  We find actual evidence, relying upon vorticity time series taken in a high
Reynolds number atmospheric experiment, that to a very good approximation the
surface boundary layer flow may be described, in a statistical sense and under
certain regimes, as an advected ensemble of homogeneous turbulent systems,
characterized by a lognormal distribution of fluctuating intensities. Our
analysis suggests that usual direct numerical simulations of homogeneous and
isotropic turbulence, performed at moderate Reynolds numbers, may play an
important role in the study of turbulent boundary layer flows, if supplemented
with appropriate statistical information concerned with the structure of large
scale fluctuations.
