Turbulence in plant canopies

Abstract

Starting from simple fundamental equations, a differential equation is obtained which prescribes the velocity distribution in plant canopies. When the density of the plant is constant with height, the differential equation gives exponential wind profile as a solution. It is assumed that logarithmic wind profile prevailes both above the plant canopies and in the lowest air layer near the canopy floor. Effect of variation of the plant density, being assumed constant with height, is investigated, and it is found that when the density is large the surface at the height of the plant canopies acts as a smooth surface for the wind profile, whereas when the density is small the earth surface becomes a smooth one. The roughness parameter, which has been introduced only as an integration constant, is expressed in terms of roughness height and density, and it is found that it has a maximum at a certain value of the density when the height is constant. © 1964, The Society of Agricultural Meteorology of Japan. All rights reserved.