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 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 Setting 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

- HEMCO: Emissions inventories for the HEMCO emissions component

Emissions for WRF-GC

Preparing emission files is not requied. WRF-GC uses Harvard-NASA Emissions Component (HEMCO) with on-line regridding. For information on obtaining HEMCO data directories, please refer to the GEOS-Chem wiki:

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

Note: The location of HEMCO data directory needs to be specified in "input.geos" and "HEMCO_Config.rc"