塔克拉玛干沙漠荒漠过渡带空气动力学粗糙度分析

根据塔克拉玛干沙漠北缘荒漠过渡带哈德、肖塘2个试验点的风、温梯度观测数据，利用风速比法计算了中性大气层结、无风沙运动条件的空气动力学粗糙度[WTBX](z0)，并分析探讨z0[WTBZ]与下垫面状况、大气稳定度及风速的相互关系。结果表明：哈德、肖塘中性条件下z₀的取值范围分别为 1.81×10^-11～1.20×10^-3m，1.00×10^-11～1.65×10^-3m，平均值为2.70×10^-5m 和6.05×10^-5m，与平坦沙面的值较为接近；z₀随下垫面性质变化明显；空气动力学粗糙度总体上随着理查逊数(R_i)增大而变大，但又呈现出一定的离散程度；空气动力学粗糙度与2 m高度风速呈显著的负指数关系；大气稳定度对空气动力学粗糙度的影响作用有待于进一步确定。 

Analysis on Aerodynamic Roughness Length in a Desert Transitional Zone of the Taklimakan Desert

In this paper,the values of aerodynamic roughness length over the Hade and Xiaotang regions were calculated under the conditions when the atmospheric stability was in a neutral stratification and there was no wind-blown sand movement using the wind speed ratio method based on the data of average wind speed and temperature obtained from 10-m-high towers at Hade and Xiaotang in a desert transitional zone of the Taklimakan desert.The correlations between aerodynamic roughness length and underlaying surface,air stability and wind speed were analyzed and discussed.The results are as follows: The aerodynamic roughness length z0 of neutral stratification was in ranges of 1.81×10-11-1.2×10-3 m and 1.00×10-11-1.65×10-3 m,their average values were 2.70×10-5 m and 6.05×10-5 m,respectively,and these values were close to those over flat sand surface.The aerodynamic roughness length z0 changed obviously with the change of underlaying surface features.On the whole,the value of aerodynamic roughness length was increased with the increase of atmospheric stability,while the discrete degree of aerodynamic roughness length was increased.There was a significant negative exponential relation between aerodynamic roughness length and wind speed at 2-m height.Atmospheric stability has a complex influential action on aerodynamic roughness length,which needs to be further studied.