GEM-MACH15 Operational Air Quality Forecast Model: An Evaluation of the First Year's Performance

GEM-MACH was implemented by Environment Canada as a new multi-scale in-line air quality (AQ) forecast system in late 2009. The operational version, GEM-MACH15, is a limited-area model with 15-km horizontal grid spacing and 58 vertical levels extending from the surface to 0.1 hPa. The model is run twice daily at the Canadian Meteorological Centre to produce 48-hour forecasts over a continental-scale domain. In this presentation, the first operational performance evaluation of GEM-MACH15 predictions for a one-year period (Aug. 2009-July 2010) will be described. Model forecasts of O3, PM2.5, and NO2 will be compared against available surface measurements from Canadian and U.S. real-time monitoring networks. A statistical analysis will be presented showing monthly forecast performance and geographical variability across Canadian and U.S. regions. A kriging technique will be applied to show the spatial distribution of model statistical performance measures. Model strengths and weaknesses will also be identified.GEM-MACH15 Operational Air Quality Forecast Model: An Evaluation of the First Year’s Performance