Assimilation of Accumulated Precipitation Data
Reference: Precipitation Data Assimilation in the WRFDA Users' Guide
Source code
Get the pre-compiled code, if you have not done so.
WRFDA/var/build/da_wrfvar.exe_4dvar (this is renamed from da_wrfvar.exe) is the executable that will be used in the 4D-VAR session.
Working directory
We recommend you create a new working directory for this exercise:
mkdir /data1/$USER/DA/rainfall
cd /data1/$USER/DA/rainfall
Input data
The test data for this rainfall tutorial case can be found in /wrfhelp/DATA/WRFDA/Rainfall
ln -fs /wrfhelp/DATA/WRFDA/Rainfall/ob/ob.rain.2008020518.06h ob07.rain
ln -fs /wrfhelp/DATA/WRFDA/Rainfall/rc/wrfinput_d01 ./fg
ln -fs /wrfhelp/DATA/WRFDA/Rainfall/rc/wrfinput_d01 .
ln -fs /wrfhelp/DATA/WRFDA/Rainfall/rc/wrfbdy_d01 .
ln -fs /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 ${your_source_code_dir}/WRFDA/run/RRTM_DATA_DBL ./RRTM_DATA
ln -fs ${your_source_code_dir}/WRFDA/run/*.TBL .
Edit namelists
A very basic namelist.input file for running this tutorial case is available at /wrfhelp/DATA/WRFDA/Rainfall/namelist.input.
cp /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 1 ${your_source_code_dir}/WRFDA/var/build/da_wrfvar.exe_4dvar >&! var4d.log
Note: this case may take a long time on the COMET classroom computers (around 30 minutes)
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