The test data for this rainfall tutorial case can be found in /kumquat/wrfhelp/DATA/WRFDA/Rainfall
ln -fs /kumquat/wrfhelp/DATA/WRFDA/Rainfall/ob/ob.rain.2008020518.06h ob07.rain
ln -fs /kumquat/wrfhelp/DATA/WRFDA/Rainfall/rc/wrfinput_d01 ./fg
ln -fs /kumquat/wrfhelp/DATA/WRFDA/Rainfall/rc/wrfinput_d01 .
ln -fs /kumquat/wrfhelp/DATA/WRFDA/Rainfall/rc/wrfbdy_d01 .
ln -fs /kumquat/wrfhelp/DATA/WRFDA/Rainfall/be/be.dat .
These are the observation, first guess, boundary, and background error files, respectively. It is necessary to link a few more files for a 4D-VAR precipitation run
ln -fs /kumquat/users/${USER}/DA/WRFDA/run/RRTM_DATA_DBL ./RRTM_DATA
ln -fs /kumquat/users/${USER}/DA/WRFDA/run/*.TBL .
A very basic namelist.input file for running this tutorial case is available at /kumquat/wrfhelp/DATA/WRFDA/Rainfall/namelist.input.
cp /kumquat/wrfhelp/DATA/WRFDA/Rainfall/namelist.input .
vi namelist.input
Pay special attention to the following namelist variables, making sure they are set to these values:
&wrfvar1
var4d=true,
var4d_lbc=false,
var4d_bin=3600,
var4d_bin_rain=21600,
...
/
...
&wrfvar4
use_rainobs=true,
thin_rainobs=true,
thin_mesh_conv=20.,
/
Run 4D-VAR with Accumulated Rainfall Observations
mpirun -np 4 /kumquat/users/${USER}/DA/WRFDA/var/build/da_wrfvar_4dvar.exe
Note! In the provided namelist, we haven't set a small limit for ntmax (maximum number of iterations of the cost function minimization) like we did for the original practice 4DVAR case. Therefore, on the classroom computers this case will take some time, probably more than 10 minutes. If you would rather move on quickly and do not care about reaching the full minimization, set ntmax=5; this will still not be instantaneous, but will only take a few minutes.