UPP Online Tutorial for UPPV4.1 | Visualization: GrADS

The GrADS utilities grib2ctl.pl (g2ctl.pl) and gribmap are able to decode GRIB1 (GRIB2) files whose navigation is on any non-staggered grid. Hence, GrADS is able to decode GRIB files generated by the UPP package and plot horizontal fields or vertical cross sections. These utilities and instructions on how to use them to generate GrADS control files are available from:

A sample script named run_unipostandgrads, included in the /UPPV4.1/scripts directory, can be used to run unipost, copygb, and plot the following fields using GrADS:

  • Sfcmaphh_dnn_GRADS.png: mean SLP and 6-hrly accumulated precipitation
  • 850mbRHhh_dnn_GRADS.png: 850 mb relative humidity
  • 850mbTempandWindhh_dnn_GRADS.png: 850 mb temperature and wind vectors
  • 500mbHandVorthh_dnn_GRADS.png: 500 mb geopotential heights and absolute vorticity
  • 250mbWindandHhh_dnn_GRADS.png: 250 mb wind speed isotacs and geopotential heights

This script can be modified to customize fields for output.

In order to use the script run_unipostandgrads, it is necessary to:

  1. Set the environment variable GADDIR to the path of the GrADS fonts and auxiliary files. For example, 

    setenv GADDIR /usr/local/grads/data

  2. Add the location of the GrADS executables to the PATH. For example,

    setenv PATH /usr/local/grads/bin:$PATH

Additional information on GrADS, including and online User's Guide and a list of basic commands can be found at http://cola.gmu.edu/grads/gadoc.