以塔克拉玛干沙漠南缘策勒绿洲西部沙漠-绿洲过渡带为研究区,选择植被盖度 < 5%裸沙样地、植被盖度10%～15%柽柳样地和植被盖度20%～25%骆驼刺样地,利用可移动梯度风测量系统,获取了系统性天气过程中距离地表20 cm、40 cm、60 cm、100 cm和200 cm高度的风速及200 cm高度的风向系列数据,对3个样地平均风速、风速脉动和风向脉动进行分析和研究。结果表明:(1)植被的存在大幅度消弱了平均风速,随着植物密度的增加平均风速逐渐降低,风速廓线显示平均风速发生明显降低的转折高度与植被冠层的平均高度相对应。(2)3个样地脉动风速均近似服从高斯分布,可见植被的存在并未改变风速脉动分布规律。各样地风速脉动强度均随指示风速的增大而增大,随距离地表高度的降低而下降。风速脉动相对值总体上呈现随植物密度增大而增大的趋势,植物群落结构的差异增加了相对风速脉动垂直分布的复杂性。(3)风向脉动幅度以裸沙样地最小、柽柳样地次之、骆驼刺样地最大,即随植物密度增加而增大。同一样地内风向脉动值不随指示风速的变化而发生明显变化。
Field measurement of wind direction at 200 cm high and wind velocity at five heights (20 cm, 40 cm, 60 cm, 100 cm and 200 cm) over three typical plots, with plant coverage of < 5%, 10%-15% and 20%-25% respectively, was conducted in the Qira desert-oasis ecotone. The purpose of this research is to help to understand the characteristics of wind fluctuation over different ground surface at the southern rim of the Taklimakan Desert. It is concluded that the vegetation type affects the change of average wind velocity, wind velocity fluctuation and wind direction fluctuation, but it has little influence on probability distribution of wind velocity fluctuation. With increasing plants density, the change range of average wind velocity and absolute wind velocity fluctuation decrease. The absolute wind velocity fluctuation increases with increase of wind velocity and with increase of height to ground surface in all three plots. Affected by plant community structure, the relative wind velocity fluctuation becomes complicated. The range of wind direction fluctuation increases with plants density, but it has no obvious change in the same plot when wind velocity changes.
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