Numerical simulations of the urban boundary layer observed during Joint Urban 2003

A prototype of an urban modeling system has been under development at the Meteorological Service of Canada (MSC) for some time, aiming at accurate prediction of urban flows and atmospheric dispersion over major North American cities. The main features of this new system include an assessment of the high resolution capability of the model for micro-alpha scale applications (down to about 200 m), an extension of our current turbulent diffusion scheme to 3D turbulence, the inclusion of urban processes with the Town Energy Balance (TEB) scheme, and the generation of surface fields characterizing urban type covers. As a first validation of the urban modeling system, high-resolution simulations will be presented that examine the urban canopy processes and their impact on the structure of the atmospheric boundary layer. These will be compared against detailed observations from the Joint Urban 2003 experimental field campaign held in Oklahoma City during July 2003, with particular attention paid to the abilities of the system to simulate the urban micro-climate.