戈壁风蚀面与植被覆盖面地表性质粗糙度长度的确定

以Monin-Obukhov相似性理论为基础, 利用量纲分析法分别推导出不同层结稳定度下确定戈壁风蚀面与植被覆盖面空气动力学参数的物理模型, 并利用该模型研究了粗糙度长度与粗糙元性质, 流经近地层流体特征以及大气层结稳定度之间的关系。得出以下结论: 戈壁风蚀面上空气动力学粗糙度长度与砾石粒径、高度、覆盖度、自由风速、摩擦速度以及大气层结稳定度有关; 植被覆盖面空气动力学粗糙度长度取决于植被类型、植被高度、覆盖度、零平面位移高度、自由风速、摩擦速度以及大气层结稳定度。

Determination of Roughness Length on Gobi Deflation Plane and Vegetated Surface

A physical model for determining the roughness length on gobi deflation plane and vegetated surface under different atmospheric stratification stability cases is developed based on the Monin-Obukhov similarity theory and the method of dimensional analysis. Then the relationship among the roughness length, the nature of the roughness units, the character of the passing wind and the atmospheric stratification stability parameter_the bulk Richardson number is studied through the model. The results show that the aerodynamic roughness length of gravel bed is a function of gravel size, coverage, free velocity, friction velocity and the atmospheric stratification stability; the roughness length of vegetation cover surface depends on the type, height, coverage of the vegetation, zero-plane displacement height, free velocity, friction velocity and the atmospheric stratification stability.