[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[GEMPAK #QEJ-861814]: GEMPAK - Date/Time Ranges in GDGRIB

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: [GEMPAK #QEJ-861814]: GEMPAK - Date/Time Ranges in GDGRIB
  • Date: Wed, 19 Sep 2007 14:19:04 -0600
> Steve,
> 
> I have managed to convert individual NARR-A GEMPAK grid files to grib format 
> and it loads perfectly in IDV. However, my goal is to convert GEMPAK grids 
> that have been averaged using GDSTAT and convert those files to gribs. These 
> averaged files as you know have a date/time range to them indead of a single 
> data/time period. Here are the two approaches I have used to define the 
> date/time:
> 
> GDATTIM= 971116/1200F000-060224/1200F000
> 
> GDATTIM= 971116/1200F000:060224/1200F000
> 
> 
> Here is my output from GDINFO showing the times.
> 
> NUM       TIME1              TIME2           LEVL1 LEVL2  VCORD PARM
> 1     971116/1200F000   060224/1200F000     1000         PRES MAXTMPK
> 2     971116/1200F000   060224/1200F000     1000         PRES MINTMPK
> 3     971116/1200F000   060224/1200F000     1000         PRES AVETMPK
> 4     971116/1200F000   060224/1200F000     1000         PRES SDVTMPK
> 5     971116/1200F000   060224/1200F000     1000         PRES CNTTMPK
> Parameters requested: GDFILE,LSTALL,OUTPUT,GDATTIM,GLEVEL,GVCORD,GFUNC.
> 
> 
> Is there another way of listing date/time ranges for GDGRIB?
> 
> 
> --Chris Warren
> 
> 
> Christopher Warren
> Graduate Research Assistant
> Plymouth State University
> Plymouth, NH 03264
> Email: cjwarren1@mail.plymouth
> 
> 
Chris,

The PDSVAL parameter can be used to set the parameter name, level, time to be 
used,
however, the time interval for your average if much largetr than an hourly value
like P06M for example.

The easiest solution to get the parameter to grib would be to use GDDIAG and
convert the MAXTMPK for that time interval to the TMXK parameter
(as defined in $GEMTBL/grid/wmogrib2.tbl parameter #15) such as:
 GFUNC    = maxtmpk
 GDATTIM  = 971116/1200f000:060224/1200f000
 GLEVEL   = 1000
 GVCORD   = pres
 GRDNAM   = tmxk^060224/1200
 GRDTYP   = s
 GPACK    = none
 GRDHDR   =  


Then use GDGRIB to convert the TMXK to grib.

I don't have a good way to encode the time period of gdtat into the grib
without doing some direct bit writing in the PDS block. The above use of
the single time in GRDNAM in gddiag gets around having to work
with the time ranges.

Steve Chiswell
Unidata User Support


Ticket Details
===================
Ticket ID: QEJ-861814
Department: Support GEMPAK
Priority: Normal
Status: Closed