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Wavelet spectra within a forest subcanopy under different wind directions and stabilities
Author(s) -
Russell Eric S.,
Liu Heping,
Lamb Brian
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2017jd026817
Subject(s) - canopy , turbulence , terrain , atmospheric sciences , anemometer , tree canopy , environmental science , stability (learning theory) , geology , spectral line , meteorology , ecology , physics , biology , computer science , astronomy , machine learning
Vertical structure of turbulence within a forest canopy is complex as a result of interactions between the flow dynamics, stability, and vegetation. It remains unclear as to how the combination of the changing stability, flow conditions, and upstream obstacles alters vertical variations in turbulence structures within canopy. Here we used data from three sonic anemometers within the forest canopy to study the interplay between these factors. The turbulence structure depended upon the wind direction and stability similarly as particular stability conditions were primarily associated with certain wind directions over the sloped terrain. The general shape of the spectra varied with the depth into the canopy, creating a perceived spectral gap near the surface that was not observed near the top of the canopy. The strength of the division between smaller scales and larger scales increased under more stable conditions as the different layers were unable to couple, limiting the passage of energy through the canopy.