塔里木盆地多种沙源类型沙通量异变特征研究

以塔里木盆地周边地区多种沙尘源地为研究区,通过塔中、肖塘、若羌、策勒四个风沙观测场获取的沙尘暴过程中贴地层风向、风速数据以及风蚀传感器实测的撞击颗粒数等数据计算出各地起沙临界摩擦速度,利用Gillette经典的垂直沙尘通量及Lettau水平沙尘通量公式对若羌、策勒、塔中、肖塘沙尘通量进行了估算,并通过各层实测的梯度风速作为背景值界定出塔里木盆地多种沙源类型沙通量变化比对特征,结果表明:垂直沙尘通量F量级为10-8kg/(m2.s),水平沙尘通量Q量级为10-4 kg/(m.s);风速相同情况下,F若羌最大,策勒次之,塔中、肖塘较小;Q若羌值最大,策勒次之,塔中第三,肖塘最小。垂直沙通量F与风速都表现出较好的线性相关,风速递增,垂直沙通量递增;风速递减,垂直沙通量递减。在风速递增幅度相同条件下,若羌Q值递增幅度最大,策勒次之,塔中、肖塘基本相同。

Study on the Variation Characteristics of Sand Dust Flux Deriving from Multi-sources Types of Sands in the Tarim Basin

In the area with multi-sources types of sand-dust around Tarim Basin,the critical friction velocity was calculated by using the parameters of near-surface layer wind direction,wind speed and impact particle numbers from the observation sites Ruoqiang,Cele,Tazhong,Xiaotang,and the dust transport flux was evaluated by Gillette classic vertical dust transport flux and Lettau horizontal dust transport flux function.The change characteristics of multi-source types of sands in Taklimakan basin were figured out by using wind speed as background value.The results showed that the value of vertical dust transport flux was in a order of 10-8 kg/(m2·s) and the horizontal dust transport flux was in a order of 10-4 kg/(m·s).Under the same wind speed,F value in Ruoqiang was the biggest,followed by Cele,Tazhong and Xiaotang,so was the Q value.The vertical dust transport flux was well linearly correlated with wind speed;it increased or decreased with the wind speed.Under the same increasing amplitude of wind speed,the increase amplitude of Q value in Ruoqiang was the biggest,followed by Cele,Tazhong and Xiaotang.