A semi-empirical approach based on surface-renewal theory for estimating the friction velocity is tested for measurements taken in the inertial sublayer. For unstable cases, the input requirements are the mean wind speed and the high-frequency trace (10 or 20 Hz) of the air or sonic temperature. The method has been extended to traces of water vapour (H 2 O) and carbon dioxide (CO 2 ) concentrations. For stable cases, the stability parameter must also be considered. The method’s performance, taking the direct friction velocity measured by sonic anemometry as a reference, was tested over a growing cotton field that included bare soil with some crop residues at the beginning of the season. In general, the proposed friction-velocity estimates are reliable. For unstable cases, the method shows the potential to outperform the wind logarithmic-law computation. Discarding cases with low wind speeds (e.g., < 0.3 m s −1 and mean wind shear < 1 Hz), the proposed approach may be recommended as an alternative method to estimating the friction velocity. There is the potential, based on the input requirements, that the proposed formulation may offer significant advantages in the estimation of the friction velocity in some marine environments.

中文翻译：

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使用标量轨迹和平均风速估计摩擦速度

测试了一种基于表面更新理论的半经验方法来估计摩擦速度，用于在惯性子层中进行的测量。对于不稳定的情况，输入要求是平均风速和空气或声波温度的高频轨迹（10 或 20 Hz）。该方法已扩展到痕量的水蒸气 (H 2 O) 和二氧化碳 (CO 2 ) 浓度。对于稳定情况，还必须考虑稳定性参数。该方法的性能以通过声波风速测量法测量的直接摩擦速度为参考，在棉田生长中进行了测试，该棉田包括在季节开始时带有一些作物残留物的裸土。一般来说，建议的摩擦速度估计是可靠的。对于不稳定的情况，该方法显示出优于风对数定律计算的潜力。丢弃低风速的情况（例如，< 0.3 ms -1 和平均风切变< 1 Hz），建议的方法可能被推荐作为估计摩擦速度的替代方法。根据输入要求，所提出的公式有可能在估计某些海洋环境中的摩擦速度方面具有显着优势。