Chapter 18
Development and Current Status
of the GEM-MACH-Global Modelling
System at the Environment and Climate
Change Canada
Jack Chen, Diane Pendlebury, Sylvie Gravel, Craig Stroud, Irena Ivanova,
Jean DeGranpré and David Plummer
Abstract The GEM-MACH-Global model is a global online meteorologychemistry system currently being developed at the Department of Environment and
Climate Change Canada (ECCC). The model is an extension of the Department’s
operational, regional GEM-MACH numerical weather and air quality prediction
system. The objectives for its development are to improve our understanding of
the long range transport and fate of criteria air contaminants, and to improve our
forecasting system by providing chemical boundary conditions for the regional air
quality forecast system, and background fields for global chemical data assimilation
(O 3 and NOy species). For this purpose, GEM-MACH-Global was recently updated
with a comprehensive photolysis module (JVAL14-MESSy) and a detailed gas-phase
chemistry module based on the SAPRC07C mechanism. Compared to its original
ADOM2 chemistry mechanism, the revised gas-phase chemistry is more explicit,
with new species and ~15 additional reactions important in the upper troposphere
and lower stratosphere (UTLS) region. Furthermore, a lightning emission module
J. Chen (B) · D. Pendlebury · S. Gravel · C. Stroud · I. Ivanova · J. DeGranpré
Air Quality Research Division, Environment and Climate Change Canada, Ontario, Canada
e-mail: jack.chen@canada.ca
D. Pendlebury
e-mail: diane.pendlebury@canada.ca
S. Gravel
e-mail: sylvie.gravel@canada.ca
C. Stroud
e-mail: craig.stroud@canada.ca
I. Ivanova
e-mail: irena.ivanova@canada.ca
J. DeGranpré
e-mail: jean.degrandpre@canada.ca
D. Plummer
Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada,
Ontario, Canada
e-mail: david.plummer@canada.ca
© Crown 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity, https://doi.org/10.1007/978-3-030-22055-6_18
107
Development and Current Status
of the GEM-MACH-Global Modelling
System at the Environment and Climate
Change Canada
Jack Chen, Diane Pendlebury, Sylvie Gravel, Craig Stroud, Irena Ivanova,
Jean DeGranpré and David Plummer
Abstract The GEM-MACH-Global model is a global online meteorologychemistry system currently being developed at the Department of Environment and
Climate Change Canada (ECCC). The model is an extension of the Department’s
operational, regional GEM-MACH numerical weather and air quality prediction
system. The objectives for its development are to improve our understanding of
the long range transport and fate of criteria air contaminants, and to improve our
forecasting system by providing chemical boundary conditions for the regional air
quality forecast system, and background fields for global chemical data assimilation
(O 3 and NOy species). For this purpose, GEM-MACH-Global was recently updated
with a comprehensive photolysis module (JVAL14-MESSy) and a detailed gas-phase
chemistry module based on the SAPRC07C mechanism. Compared to its original
ADOM2 chemistry mechanism, the revised gas-phase chemistry is more explicit,
with new species and ~15 additional reactions important in the upper troposphere
and lower stratosphere (UTLS) region. Furthermore, a lightning emission module
J. Chen (B) · D. Pendlebury · S. Gravel · C. Stroud · I. Ivanova · J. DeGranpré
Air Quality Research Division, Environment and Climate Change Canada, Ontario, Canada
e-mail: jack.chen@canada.ca
D. Pendlebury
e-mail: diane.pendlebury@canada.ca
S. Gravel
e-mail: sylvie.gravel@canada.ca
C. Stroud
e-mail: craig.stroud@canada.ca
I. Ivanova
e-mail: irena.ivanova@canada.ca
J. DeGranpré
e-mail: jean.degrandpre@canada.ca
D. Plummer
Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada,
Ontario, Canada
e-mail: david.plummer@canada.ca
© Crown 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity, https://doi.org/10.1007/978-3-030-22055-6_18
107