[ncl-talk] Trouble with GFS grib table

[David Brown]

Hi Walter,
Well the GFS analysis is not static. New parameters are added from
time to time. NCEP updates their GRIB tables as the need arises as
well. The tables that NCL uses are updated periodically to incorporate
changes that NCEP makes, but there is necessarily a lag since for now
at least this is a manual process.
In this case, the message about parameter 191 in NCEP table 133 does
indicate a new parameter that NCL has not yet incorporated. For the
record, the docs
(http://www.nco.ncep.noaa.gov/pmb/docs/on388/table2.html#TABLE133) say
this parameter represents "Sunshine Duration" with units of seconds.
The other messages document a record in the file that will never have
a name. GRIB 1 generally uses the number 255 to mean "missing". So in
this case there is both a table with the "missing" designation and in
that table there is a parameter that is "missing". I have no idea what
this record is supposed to represent or why it appears. NCL is just
letting you know about it. Perhaps the GFS folks could explain its
purpose.
 -dave

On Thu, Jun 25, 2015 at 3:51 PM, Walter Hannah <walter at hannahlab.org> wrote:
> Hi,
>
> I downloaded some analysis data from the NOMADS server, specifically:
>
> http://nomads.ncdc.noaa.gov/data/gfsanl/
>
> But when I try to read the files with NCL, I get this message:
>
> warning:NclGRIB: Unrecognized parameter table (center 7, subcenter 0, table
> 255), defaulting to NCEP operational table: variable names and units may be
> incorrect
> warning:NclGRIB: Unknown grib parameter number detected (255, center 7,
> table version 255 grib record 3), using default variable name (VAR_255)
> warning:NclGRIB: Unknown grib parameter number detected (191, center 7,
> table version 133 grib record 240), using default variable name (VAR_191)
>
> Looking at some previous ncl-talk tthreads, I think I understand the issue,
> but I'm confused that the GFS analysis wouldn't be consistent with the
> default NCEP grib tables.
>
> Can anyone shed some light on what's going on here?
>
> Thanks,
> Walter
>
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