WRF ARW User's Guide - MMM - UCAR

WRF-VAR
files should be arranged as follows: directory name is the forecast initial time, time info
in the file name is the forecast valid time. 2008020512/wrfout_d01_2008-02-
06_00:00:00 mean a 12-hour forecast valid at 2008020600 initialized at 2008020512.
Example dataset for a test case (90 x 60 x 41 gridpoints) can be downloaded from
http://www.mmm.ucar.edu/wrf/users/wrfda/download/testdata.html, untar the
gen_be_forecasts_20080205.tar.gz, you will have:
>ls $FC_DIR
-rw-r--r-- 1 users 11556492 2008020512/wrfout_d01_2008-02-06_00:00:00
-rw-r--r-- 1 users 11556492 2008020512/wrfout_d01_2008-02-06_12:00:00
-rw-r--r-- 1 users 11556492 2008020600/wrfout_d01_2008-02-06_12:00:00
-rw-r--r-- 1 users 11556492 2008020600/wrfout_d01_2008-02-07_00:00:00
-rw-r--r-- 1 users 11556492 2008020612/wrfout_d01_2008-02-07_00:00:00
-rw-r--r-- 1 users 11556492 2008020612/wrfout_d01_2008-02-07_12:00:00
In the above example, only 1 day (12Z 05 Feb to 12Z 06 Feb. 2002) of forecasts, every
12 hours are supplied to gen_be_wrapper to estimate forecast error covariance. It is only
for demonstration. The minimum number of forecasts required depends on the application,
number of grid points, etc. Month-long (or longer) datasets are typical for the
NMC-method. Generally, at least 1-month dataset should be used.
Under WRFDA/var/scripts/gen_be, gen_be_wrapper.ksh is used to generate the BE
data, following variables need to be set to fit your case:
export WRFVAR_DIR=/users/noname/work/code/trunk/phoenix_g95_opt/WRFDA
export START_DATE=2008020612 # the first perturbation valid date
export END_DATE=2008020700 # the last perturbation valid date
export NUM_LEVELS=40 # e_vert - 1
export BIN_TYPE=5
export FC_DIR=/users/noname/work/exps/friendlies/expt/fc # where wrf forecasts are
export RUN_DIR=/users/noname/work/exps/friendlies/gen_be${BIN_TYPE}
Note: The START_DATE and END_DATE are perturbation valid dates. As show in the
forecast list above, when you have 24-hour and 12-hour forecasts initialized at
2008020512 through 2008020612, the first and final forecast difference valid dates are
2008020612 and 2008020700 respectively.
Note: The forecast dataset should be located in $FC_DIR. Then type:
> gen_be_wrapper.ksh
Once gen_be_wrapper.ksh runs completed, the be.dat can be found under $RUN_DIR
directory.
To get a clear idea about what are included in be.dat, the script
gen_be_plot_wrapper.ksh may be used to plot various data in be.dat such as:
WRF-ARW V3: User’s Guide 6-36