A Process Analysis of the Impact of Air-Quality/Weather Feedbacks Using GEM-MACH
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.
KeywordsEnvironment Canada Synoptic Condition Code Modification Improve Model Performance Subsequent Night
- 2.Bohren CF, Huffman DR (1983) Absorption and scattering of light by small particles. Wiley and Sons, Toronto, 530 ppGoogle Scholar
- 6.Gong W et al (2012) Impact of aerosol activation on modelled regional particulate matter mass and size distribution due to cloud processing. In: Steyn DG, Timmermans R (eds) Air pollution modelling and its application XXII. Springer, Dordrecht, in pressGoogle Scholar
- 8.Ménard S et al (2013) Current and future developments in numerical air quality forecasting in Canada, these proceedingsGoogle Scholar