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[LDM #ZGC-437176]: Dealing with unreadable GRIB files

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  • Subject: [LDM #ZGC-437176]: Dealing with unreadable GRIB files
  • Date: Fri, 22 Feb 2013 16:49:49 -0700
Rich,

I'm afraid I know very little about GRIB2 files. So I've forwarded this reply 
to some people who know much more than I.

> Guys,
> 
> The LDM grib file is 6.2GB, while if I download the grib2 file from the TDS:
> wget 
> http://motherlode.ucar.edu:8080/thredds/fileServer/fmrc/NCEP/GFS/Global_0p5deg/files/GFS_Global_0p5deg_20130222_0000.grib2
> 
> it is only 3.8GB.
> 
> What the heck?
> 
> I guess I need "wgrib" or something to check these out?
> 
> -Rich
> 
> 
> On Fri, Feb 22, 2013 at 6:31 PM, Unidata IDD Support
> <address@hidden> wrote:
> > Rich,
> >
> >> >> In the past 9 months we have had 22 files NAM files and 33 GFS files
> >> >> that the TDS was unable to read (produces 0 length GRIB index files).
> >> >>
> >> >> When 0 length GRIB index files get created, the TDS times out on these
> >> >> datasets, and our workflow is broken.
> >> >
> >> > Understandable, that is not OK!
> >> >
> >> >>
> >> >> This is an error rate of about 10%.
> >> >
> >> > Well, closer to 2% (4 runs per day), unless you are only requesting one 
> >> > synoptic time per day, but even 2% is far greater than one would expect, 
> >> > we see generally 99.98 reliability..if not better.
> >
> > TCP unreliability is much, much less than 2%. It's far more likely that 
> > there's something wrong with the decoder or the GRIB file.
> >
> > Do you have something that can check the validity of a GRIB file?
> >
> > Regards,
> > Steve Emmerson
> >
> > Ticket Details
> > ===================
> > Ticket ID: ZGC-437176
> > Department: Support IDD
> > Priority: Normal
> > Status: Closed
> >
> 
> 
> 
> --
> Dr. Richard P. Signell   (508) 457-2229
> USGS, 384 Woods Hole Rd.
> Woods Hole, MA 02543-1598


Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: ZGC-437176
Department: Support IDD
Priority: Normal
Status: Closed