Keywords: atmospheric boundary layer, urban area, wind velocity, roughness length, stratification, surface Rossby number independence, universal profile, blending height, radiosounding, sodar measurement, Portugal
On wind velocity profiles over urban area
The horizontally homogeneous atmospheric boundary layer over rough surface with a large roughness length z0 is introduced to model the simplest cases of the Urban Planetary Boundary Layer (UABL) over the flat plain. The system of the equations of motion was non-dimensionalised and it has been demonstrated that the Rossby number similarity exists for the core of the UABL. That means that the non-dimensional profiles of the horizontal Reynolds stresses, eddy viscosity and velocity defect components are universal and independent of surface characteristics, contrary to the non-dimensional components of the velocity which are not universal. Radiosounding launched in Barcelona (ES), Lisboa, Evora and Neves Corvo (PT) and sodar measurements for wind above Prague (CR) are compared with the universal profiles determined by numerical simulation.