Remote sensing techniques for river monitoring facilitate faster measurement campaigns compared to traditional methods, reduce risks to personnel and instruments, and allow measurements under critical flow conditions. An alpha coefficient (α) is commonly employed to convert surface velocities, obtained by contactless techniques, into depth-averaged velocities, which are used for the application of the velocity-area method for assessing discharge. Some optical-based software programs use a constant α value, based on a theoretical “standard”. However, analyses of empirical vertical velocity profiles in real cases reveal that α can significantly deviate from this standard due to various factors (roughness, turbulence, etc.).

中文翻译：

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一种基于地表速度的河流流量测量中估计 α 系数的简化方法


与传统方法相比，用于河流监测的遥感技术有助于加快测量速度，降低人员和仪器的风险，并允许在临界流量条件下进行测量。通常采用 α 系数 （α） 将通过非接触式技术获得的表面速度转换为深度平均速度，用于应用速度-面积法来评估放电。一些基于光学的软件程序使用基于理论“标准”的常α值。然而，对实际情况下的经验垂直速度分布的分析表明，由于各种因素（粗糙度、湍流等），α可能会显著偏离该标准。