THE ENERGY BUDGET AT THE EARTH'S SURFACE: AIR FLOW AND TURBULENCE CHARACTERISTICS IN A JAPANESE LARCH PLANTATION.

摘要

Mean horizontal windspeed profiles within and above a plantation of Japanese larch were obtained. A log-profile analysis of above-vegetation windspeeds yielded a wide range of values for the roughness length parameter (zo) and the zero plane displacement height (D),with these two parameters being highly correlated with each other. The computed Eulerian space scale of turbulence within the vegetation showed deeper penetration of large eddies after needle fall and during high winds. Power spectra showed that at the base of the plantation most of the variation in windspeed was associated with gusts of about 100meters wavelength. Power spectra at the most dense portion of the plantation canopy showed considerable modification due to the tree spacing. (Author)