GEMPAK Status Report

Steve Chiswell
September 12, 2005

Purpose of GEMPAK status report

The activities carried out toward GEMPAK development and support fulfill the following endeavors as described in the Unidata 2008 NSF proposal:


GEMPAK Downloads
  5.6.L 5.6.M 5.7.1 5.7.2 5.7.3 5.7.4 5.8.1 5.8.2a 5.8.3a
Source Code 158 114 171 445 108 393 252 301 179
Linux Binary 233 260 159 661 395 649 427 529 217
FreeBSD Binary 29 42 9 23 34 105 8 21 20
Solaris Sparc Binary 26 23 10 34 19 29 21 14 21
Solaris x86 Binary 4 10 3 24 2 14 21 7 3

Current Status

GEMPAK application training workshop

The Unidata applications training workshop for GEMPAK was conducted July 25-27, 2005. This year there were 41 registrants for the GEMPAK workshop (space was available for 18 participants; 22 were initially accepted for GEMPAK). The workshops were webcast in real-time. Due to the increased availability and usage of online documents, hardcopies of the GEMPAK manual were not distributed this year for the first time (printing costs were determined to be $85 per manual).

GEMPAK 5.8.3a release

GEMPAK 5.8.3a completes transition of all programs to new grid library routines which allow computations involving grids of different navigations.

GEMPAK gridded data diagnostic functionality has been enhanced to allow for computations over layers containing multiple levels of the vertical coordinate. This functionality allows for a new set of LYR_ functions to be entered in GFUNC or GDPFUN to calculate layer quantities. Additional layer diagnostics will be added in future releases.

Three new ensemble diagnostics have been added in this release. They are:

  1. ENS_SSPRD ( scalar_input_arg ) -- Computes the spread (sample standard deviation) over the members of an ensemble.
  2. ENS_VAVG ( vector_input_arg ) -- Computes the average of a vector over the members of an ensemble. The result is a vector field.
  3. ENS_VSPRD ( vector_input_arg ) -- Computes the spread (sample standard deviation) of a vector over the members of an ensemble.

The XW driver has been modified to allow the user to "take a picture" of the current frame. here is a new GEMPAK command, GSAVE, that takes the output file name as an argument and saves the frame to the file in the GIF format. This command operates from any GEMPAK text-interface program that draws data to an X Window. The export GIF functionality was also added to NMAP2.

The ensemble cyclone tracks generated by various forecast models (GFS, NAM, UKMET, NCEP Ensemble, ...) can now be decoded and displayed (in NMAP2 and GPMAP) as a new miscellaneous data type. In many respects, these data sets are similar to the ATCF forecast track data which is decoded "on the fly" and displayed as miscellaneous data type ATCF in NMAP2 and as parameter ATCF in GPMAP. Ensemble tracks can be found on the NCEP/EMCweb pages.

The objective analysis (OA) programs OABSFC and OABSND have a new parameter OABND. OABND specifies the bounds file(s) to use for 'blocking', that is masking out geographical areas based on bounded areas.

GEMPAK 5.8.2 release

GEMPAK 5.8.2 adds ensemble creation using sets of grid files. This release adds the ability to specify sets of grid files to be processed in ensemble calculations. Currently, ensemble means are computed. Additional ensemble functions will be added in future releases. Ensemble calculations can use grids on different navigations, expanding the functionality of the general grid library rewrite first introduced in version 5.8.1.

Time binning of observational data has been added to NMAP2. Time binning allows observations to be combined from different times into NMAP frames for display. This capability is especially useful for observations that are not concentrated at nominal observation times.

Watch Outline Update (WOU) and Watch County Notification (WCN) displays now support county fill in addition to outline. Status update displays have been enhanced to allow the option of only displaying the most recent status line via the WTCH attributes.

A stand-alone GRIB2 decoder NAGRIB2 has been added to the core development. The ability to pack and store data in GRIB2 format within GEMPAK grid files will be added in a future release.

GEMPAK 5.8.1 release

GEMPAK 5.8.1 adds internal grid interpolation to facilitate computations involving grids of different navigations. A general grid library rewrite has been done to improve time handling.

Unidata additions include improved GRIB2 handling for products available in the DVB-S NWSTG channel, updated tables, and NMAP2 modifications to allow parameter and tilt selection for Level II radar data within NMAP2.

GEMPAK 5.7.4 release

GEMPAK 5.7.4 added QuikSCAT wind plotting from BUFR products available via Unidata IDD.

Garp model data access was rewritten to take advantage of GEMPAK's template functions, which now allows access to gridded data in multiple directories, as was possible in all other GEMPAK programs previously. As a result, the distributed configuration files for GEMPAK will now store different models in unique directories, and can take advantage of file storage by forecast hour making access to increased number of grid times/levels/parameters possible and allowing easier configuration for local scouring.

NWX tables were updated for new Communication Identifiers as a result of NWS implementation of phased CID changes.

GEMPAK 5.7.3 release

GEMPAK 5.7.3 adds loop capability to NSHARP, NIDS alphanumeric overlay capability, 16 loop/briefing frames and improved range/interval time selection for NMAP2.

GEMPAK 5.7.2 release

GEMPAK 5.7.2 contains many updates to NMAP2 including improved map database selection, time interval and range selection, and the addition of a GUI for Advanced Objective Dvorak Technique. Additional changes include updates to several decoders, and algorithms for model precipitation accumulation time periods.

Unidata enhancements to this release include the ability to display Level II nexrad data in the bzip2 compressed format, eliminating the need to uncompress the data when received by the LDM.

GEMPAK 5.7.1 release

Beginning with GEMPAK 5.7.1, NCEP will employ a new version numbering method based on quarterly releases as described in the GEMPAK 5.7.1 release notes. Unidata releases generally follow 1 to 3 months after receiving the NCEP release depending on the details of the release and UPC development of additional features.

Radar mosaics for GIS

Iowa State is actively using GEMPAK radar mosaics with their mesonet products in GIS applications. To facilitate this process, I developed the GEMPAK program NEX2IMG to generate composite images which can be used with a file to provide GIS navigation information. Daryl Herzmann has put together a How-To document to help other sites set up their own radar mapservers.

Previous developments

  • See April 2005 status report for past information.

    Ongoing Additions

    COMET case studies available via CODIAC

    COMET case studies are compatible with the GEMPAK/NAWIPS environment, and are being made available via the CODIAC system.

    GEMPAK workshop and tutorial online

    All the documentation for the GEMPAK workshop is made available through the GEMPAK tutorial. Included in the presentation are numerous sample exercises and output samples. This format of presentation allows workshop participants to be able to review or utilize any of the material at their home institution. The tutorial is updated as new features dictate.