Development of a new Canadian operational air quality forecast model

Development and implementation of the next generation of Canada's operational air quality (AQ) forecast model is underway at Environment Canada (EC). The goal of this project is the replacement in 2008 of the current operational off-line AQ forecast model, CHRONOS, by GEM-MACH, an on-line chemical transport model. To construct GEM-MACH, chemistry modules have been implemented directly inside GEM, EC's operational multi-scale meteorological forecast model. This new on-line AQ forecast model will be able to exploit EC's massively parallel supercomputer via the parallelism options already implemented in GEM. Physical and chemical processes related to AQ are solved on GEM's "native" grid, thus avoiding the spatial and temporal interpolations of the meteo-rological fields that are required by CHRONOS.