Detection of Entrainment Influences on Surface-Layer Measurements and Extension of Monin–Obukhov Similarity Theory
Detection of Entrainment Influences on Surface-Layer Measurements and Extension of Monin–Obukhov Similarity Theory
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DOI：
10.1007/s10546-014-9920-8
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发表时间：
2014-04
影响因子：
4.3
通讯作者：
A. Boer;A. Moene;A. Graf;D. Schüttemeyer;C. Simmer
中科院分区：
文献类型：
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作者：
A. Boer;A. Moene;A. Graf;D. Schüttemeyer;C. Simmer
我们提出了一种仅使用表面层变量的统计数据和光谱来检测边界层过程对表面层测量的影响的方法。我们通过边界层测量验证了我们的检测方法。此外，我们确认 Monin-Obukhov 相似函数非常适合在两个不同均匀表面获得的温度方差数据。然而，我们发现，在夹带空气到达表面层的几天内，湿度方差测量值偏离了两个研究表面之一上方的通用函数。这些结果证实，在分析地表数据时应谨慎使用莫宁-奥布霍夫相似理论。最后，我们建议在通量方差关系中使用一个额外项，该项取决于湿度的夹带比和边界层高度。如果边界层测量不可用，我们将展示如何根据湿度分布的偏度来近似湿度夹带比。
We present a method to detect influences of boundary-layer processes on surface-layer measurements, using statistics and spectra of surface-layer variables only. We validated our detection method with boundary-layer measurements. Furthermore, we confirm that Monin–Obukhov similarity functions fit well to temperature-variance data obtained at two different homogeneous surfaces. However, we found that humidity variance measurements deviate from the universal functions above one of the two studied surfaces for days on which entrained air reached the surface layer. These results confirm that Monin–Obukhov similarity theory should be used with care in the analysis of surface-layer data. Finally, we propose the use of an extra term in flux-variance relations that depends on the entrainment ratio for humidity and on the boundary-layer height. If boundary-layer measurements are not available, we show how the entrainment ratio for humidity can be approximated from the skewness of the humidity distribution.