Mini-Sodar Detection of Local Circulations in a Managed Pine Plantation

Lagrangian dispersion modeling requires few inputs as critical as that of the Lagrangian scale of turbulence. In spite of its paramount importance, this turbulence characteristic has been poorly quantified in large part because of the paucity of data in the literature arising from the difficulties inherent in such measurements. This difficulty is compounded even further in the case of canopy turbulent diffusion where traditionally the few experimental techniques used to determine the Lagrangian timescale are not applicable (soap bubbles for instance). This state of affairs is rapidly evolving as this paper illustrates: Lagrangian time scales are derived from LES results obtained inside a forest canopy for a neutral case and their behavior as a function of height in the forest environment is evaluated. Batchelor's Lagrangian similarity hypothesis is also discussed in the light of these results. Finally, the sensitivity of various turbulence scales formulations to diffusion in Lagrangian models is evaluated and discussed.