This package contains the GenChem system, which includes a chemical pre-processor (GenChem.py) for converting chemical equations into differential form for use in atmospheric chemical transport models (CTMs). Although primarily intended for users of the EMEP MSC-W chemical transport model (https://github.com/metno/emep-ctm) and related systems, GenChem also features a simple box-model testing system (boxChem), which can run as a stand-alone chemical solver, enabling for example easy testing of chemical mechanisms against each other.
To get started, read the documentation article and guide:
https://gmd.copernicus.org/articles/13/6447/2020/
https://genchem.readthedocs.io/en/latest/index.html
Updates:
2023-12: Converted system to use CloudJ photolysis, c.f. van Caspel et al. (2023):
https://doi.org/10.5194/gmd-16-7433-2023
By default, all chemical mechanisms employ photolysis rates based
on MCM in boxChem. However, when "use_cloudj = T" is set in the config
namelist file, (clear-sky) photolysis rates calculated using the Cloud-J v7.3e
photolysis code are used instead. The EMEP model can only use Cloud-J from v4.51 onward,
using the Briegleb averaging cloud effect scheme by default.
To reflect the CloudJ update, in addition to a few minor changes, the default
chemical mechanism has been updated to EmChem19c (c for cloudj). The changes include
specified background concentration for CH4 and H2, and the inclusion of three
explicit glyoxal photolysis channels.
2022-12-21: Added EmChem19X, and updated READMEs to refer to NEW report:
Update and comparison of atmospheric chemistry mechanisms for the EMEP MSC-W model system - EmChem19a, EmChem19X, CRIv2R5Em, CB6r2Em, and MCMv3.3Em,
Robert Bergström, Garry D. Hayman, Michael E. Jenkin and David~Simpson,
Technical Report MSC-W 1/2022,
EMEP MSC-W, Norwegian Meteorological Institute, Norway
https://emep.int/publ/reports/2022/MSCW_technical_1_2022.pdf
2022-06-14: Revised tag: 1.1 2022-06-13: Added -g --gnfr flags to enable GNFR emissplits, and renamed files, e.g. emissplit_snap_defaults_voc.csv
2020-12-21: GMD article published! Link above updated
2020-10-22: GMD article accepted for publication.
2020-09-03: Bug fix: changed log to log10 in Shorthands file for CB6r2Em changed group name of PANs to PANS in Species file Moved chem/scripts/GenIn_Shorthands.txt to chem/generic_Shorthands.txt to make this file more visible. Added -i, -v args to getboxconcs.py in box/scripts