Low-level jets and shear-sheltering theory: experimental results from Oklahoma, USA

Turbulence and wind-profile data over a quasi-ideal experimental site in Oklahoma, USA are used to assess the shear-sheltering theory applied to low-level jets in the nocturnal stable boundary layer. The theory is predicated upon the idea of low-level jets blocking large eddies aloft, preventing them from propagating to the surface. Low-level jet events are identified and classified, and a spectral analysis of the surface turbulence during these events is presented. Enhancement of surface turbulence intensity and of the relative contribution of large scales to total (co)variances is observed for low-level jet cases with strong shear, suggesting the absence of shear sheltering at the site. Atmospheric modeling is suggested to further assess the relevance of shear-sheltering theory to atmospheric flows.