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20001004: data for GEMPAK

>From: "Francisco Javier Soley Alfaro." <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200010041543.e94Fhmb04961

>
>Dear Steve Chiswell:
>
>Thank you for your prompt reply.
>
>
>> >
>> > The GEMPAK documentation that we provide is the GEMPAK distribution tarfil
> e
>> > under the doc/User_Guide directory. These files are postscript and
>> > may be printed on a laser writer.
>> >
>> > I also provide online html versions of chapter 3 and 4 of the above user g
> uide
>> > in the GEMPAK tutorial web pages at:
>> > http://www.unidata.ucar.edu/packages/gempak/tutorial/manual/toc.html
>>
>> The installation of Gempak was a very laborious process for reasons I will
>> not go into right now. At this moment we do not have a data set to start
>> running some exercises. Most probably the installation of the LDM package
>> will take several weeks. We have some data sets in binary gridded format
>> which were used with  McIdas. Our request for information on grib format
>> was to see if could use that data in gempak without having to do format
>> transformation.
>>
>> > The above address ncardata.ucar.edu\docs\grb\guide.txt is not
>> > an address that belongs to Unidata, and I have been unable to
>> > determine what type of document you are refering to.
>> > The name grb leads me to believe that you are refering to some sort of GRI
> B
>> > guide. If you are trying to find information on GRIB and not GEMPAK, then
>> > you can use:
>> > ftp://ftp.ncep.noaa.gov/pub/nws/nmc/docs/gribed1/
>>
>> We will download that information. Thank you.
>>
>> Vilma has the manual you mentioned above. In it several data sets are used
>> for the different exercises. Could you send us one of this data sets (the
>> smallest to avoid possibe transmission problems) so that we can start
>> playing with gempak before LDM is installed?
>
>Javier Soley
>


Javier,

To use GRIB data within GEMPAK, the data will need to be converted to
a GEMPAK grid file. You can do this with either the program NAGRIB
(as described in the user manual), or the program DCGRIB (which can
be used to decode realtime data from the LDM through the pqact.conf
entries are are shown in our tutorial).

If you have the grib file, you can probably decode it using:
cat gribfile | dcgrib -d - PACK YYYYMMDDHH_model.gem
In the above, you will need to have sourced the Gemenviron file into your
csh environmant so that the GEMPAK tables are found by the program.
The YYYYMMDDHH characters will be replaced by the date and time found 
in the GRIB data.

There are sample data files in gempak5.4/data directory.
The files with .sfc and .shp are surface data files from
land and ship stations respectively. The .snd file is upperair (radiosonde)
data, and .grd is a gridded data file.

If you need additional data, then the case study is probably a good
start for excersises:
http://www.joss.ucar.edu/cometCases/
You can obtain files in GEMPAK format for many types of weather events that
might be useful for either learning the software package, or for
teaching students elements of meteorology.

If you need more help in setting up a data set, let me know and I will create
one for you.

Steve Chiswell
Unidata User Support