@article{d536a031bdf34a41b004523cea82f1fd,
title = "Inverse Cascade Evidenced by Information Entropy of Passive Scalars in Submerged Canopy Flows",
abstract = "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 K{\'a}rm{\'a}n 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.",
keywords = "canopy turbulence, inverse cascade, land-atmosphere exchange, scalar mixing",
author = "Khaled Ghannam and Davide Poggi and Elie Bou-Zeid and Katul, {Gabriel G.}",
note = "Funding Information: K. G. and G. K. acknowledge support from the U.S. National Science Foundation (NSF‐AGS‐1644382 and NSF‐IOS‐1754893). K. G. and E. B. Z. also acknowledge support from the Princeton Environmental Institute. All authors thank the anonymous reviewers for their constructive comments. The experimental data used in this work are archived at the DataSpace digital repository of Princeton University (Geophysical Fluid Dynamics Laboratory) with a persistent URL ( http://arks.princeton.edu/ark:/88435/dsp01qj72pb044 ) and a DOI: https://doi.org/10.34770/7hyr-rf67 . Funding Information: K.?G. and G.?K. acknowledge support from the U.S. National Science Foundation (NSF-AGS-1644382 and NSF-IOS-1754893). K.?G. and E.?B.?Z. also acknowledge support from the Princeton Environmental Institute. All authors thank the anonymous reviewers for their constructive comments. The experimental data used in this work are archived at the DataSpace digital repository of Princeton University (Geophysical Fluid Dynamics Laboratory) with a persistent URL (http://arks.princeton.edu/ark:/88435/dsp01qj72pb044) and a DOI: https://doi.org/10.34770/7hyr-rf67. Publisher Copyright: {\textcopyright}2020. American Geophysical Union. All Rights Reserved.",
year = "2020",
month = may,
day = "16",
doi = "10.1029/2020GL087486",
language = "English (US)",
volume = "47",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "9",
}