A Process Analysis of the Impact of Air-Quality/Weather Feedbacks Using GEM-MACH

  • Paul A. MakarEmail author
  • Wanmin Gong
  • Junhua Zhang
  • Jason Milbrandt
  • Sylvie Gravel
  • Balbir Pabla
  • Philip Cheung
Conference paper
Part of the Springer Proceedings in Complexity book series (SPCOM)


Environment Canada’s “Global Environmental Multiscale – Modelling Air-quality and Chemistry” (GEM-MACH) is the Canadian operational air-quality model, used to provide forecasts of ozone, PM2.5 and air-quality health metrics to the Canadian public. The operational GEM-MACH is an on-line model, but is not fully coupled, in that the chemical variables are not used to modify the weather. The model was converted to fully coupled status as part of Environment Canada’s participation in phase 2 of the Air-Quality Model Evaluation International Initiative, with three classes of modifications: (1) Additions required in order to allow feedbacks to take place between weather and chemistry; (2) Model improvements necessary to ensure feedback accuracy; (3) Model improvements to allow the use of AQMEII-2 prescribed inputs and diagnostic outputs.

The revised model is being used to generate four annual simulations of air-quality over North America, for “feedback” and “base-case” simulations for the years 2006 and 2010. Here, the initial test simulation results for 2006 of surface O3 and PM2.5 are compared using a simple statistical package, as a means of identifying cases wherein feedbacks have the greatest influence on the model’s chemical output. These instances will be put forward for further study under the multi-model framework of AQMEII-2.


Environment Canada Synoptic Condition Code Modification Improve Model Performance Subsequent Night 
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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Paul A. Makar
    • 1
    Email author
  • Wanmin Gong
    • 1
  • Junhua Zhang
    • 1
  • Jason Milbrandt
    • 2
  • Sylvie Gravel
    • 3
  • Balbir Pabla
    • 1
  • Philip Cheung
    • 1
  1. 1.Air Quality Research DivisionEnvironment CanadaTorontoCanada
  2. 2.Recherche en Prévision NumériqueEnvironment CanadaDorvalCanada
  3. 3.Air Quality Research DivisionEnvironment CanadaDorvalCanada

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