丘间低地不同部位风沙流结构特征

 为了研究丘间低地不同部位风沙流结构特征,摸清风沙运动规律,为丘间低地风沙治理提供理论依据,使用阶梯式集沙仪对丘间低地风沙流进行了观测。结果表明,丘间低地不同部位风沙流结构存在明显差异,输沙率随沙源距离的增加而减小,风速越大,差异越明显,沙源丰富度和地形是造成差异的主要原因。在0~80 cm范围内,输沙量与风速呈指数函数关系,输沙率与高度呈幂函数关系。丘间低地风沙流结构特征值λ在沙源不同距离处均大于1,而且随着风速的增加,λ逐渐增加,风沙流趋向于更加不饱和状态。从近沙源处开始往后,λ基本呈增加趋势。

Aeolian-sand Flow Structure Characteristics at Different Positions in Inter-dune Lowland

Field observation of Aeolian-sand flux with stepped sand sampler was conducted to study the Aeolian-sand structure and aeolian sand movement law at different positions in inter-dune lowland in Minqin, Gansu of China, further to provide a theory basis for controlling blowing sand. Three stepped sand samplers of 80 cm height were installed along the main wind direction. Results indicate that there is a significant difference of sand transportation rate among the three positions, showing a decreasing trend along the main wind direction away from sand source. The larger the wind speed is, the more obvious the difference is. The reasons resulting in this difference are due to undulating terrain and sand supply abundance. Within 0-80 cm height, the relationship of sand transportation rate with wind speed fits a  exponential function and an power relationship with height separately. The structural characteristic values (λ) of  aeolian-sand flow are all larger than 1 in all position. There is an increasing trend of the λ value along the main wind direction away from sand source and the increase of wind speed, which indicates that aeolian-sand flow become more unsaturated.