Global Chemistry Modeling

Group Lead: Dan Marsh

There are several models being developed and used in ACOM for global chemistry modeling.

CAM-Chem and the Whole-Atmosphere Community Climate Model (WACCM)  are versions of the NCAR Community Earth System Model that couple the Community Atmosphere Model with chemistry based on MOZART.  Both CAM-Chem and WACCM can operate in two modes; 'free-running' with fully coupled chemistry and climate, or with dynamics contrained to analyzed meteorological fields (e.g., GEOS-5 or MERRA).  WACCM has a model top that extends to ~140 km and includes a stratospheric/mesospheric chemical mechanism with both neutral and ionized constituents.  WACCM is particularly suited for studies from the upper troposphere through the mesosphere.

The Model for OZone and Related chemical Tracers (MOZART) is a global 3-D chemical transport model, driven by offline meteorological fields, that has been developed at NCAR, the Max-Planck-Institute for Meteorology, and NOAA/GFDL. MOZART-4 is suitable for tropospheric chemistry studies, however it is no longer being developed or supported and is superseded by CAM-chem.

Assessments and Intercomparisons

The Global Chemistry Modeling group participates in numerous model assessments and model intercomparison projects:



  • WACCM and CAM-chem held working group meetings at the 21st Annual CESM workshop June 20-23, 2016. Presentations are now online.
  • Presentations from the CAM-chem and WACCM working group meetings in February 2016 are available on the CESM Winter Working Group Meetings page.




ACOM | Atmospheric Chemistry Observations & Modeling