Flow structures and scale interactions in stable atmospheric boundary layer turbulence

Abstract

Atmospheric boundary layer turbulence in stably stratified conditions is characterised by an intermittent, unsteady behaviour. The intermittency can result from localised flow acceleration due to non-turbulent motions, which can exhibit structures such as ramp-cliff convective patterns, waves or microfronts. Based on a timeseries clustering method, we characterise interactions between scales of motion in a dataset of near-surface stable boundary layer turbulence. Individual flow structures are investigated in two weak-wind flow regimes exhibiting distinct scale interaction properties. The signature of flow structures differs despite comparable wind and stability properties.