Reference: Download the tutorial presentation

Source code

Get the pre-compiled code, if you have not done so.

WRFDA/var/build/da_wrfvar_3dvar.exe is the executable that will be used in this session.

Choice of your working directory

We recommend running each session in a separate directory, so that it will be easier to check for the necessary input files and look for what output files are created after a successful run.

We recommend you create /kumquat/users/${USER}/DA/radar and cd there to be your working directory for this session.

mkdir /kumquat/users/${USER}/DA/radar

cd /kumquat/users/${USER}/DA/radar

Input files

The radar case is different from the CONUS60 case you have used in obsproc, running WRFDA-3DVAR and gen_be sessions. It is a simple test case which contains only 12 data points (view observation locations), real data will obviously have many more observations.

The procedure is the same as Running WRFDA-3DVAR except for an extra radar input file and adding and changing some namelist.input settings.

ob.radar is in plain text format. Edit it to see the content. Its format is simple, but the radar data preprocessing is not trivial and it is user's responsibility.

cp /kumquat/wrfhelp/DATA/WRFDA/Radar/ob.radar ./ob.radar

ln -fs /kumquat/wrfhelp/DATA/WRFDA/Radar/ob.ascii ./ob.ascii
ln -fs /kumquat/wrfhelp/DATA/WRFDA/Radar/wrfinput_d01 ./fg
ln -fs /kumquat/wrfhelp/DATA/WRFDA/Radar/be.dat ./be.dat
ln -fs /kumquat/users/${USER}/DA/WRFDA/run/LANDUSE.TBL ./LANDUSE.TBL

Edit namelist.input

A sample file for this test case is provided in /kumquat/wrfhelp/DATA/WRFDA/Radar/namelist.input

cp /kumquat/wrfhelp/DATA/WRFDA/Radar/namelist.input ./namelist.input

vi namelist.input

&wrfvar2
calc_w_increment = .true.
/
&wrfvar4
use_radarobs = .true.
use_radar_rv = .true.
use_radar_rf = .true.
/

...
&domains
i_parent_start=33,
j_parent_start=33, These two settings are needed because our first guess is from the inner domain of a nested WRF run.

Run WRFDA

Note that, as with other cases in this tutorial, the executable has been renamed (when building your own code it will be named da_wrfvar.exe

mpirun -np 4 /kumquat/users/${USER}/DA/WRFDA/var/build/da_wrfvar_3dvar.exe

Check output

Use ncl scripts introduced in previous exercises to analyze the output.

Check analysis increments of moisture fields.

Check the statistics file.

Other practice

Compare the results using different settings:
use_radar_rv = .true. only
use_radar_rf = .true. only
both use_radar_rv = .true. and use_radar_rf = .true.