Re: 20040506: netCDF Decoders - Sun UNIX - CDLs

On Fri, 21 May 2004, Beth Hall wrote:

> Robb --
>
> Thanks for the advice on the CDL's.  You mentioned how to use most of the
> CDL's except for the gfs_211.cdl.  This one is of most interest to me
> since it seems to be for a much higher resolution (80 km) than the others
> and still shows the forecast data.  However, I'm having a hard time
> knowing what the actual lat/lon coordinates are for this 80 km grid.  Is

Beth,

The coordinates are constant.

Lat/lon values of the corners of the grid
(1,1)   12.190N, 133.459W
(1,65)  54.536N, 152.856W
(93,65)         57.290N, 49.385W
(93,1)  14.335N, 65.091W

Here's the basic info on all the grids at:

http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html

Actually http://www.nco.ncep.noaa.gov/pmb/docs/on388 give the details of
parameters, etc too.

Other info:

http://www.nco.ncep.noaa.gov/pmb/docs/headers/awpgfs/#TABLEGP


Robb....

> this, perhaps a separate file that would specify this information, for I
> don't think I need it for every dataset I want to use -- it should stay
> fairly constant, right??
>
> Thanks,
> Beth Hall
>
> On Fri, 7 May 2004, Robb Kambic wrote:
>
> > On Thu, 6 May 2004, Unidata Support wrote:
> >
> > >
> > > ------- Forwarded Message
> > >
> > > >To: address@hidden
> > > >From: "Beth Hall" <address@hidden>
> > > >Subject: netCDF Decoders - Sun UNIX - CDLs
> > > >Organization: DRI
> > > >Keywords: 200405070023.i470NhxJ020678 netCDF decoders gribtonc CDL
> > >
> > > Institution: Desert Research Insitute
> > > Package Version: decoders-3.0.3
> > > Operating System: Sun UNIX
> > > Hardware Information: Sun
> > > Inquiry: I'm trying to access data from the ldm feed, partiticularly
> > > the GFS data.  I feel very lost, but finally found the gribtonc
> > > command.  I originally used the gfs_211.cdl file, but it gave me no
> > > lat/lon coordinates, just x and y.
> >
> > Beth,
> >
> > No lat/lon are given because of rounding errors, no accurate values. The
> > lat/lon are mainly for human information.
> >
> >
> >
> > With this cdl, the ncdump -h said
> > > there were 21 records (I'm assuming this refers to the forecasts,
> > > themselves).
> >
> > Your correct the records are for forcast times:
> >
> >  valtime_offset = 0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78,
> > 84, 90, 96, 102, 108, 114, 120 ;
> >
> >
> >  I did some web searching and found that there were other
> > > CDLs including a 1 degree CDL.
> >
> > The 1 degree grids are only on the CONDUIT feed, not the standard NOAAPORT
> > feed.
> >
> >
> >   I tried it along with the
> > > gfs_21-24.cdl, gfs_25-26.cdl, and the gfs_37-44.cdl.  Several of those
> > > actually have the lat/lon coordinate information, but now show 0
> > > records (no forecast data?).
> >
> > Maybe you don't have the correct pqact entries, here's the ones we are
> > using. Remember the white spaces are tabs between the parts of the
> > entries.
> >
> > # GFS model on global 5.0 x 2.5 degree grids
> > HRS     ^H.[A-D]... .... (..)(..).*/m(SPEC62MRF|MRF)
> >         PIPE    /usr/local/ldm/decoders/gribtonc
> >         etc/gfs_21-24.cdl
> >         data/pub/decoded/netcdf/GRIB/(\1:yyyy)(\1:mm)\1\2_gfs_21-24.nc
> >
> > # GFS model on global 5.0 x 5.0 degree grid
> > HRS     ^H.[EF]... KWB. (..)(..)
> >         PIPE    /usr/local/ldm/decoders/gribtonc
> >         etc/gfs_25-26.cdl
> >         data/pub/decoded/netcdf/GRIB/(\1:yyyy)(\1:mm)\1\2_gfs_25-26.nc
> >
> >
> > # GFS model on thinned grids, interpolated to global 5.0 x 2.5 regular
> > grid
> > HRS     ^H.[I-P]... KWB. (..)(..).*(/mAVN|/mSSIAVN)
> >         PIPE    /usr/local/ldm/decoders/gribtonc
> >         -q "lin,dlat=2.5,dlon=5.0" etc/gfs_37-44.cdl
> >         data/pub/decoded/netcdf/GRIB/(\1:yyyy)(\1:mm)\1\2_gfs_37-44.nc
> >
> > I know the data must be there, but clearly
> > > don't understand what these different CDLs are doing, which one I
> >
> > The cdl file are templates for making the NetCDF files, the number
> > designation at the end of the cdl refers to the grib sections ie 21-24
> > that are stitched together to form the whole grib file.
> >
> > Robb...
> >
> > > should use, and which ones give me the lat/lon coordinate information.
> > > Can you help?  Thanks.
> > >
> > > --
> > > NOTE: All email exchanges with Unidata User Support are recorded in the
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> > >
> > > ------- End of Forwarded Message
> > >
> >
> > ===============================================================================
> > Robb Kambic                            Unidata Program Center
> > Software Engineer III                          Univ. Corp for Atmospheric 
> > Research
> > address@hidden                 WWW: http://www.unidata.ucar.edu/
> > ===============================================================================
> >
>

===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================