青海湖沙地人工治理沙丘的风速廓线变化特征

Variable Characteristics of Wind Profile of the Artificial Sand Dune in Sandy Land around the Qinghai Lake

对青海湖湖东沙地麦草方格沙障结合沙棘实生苗的人工治理沙丘进行风速廓线及其风沙防护效益研究,结果表明,人工治理措施明显降低了沙丘各部位的近地层风速,增强了高层风速。与流动沙丘相比,垂向风速增加率的差异使人工治理沙丘不同部位的超越高度值出现"坡脚>坡中>丘顶"的规律。风速垂向气流的变异导致不同高度层的防风固沙效果不同,低层风沙防护效益显著高于中、高层。同时结合坡度,植被盖度等因子,分析了影响风速廓线的变化原因,从而为青海湖沙地人工治理效果进行评估与初步指导。

Through the study of wind profile and sand flow in the sand area of the eastern shore of Qignhai Lake,which the technique of straw-checkerboard combining with sea-buckthorn seeding is experimented and promoted,it can be found that the low layers wind speed decreased obviously while high layers got increased in each position of artificial sand dune compared with the mobile dune.This is mainly due to the vertical change rates of the wind speed.Moreover,there is a surpass height which is higher at the foot of the slope and lower at the top between the artificial and mobile sand dunes,which leads to the better effects of wind prevention and sand fixation in the surface layer.Besides the difference of sand dune gradient,vegetation coverage and the average sand grain size have effects on the change of the wind profile.These results above will make a preliminary evaluation and provide basic guide to the management of desertification around the Qinghai Lake.