戈壁地表风沙运动特征的野外观测研究

Research on the Characteristics of Blowing Sand Drift Over Gobi Surface by Field Experiment.

通过野外观测实验探讨了戈壁地表风沙运动的若干特征。结果表明：戈壁地表风沙活动层主要集中在距地表60 cm高度内;不同粒径沙粒输沙强度的垂向分布不同,以0.25~0.5mm为过渡区,〈0.25mm颗粒输沙强度随高度增大先增加而后按指数规律递减,〉0.5mm颗粒则随高度增加呈线性递减,且粒径越大,递减的梯度越小;风沙流中颗粒的粒度组成不仅受风速和颗粒起动风速影响,而且还与地表粒度组成直接相关;输沙率与风速之间关系服从指数规律,公式形式为q=α.eβ.u,其中α、β为相关系数,u为地面2m高处风速。

Some characteristics of sand-drift over Gobi surface are discussed based on the field measurement.The author draws following conclusions： The activity layer height of drifting sand is within 60cm away from surface.The vertical profiles of sand transport intensity is different with its grain-size.Transition range is 0.25~0.5mm Particle diameters,sand transport intensity of the particles diameter less than 0.25mm increases first and then decreases according to the exponential rule with the increase of height,but that of the particles diameter larger than 0.5mm decreases following the linear rule with the increase of height,and the decrease grads would be attenuation with the sand grain diameter increase.The grain gradation in wind flux is relative to not only the wind velocity and the threshold velocity of sand-driving,but the grain gradation of the underlying surfaces.The relationship between sand transporting rate and wind speed follows the exponential growth regular,the experiment formula is： q=α·eβ·u,where α、β are the relative coefficients,u is the wind speed at 2m height（m/s）.