Środowiskowe Seminarium Fizyki Atmosfery

A series of numerical simulations of the flow through resolved street-level building structures is performed with the EULAG large-eddy simulation model. In analogy to the theoretical formulation of the microscopic fluid flows in porous media the three-dimensional urban morphology (building layout and density) and microstructure of the flow at the building and street level scales are related to the macroscopic properties of the atmosphere (e.g. pressure gradients) at the scale of the whole city. The postprocessing analysis relates topological and geometrical properties of urban morphology (porosity, rugosity) with estimates of the momentum flux and the aerodynamical resistance of the buildings (permeability and tortuosity).

In the mesoscale weather and air-quality prediction models dynamical effects of the urban microscale flow are represented typically within the urban canopy parametrizations (UCP) as a regions of high roughness, with an effective roughness length and the surface displacement height. The current studies prepares the ground for the next level of sophistication in multi-layer UCP parameterizations which accounts for homogeneity and anisotropy of the urban media.