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Wavelet Analysis of Coherent Structures Above Maize and Soybean Crops
Boundary-Layer Meteorology ( IF 4.3 ) Pub Date : 2022-05-20 , DOI: 10.1007/s10546-022-00705-w
Curto Lucia, María I. Gassmann

Turbulent coherent structures developed in the atmospheric surface layer are responsible for a large part of momentum and scalar fluxes exchanged with canopy layers. Their participation in processes such as evapotranspiration, pathogen infections, mechanical damage due to wind gustiness, modifies crop yield, with generally negative effects. Although South America has a variety of land covers, studies of these subjects are not common in the region. Here, we characterize the time scales of turbulent coherent structures above extensive maize and soybean crops using the wavelet methodology. The role of canopy-height changes associated with crop growth on turbulent structures development is analyzed. The effect of atmospheric stability on the characteristics of the structures detected is also studied. Wavelet analysis shows that both momentum and sensible heat are transported mostly by eddies of 350–400 s periods and also by more intense eddies of 40–50 s period. For momentum fluxes, the former period range prevails under strongly unstable conditions, while the second is present mostly under near-neutral situations. On the contrary, 40–50 s-lasting structures dominate the sensible heat transport under free convection conditions, while longer-lasting eddies transport heat in near-neutral conditions. Stability is the main factor allowing the coherent-structure topological classification, while the crop height is not important. Structures are identified through measurements performed at relative heights greater than those usually discussed in the literature, which indicates the need for further research into coherent-structure modelling.



中文翻译:

玉米和大豆作物上相干结构的小波分析

大气表层中形成的湍流相干结构是与冠层交换的大部分动量和标量通量的原因。它们参与蒸发蒸腾、病原体感染、阵风造成的机械损伤等过程,会改变作物产量,通常会产生负面影响。尽管南美洲有多种土地覆盖,但对这些主题的研究在该地区并不常见。在这里,我们使用小波方法来表征粗放玉米和大豆作物上方的湍流相干结构的时间尺度。分析了与作物生长相关的冠层高度变化对湍流结构发展的作用。还研究了大气稳定性对检测到的结构特征的影响。小波分析表明动量和显热主要由 350-400 秒周期的涡流传输,也由 40-50 秒周期的更强烈的涡流传输。对于动量通量,前一个周期范围在强不稳定条件下占主导地位,而第二个周期范围主要存在于接近中性的情况下。相反,在自由对流条件下,持续时间为 40-50 s 的结构主导显热传输,而持续时间更长的涡流在近中性条件下传输热量。稳定性是允许连贯结构拓扑分类的主要因素,而作物高度并不重要。通过在高于文献中通常讨论的相对高度进行的测量来识别结构,这表明需要进一步研究相干结构建模。前一个周期范围主要存在于极不稳定的条件下,而第二个周期范围主要存在于接近中性的情况下。相反,在自由对流条件下,持续时间为 40-50 s 的结构主导显热传输,而持续时间更长的涡流在近中性条件下传输热量。稳定性是允许连贯结构拓扑分类的主要因素,而作物高度并不重要。通过在高于文献中通常讨论的相对高度进行的测量来识别结构,这表明需要进一步研究相干结构建模。前一个周期范围主要存在于极不稳定的条件下,而第二个周期范围主要存在于接近中性的情况下。相反,在自由对流条件下,持续时间为 40-50 s 的结构主导显热传输,而持续时间更长的涡流在近中性条件下传输热量。稳定性是允许连贯结构拓扑分类的主要因素,而作物高度并不重要。通过在高于文献中通常讨论的相对高度进行的测量来识别结构,这表明需要进一步研究相干结构建模。在自由对流条件下,持续时间为 40-50 s 的结构主导显热传输,而持续时间更长的涡流在近中性条件下传输热量。稳定性是允许连贯结构拓扑分类的主要因素,而作物高度并不重要。通过在高于文献中通常讨论的相对高度进行的测量来识别结构,这表明需要进一步研究相干结构建模。在自由对流条件下,持续时间为 40-50 s 的结构主导显热传输,而持续时间更长的涡流在近中性条件下传输热量。稳定性是允许连贯结构拓扑分类的主要因素,而作物高度并不重要。通过在高于文献中通常讨论的相对高度进行的测量来识别结构,这表明需要进一步研究相干结构建模。

更新日期:2022-05-22
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