CMAQv5.0 Two-way model release notes

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WRF-CMAQ September 2012 revision release notes

A new robust coupling scheme was implemented in the two-way CMAQ model and the stencil exchange (stenex) library. The September 2012 release includes both the two-way source codes and updated stenex codes. Follow the build process described below and link in this new version of the stenex library during the WRF-CMAQ build.

WRF-CMAQ Two-way model release notes (2/22/2012)

David Wong, Jon Pleim and Rohit Mathur

General notes:

  1. This version of the two-way model is built using WRF 3.3 and CMAQ 5.0. It requires the latest libraries: IOAPI version 3.1, STENEX and PARIO.
  2. It only supports CAM and RRTMG radiation schemes.
  3. This two-way model does not support saprc99 and AE5.

Aerosol information for direct feedback effect:

All three modes of seven components: water soluble mass (mass_ws), water insoluble mass (mass_wi), elemental carbon (mass_ec), sea salt (mass_ss), water (mass_h2o), diameters and standard deviations are passed to WRF to affect the radiation calculation directly.

  • AE6
     water soluble:

       mass_ws (i mode) = ASO4I + ANH4I + ANO3I
       mass_ws (j mode) = ASO4J + ANH4J + ANO3J +
                                          AMGJ  + AKJ   + ACAJ
       mass_ws (k mode) = 0.0

    water insoluble:

       mass_wi (i mode) = APOCI  + AOTHRI + APNCOMI
       mass_wi (j mode) = AALKJ  + AXYL1J + AXYL2J  +
                                         AXYL3J + ATOL1J + ATOL2J  +
                                         ATOL3J + ABNZ1J + ABNZ2J  +
                                         ABNZ3J + AOLGAJ + APOCJ   +
                                         ATRP1J + ATRP2J + AISO1J  +
                                         AISO2J + AISO3J + ASQTJ   +
                                         AOLGBJ + AOTHRJ + APNCOMJ +
                                         AFEJ   + AALJ   + ASIJ    +
                                         ATIJ   + AMNJ
       mass_wi (k mode) = ACORS  + ASOIL

    elemental carbon:

       mass_ec (i mode) = AECI
       mass_ec (j mode) = AECJ
       mass_ec (k mode) = 0.0

    sea salt:

       mass_ss (i mode) = 0.0
       mass_ss (j mode) = ANAJ + ACLJ
       mass_ss (k mode) = ACLK + ASO4K + ASECAT


       mass_h2o (i mode) = AH2OI
       mass_h2o (j mode) = AH2OJ
       mass_h2o (k mode) = AH2OK

General run time setting:

  1. NUM_LAND_USE_TYPE -- number of land use types: MODIS is 20, USGS is 24, NLCD is 50 (make sure the WRF portion of the run script contains num_land_cat in the namelist physics section)
  2. rad_option -- radiation scheme: 3 = CAM, 4 = RRTMG
  3. radt -- WRF radiation scheme dt in minutes

Run time environment variable:


RUN_CMAQ_DRIVER turn on CMAQ portion of the twoway model (default is F)
DO_SW_CAL turn on short-wave feedback calculation (default is F)
WRF_CMAQ_FREQ WRF and CMAQ calling frequency (default is 1) e.g. setting to 4 would couple WRF and CMAQ every 4th WRF step
WRF_COL_DIM WRF west_east_stag dimension size
WRF_ROW_DIM WRF south_north_stag dimension size
WRF_LAY_DIM WRF bottom_top_stag dimension size
number of columns in the CMAQ domain
CMAQ_ROW_DIM number of rows in the CMAQ domain
TWOWAY_DELTA_X distance between the WRF and CMAQ lower left corner in the x-direction (default is 5)
TWOWAY_DELTA_Y distance between the WRF and CMAQ lower left corner in the y-direction (default is 5)
IOAPI_OFFSET_64 turn on 64bit offset in IOAPI library (default is F)


DO_LW_CAL turn on long-wave feedback calculation (default is F)
CREATE_PHYSICAL_FILE create intermediate meteorological data for diagnostic purposes (default is F)
WRF_LC_REF_LAT Lambert conformal reference latitude
FILE_TIME_STEP time step size of the physical meteorological output file (default = 10000)
SD_TIME_SERIES turn on sub-domain monitoring capability (default is F)
SD_SCOL sub-domain starting column
SD_ECOL sub-domain ending column
SD_SROW sub-domain starting row
SD_EROW sub-domain ending row
SD_CONC_SPCS sub-domain monitoring species list

Two-way model construction procedure:

 1. Download WRF 3.3 and unzip it
     (recommend command: tar xfz the_zip_file)
     At the end of this step, you will see a new directory WRFV3 and
     rename it to WRFV33

 2. Go through regular building CMAQ model process. Locate BLD_* directory, rename it to cmaq50 and move it to WRFV33. 

 3. Download twoway.tar.gz and unzip it. A twoway directory is formed and
    move it inside WRFV33

 4. Go into directory WRFV33 and execute the following command:
    This command will update all necessary files in WRF and CMAQ to create the 
    two-way model. You can find the original file inside twoway/misc/orig directory.

 5. Download IOAPI_3.1, latest PARIO and STENEX and install them

 6. Configure WRF by typing configure (this will create configure.wrf file)

     (If you have never done WRF configure before, here are some guidelines:

       * if the configure script does not find the NETCDF path, follow
         the prompt to enter the explicit NETCDF include path and library

       * choose the appropriate supported platform

       * in the compile for nesting section, choose the default value)

 7. Define the following environment variables:

      FC      (compiler you will use, at this point, we only support pgi and ifort)
      IOAPI   (path of the ioapi 3.1 library, e.g. /home/wdx/lib/x86_64/ifc/ioapi_3.1)
      PARIO   (path of the PARIO library, e.g. /home/wdx/lib/x86_64/ifc/pario_3.1)
      STENEX  (path of the STENEX library, e.g. /home/wdx/lib/x86_64/ifc/se_snl)
      MPI_INC (path of the mpif.h, e.g. /usr/local/intel/impi/

    Type the following command: twoway/reconfigure
 8. compile the code by typing "compile em_real >& mylog"

Running the two-way model:

A one day tutorial dataset is available at the CMAS site for download. A run script, wrf_em.queue.16b-CA-sf-5-1-v3350_rrtmg is included in this tutorial dataset package.


"WRF-CMAQ two-way coupled system with aerosol feedback: software development and preliminary results": Wong et al., 2011, Geoscientific Model Development. It is available for download at:

For an overview of the 2-way Coupled WRF-CMAQ see:

and for more details on the 2-way Coupled WRF-CMAQ system see: