Direct Flux Measurements from Mobile Platforms at Sea: Motion and Airflow Distortion Corrections Revisited
Direct Flux Measurements from Mobile Platforms at Sea: Motion and Airflow Distortion Corrections Revisited
复制标题
海上移动平台的直接通量测量：重新审视运动和气流畸变校正
DOI：
10.1175/jtech-d-14-00137.1
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发表时间：
2015
影响因子：
2.2
通讯作者：
B. Ward
中科院分区：
文献类型：
--
作者：
S. Landwehr;Niall O’Sullivan;B. Ward
摘要基于船舶的风速和直接通量测量受到气流畸变的影响，气流畸变会导致风矢量的倾斜以及风速的加速或减速。直接通量测量还受到平台波动速度的影响。经典的方法是首先根据平台角速度和平移速度校正风速，然后将风矢量旋转到平均流中。这项研究发现，对于正在进行的船舶，这会导致高估的矢量倾斜和偏差通量估计。这可能解释了一个常见的现象，即从过境船只获得的通量估计值的质量低于在台站进行的测量值。这里提出了一种替代方法，其中从3D风速测量值估计气流畸变引起的风矢量倾斜，并将其应用于表观风矢量。倾斜校正是在对平台速度的波动部分进行校正之后，而在对平台速度的波动部分进行校正之前进行的。
AbstractShip-based measurements of wind speed and direct fluxes are affected by airflow distortion that can lead to a tilt of the wind vector as well as acceleration or deceleration of the wind speed. Direct flux measurements are additionally affected by the fluctuating velocity of the platform. The classic approach is to first correct the wind speed for angular and translational platform velocities and thereafter rotate the wind vector into the mean flow. This study finds that for ships under way, this leads to an overestimation of the vector tilt and biased flux estimates. This may explain the common observation that flux estimates from ships in transit have lower quality than measurements taken on station. Here an alternative approach is presented, where the flow-distortion-induced tilt of the wind vector is estimated from the 3D wind speed measurements and applied to the apparent wind vector. The tilt correction is carried out after correction for the fluctuating part of the platform velocity but befo...