WRF Pre-Processing System Version 4.6.0http://www2.mmm.ucar.edu/wrf/users/The WRF Pre-Processing System (WPS) is a collectionof Fortran and C programs that provides data used asinput to the real.exe program. There are three main programs and a number of auxiliary programs that are part of WPS.For questions and help to run the program, please see the User's Guide athttp://www2.mmm.ucar.edu/wrf/users/docs/user_guide_v4/contents.htmland send email to wrfhelp@ucar.edu.===================================================Main programs: geogrid.exe, ungrib.exe, metgrid.exeInput to the main programs is through the namelistfile "namelist.wps".  Each main program has an exclusive namelist record (named "geogrid", "ungrib",or "metgrid", respectively), and the three programs have a group record (named "share") that each programreads.geogrid-------1) Defines the model horizontal domain2) Horizontally interpolates static data to the modeldomain3) Output conforms to the WRF I/O APIungrib------1) Decodes Grib Edition 1 and 2 data2) Uses tables to decide which variables to extract3) Supports isobaric and generalized vertical coordinates4) Output is in a non-WRF-I/O-API form, referred to as an   intermediate formatmetgrid-------1) Ingest static data and raw meteorological fields2) Horizontally interpolate meteorological fields to the    model domain3) Output conforms to WRF I/O APIParallelismThe geogrid and metgrid programs may be run asdistributed memory parallel jobs to reduce the time-to-solution.  These two programs use MPI callsdirectly, compared to WRF, which has an abstractionlayer (RSL or RSL_LITE).Grib Edition 2The Grib Edition 2 compression requires three librariesexternal to the WPS source code: zlib, png, and jasper.It is recommended that users request support from theirsystem administrators when installing these packages.Users can compile the code without these libraries by selecting the "NO GRIB2" options in the build.Building WPSSimilar to the WRF package, WPS uses a two-step buildmechanism,   ./configure   ./compilewhich directs the unix make underneath.If the user is on a recognized architecture, theconfigure script will display a list of availablecompile options (usually serial vs parallel, Grib 2enabled vs a "NO GRIB2" option).  For some OS options,there are multiple compilers that are supported.The configure option lists both "build GRIB2" and"do not build GRIB2" options.  It is suggested thatthe first builds be without the GRIB Edition 2capability.The utility plotting programs requiring NCAR Graphics are not compiled automatically. Library paths must be set correctlyin configure.wps and then compiled using ./compile plotfmt./compile plotgridsBuilding WPS with CMakeThe WPS cmake build follows the same procedure as the WRFbuild procedure, using the following:   ./configure_new   ./compile_new  The prompts will look similar and present the user withavailable options specific to their system.Running WPS (for serially compiled code)geogrid.exe------------ edit namelist.wps (&share and &geogrid sections)- make sure the correct GEOGRID.TBL is used (ls -l geogrid/GEOGRID.TBL*)- type 'geogrid.exe' to run- check output in geogrid.logungrib.exe----------- edit namelist.wps for start_date and end_date, output file prefix   (&share and &ungrib sections)- link correct Vtable:  ls -l ungrib/Variable_Tables  For example, for NCEP GFS (or AVN, FNL) data,  ln -sf ungrib/Variable_Tables/Vtable.GFS Vtable- link grib data files:  link_grib.csh /data-directory/file*- type 'ungrib.exe >& ungrib.out' to run- check output in ungrib.log and ungrib.outmetgrid.exe------------ edit namelist.wps (&share and &metgrid sections)- make sure the correct METGRID.TBL is used (ls -l metgrid/METGRID.TBL*)- type 'metgrid.exe' to run- check output in metgrid.logThere are a number of utility programs that will bebuilt in WPS/util/ directory:avg_tsfc.exe------------purpose: computes a daily mean of the surface air temperature, reads the namelist.wps fileusage:avg_tsfc.exeg1print.exe-----------purpose: read a Grib Edition 1 file, output information to build a Vtableusage:g1print.exe GRIB1_fileg2print.exe-----------purpose: read a Grib Edition 2 file, outputinformation to build a Vtableusage:g2print.exe GRIB2_filemod_levs.exe------------purpose: reduce levels in a intermediate fileso that different GRIB sources may be usedfor the initial and lateral boundary time periodsusage:mod_levs.exe OLD_intermetdiate:date_string \             NEW_intermetdiate:date_stringProcesses a single file at a time, uses the pressure levels defined in the namelist.wps file.plotfmt.exe-----------purpose: generate NCAR Graphics metacode 2dhorizontal plots of each field and level in theintermediate fileusage:plotfmt.exe intermediate_file:date_stringplotgrids.exe-------------purpose: generate an NCEAR Graphics metacodeplot of the domain locations, one frame withall of the domain locations plotted, reads thenamelist.wps file to get the domain informationusage:plotgrids.exerd_intermediate.exe-------------------purpose: read an intermediate file and printthe information to the screenusage:rd_intermediate.exe intermediate_file:date_stringcalc_ecmwf_p.exe-------------------purpose: when using ECMWF model data in GRIB format,computes the 3-d pressure, height, and RH fields fromthe output of ungrib.exe, and writes these fields toa new set of intermediate files to be used in additionto those produced by ungrib. All times between the start_dateand end_date specified in the &share namelist will beprocessed.usage:calc_ecmwf_p.exeStatic Input DataThe static input data is provided in two tar files: onecontains full resolution data (30", 2', 5' and 10') and the othercontains only 10' low-resolution data. The data may be downloaded fromhttp://www2.mmm.ucar.edu/wrf/users/download/get_source.html.Meteorological Input DataThe meteorological input data for WPS is the GRIBEdition 1 GFS data from NCEP.  A test data set (Jan 2000, 24/12Z to 25/12Z) is available fromhttp://www2.mmm.ucar.edu/wrf/users/download/get_source.html.Sample WPS output data for WRFSamples of the output data from WPS for use in WRF for theJan 2000 and June 2001 cases are provided fromhttp://www2.mmm.ucar.edu/wrf/users/download/get_source.html.