Thin structure of diurnal variations of the vertical wind speed and direction gradients from minisodar data

Abstract

Based on remote daily hourly measurements of the vertical profiles of three wind velocity components with an AV4000 minisodar in the atmosphere at altitudes of 5–200 m, the thin structure of the vertical wind speed and direction gradients has been analyzed with 10-minute time averaging and spatial resolution ∆z = 5 m. The vertical wind speed and direction gradients (the wind shear and veer) depend on the time of the day. In the altitude dependence of the vertical wind direction gradient, four layers can be distinguished: the near-ground layer from 5 to 20–25 m, the mixing layer with practically zero gradient ∆α, the surface layer at altitudes of 100–150 m, and the transitive layer at higher altitudes. The vertical wind direction gradient changes in the range −15° \(\leq \Updelta \alpha \left(z{,}t\right)\leq\) +20°.