The Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) is a comprehensive aerosol chemistry module designed to dynamically partition H2SO4, MSA, HNO3, HCl, NH3 and secondary organic aerosol (SOA) to different aerosol size bins/modes, driven by particle-phase thermodynamics and heterogeneous chemical reactions (Zaveri et al., JGR, doi:10.1029/2007JD008782, 2008; Zaveri et al., JAMES, doi:10.1029/2020MS002346, 2021).  It has been implemented into CESM2, but is not yet available in the standard code.  A full description of this implementation is in Lu et al., JGR-Atmospheres, doi:10.1029/2021JD034809, 2021).  

Get the CESM code with MOSAIC implemented

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git clone httpsclone https://github.com/ESCOMP/CAM CAM -b  zzzz_cam6_3_018_mosaic_branch

CESM tutorials should be helpful if you are not familiar with CESM/CAM-chem, and how to set up a case from the code.

There is not a compset for the MOSAIC scheme so you must make the changes listed below.

Change env_build.xml

Once you set up your case from the code through create_newcase, you need to change a few files to use MOSAIC. 

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3) If you want to save these newly added species to the history output files (e.g., *h0*, *h1*, etc.), of course, you need to add these to fincl1, fincl2, etc.  You will also need to remove the old aerosol species (ncl_*) from the default output. 

Additional information

• The current CAM-chem/MOSAIC was implemented in CAM6.3.018, which is similar to the CESM2.2 public version but with some minor updates made to CAM. 
• We have only used it using the "FCnudged" compset. No other compsets have been tested yet. 
• You should use "MAM4" to use MOSAIC at this moment, since some parts of the code were hard coded to MAM4 (MAM3 and MAM7 are not compatible with MOSAIC). We are hoping that it can be more flexible in the future when MOSAIC is available in the default version.

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