Nest Run (2-way, 1 Input File): Real and WRF

Run the model (real.exe & wrf.exe)

1. Ensure that you are in the WRFV3/ directory. For this case we are going to run in the test/em_real/ directory.

cd test/em_real

2. Edit namelist.input
    Add the changes below to the namelist.input file. Pay special attention to the highlighted values.
    Note: For detailed explanations of these variables, as well as suggestions for best practices, see the Best Practices WRF Namelist page, or Chapter 5 of the WRF User's Guide

run_days = 0,
run_hours = 48,
run_minutes = 0,
run_seconds = 0,
start_year = 2016, 2016,
start_month = 10, 10,
start_day = 06, 06,
start_hour = 00, 00,
end_year = 2016, 2016,
end_month = 10, 10,
end_day = 08, 08,
end_hour = 00, 00,
interval_seconds = 21600
input_from_file = .true., .false.,
history_interval = 180, 60,
frames_per_outfile = 1000, 1000,
restart = .false.,
restart_interval = 5000,
time_step = 120,
max_dom = 2,
e_we = 91, 88,
e_sn = 100, 79,
s_vert = 1, 1,
e_vert = 45, 45,
num_metgrid_levels = 32
dx = 27000,
dy = 27000,
i_parent_start = 1, 25,
j_parent_start = 1, 46,
parent_grid_ratio = 1, 3,
parent_time_step_ratio = 1, 3,
feedback = 1,

Note: We changed input_from_file to .false. for domain 2. This indicates to the real program that we only need a wrfinput file for d01, since all values for d02 will be interpolated down from d01.

3. If you still have the wrfbdy_d01 and wrfinput_d01 created during the Single Domain Run, you can skip this step and
    proceed to step 4 (If you are not sure, repeat this step - it does not take long).

Link in the met_em files created with metgrid.exe (created for the Single Domain Run)

   ln -sf ../../../WPS/met_em.d01.2016-10* .

Run real.exe (verify that the program ran correctly)
Note: This will overwrite the wrfinput_d01 and wrfbdy_d01 files you may have from previous runs, so save your old files somewhere else if you would like to keep them.
Check that the following two files have been created (NOTE: no wrfinput_d02 will be created, as we set "input_from_file=.false." for domain 2)

   wrfinput_d01
   wrfbdy_d01

What is contained in these files?
 

4. Run wrf.exe (verify that the program ran correctly)
    Check that the following files have been created
     Note: This will overwrite wrfout_d01_2016-10-06_00:00:00 from your Single Domain Run,
    so save your old file somewhere else if you would like to keep it.

   wrfout_d01_2016-10-06_00:00:00
   wrfout_d02_2016-10-06_00:00:00

The wrfout files will contain all the time periods for this run.
wrfout for domain 2 will contain more time periods, as history_interval was set to 1h for domain 2 and 3h for domain 1.
 

5. Quick check of the contents of the wrfout file:

a. Use the ncdump utility:
    ncdump -h wrfout_d01_2016-10-06_00:00:00
    ncdump -v Times wrfout_d01_2016-10-06_00:00:00 (to see which forecast times are in the file)
    Note: run_hours was set to 48, so there should only be 48 hours of output
b. Use the ncview utility.

6. Use any of the supported graphical tools to display the model output.

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