A Note on Scalar-Gradient Sharpening in the Stable Atmospheric Boundary Layer

The scalar front generated by the horizontal self advection of a dipolar vortex through a mod-est scalar gradient is investigated. This physical scenario is an idealization of the emergenceof strong temperature ramps in the stable atmospheric boundary layer. The proposed mecha-nism is discussed and a two-dimensional analogy is studied in depth using direct numericalsimulation. More specifically, the scalar-gradient sharpening is investigated as a function ofthe Reynolds number. It appears that the process of gradient sharpening at large-eddy scalesmay be challenging for turbulence-resolving methods applied to the stable-boundary-layerregime.