Motion-correlated flow distortion and wave-induced biases in air-sea flux measurements from ships
Motion-correlated flow distortion and wave-induced biases in air-sea flux measurements from ships
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DOI：
10.5194/acp-15-10619-2015
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发表时间：
2015-01-01
影响因子：
6.3
通讯作者：
Norris, S. J.
中科院分区：
文献类型：
--
作者：
Prytherch, J.;Yelland, M. J.;Norris, S. J.
直接测量湍流的动量、热量、水分和气体的海气通量通常是用安装在船上的传感器来完成的。基于船舶的湍流风测量可以使用成熟的技术对平台运动进行校正，但是与波浪和平台运动相关的尺度偏差在通量测量中仍然很明显。目前还不确定这个信号是由于平台上气流的时变畸变还是由于影响湍流的风波相互作用。从标量测量中消除这种运动尺度偏差的方法先前已经发表，但它们在动量通量测量中的应用仍然存在争议。在这里，我们表明，测量到的运动尺度偏差与船舶水平速度有关，并且对其进行修正可以减少测量到的动量通量对船舶风向的依赖。我们得出的结论是，偏差是由于实验误差和时变的运动相关的流动畸变是可能的来源。
Direct measurements of the turbulent air-sea fluxes of momentum, heat, moisture and gases are often made using sensors mounted on ships. Ship-based turbulent wind measurements are corrected for platform motion using well established techniques, but biases at scales associated with wave and platform motion are often still apparent in the flux measurements. It has been uncertain whether this signal is due to time-varying distortion of the air flow over the platform or to wind-wave interactions impacting the turbulence. Methods for removing such motion-scale biases from scalar measurements have previously been published but their application to momentum flux measurements remains controversial. Here we show that the measured motion-scale bias has a dependence on the horizontal ship velocity and that a correction for it reduces the dependence of the measured momentum flux on the orientation of the ship to the wind. We conclude that the bias is due to experimental error and that time-varying motion-dependent flow distortion is the likely source.