Surface layer turbulence has an important influence on land-air interactions and pollutant dispersion, and studying the characteristics of surface layer turbulence in complex terrain can contribute to understanding land-air interactions, improving model surface layer parameterization, and enhancing pollution prediction capabilities. The surface layer turbulence observations from the Semi-Arid Climate and Environment Observatory (SACOL) of Lanzhou University in 2008 were processed in this study. High-quality turbulence parameters were calculated, the statistical and transfer characteristics of turbulence were analyzed, and the formation of turbulence was assessed in terms of dynamics and thermodynamics. The atmospheric stability in the semiarid region of the Loess Plateau is basically dominated by neutral/near-neutral and weakly unstable/weakly stable conditions; this pattern is significantly different from the preponderance of unstable and stable layers at other sites. The turbulence intensity differs significantly in both the horizontal and vertical directions and basically shows the relationship . The mean values of and are 0.42 and 0.40, respectively, and the mean value of is 0.14, which is different from the general pattern of , indicating that the turbulence intensity at SACOL is characterized by a large lateral wind contribution. The dimensionless standard deviations of the nonneutral wind velocity components satisfy the “1/3rd law,” and the dimensionless standard deviations of u, , and components are 3.35, 2.98, and 1.26, respectively, in the semiarid Loess Plateau. These values are larger than those over flat terrain. The contribution of the shear term to the formation of turbulence is greater than that of the buoyancy term, and the mean annual values of the shear term and the buoyancy in the kinetic energy budget equation in SACOL are 47.94 × 10⁻⁴ m²·s⁻³ and 11.32 × 10⁻⁴ m²·s⁻³, respectively. The annual mean values of the momentum transfer coefficient and the heat transfer coefficient under near-neutral conditions are 8.54 × 10⁻³ and 2.52 × 10⁻³, respectively.

中文翻译：

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黄土高原半干旱区复杂地形表层湍流特征

表层湍流对陆气相互作用和污染物扩散具有重要影响，研究复杂地形中表层湍流特征有助于理解陆气相互作用，改进模型表层参数化，提高污染预测能力。本研究处理了兰州大学半干旱气候与环境观测站（SACOL）2008年的表层湍流观测数据。计算了高质量的湍流参数，分析了湍流的统计和传递特性，从动力学和热力学两个方面对湍流的形成进行了评估。黄土高原半干旱区大气稳定性基本以中性/近中性和弱不稳定/弱稳定状态为主；这种模式与其他地点的不稳定和稳定层的优势明显不同。水平和垂直方向的湍流强度差异显着，基本显示出关系. 的平均值和分别为0.42和0.40，和的平均值为0.14，它是从一般模式不同，表明 SACOL 的湍流强度以较大的侧向风贡献为特征。在半干旱黄土高原，非中性风速分量的无量纲标准差满足“1/3 定律”， u、、和分量的无量纲标准差分别为3.35、2.98 和1.26。这些值大于平坦地形上的值。剪切项对湍流形成的贡献大于浮力项，SACOL动能收支方程中剪切项和浮力的年均值为47.94×10 ^-4  m ² ·s ⁻³和 11.32 × 10 ⁻⁴  m分别为² ·s ^-3。近中性条件下动量传递系数和传热系数的年平均值分别为8.54×10 ^-3和2.52×10 ^-3。