Turbulence spectral structures and dissipation rates above and within the forest canopy

Three-dimensional velocity components and temperature were measured using the new three-dimensional sonic anemometers/thermometers at two levels, above and within the forest canopy, in the Changbai Mountains of Northeast China. Turbulence spectral structure, local isotropy property and dissipation rates above and within the forest canopy were calculated using the eddy correlation method. Results show that the normalized turbulent spectral curves have-2/3 slopes in the inertial subrange. While the shapes of the spectra are in good agreement with the Kansas flat terrain results, the atmospheric turbulence is anisotropic above the forest canopy. Within the forest canopy, the turbulence is approximately isotropic. Compared with measurements from previous studies over flat terrain, the velocity and temperature spectra rates above and inside the forest canopy appear to shift toward higher frequencies. The turbulent kinetic energy and heat energy dissipation rates above and inside the forest canopy are much la