Large Scale Intermittency in the Atmospheric Boundary Layer

TL;DR

This paper provides evidence that the atmospheric boundary layer exhibits large-scale intermittency characterized by a lognormal distribution of turbulence intensities, linking high Reynolds number observations with turbulence simulations.

Contribution

It demonstrates that boundary layer flow can be statistically modeled as an ensemble of homogeneous turbulent systems with large-scale intermittency, supported by high Reynolds number data.

Findings

Boundary layer flow approximates an ensemble of homogeneous turbulence

Large-scale fluctuations follow a lognormal distribution

Moderate Reynolds number simulations can inform boundary layer studies

Abstract

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.