Running WRF-GC

Running WRF-GC is similar to WRF-Chem.

Running the WPS

Running the WRF Preprocessing System (WPS) is to prepare input to drive WRF. Please refer to the WRF User's Guide for more detail:

• http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3.9/users_guide_chap3.html

- Step 1: Define model domains with geogrid

In the "geogrid" namelist record, the projection of the simulation domain is defined. Only two possible map projections and specified parameters are supported in WRF-GC:

• Mercator /'mercator' (truelat1)

• Unrotated regular latitude-longitude /'lat-lon' (pole_lat, pole_lon, stand_lon)

- Step 2: Extracting meteorological data from GRIB files with ungrib

Downloading meteorological data for the real data case

• http://www2.mmm.ucar.edu/wrf/users/download/free_data.html

- Step 3: Horizontally interpolating meteorological data with metgrid

Preparing GEOS-Chem shared data directories

The GEOS-Chem shared data directories contain many large files necessary for the WRF-GC. Please Set up the top-level root directory for GEOS-Chem shared data, which is called ExtData. Please create the /dir/to/data/ExtData and set your directories in the "input.geos" file:

       Root data directory : /dir/to/data/ExtData

The ExtData directory structure cotains two subdirectories:

- CHEM_INPUT: Non-emissions data for GEOS-Chem chemistry modules

• Download the CHEM_INPUT data directories via anonymous FTP from the Harvard data directory archive (ftp.as.harvard.edu). Please refer to : http://wiki.seas.harvard.edu/geos-chem/index.php/Downloading_GEOS-Chem_source_code_and_data

- HEMCO: Emissions inventories for the HEMCO emissions component

• Download the HEMCO data directories with a pakeage provided by GEOS-Chem Support Team. Please refer to : http://wiki.seas.harvard.edu/geos-chem/index.php/HEMCO_data_directories#Downloading_the_HEMCO_data_directories

• Set the HEMCO data directory in the "HEMCO_Config.rc" file

       Root : /dir/to/data/ExtData/HEMCO

Emissions for WRF-GC

Preparing emission files is not requied. WRF-GC uses Harvard-NASA Emissions Component (HEMCO) with on-line regridding. Configure HEMCO refer to the "HEMCO_Config.rc" file inside the run directory for WRF. For more information on HEMCO data directories, please refer to the GEOS-Chem wiki:

• http://wiki.seas.harvard.edu/geoschem/index.php/HEMCO_data_directories

Preparing chemical initial/boundary condition data

Chemical initial and boundary condition data are used output from global simulation MOZART-4/GEOS-5 similar to WRF-Chem. Please download the data from :

• https://www.acom.ucar.edu/wrf-chem/mozart.shtml

The Mozart data are processed by the WRF-Chem processor called mozbc. Please download the mozbc utility, including instructions and input files from :

• https://www.acom.ucar.edu/wrf-chem/download.shtml

Running WRF-GC

To Configure WRF-GC, you need to edit three files inside the WRF run directory.

- HEMCO_Config.rc (Please refer to: http://wiki.seas.harvard.edu/geos-chem/index.php/GEOS-Chem_Input_Files#The_HEMCO_Config.rc_file)

• HEMCO_Config.rc file contains a set of switches to enable and disable emission inventories, such as:

      # ExtNr ExtName           on/off  Species
      0       Base              : on    *
          --> HEMCO_RESTART     :       false
          --> AEIC              :       true
          --> BIOFUEL           :       true
      ... etc not shown here ...

• Errors with HEMCO component when running a simulation are output into a log file called "HEMCO.log".

- input.geos

• Simulation Menu (except Root data directory) and Timestep Menu in input.geos can be safely ignored.

• Determine the Advected Species Menu, Transport Menu, Convection Menu, Emission Menu, Aerosol Menu, Deposition Menu and Chemistry Menu according to your specific simulation (Please refer to : http://wiki.seas.harvard.edu/geos-chem/index.php/GEOS-Chem_Input_Files).

• Other Menus in "input.geos" can be safely ignored.

- namelist.input

To run WRF-GC, use the distributed-memory parallel version of WRF's real.exe and wrf.exe, like -

       mpirun -np 6 ./wrf.exe

To monitor output from WRF&GEOS-Chem, you can tail the "rsl.out.000" file:

       tail -f rsl.out.0000

Output from WRF&GEOS-Chem are unified into the WRF output format (NetCDF Classic) files starting with wrfout.