摘要
通过对研究区域风速和沙通量的实测数据,分析了策勒绿洲—沙漠过渡带上流动沙地、半流动沙地和固定沙地下垫面风沙活动参数,并进行了不同下垫面模型的推导与验证。研究结果表明:(1)空气动力学粗糙度受到地表植被盖度和风速的共同影响,流动沙漠起沙后,空气动力学粗糙度随风速的增大而升高,半流动沙漠和固定沙漠空气动力学粗糙度随风速的增大而降低,空气动力学粗糙度随地表植被盖度和植被高度等的增大而升高。(2)策勒绿洲—沙漠过渡带流动沙漠、半流动沙漠、固定沙漠的沙通量模型利用Bagnold模型与实际沙通量校正后确定,流动沙漠、半固定沙漠、固定沙漠的幂值分别为3.65、3.57、2.92,B值分别为4.33×10^(-11)、6.27×10^(-11)、2.61×10^(-9)。(3)2014年3~9月,策勒绿洲沙漠过渡带流动沙漠、半流动沙漠(植被盖度约为10%)、固定沙漠(植被盖度约为40%)的输沙通量分别为5 679.4 kg·m^(-1)、1 033 kg·m^(-1)和176.2 kg·m^(-1),植被对下垫面沙通量的影响显著,半流动沙漠的沙通量为流动沙漠的18.2%,固定沙漠沙通量占流动沙漠沙通量的3%。
Sand flux is a parameter which measure wind capacity to move sand, and the difference of terrain and vegetation coverage lead to the difference of the erosion of sand bed and sand-blown activity. With measuring da- ta of wind velocity and sand flux in the field of Cele oasis-desert ecotone, Xinjiang, China, the responding param- eters for the model corrected by Bagnold were obtained, which would offer a way to estimate the weight of sand flux. The results of the study have showed as follows ： firstly, aerodynamics roughness was affected by the under- lying surface and wind velocity, plant coverage increased the roughness and the wind velocity played opposite effect, the roughness values in the mobile sandland, semi-mobile sandland, and fixed sandland were 0.03 cm, 0.10 cm and 22 cm respectively. Secondly, the responding B value in mobile sandland was 4.33 × 10-11, semi-mo- bile sandland model was 6.27 × 10-11, and fixed sandland model was 2.61 × 10-9. These models had excellent rele- vance with the measured value, which can be explained that the calculated value of sand flux in mobile sandland was 0.93 times to the measured value, and the semi-mobile sandland was 1.07 times, and the coefficient value in mobile sandland and semi-mobile sandland was 0.88 and 0.99 respectively, and the model with the high tested value was applicable in this underlying surface. Thirdly, taking advantage of these models to estimate sand trans- portation weight from March to September, 2014, the calculation results of model indicated that mobile sandland transportation was about 5 679.4 kg. m-1 in Cele oasis-desert ecotone, semi-mobile sandland transportation was 1 033 kg. m-1, accounting for 18.2% of the mobile sandland, and fixed sandland transportation was 176.2 kg. m-1, accounting for 3% of mobile sandland. These data indicated that the existed plants played a vital role in prevent- ing wind velocity and wind-blown disasters. This paper combined the measurement value in the field with the classical aerodynamics model created by Bagnold. As the parameters of the model changed with different underly- ing, the sand flux was calculated and sand disasters of different plant coverage area were predicated with the mod- els in Cele oasis-desert ecotone. As a whole, the research method is scientific and study results are credible.
出处
《干旱区地理》
CSCD
北大核心
2017年第3期533-540,共8页
Arid Land Geography
基金
国家国际科技合作专项项目(2015DFR31130)
中国科学院"西部青年学者"项目
