Recent Upgrades to the Operational Air Quality Forecasting Systems in Canada: Description and Performance Analysis

In 2016, Environment and Climate Change Canada introduced major upgrades to its Regional Air Quality Deterministic Prediction System (RAQDPS), operated by the Canadian Meteorological Centre Operations (CMCO). At the heart of the RAQDPS is still the GEM-MACH model, an on-line coupled meteorology‒chemistry model, but upgrades were made both to the GEM (weather) and the MACH (chemistry) modules. The spatial configuration still includes a rotated uniform North American grid at 10-km horizontal grid spacing and with 80 vertical levels, but with a modified orientation, and now using a new vertical coordinate (log-hydrostatic-pressure hybrid) with discretization on a staggered vertical grid of the Charney-Phillips type. Various improvements were made to the weather module, notably including the introduction of a Bermejo-Conde mass-conserving scheme for tracers. The CHEM module has additional changes that include an improved treatment of surface fluxes and vertical diffusion, leaf-area scaling in the gas-phase dry deposition scheme, and three-dimensional seasonal chemical lateral boundary conditions. 

This suite of changes impacted both the RAQDPS forecast and the wildfire smoke forecast from the cloned FireWork system.  Recent RAQDPS and FireWork system performance will be summarized, with a discussion on the benefits of the various changes mentioned above.