化明显,而200 cm高处的风速相对稳定。在风蚀坑横轴方向,在风蚀坑中心线两侧各5 m范围内风速增加,且风蚀坑东北侧或阳面风速明显低于风蚀坑西南侧或阴面。在治理风蚀坑时,不仅要治理风蚀坑底面位置,同时也要治理风蚀坑阴、阳面两侧的坡面,才能有效地控制风蚀坑扩展。

The blowouts formed by activated fixed dunes have distributed in spot-like shifting sand,which can change into moving dunes and enlarge the area of sandy land. The wind speed changes at different height and in different parts of blowouts in fixed dunes of Hunshandake Sandy Land have been measured by use of HOBO wind speed/direction automatic recorder. The results show that after blowing in blowouts in longitudinal direction,the wind has gradually enhanced upward along the slope and become higher than the control（ CK） position,the wind speed has changed obviously below 50 cm in blowout,and the wind speed has been relatively stable at 200 cm. In horizontal direction of blowout,the wind speed has strengthened in the range of 5 m beside the center line of blowout,and the wind speed in the northeast side and sunny side of the blowout has been lower obviously than the one in the southwest side and the nightside of the blowout. In order to effectively control the enlarge of blowout,it needs to control the bottom of blowout and the slope side of sunny side and nightside of the blowouts.