塔克拉玛干沙漠平坦沙地风沙流结构的空间差异性研究

利用高频率全自动集沙仪,于2015年4月28日至2015年7月30日在塔克拉玛干沙漠腹地平坦流动沙地开展了风沙流的空间观测,分析了该地区平坦沙地风沙流结构的空间差异性.结果表明:(1)4次天气过程4组集沙仪风沙流结构都符合幂函数分布,但是4组集沙仪同一高度的输沙率和输沙量以及总水平输沙量差异较大.4次天气过程中,25cm高度平均输沙量在3.31~5.35g之间,随着高度增加,平均输沙量差异性呈现减小趋势,100cm高度时平均输沙量在0.22~0.49g之间;4次天气过程中,4组集沙仪平均总沙尘水平通量在1.22~233.47kg/m之间.风沙流的不均匀性是造成此现象的主要原因.(2)采样频率对风沙流结构没有影响,5min以后风沙流结构基本稳定.

The Spatial Difference of Wind Sand Flow Structure over a Flat Sandy Surface of the Taklimakan Desert

The observations of wind-sand flow were carried out over a flat sandy surface in the hinterland of the Taklimakan Desert with high frequency automatic sand collectors during April 28,to July 30,2015,and then the spatial difference of wind-sand flow structure was analyzed.The results indicated that:(1)for four dust events,the Aeolian sand as a function of height could be expressed by using apower function for the four sets of sand collectors.However,there were great differences on sand transport rate and the amounts of Aeolian sand at the same height,and the total amounts of Aeolian sand that transported pass unit width also had great differences of the four groups-sand collector.The average amount of aeolian sand at the 25 cm high varied from 3.31~5.35 g,the differences of amount of aeolian sand decreased with height,varying from 0.22~0.49 g at the 100 cm high.The average total horizontal dust flux of the same sand collector for the four dust events ranged form1.22~233.47kg/m.This phenomenon was due to the inhomogeneity of wind-sand flow.(2)The sampling frequency had no effect on the structure of wind-sand flow,and the wind-sand flow structure was tending towards stability after 5 minutes.