Photolysis and chemistry configuration files
Note
You won’t need to edit these configuration files unless you are changing the photolysis and/or chemistry mechanisms used in your GEOS-Chem Classic simulation.
Photolysis configuration files
These are found in the ExtData/CHEM_INPUTS/CLOUD-J/
directory
structure. Cloud-J is used by default in GEOS-Chem compute photolysis
rates. If using legacy FAST-JX instead then configuration files are located
in the ExtData/CHEM_INPUTS/FAST-JX/
directory. See the configuration
file geoschem_config.yml
for which subdirectory within these folders
you are configured to use. See the README in the data directory for information
about these files.
Chemical mechanism configuration files
GEOS-Chem Classic simulations use source code generated by The Kinetic PreProcessor. If you need to update the default chemistry mechanism, you will need to do the following steps:
Modify the relevant KPP configuration files (described below);
Run KPP to generate updated source code for GEOS-Chem Classic;
Compile GEOS-Chem Classic to create a new executable;
Start your GEOS-Chem Classic simulation.
Chemical mechanism configuration files are located in these folders:
- KPP/fullchem
Contains configuration files for the default “full-chemistry” mechanism (NOx + Ox + aerosols + Br + Cl + I).
fullchem.kpp
: Main configuration file for the fullchem mechanism.fullchem.eqn
: List of species and reactions for the fullchem mechanism.
- KPP/carbon
Contains configuration files for the carbon gases mechanism (CH4-CO2-CO-OCS):
carbon.kpp
: Main configuration file for the carbon mechanism.carbon.eqn
: List of species and reactions for the carbon mechanism.
- KPP/custom
Contains configuration files that you can edit if you need to create a custom mechanism. We recommend that you create the custom in this folder and leave
KPP/fullchem
andKPP/Hg
untouched.custom.kpp
: Copy offullchem.kpp
custom.eqn
: Copy offullchem.eqn
.
- KPP/Hg
Contains configuration files for the mercury chemistry mechanism:
Hg.kpp
: Main configuration file for the Hg mechanism.Hg.eqn
: List of species and reactions for the Hg mechanism.
Please see the following references for more information about KPP:
The KPP user manual (kpp.readthedocs.io)
Supplemental Guide: Update chemical mechanisms with KPP