MOZART: Model for OZone and Related chemical Tracers

MOZART chemical mechanism

The chemical mechanisms used in MOZART, CAM-chem and WACCM are developed, maintained and updated at NCAR, with collaborations from Forschungszentrum Jülich and the community. The MOZART-4 chemical mechanism and model description are published in Emmons et al. (2010). The MOZART-4 mechanism contains a detailed description of tropospheric inorganic chemistry and of organic species with 3 carbons or less, and a reasonably thorough treatment of isoprene chemistry. Larger alkanes and alkenes, terpenes, and aromatics are also included in the mechanism, albeit with lumping and simplification.

MOZART-T1:  The MOZART tropospheric chemistry mechanism has been updated to include an expansion of the isoprene oxidation scheme, splitting lumped aromatics and terpenes to individual species, and a more detailed representation of organic nitrates. 

MOZART-TS1: The T1 tropospheric mechanism, with halogen compounds and reactions to represent stratospheric chemistry.

TSMLT1:  A comprehensive mechanism for use in WACCM, including chemistry for the Troposphere, Stratosphere, Mesosphere and Lower Thermosphere.

The species and reactions included in the T1-TS1-TSMLT1 family of mechanisms are provided in these documents: Species List and Table of Reactions.  A full description of the mechanism and its implementation in CESM2 is in preparation (Emmons et al., to be submitted to JAMES).

MOZART chemical transport model (CTM)

The MOZART CTM has not been updated since the publication of MOZART-4 in 2010, and therefore is quite out of date. The source code is freely available to the community, however it is no longer being developed or supported. Documentation on Downloading and Running MOZART-4 Source Code

The capabilities of MOZART-4, with numerous improvements, are available in CAM-chem and we recommend that it be used instead of MOZART-4.  CAM-chem is a component of the Community Earth System Model, so can be run as a fully coupled free-running climate model, but can also be run with specified dynamics (nudged to reanalysis meteorology) to produce results similar to the MOZART CTM.

MOZART-4 output for several years is made available for regional model boundary conditions from the WRF-chem webpage.  These are now superseded by CAM-chem output for Jan 2001-June 2017.  See the CAM-chem wiki page for instructions to access these files.

Several tools are available for processing MOZART-4 or CAM-chem output or inputs.

WACCM chemical forecasts

Chemical Forecasts from WACCM are run each day, providing a 3-day forecast of global tropospheric composition. 

MOZART-4 Chemical Forecasts (no longer being produced)

MOZART-4 chemical forecasts are no longer being created.  You can see images of the historical forecasts at

MOZART-4 simulations (up to Jan 26, 2018) are available for downloading, with options for subsetting on the WRF-Chem MOZART download webpage.  

MOZART forecasts have been used as boundary conditions for regional forecasts:


Please contact Louisa Emmons if you have further questions.




ACOM | Atmospheric Chemistry Observations & Modeling