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DY: Fachverband Dynamik und Statistische Physik

DY 28: Fluid Physics and Turbulence

DY 28.4: Vortrag

Dienstag, 10. März 2026, 15:00–15:15, ZEU/0118

Numerical investigation of surface wind veer in a transitional Atmospheric Boundary Layer — •Maharun Nesa Shampa, Heiko Schmidt, and Marten Klein — Brandenburgische Technische Universität Cottbus-Senftenberg, Cottbus, Germany

The Atmospheric Boundary Layer (ABL) is defined as the lower part of the atmosphere that dynamically couples the free atmosphere and Earth’s surface. Transitional features and strong variability in boundary layer thickness due to surface heating and cooling pose a challenge for modeling atmospheric dynamics, placing a burden on flow profile and surface-flux parameterizations. This study addresses the mentioned challenge by investigating an idealized ABL, the so-called Ekman Boundary Layer (EBL) using a stochastic One-dimensional Turbulence (ODT) model as standalone tool. The EBL is characterized by absence of stratification such that a statistically stationary force balance between the pressure-gradient, Coriolis and drag forces is reached asymptotically for a prescribed synoptic pressure gradient. A single non-dimensional parameter, the Reynolds number, characterizes the flow regime and reflects the range of the turbulent scales participating in the flow. It is demonstrated that ODT is capable of capturing surface properties (like friction velocity, wind-turning angle) compatible with reference data and appropriate parameterization for transitional Reynolds numbers. In addition, the model offers additional insight into the boundary layer structure and statistical flow properties, which are likewise discussed. By constraining the stochastic sampling of turbulent length scales, an outlook to cut-off mechanisms is given.

Keywords: Atmospheric Boundary Layer; Numerical simulation; Stochastic modeling; One-Dimensional Turbulence