Near Surface Flow Behavior in Katabatic Winds Over Steep Slopes

Katabatic winds over the Antarctic are exceptionally persistent, more so than any other winds on Earth. Despite their significance to the Antarctic climate, the turbulent behavior of these near-surface flows is not well understood. Because of the complex geometry of the problem, field measurements have necessarily been limited in scope and have typically featured coarse resolutions. High-fidelity simulations such as large-eddy simulations (LES) provide a fruitful pathway to address this knowledge gap. However, previous LES studies are constrained by deficiencies in wall-layer models based on the Monin-Obukhov similarity theory for the evaluation of surface fluxes. This study proposes a suite of wall-resolved LES to examine near-slope turbulence across various Grashof numbers and slope angles. We analyze first- and second-order statistics as well as budgets of TKE and Reynolds stress/fluxes to gain insights into the behavior of near-surface transport and propose modifications to existing wall-layer closure models for this type of flow.