For this case study we are going to use the the Hurricane Katrina Case - this only works for tracking cyclones
Case dates are 2005-08-29_00 to 2005-08-30_00, and data are available 6-hourly.
 

Source Code

For this case you have to get the pre-compiled code, which was compiled with the vortex following capability.

Set-up WPS

• Make sure you are in the WPS directory.    
   
   
• Edit namelist.wps to configure the simulation domain and produce input data files for the WRF model.
  We are going to create a single domain over the Gulf of Mexico - the nest will be added when we run WRF.
  The domain size will be 98x70 grid points, with a grid resolution of 30km. We will use a Mercator projection.
   
  • Make the following changes to the namelist.wps file:
    

        max_dom = 1,
        start_date = '2005-08-28_00:00:00',
        end_date = '2005-08-29_00:00:00',
        interval_seconds = 21600,
        i_parent_start = 1,
        j_parent_start = 1,
        e_we = 91,
        e_sn = 74,
        dx = 30000,
        dy = 30000,
        map_proj = 'mercator',
        ref_lat = 28.00
        ref_lon = -89.00
        truelat1 = 0.0,
        truelat2 = 0.0,
        stand_lon = -89.00
        geog_data_path =

  • geo_data_path: Make sure to set the path to the geogrid static input data to point to the location on the classroom machines.  
    
    
  • Some basic descriptions of the namelist variables are available from the OnLine Tutorial page (geogrid ; ungrib ; metgrid)
  • More detailed information is available in Chapter 3 of your ARW User's Guide
     
     
    
• Run plotgrids.ncl (located in the ./util/ directory) to see where your grid is located:
   
       ncl util/plotgrids.ncl
   
       This program reads the grid location from namelist.wps (namelist record &geogrid) and creates a grid plot.

  

Run geogrid  

Configure the model grid and generate the geographical data file "geo_em.d01.nc" by running the program geogrid.exe:
 
     ./geogrid.exe

 

Run ungrib

Degrib and reformat meteorological data from another model. In this case, the data come from the GFS/AVN model.

• Link the GRIB data using the script file link_grib.csh:
   
       ./link_grib.csh /kumquat/wrfhelp/DATA/Katrina/avn_050828_00
  
        NOTE: There is no "." at the end of this command, as this is a script that is run.
                  Take care to link to FILES and not to a DIRECTORY.
                  Only the root section of all the files is needed, and not a list of independent files.
  
       We are using GFS GRIB version 1 data as input
   
  
• Link the correct Vtable (the input data for this case is GFS, so use the GFS Vtable):
   
       ln -sf  ungrib/Variable_Tables/Vtable.GFS   Vtable
   
   
• Ungrib the input data by running the program ungrib.exe:
   
       ./ungrib.exe
   
       This will create a number of files:
   
            FILE:2005-08-28_00
            FILE:2005-08-28_06
            FILE:2005-08-28_12
            FILE:2005-08-28_18
            FILE:2005-08-29_00
   

Run metgrid

Interpolating external model data to your model grid (created by geogrid and ungrib), and create input data for WRF by running the program metgrid.exe:
 
     ./metgrid.exe
 
     This will create a number of files:
 
          met_em.d01.2005-08-28_00:00:00.nc
          met_em.d01.2005-08-28_06:00:00.nc
          met_em.d01.2005-08-28_12:00:00.nc
          met_em.d01.2005-08-28_18:00:00.nc
          met_em.d01.2005-08-29_00:00:00.nc
 
Try the netcdf data browser 'ncview' to quickly examine your data files from metgrid.  

 

Set-up WRF

• Make sure you are in the WRFV3_VORTEX directory.    
   
   
• cd to directory test/em_real
   
   
• Edit the namelist.input file to reflect the domain / date information of the Hurricane Katrina case (NOTE: we are running with 2 domains, although we only created one domain in WPS)
   
       run_hours = 24,
       start_year = 2005, 2005,
       start_month = 08, 08,
       start_day = 28, 28,
       start_hour = 00, 00,
       end_year = 2005, 2005,
       end_month = 08, 08,
       end_day = 29, 29,
       end_hour = 00, 00,
       interval_seconds = 21600,
       input_from_file = .true.,.false.,
       history_interval = 180,180,
       frames_per_outfile = 1, 1,
       restart = .false.,
       restart_interval = 5000,    
       max_dom = 2,
       e_we = 91, 97,
       e_sn = 74, 97,
       e_vert =30, 30,
       num_metgrid_levels = 27,
       num_metgrid_soil_levels = 4,
       dx = 30000, 10000,
       dy = 30000, 10000,
       grid_id = 1, 2, 3,
       parent_id = 0, 1, 2,
       i_parent_start = 1, 40,
       j_parent_start = 1, 10,
       parent_grid_ratio = 1, 3,
       parent_time_step_ratio = 1, 3,
  
   
  • input_from_file=.false. for domain 2 indicates that we will NOT be creating input data for domain 2.
  • Read more about:
    • 2-way nested runs, using only met_em_d01 input files (we are currently following this option - which is the only option available for moving nests)
    • 2-way nested runs, using met_em_d01 and met_em_d02 input files
  • Set frames_per_outfile to 1 - this will create a new wrfout file for each output time
  • The parent_start values are for the initial nest location - make sure your vortex is in this location at start time.
     
  • To learn more about the namelist variables view the OnLine Tutorial page, or
  • For more details, see Chapter 5 of your ARW User's Guide
     
     

Run real

• Link the metgrid output data files from WPS to the current directory:
   
       ln -sf ../../../WPS/met_em* .
   
• Run the executable real.exe to produce model initial and lateral boundary files.
   
  If successful, the following input files for wrf will be created:
   
       wrfbdy_d01
       wrfinput_d01
   
  View the log files to ensure the run was successful.
  

 

Run wrf

• Run the executable wrf.exe for a model simulation and forecast.
   
  Running a 12 hour simulation for this case will take a few minutes on the classroom machines.
  If successful, this will generate the following history files (note - there is one file per output time):
   
          wrfout_d01_2005-08-29_00:00:00
          wrfout_d01_2005-08-29_03:00:00
          wrfout_d01_2005-08-29_06:00:00
          wrfout_d01_2005-08-29_09:00:00
          wrfout_d01_2005-08-29_12:00:00
          wrfout_d02_2005-08-29_00:00:00
          wrfout_d02_2005-08-29_03:00:00
          wrfout_d02_2005-08-29_06:00:00
          wrfout_d02_2005-08-29_09:00:00
          wrfout_d02_2005-08-29_12:00:00
  

 

Check your output:

• Check to see what is printed to the log files.
• Tail the log files and look for "SUCCESS COMPLETE WRF".
• Try the netcdf data browser 'ncview' to examine your wrf output file
   
  
• Generate graphics with one of the supplied packages.
   
  

If this was successful, you can continue to run another practical example.