气候变化领域集成服务门户(CCPortal): Inverse Cascade Evidenced by Information Entropy of Passive Scalars in Submerged Canopy Flows

CCPortal

DOI	10.1029/2020GL087486
	Inverse Cascade Evidenced by Information Entropy of Passive Scalars in Submerged Canopy Flows
	Ghannam K.; Poggi D.; Bou-Zeid E.; Katul G.G.
发表日期	2020
ISSN	0094-8276
卷号	47 期号:9
英文摘要	Turbulent mixing of scalars within canopies is investigated using a flume experiment with canopy-like rods of height h mounted to the channel bed. The data comprised a time sequence of high-resolution images of a dye recorded in a plane parallel to the bed at z/h= 0.2. Image processing shows that von Kármán wakes shed by canopy drag and downward turbulent transport from upper canopy layers impose distinct scaling regimes on the scalar spectrum. Measures from information theory are then used to explore the dominant directionality of the interaction between small and large scales underlying these two spectral regimes, showing that the arrival of sweeps from aloft establishes an inertial-range spectrum with forward “information” cascade. In contrast, wake growth with downstream distance leads to persistent upscale transfer (inverse cascade) of scalar variance, which hints at their nondiffusive character and the significance of the stem diameter as an active length scale in canopy turbulence. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	Image processing; Wakes; Canopy turbulence; Downstream distances; Flume experiment; High resolution image; Information entropy; Scalar variance; Turbulent mixing; Turbulent transports; Information theory; canopy exchange; diameter; drag; dye tracer; entropy; flume experiment; turbulence; turbulent mixing
语种	英语
来源期刊	Geophysical Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170371
作者单位	Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, United States; Dipartimento di Ingegneria dell'Ambiente, del Territorio e delle Infrastrutture, Politecnico di Torino, Turin, Italy; Nicholas School of the Environment, Duke University, Durham, NC, United States; Department of Civil and Environmental Engineering, Duke University, Durham, NC, United States
推荐引用方式 GB/T 7714	Ghannam K.,Poggi D.,Bou-Zeid E.,et al. Inverse Cascade Evidenced by Information Entropy of Passive Scalars in Submerged Canopy Flows[J],2020,47(9).
APA	Ghannam K.,Poggi D.,Bou-Zeid E.,&Katul G.G..(2020).Inverse Cascade Evidenced by Information Entropy of Passive Scalars in Submerged Canopy Flows.Geophysical Research Letters,47(9).
MLA	Ghannam K.,et al."Inverse Cascade Evidenced by Information Entropy of Passive Scalars in Submerged Canopy Flows".Geophysical Research Letters 47.9(2020).