The Properties of Turbulence in and above a Sorghum Canopy with 2nd Order Closure Model

Most meteorologists have reported that higher order closure models are better than the K-theory model for estimation of environment in the canopy, but solving a higher order closure model requires boundary conditions for turbulence, which is measured directly by a sonic anemometer. However, sonic anemometers are expensive so few scientists in agriculture use high order closure models. In the present research, estimation of the wind profile in and above a sorghum canopy was carried out by use of a 2nd order closure model with mean wind velocity at a single height above the canopy. Comparison between the observed and calculated profiles indicated that the former was well represented by the latter in general. This indicates that the present calculation scheme can be used for estimation of wind profiles in the canopy without observation of the turbulence. It revealed that most large scale turbulence was generated at the upper part of a sorghum canopy during the heading stage, and that measuring the plant area density should be a more important canopy meteorological observation than the leaf area index during theheading stage, since the non-leaf portion of plant area is not negligible.