Abstract: Observations of wind speed, temperature and humidity over large windbreak network are.with tethered ballon found that near-surface layer can be divided into two layers, lower boundary layer and turbulent boundary layer. Their thicknesses and profile distribution are related to Richardson number (Ri). All profiles under neutral stratification are satisfied with logarithmic law.In these layers, especially in turbulent boundary layer,the friction velocities U." are increased by one order of magnitude than that in open land,and the roughnesses Z"₀ by two ones or more.

Key words: Boundary layer, Friction velocity, Roughness, Profile distribution, Richardson number