Diurnal Dynamics of Standard Deviations of Three Wind Velocity Components in the Atmospheric Boundary Layer

Resumo

Diurnal dynamics of the standard deviation (SD) of three wind velocity components measured with a minisodar in the atmospheric boundary layer is analyzed. Statistical analysis of measurement data demonstrates that the SDs for x- and y-components σ_x and σ_y lie in the range from 0.2 to 4 m/s, and σ_z = 0.1–1.2 m/s. The increase of σ_x and σ_y with the altitude is described sufficiently well by a power law with exponent changing from 0.22 to 1.3 depending on time of day, and σ_z increases by a linear law. Approximation constants are determined and errors of their application are estimated. It is found that the maximal diurnal spread of SD values is 56% for σ_x and σ_y and 94% for σ_z. The established physical laws and the obtained approximation constants allow the diurnal dynamics of the SDs for three wind velocity components in the atmospheric boundary layer to be determined and can be recommended for application in models of the atmospheric boundary layer.