degrib msg and submsg

[Bernd Becker]

Wesley,

see below:

On Tue, 2007-10-09 at 10:33 -0400, Wesley Ebisuzaki wrote:
> Patrick,
>
> Patrick Reuter wrote:
> > Dear all,
> >
> > I download grib2 files and have problems to degrib into Grads.
> >
> > I have the following inventory :
> >
> > 1:115:d=2007100706:HGT:850 mb:15 hour fcst
> > 2:227347:d=2007100706:TMP:850 mb:15 hour fcst
> > 3:315793:d=2007100706:RH:850 mb:15 hour fcst
> > 4.1:411471:d=2007100706:UGRD:850 mb:15 hour fcst
> > 4.2:411471:d=2007100706:VGRD:850 mb:15 hour fcst
> >
> > And I want to extract BOTH the UGRD/VGRD values. Here are my degrib
> > commands :
> >
> > ./degrib grib2file -C -msg 4.1 -Flt -Interp -GrADS -out UGRD
> > ./degrib grib2file -C -msg 4.2 -Flt -Interp -GrADS -out VGRD
> >
> The notation 4.1 (message #4, submessage #1) is unique to wgrib2.  You
> should consult the degrib documentation to see how they handle submessages.
>
> If all else fails, you can also use wgrib2 to convert submessages to
> messages by
>
>           wgrib2 -grib new_grib old_grib
>
> > The first command works fine, but in the second command, I always get
> > the following error message :
> >
> > ERROR: In call to Grib2Convert.
> > ERROR: In call to ReadGrib2Record.
> > ERROR: Unpack library error code (0 2)
> >
> > In other words, since the VGRD data is always stored in GRIB2
> > submessages, I can't access to it.
> >
> > Is anybody familiar with my problem ?
> >
> > Thanks in advance
> >
> >   Patrick
> BTW if the grib2 files are lat-lon/mercator/gaussian-grid then you should
> consider converting the files into netcdf using wgrib2.  The netcdf files
> can be opened by GrADS using the sdfopen command.  I believe that
> degrib can produce netcdf files too.
>

Is netcdf the death-knell for GRIB1 and 2 data on a global scale?
I suppose the NEtcdf files will be about 4 times larger  on average.
This would increase I/O times and storage requirements.

When will NetCdf use compression?

Thanks,
Bernd.

>    Wesley
--
Bernd Becker   The Monthly Outlook
Met Office  FitzRoy Road  Exeter   Devon EX1 3PB  United Kingdom
Tel.: +44 (0) 1392 884511 Fax: +44 (0)870 900 5050
E-mail:bernd.becker at metoffice.com  -  http://www.metoffice.com