On the similarity of the characteristics of turbulence in an unstable boundary layer

Abstract

The statistics of turbulence, such as the standard deviation of fluctuating velocities, in an unstable atmospheric boundary layer are assumed to be characterized by the combination of three specific lengths, Monin-Obukhov length L, observation height z and the height of mixing layer h. Unlike Monin-Obukhov similarity, even near the ground the effect of h is taken into account. According to observation, the length scale of the vertical velocity is proportional to z at least near the ground, but the lateral component depends mostly on h alone. The length scale of the longitudinal component depends on z and h.