Example scripts for use with HEMCO

Generate a HEMCO_sa_Spec.rc file for HEMCO Standalone

The HEMCO Standalone model reads species metadata (name, molecular weight, Henry’s law constants) from a text file named HEMCO_sa_Spec.rc. The default HEMCO_sa_Spec.rc file corresponds to the “standard” GEOS-Chem full-chemistry simulation and looks similar to this:

# List species below. For each species, the following entries must be given:
# ID        : species ID
# NAME      : species name
# MW        : molecular weight (g/mol)
# K0        : Henry constant at 298 K (M/atm, liquid over gas)
# CR        : Henry temperature dependency (-d ln(KH)/d(1/T)
# pKA       : acid dissociation constant
#
# NOTE: These are the species corresponding to the standard simulation!
#
#ID NAME           MW      K0                CR        PKA
1   NO             30.00   0.000000E+00      0.00      0.00
2   O3             48.00   0.000000E+00      0.00      0.00
3   PAN           121.00   0.000000E+00      0.00      0.00
4   CO             28.00   0.000000E+00      0.00      0.00
5   ALK4           58.12   0.000000E+00      0.00      0.00
6   ISOP           68.12   0.000000E+00      0.00      0.00

You may easily generate a HEMCO_sa_Spec.rc corresponding to a other GEOS-Chem simulations with the GCPy example script make_hemco_sa_spec.py.

First, activate the GCPy Python environment (unless you have installed GCPy from PyPI, in which case no further action is needed).

$ conda activate gcpy_env
(gcpy_env) $

You will see the (gcpy_env) prefix added to the command prompt.

Next, run the make_hemco_sa_spec.py script on the geoschem_species_metadata.yml file generated by a GEOS-Chem simulation. This file is typically created in the OutputDir folder of a GEOS-Chem run directory.

(gcpy_env) $ python -m gcpy.examples.hemco.make_hemco_sa_spec /path/to/geoschem_species_metadata.yml

Move the HEMCO_sa_Spec.rc file to your HEMCO standalone run directory. Then deactivate the GCPy Python environment.

(gcpy_env) $ conda deactivate
$