Configure your simulation


We recommend that you configure your simulation before downloading data files. You can use the configuration settings with a dry-run simulation to download only the data that you will need.

You will need to edit various configuration files in order to specify options for your GEOS-Chem Classic simulation. These are described below.

Commonly-updated configuration files

When starting a new GEOS-Chem Classic simulation, you will usually edit most (if not all) of these configuration files:

All of the above-mentioned files are included in your GEOS-Chem Classic run directory.

Please see our Customize simulations with research options Supplemental Guide to learn how you can customize your simulation by activating alternate science options in your simulations.

Less-commonly updated configuration files

If you need to add or delete species, or to change the default photolysis and/or chemistry mechanism settings in your simulation, you’ll need to edit these configuration files: