WRF ARW User's Guide - MMM - UCAR

Check your output
OBSGRID
Examine the obsgrid.out file for error messages or warning messages. The program should
have created the files called metoa_em*. Additional output files containing information about
observations found and used and discarded will probably be created, as well.
Important things to check include the number of observations found for your objective analysis,
and the number of observations used at various levels. This can alert you to possible problems in
specifying observations files or time intervals. This information is included in the printout file.
You may also want to experiment with a couple of simple plot utility programs, discussed below.
There are a number of additional output files, which you might find useful. These are discussed
below.
Output Files
The OBSGRID program generates some ASCII text files to detail the actions taken on
observations through a time cycle of the program. In support of users wishing to plot the
observations used for each variable (at each level, at each time), a file is created with this
information. Primarily, the ASCII text files are for consumption by the developers for diagnostic
purposes. The main output of the OBSGRID program is the gridded, pressure-level data set to be
passed to the real.exe program (files metoa_em*).
In each of the files listed below, the text ".dn.YYYY-MM-DD_HH:mm:ss.tttt" allows each time
period that is processed by OBSGRID to output a separate file. The only unusual information in
the date string is the final four letters "tttt" which is the decimal time to ten thousandths of a
second. These files will be dependant on the domain being processed.
metoa_em*
The final analysis files at surface and pressure levels. Generating this file is the primary goal of
running OBSGRID.
These files can now be used in place of the met_em* files from WPS to generate initial and
boundary conditions for WRF. To use these files when running real.exe you can do one of two
things:
1. Rename or link the metoa_em* files back to met_em*. This way real.exe will read the
files automatically.
2. Use the auxinput1_inname namelist option in WRF’s namelist.input file to overwrite the
default filename real.exe uses. To do this, add the following to the &time_control section
of the WRF namelist.input file before running real.exe (use the exact syntax as below –
do not substitute the and for actual numbers):
WRF-ARW V3: User’s Guide 7-9