An overview of urban modeling at the Meteorological Service of Canada

The Meteorological Service of Canada (MSC) has recently launched a program to improve the representation of cities in the Canadian meteorological models, aiming at accurate prediction of urban flows and atmospheric dispersion over populated North American cities, as part of an integrated multi-scale advanced emergency response system. The main features of the new urban modeling system include: 1) assessment of the high-resolution capability of the mesoscale models to simulate flows ranging from meso-gamma down to micro-beta scales, 2) extension of our current turbulent diffusion scheme to 3D turbulence, 3) inclusion of urban processes with the Town Energy Balance (TEB) urban canopy scheme and generation of new land covers characterizing urban types for use in TEB. A classification methodology based on satellite imagery has been developed to generate those databases for major cities. As a first validation of the urban modeling system, high-resolution simulations of the structure of the atmospheric boundary layer are currently done for Oklahoma City, and compared against observations from the Joint Urban 2003 experiment. A field campaign (MUSE - Montréal Urban Snow Experiment) was conducted during March-April 2005 to document the energy exchanges between the urban canopy and the atmosphere under cold, snowy situations and during the snow melting period. Work is also under way to simulate a winter case over Montréal using the MUSE observations. An overview of the various components of the MSC urban modeling program will be presented, together with an outlook at future activities.