Intermittency of surface-layer wind velocity series in the mesoscale range.

We study various time series of surface-layer wind velocity at different locations and provide evidences for the intermittent nature of the wind fluctuations in mesoscale to large-scale range. By means of the magnitude covariance analysis, which is shown to be a more efficient tool to study intermittency than classical scaling analysis, we find that all wind series exhibit similar features than those observed for laboratory turbulence. Our findings suggest the existence of a "universal" cascade mechanism associated with the energy transfer between synoptic motions and turbulent microscales in the atmospheric boundary layer.