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

Re: era40 cdl template (fwd)




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

---------- Forwarded message ----------
Date: Sat, 24 Apr 2004 11:36:42 -0400 (EDT)
From: Brent A McDaniel <address@hidden>
To: Robb Kambic <address@hidden>
Subject: Re: era40 cdl template


The output of gribdumb -h shows that the header info is wrong in the raw
grib file.  The header info shows the odd names that show up in the .cdl
file generated by gribtocdl.  I'm leaving the country for 2 weeks tomorrow
but when I return I'll contact the nss folks at ucar and see if others
have dealt with this.  I'll keep y'all posted.

Thanks for the help!

--Brent



On Fri, 23 Apr 2004, Robb Kambic wrote:

> Brent,
>
> Could you run gribdump on the raw file and show me the headers for the
> different parameters? Are the parameter names correct in gribdump? If not
> could you match the parameters to the correct names so I can make a table
> for gribtonc then you will get the correct names in the output.  Also
> have you contacted UCAR  about this problem, they might already have a
> table.
>
> RObb...
>
> On Thu, 22 Apr 2004, Brent A McDaniel wrote:
>
> >
> > Hi Robb,
> >
> > Thanks for the reply.  Here's a sample of the output from gribtonc:
> > ...
> > Apr 12 18:33:04 gribtonc[13809]: 27203: wrote reserved(107,11,*,*) to 
> > output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27204: wrote thnd_prob(107,10,*,*) to 
> > output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27205: wrote Pm(107,10,*,*) to output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27206: wrote Psl_et(107,10,*,*) to 
> > output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27207: wrote LI(107,10,*,*) to output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27208: wrote LI4(107,10,*,*) to output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27209: wrote Kind(107,10,*,*) to output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27210: wrote mois_div(107,10,*,*) to 
> > output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27211: wrote bvf_2(107,10,*,*) to output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27212: wrote gflux(107,10,*,*) to output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27213: wrote cape(107,10,*,*) to output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27214: wrote reserved(107,10,*,*) to 
> > output.nc
> > Apr 12 18:33:04 gribtonc[13809]: 27215: wrote thnd_prob(107,9,*,*) to 
> > output.nc
> > ...
> >
> >
> > As far as sending a sample, unforunately the grib file is quite large
> > (~666mb) and I don't know how to subset that.  Is there an easy way to do
> > that?
> >
> > Thanks for the help!
> >
> > Cheers,
> >
> > Brent
> >
> >
> > On Tue, 20 Apr 2004, Robb Kambic wrote:
> >
> > > Brent,
> > >
> > > If nobody has the proper cdl file then could you send me a sample file?
> > > My speculation is that a table is being used to convert variables from
> > > ECMWF variables to the NCEP variable names.  Reason for the weird names.
> > > Also, what was the log messages from gribtonc like?
> > >
> > > Robb...
> > >
> > > On Tue, 20 Apr 2004, Brent A McDaniel wrote:
> > >
> > > >
> > > > I've just begun to use the ECMWF ERA40 data that is available from the
> > > > NCAR data archives.  I'm using the 4x daily upper air pressure level 
> > > > data
> > > > that has 11 variables: geopotential, temperature, u wind component, v 
> > > > wind
> > > > component, w wind component, relative humidity, specific humidity,
> > > > vorticity, divergence, potential vorticity, ozone mass mixing ratio.  
> > > > The
> > > > data is archived in grib format for 1 month.
> > > >
> > > > Running wgrib -v e4oper.pl.195801 |more results in:
> > > > 1:0:D=1958010100:var60:1 mb:kpds=60,100,1:anl:ECMWF stream?:"undefined
> > > > 2:21240:D=1958010100:Z:1 mb:kpds=129,100,1:anl:ECMWF 
> > > > stream?:"Geopotential (at the surface = orography) m**2 s**-2
> > > > 3:42480:D=1958010100:T:1 mb:kpds=130,100,1:anl:ECMWF 
> > > > stream?:"Temperature K
> > > > 4:63720:D=1958010100:U:1 mb:kpds=131,100,1:anl:ECMWF 
> > > > stream?:"U-velocity m s**-1
> > > > 5:84960:D=1958010100:V:1 mb:kpds=132,100,1:anl:ECMWF 
> > > > stream?:"V-velocity m s**-1
> > > > 6:106200:D=1958010100:Q:1 mb:kpds=133,100,1:anl:ECMWF stream?:"Specific 
> > > > humidity kg kg**-1
> > > > 7:127440:D=1958010100:W:1 mb:kpds=135,100,1:anl:ECMWF stream?:"Vertical 
> > > > velocity Pa s**-1
> > > > 8:148680:D=1958010100:VO:1 mb:kpds=138,100,1:anl:ECMWF 
> > > > stream?:"Vorticity (relative) s**-1
> > > > 9:169920:D=1958010100:D:1 mb:kpds=155,100,1:anl:ECMWF 
> > > > stream?:"Divergence s**-1
> > > > 10:191160:D=1958010100:R:1 mb:kpds=157,100,1:anl:ECMWF 
> > > > stream?:"Relative humidity %
> > > > 11:212400:D=1958010100:O3:1 mb:kpds=203,100,1:anl:ECMWF stream?:"Ozone 
> > > > mass mixing ratio kg kg**-1
> > > > 12:233640:D=1958010100:var60:2 mb:kpds=60,100,2:anl:ECMWF 
> > > > stream?:"undefined
> > > > ...
> > > >
> > > > which appears to be the variables that are supposed to be there 
> > > > although I
> > > > don't see potential vorticity (is that the undefined?).
> > > >
> > > > I then run gribtocdl to generate the .cdl file:
> > > > gribtocdl -v e4oper.pl.195801 > era40.jan.1958.cdl
> > > >
> > > > and then run gribtonc to convert to netcdf:
> > > > gribtonc -v -l- era40.jan.1958.cdl output.nc < e4oper.pl.195801
> > > >
> > > > This works properly and I get a netcdf file.  When I look at it though,
> > > > all the variable names are wierd.  Looking at the .cdl file I see that 
> > > > in
> > > > there the variable names aren't Z,T, U etc that were in the grib file
> > > > they are things like thund_prob, K index at isobaric levels, and other 
> > > > odd
> > > > things.  The time is also off, showing the initial time as time since 
> > > > 1994
> > > > (data being tested was 1958).  I did check one thing though.  I plotted
> > > > the 3rd variable in the created netcdf file (which should be 
> > > > temperature)
> > > > and compared it the ncep reanalysis temperature field for jan 1958 and
> > > > they match up nicely so the data is somewhat correct.
> > > >
> > > > So, can someome help me out with this?  Does anyone have a .cdl template
> > > > for the ERA40 data set already?  I'm most concerned with the time
> > > > variables as I'm not sure exactly how grib keeps track of time.
> > > >
> > > > Thanks for any and all help.
> > > >
> > > > Cheers,
> > > >
> > > > Brent
> > > >
> > > >  --
> > > > Brent A. McDaniel
> > > >
> > > > Dept of Earth and Atmospheric Sciences
> > > > Georgia Institute of Technology
> > > > Atlanta, Ga.  USA
> > > >
> > >
> > > ===============================================================================
> > > Robb Kambic                                  Unidata Program Center
> > > Software Engineer III                        Univ. Corp for Atmospheric 
> > > Research
> > > address@hidden               WWW: http://www.unidata.ucar.edu/
> > > ===============================================================================
> > >
> >
> > --
> > Brent A. McDaniel
> >
> > Dept of Earth and Atmospheric Sciences
> > Georgia Institute of Technology
> > Atlanta, Ga.  USA
> >
>
> ===============================================================================
> Robb Kambic                              Unidata Program Center
> Software Engineer III                    Univ. Corp for Atmospheric Research
> address@hidden                   WWW: http://www.unidata.ucar.edu/
> ===============================================================================
>

-- 
Brent A. McDaniel

Dept of Earth and Atmospheric Sciences
Georgia Institute of Technology
Atlanta, Ga.  USA