Sonic anemometer tilt correction algorithms
Sonic anemometer tilt correction algorithms
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DOI：
10.1023/a:1018966204465
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发表时间：
2001-04-01
影响因子：
4.3
通讯作者：
Stage, SA
中科院分区：
文献类型：
--
作者：
Wilczak, JM;Oncley, SP;Stage, SA
声波风速计衍生的应力估计风速计的倾斜的灵敏度进行了研究。最大的应力误差出现在不稳定层结（z/L < 0）和深对流边界层。然后比较了三种确定相对于平均流线坐标系的倾斜角和计算倾斜校正应力的方法。最常用的方法，涉及风速计的轴的双重旋转，示出导致显着的运行到运行的应力误差，由于平均垂直速度的采样不确定性。另一种方法，需要一个三倍旋转的风速计轴，显示td导致更大的运行到运行的应力误差，由于平均垂直速度和侧风应力的组合采样误差。对于跨流应力很重要的海洋测量，由于未校正的横向倾斜分量，双旋转方法高估了表面应力。第三种方法，使用平面拟合技术，示出，以减少运行到运行的应力误差，由于抽样效应，并提供了一个无偏的估计的横向应力。
The sensitivity of sonic anemometer-derived stress estimates to the tilt of the anemometer is investigated. The largest stress errors are shown to occur for unstable stratification (z/L < 0) and deep convective boundary layers. Three methods for determining the tilt angles relative to a mean streamline coordinate system and for computing the tilt-corrected stresses are then compared. The most commonly used method, involving a double rotation of the anemometers' axes, is shown to result in significant run-to-run stress errors due to the sampling uncertainty of the mean vertical velocity. An alternative method, requiring a triple rotation of the anemometer axes, is shown td result in even greater run-to-run stress errors due to the combined sampling errors of the mean vertical velocity and the cross-wind stress. For measurements over the sea where the cross-stream stress is important, the double rotation method is shown to overestimate the surface stress, due to the uncorrected lateral tilt component. A third method, using a planar fit technique, is shown to reduce the run-to-run stress errors due to sampling effects, and provides an unbiased estimate of the lateral stress.