Shear-Sheltering and Its Impact on Atmospheric Turbulence

The present paper explores the role that nocturnal low-level jets exert on the lower nocturnal boundary layer. In particular, this paper investigates their role in the modulation of surface turbulence near the surface. This presentation also discusses the controversy regarding the existence of atmospheric shear sheltering over contrasting surfaces. In a seminal experiment aimed at validating the Hunt and Durbin (1999) theory, Smedman (2004) reported the existence of shear sheltering in real atmospheric conditions. However, other existing studies did not find any evidence of eddy blocking in the presence of a low-level jet near the ground despite the use of large datasets and contrasting environmental conditions. In this present presentation, an explanation is offered in the present study which reconciles all three experimental studies, thus elucidating the apparent contradiction. Furthermore, this paper conclusively supporting the presence of shear-sheltering in the presence of low-level jet. Implications for surface-atmosphere exchange in contrasting surfaces and atmospheric stabilities are discussed.