塔中地区近地层风沙流的结构特征

Structural Characteristics of Near Surface Wind Blown Sand in Central Tarim Basin

[目的]分析特定高度的风沙流结构,阐明其风沙流运动规律,为防沙治沙提供理论依据。[方法]采用全方位微梯度集沙仪和风速仪,收集2014年7月至2014年8月风沙流输沙样,通过对近地层0—85mm风沙流输沙率、风速进行分析。[结果]输沙率与风速的最佳拟合关系为幂函数,相关系数为0.968 7。随风速的增大,风沙流输沙率主要集中在0—35mm,0—5和15—35mm百分含量基本呈上升的趋势,5—15和35—85mm百分含量基本呈下降的趋势。[结论]风沙流运动是一种贴近地面沙物质的搬运过程,随风速的增大,输沙量越来越集中在0—35mm范围内。因此,采取各种措施改变近地表层的风状况及风沙流结构就能有效地削弱风沙活动的强度。

[Objective] To analyze the structure of wind blown sand at a specific height, in order to clarify the disciplinarian of wind blown sand, and provide the theoretical basis for preventing and controlling desertification in central Tarim Basin.[Methods] Omni-directional microinverse sand trap and anemometer were used to collect sand transport sample of wind blown sand from July to August in 2014 and wind-sand transport rate, wind speed in the near surface layer （0-85 mm） were analyzed.[Results] The most fitting relationship between sand transport rate and wind speed was power function, the correlation coefficient was 0.9687. Along with the increase of wind speed, sand transport rate mainly concentrate on 0-35 mm layer,meanwhile, it showed ascending trend in 0-5 mm and 15-35 mm layers, and descending trend in 5-15 mm and 35-85 mm layers.[Conclusion] Wind blown sand movement is the process of sand sediment transport in the near surface layer, and sand sediment discharge more and more concentrated on the range from 0 mm to 35 mm with the increase of wind speed. Thus, it requires taking various measures to change the state of near earth surface wind blown sand structure and meanwhile which can effectively weaken the strength of the sandstorm activities.