不同灌木覆盖状态下防风机理研究  

Windbreak mechanism under different shrub cover conditions

作　　者：魏宝[1] 丁国栋[1,2] 吴斌[1,2] 张宇清[1,2] 包岩峰[1] 高广磊[1] 石慧书 赵进宏 

机构地区：[1]北京林业大学水土保持学院,水土保持与荒漠化防治教育部重点实验室 [2]宁夏盐池荒漠生态系统定位研究站 [3]宁夏盐池县环境保护和林业局

出　　处：《北京林业大学学报》2013年第5期73-78,共6页Journal of Beijing Forestry University

基　　金："十二五"国家科技支撑计划项目(2012BAD16B02);教育部博士点基金项目(20090014110003);北京林业大学科技创新计划项目(TD2011-04)

摘　　要：通过野外观测,定量研究毛乌素沙地西南缘不同灌木覆盖状态下的防风机理。以沙蒿灌木林地和沙柳灌木林地为研究对象,裸沙地作为对照,用多剖面自计式遥测风速仪连续观测、记录距离地面0.1、0.5、1.0、2.0、3.0、4.0、5.0和6.0 m 8个不同垂直高度位置的风速变化。通过对风速测定结果的统计分析,绘制3种状态下的风速廓线图,并计算风速廓线方程、边界层位移厚度、边界层动量损失厚度和空气动力学粗糙度。结果表明:沙蒿灌木林和沙柳灌木林在近地层较裸露沙地有明显的降低风速作用,随着风速增大这种作用逐渐减弱。不同地表覆盖的空气动力学粗糙度随着风速的增大而呈对数减小。当风速较大时,边界层位移厚度比空气动力学粗糙度能更实际地反映整体观测高度范围内风速降低的状况。从空气动量的角度分析,有植被覆盖的地表空气动量损失比较稳定,裸沙地的空气动量损失则随风速增大而减小。Windbreak mechanism under different shrub cover conditions was quantitatively studied by carrying out a field investigation in southwestern marginal zone of the Mu Us Sandy Land, northwestern China. Artemisia ordosica and Salix psammophila shrub land were taken as the object of this study. Bare sand was set as control and the wind velocities at 0. 1, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 m height upon research grounds were recorded. By doing statistical analysis of wind velocity measurements, drawing wind profile, calculating the wind profile equation, boundary layer thickness, aerodynamic roughness, we got the conclusion that both A. ordosica and S. psammophila shrub land decreased wind velocity of boundary layer much more significantly than bare land, and this effect decreased with wind velocity increasing. Aerodynamic roughness of shrub land decreased logarithmically with wind velocity increasing. When wind velocity was high, boundary layer displacement thickness would reflect the decrease of wind velocity at observation height more realistically than aerodynamic roughness. Analyzing from the air momentum, the loss of air momentum on the surface covered with vegetation was relatively stable. While the loss of air momentum on bare sand would decrease as wind velocity increasing.

关 键 词：灌木覆盖 防风机理 风速廓线 边界层厚度 毛乌素沙地 

分 类 号：S761.2[农业科学—森林保护学]