Pre-flight checklist

Here is a list of all the steps that should be performed before running WRF-GC. This may be useful if you are familiar with the model or prefer to see an overview of the process. The specifics are in the PDF guide and also in other sections of this documentation.

Downloading WRF-GC and input data (do once)

  • Download the WRF model and the WPS pre-processor.

  • Download WRF-GC. Go into the WRF model and delete the chem folder, then download WRF-GC into WRF/chem folder.

  • Download the GEOS-Chem input data. If you already run GEOS-Chem, remember the GEOS-Chem input data path. Otherwise, download GEOS-Chem data directories. All CHEM_INPUTS are required, then choose inventories you need for HEMCO.

  • Download the WPS geographical input data. See Preparing your system.

Compiling WRF-GC


Your WRF root directory may be WRFV3 or WRF. We use WRF for consistency.

  • Configure your bash/shell environment. It should have NETCDF, HDF5, the appropriate PATH with access to netCDF binaries, and specify the MPI type, etc.

  • Go into WRF and configure to your environment. Run ./configure -hyb (WRF version 3) or ./configure (WRF version 4+). Choose your compiler and (dmpar) option corresponding to your compiler.

  • Go into WRF/chem and run make install_registry. This is very important. If you did not do this before the following steps, you have to start over from here.

  • Compile WRF-GC: ./compile em_real.


If you change the code but not the species list, then run ./compile em_real to recompile directly.

If you change the species list, then ./clean -a needs to be issued, then ./configure -hyb from scratch and ./compile em_real.

Compiling WPS

Compile WPS after you compile WRF-GC. ./configure, ./compile.

Running WRF-GC

  • Update configuration files to correct paths. Paths to your GEOS-Chem input data are specified in three locations: HEMCO_Config.rc, and twice in input.geos.

  • Update namelist.input to be consistent with namelist.wps.

  • Link the meterology data to your run directory (ln -sf ../../WPS/met_em* .)

  • Run real.exe using MPI (e.g., mpirun -np $SLURM_NTASKS ./real.exe - depending on your cluster configuration you may need to batch this).

  • Create the initial/boundary conditions using mozbc or another tool. Refer to Chemical Initial/Boundary Conditions (IC/BC).

  • Run WRF-GC. Run wrf.exe.