Momentum diffusivity profiles in and above a forest canopy

N. M. ZOUMAKIS

Abstract

Semi-empirical and theoretical formulations which have been proposed to describe the transition-layer mean wind-speed profiles (Zoumakis, 1992c; 1993c; 1993d; 1994) are used to derive relationships between the roughness length zo, zero-plane displacement d, and transition-layer depth z*, and to estimate the diffusivity coefficients K of turbulence transfer mechanisms within and above tall vegetation and forest canopies. The theoretical estimates of d, z* and K compare well with data from various sources and the theoretical analysis from Thorn (1971), Landsberg and Jarvis (1973), Bache (1986) and Zoumakis (1994).

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