Abstract

Representing land-atmosphere exchange processes as lower boundary conditions remains a challenge in numerical weather predictions. One important reason is the lack of understanding of heterogeneities in topography, land cover, stability, and their effects on all aspects of the flow field and scalar transport. Well-resolved flow measurements can shed light on these near-surface processes, yielding improved modeling approaches. Yet, it is precisely the heterogeneous characteristics in question—along with the large separation of scales—that make field measurements notoriously challenging. To address some of the difficulties encountered in probing the atmospheric surface layer, a unique and economically scalable field measurement platform was designed around the nanoscale thermal anemometry probe technology, which has previously been used successfully at high Reynolds numbers in laboratory settings. The small size of the nanoscale sensors not only provides a high spatial resolution but also allows for velocity and temperature measurements with the same constant current operating circuit. This operating mode is more economical and straightforward to construct than conventional constant temperature anemometry systems, providing a scalable platform for multi-point measurements. The measurement platform was deployed at the Surface Layer Turbulence and Environmental Science Test site in Utah’s West Desert as part of the Idealised horizontal Planar Array study for Quantifying Surface heterogeneity. Streamwise velocity and temperature data were acquired within the first meter above ground with good agreement in spectral behavior to well-known scaling laws in wall-bounded flows.

Graphic Abstract

中文翻译：

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使用新型高分辨率传感器阵列研究大气表层

摘要

将低层边界条件表示为陆地-大气交换过程仍然是数值天气预报中的一个挑战。一个重要的原因是缺乏对地形，土地覆盖，稳定性及其对流场和标量运输各个方面的影响的异质性的了解。良好解决的流量测量可以阐明这些近地表过程，从而提供改进的建模方法。然而，正是所涉及的异质性特征以及刻度的较大分隔，才使现场测量极具挑战性。为了解决探测大气表层时遇到的一些困难，围绕纳米级热风速计探测技术设计了一个独特且经济可扩展的现场测量平台，以前已在实验室环境中成功地以高雷诺数成功使用。纳米级传感器的小尺寸不仅提供了很高的空间分辨率，而且还允许使用相同的恒流工作电路进行速度和温度测量。该操作模式比常规的恒温风速测量系统更经济，更直接地构造，为多点测量提供了可扩展的平台。该测量平台已部署在犹他州西部沙漠的表层湍流和环境科学测试现场，这是用于量化表面异质性的理想化水平平面阵列研究的一部分。

图形摘要