Turbulence structure in the urban roughness sublayer: LES reference studies and comparison with data from wind tunnel, scale model and field measurements
Responsible: Marcus Oliver Letzel
Project type: ​DFG research project within the priority programme ​MetStröm
Duration: 15/07/2007-14/07/2009

The multi-scale turbulence within and above urban areas poses an open question concerning generation and interaction of coherent structures that is essential for urban turbulence parameterizations in meteorological models: does it resemble vegetation canopy turbulence or surface layer turbulence or does it form an own turbulence type?
This large-eddy simulation (LES) reference study investigates the turbulence structure of the urban roughness sublayer for different canonical cities with consideration of thermal effects. The reasons for the choice of LES for this study are: a) LES is the only numerical method to explicitly resolve the multi-scale turbulence within and above real-size obstacles without significant influence of parameterizations and b) LES offers more applications and is able to deliver more extensive data than the wind tunnel. The project aims at an unprecedented combination of domain size and resolution. Quality assurance includes comparison with data from wind tunnel, scale model and field measurements.