Modeling

CAM-chem

The Community Atmosphere Model with Chemistry (CAM-chem) is a component of the NCAR Community Earth System Model (CESM) and is used for simulations of global tropospheric and stratospheric atmospheric composition.  CAM-chem uses the MOZART chemical mechanism, with various choices of complexity for tropospheric and stratospheric chemistry.  The first version of CAM-chem is described in Lamarque et al. (2012), CAM-chem as used for CCMI and HTAP is described in Tilmes et al. (2016), CAM-chem in CESM1.2 is described in Tilmes et al. (2015).

CESM2, including CAM6-chem, is the current version. This version includes a significantly updated tropospheric chemistry mechanism (MOZART-T1) [Emmons et al., 2020], along with a volatility basis set (VBS) parameterization for the formation of secondary organic aerosols (SOA) [Tilmes et al., 2019]. CESM2.0 and CESM2.1 were used for CMIP6 simulations, so if you are interested in simulating results to be consistent with those results it is recommended to use CESM2.1.

CESM2.2 contains several answer-changing updates included in all compsets:

  • NOx-dependent VBS-SOA formation [Jo et al., 2020]
  • Updated aerosol scavenging in convective clouds
And additional capabilities:
  • MUSICA-V0, CAM-chem with a regionally refined grid using the Spectral Element dynamical core
  • Compsets for the MOZART-TS2 chemistry [Schwantes et al., 2020]
  • Compsets for physics-side nudging
  • Compsets for spectral element grids

More information on downloading and using CAM-chem is available from the CAM-chem wiki page and the CESM Chemistry Climate Working Group webpage.

CESM Working Group meetings are held each year in the winter and at the CESM Annual Workshop in June:
Annual workshops
Winter Working Group meetings

Future developments will be coordinated under the MUSICA activity and the community is invited to contribute to that effort!

Surface O3 (white) and NO2 (orange). NCAR CAM-chem animation by Siyuan Wang;
created using 6-hour outputs of NCAR CAM-chem half-degree run (data courtesy of Louisa Emmons).

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ACOM | Atmospheric Chemistry Observations & Modeling