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WPS<br />
F. g2print.exe<br />
Similar to g1print.exe, the g2print.exe program takes as its only command-line argument<br />
the name of a GRIB Edition 2 file. The program prints a listing of the fields, levels, and<br />
dates of the data in the file.<br />
G. plotfmt.exe<br />
The plotfmt.exe is an NCAR Graphics program that plots the contents of an intermediate<br />
format file. The program takes as its only command-line argument the name of the file to<br />
plot, and produces an NCAR Graphics metafile, which contains contour plots of each<br />
field in input file. The graphics metafile output, gmeta, may be viewed with the idt<br />
command, or converted to another format using utilities such as ctrans.<br />
H. rd_intermediate.exe<br />
Given the name of a singe intermediate format file on the command line, the<br />
rd_intermediate.exe program prints information about the fields contained in the file.<br />
Writing Meteorological Data to the Intermediate Format<br />
The role of the ungrib program is to decode GRIB data sets into a simple intermediate<br />
format that is understood by metgrid. If meteorological data are not available in GRIB<br />
Edition 1 or GRIB Edition 2 formats, the user is responsible for writing such data into the<br />
intermediate file format. Fortunately, the intermediate format is relatively simple,<br />
consisting of a sequence of unformatted Fortran writes. It is important to note that these<br />
unformatted writes use big-endian byte order, which can typically be specified with<br />
compiler flags. Below, we describe the WPS intermediate format; users interested in the<br />
SI or MM5 intermediate formats can first gain familiarity with the WPS format, which is<br />
very similar, and later examine the Fortran subroutines that read and write all three<br />
intermediate formats (metgrid/src/read_met_module.F90 and<br />
metgrid/src/write_met_module.F90, respectively).<br />
When writing data to the WPS intermediate format, 2-dimensional fields are written as a<br />
rectangular array of real values. 3-dimensional arrays must be split across the vertical<br />
dimension into 2-dimensional arrays, which are written independently. It should also be<br />
noted that, for global data sets, either a Gaussian or cylindrical equidistant projection<br />
must be used, and for regional data sets, either a Mercator, Lambert conformal, polar<br />
stereographic, or cylindrical equidistant may be used. The sequence of writes used to<br />
write a single 2-dimensional array in the WPS intermediate format is as follows (note that<br />
not all of the variables declared below are used for a given projection of the data).<br />
integer :: version ! Format version (must =5 for WPS format)<br />
integer :: nx, ny ! x- and y-dimensions of 2-d array<br />
integer :: iproj ! Code for projection of data in array:<br />
<strong>WRF</strong>-<strong>ARW</strong> V3: User’s <strong>Guide</strong> 3-30