Ultrasonic anemometers for in-canopy turbulence research

我的研究重点是靠近地球表面的大气湍流。我是一个实地实验分析湍流在现实世界的环境中，特别是在树冠和接近粗糙的表面（森林，作物，城市，雪）。了解这些表面附近的大气湍流对于预测污染物的扩散，包括有毒排放物或物体（如种子），或计算地球表面与大气之间的微量气体交换至关重要。通常，这些粗糙的表面是部分多孔的，我特别感兴趣的是发展和改进通过这些元素和从上覆流湍流交换的理论。在我的实地研究中，我依赖于测量大气流动中风和温度的快速波动的仪器。我提出了一个阵列的六个快速响应传感器，使用超声波测量湍流（超声波风速计）。我需要六个传感器来充分采样气流，因为在植物树冠内，以及靠近其他粗糙表面的地方，湍流在空间中是非常不规则的。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对这些粗糙多孔的地表-大气界面上的空气湍流运动有宝贵的了解。这些仪器可以在各种配置中操作，例如，作为塔上的垂直剖面，作为冠层内的水平线，甚至作为部署在更大距离上的独立仪器。该设备将在研究生培训中发挥核心作用，并将在今后的许多实验中灵活使用。此外，作为一个发现补助金的一部分，我开发的替代方法来跟踪湍流结构使用快速温度探头的空间阵列（热电偶阵列）。为了验证和补充这种方法，我将比较的结果与那些从所要求的超声波风速计阵列。

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.