不同盖度沙蒿群丛防风作用研究

以天然沙蒿群丛为研究对象，初始盖度为60%，人工降低其盖度为50%，40%和30%，用多剖面自计式遥测风速仪连续观测记录沙蒿林内距离地面0.1 m，0.5 m，1.0 m，2.0 m，3.0 m，4.0 m，5.0 m和6.0 m高度处的风速变化。当沙蒿群丛盖度由30%增加到60%，风速廓线变化不明显，风速廓线方程、空气动力学粗糙度、边界层位移厚度和边界层动量损失厚度的值较为接近，没有随盖度呈现出规律性的变化，在这个盖度变化范围内，沙蒿群丛降低风速的作用相似。

Study on Windbreak Effect of Artemisia ordosica Community over Different Vegetation Coverage

In traditional study,wind velocity,aerodynamic roughness,friction velocity,drag coefficient and other parameters are often used to evaluate the restriction effect of vegetation on wind erosion,but the studies on wind energy dissipation of vegetation using boundary layer displacement thickness and momentum loss thickness are relatively insufficient.In this paper,the windbreak effect of Artemisia ordosica community over different vegetation coverage was quantitatively studied after carrying out a field investigation in southwestern marginal zone of the Mu Us Sandy land.Artemisia ordosica was selected in the study,its initial coverage was 60%,it was artificially decreased down to 50%,40% and 30%,and the wind velocities at 0.1,0.5,1.0,2.0,3.0,4.0,5.0 and 6.0 m were recorded.When the coverage of Artemisia ordosica community was increased from 30% to 60%,wind profile did not change significantly,and the values of wind profile equation,aerodynamic roughness,boundary layer displacement thickness and momentum loss thickness were similar.As those parameters did not show a regular change with changing vegetation coverage,it is believed that vegetation coverage and windbreak effect of Artemisia ordosica community are similar.