Ultrasonic anemometers for in-canopy turbulence research

我的研究重点是接近地球表面的大气湍流。我是一名现场实验者，分析真实世界环境中的湍流，特别是在树冠内和接近粗糙表面(森林、庄稼、城市、雪)的地方。了解这些表面附近的大气湍流对于预测污染物的扩散，包括有毒物质的释放或物体(例如种子)的扩散或计算地球表面与大气之间的痕量气体交换是至关重要的。通常，这些粗糙的表面部分是多孔的，我特别感兴趣的是发展和改进通过这些元素的湍流交换理论，以及从上覆流到上覆流的理论。在我的实地研究中，我依赖于测量大气气流中风和温度非常快速波动的仪器。我提出了一个由六个快速响应传感器组成的阵列，这些传感器使用超声波来测量湍流(超声波风速计)。我需要六个传感器来充分采样流动，因为在植物树冠内，以及靠近其他粗糙表面的地方，空间中的湍流非常不规则。我对这些差异(水平和垂直梯度)以及空间相关性特别感兴趣。这类数据将使我们能够有价值地洞察空气在这些粗糙和疏松的表面-大气界面上的湍流运动。这些仪器可以在不同的配置下操作，例如，作为塔上的垂直剖面、作为天篷内的水平线，甚至作为部署在更远距离上的独立仪器。这种设备将在研究生培养中发挥核心作用，并将在未来的许多实验中以灵活的方式使用。此外，作为发现资助的一部分，我将开发使用快速温度探测器(热电偶阵列)的空间阵列来跟踪湍流结构的替代方法。为了验证和补充这一方法，我将把结果与所要求的超声波风速计阵列的结果进行比较。

My research focuses on atmospheric turbulence close to the Earth's surface. I am a field experimentalist analyzing turbulence in real-world environments especially within canopies and close to rough surfaces (forests, crops, cities, snow). An understanding of atmospheric turbulence close to these surfaces is essential to predict the dispersion of pollutants including toxic releases or objects (e.g. seeds) or to calculate the exchange of trace-gases between Earth's surface and the atmosphere. Often, these rough surfaces are partially porous, and my special interest is to develop and to improve theories of turbulent exchange through these elements and to/from the overlying flow. In my field research I rely on instruments that measure very fast fluctuations of wind and temperature in atmospheric flows. I propose an array of six fast-response sensors that use ultrasound to measure turbulence (ultrasonic-anemometers). I need six sensors to adequately sample the flow because within plant canopies, and close to other rough surfaces, turbulence is very irregular in space. I am particularly interested in these differences (horizontal and vertical gradients) as well as in spatial correlations. Data of this kind will allow valuable insights into the turbulent movement of air at these rough and porous surface-atmosphere interfaces. The instruments can be operated in various configurations e.g. as a vertical profile on a tower, as a horizontal line within a canopy or even as stand-alone instruments deployed over larger distances. This equipment will play a central role in the training of graduate students and will be used in a flexible way in numerous future experiments. Further, as part of a discovery grant I am to develop alternative approaches to track turbulent structures using spatial arrays of fast temperature probes (thermocouple arrays). To validate and complement that approach I will compare the results with those from the requested ultrasonic-anemometer arrays.