MOZART: Model for OZone and Related chemical Tracers

MOZART chemical mechanisms

The MOZART chemical mechanisms used in CAM-chem and WACCM (components of the Community Earth System Model) are developed, maintained and updated at NCAR, with collaborations from the community. A full description of the mechanism and its implementation in CESM2 has been published: Emmons et al., JAMES, 2020. The aerosol schemes used in CESM2, including the Secondary Organic Aerosol (SOA) Volatilty Basis Set (VBS) scheme and the Modal Aerosol Model (MAM), are described in detail in Tilmes et al., JAMES, 2019. The stratospheric chemistry is discussed further in Gettelman et al., JGR, 2019.

The current family of MOZART chemical mechanisms include:

T1: The MOZART tropospheric chemistry mechanism has been updated and expanded significantly from MOZART-4 to include an expansion of the isoprene oxidation scheme, splitting lumped aromatics and terpenes to individual species and updating their oxidation products, and a more detailed representation of organic nitrates. A preliminary version of the T1 mechanism, including a description of the aromatic oxidation, was published in (Knote et al., 2014). Previous MOZART-4 users should note that the new treatment of aromatics replaces the MOZART-4 lumped aromatic (confusingly called 'TOLUENE') with the specific species BENZENE, TOLUENE and XYLENES. The lumped monoterpene is now called MTERP, and a sesquiterpene, BCARY, has been added.

TS1: The T1 tropospheric mechanism, plus 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.

TS2: Expanded isoprene and terpene oxidation (Schwantes et al., 2020).

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The MOZART CTM has not been updated since the publication of MOZART-4 in 2010, and therefore is quite out of date.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.

The MOZART-4 chemical mechanism and model description were 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. 


Please direct questions/comments about this page to:

Louisa Emmons