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19991011: AWIPS Upper air netCDF CDL (fwd)

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  • Subject: 19991011: AWIPS Upper air netCDF CDL (fwd)
  • Date: Mon, 11 Oct 1999 14:20:12 -0600 (MDT)

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

---------- Forwarded message ----------
Date: Mon, 11 Oct 1999 14:09:11 -0600
From: Don Murray <address@hidden>
To: address@hidden
Subject: 19991011: AWIPS Upper air netCDF CDL


Hi Darien-

I saw the note you sent to Dolores Kiessling at COMET about the
existence (or lack thereof) of upper air netCDF files in AWIPS. Guess
that explains why I couldn't find any! ;-)

I have a couple of questions that hopefully you can find the answers
to. We have a Perl decoder for upper air reports (TTAA, TTBB, etc) and
were using the NUWG CDL for this. We thought it would be a good idea to
be more AWIPS compatible, so we are upgrading our decoder to use the
AWIPS CDL that was in the AWIPS code you gave us to look at. The NUWG
and AWIPS CDLs for upper air data are very similar, but I have some
questions about the differences.

1) In the NUWG convention, dewpoint was stored as the temperature:

        float tdMan(recNum, manLevel) ;
                tdMan:long_name = "Dew Point - Mandatory level" ;
                tdMan:units = "Celsius";
                tdMan:_FillValue = -99999.f;

but in the AWIPS CDL, it is listed as dewpoint depression:

        float tdMan(recNum, manLevel) ;
                tdMan:long_name = "Dew Point Depression - Mandatory level" ;
                tdMan:units = "kelvin" ;
                tdMan:valid_range = 0.f, 60.f ;
                tdMan:_FillValue = 99999.f ;

I'm wondering if you (or anyone else) knows why this change was
made (like "it was a better way to do it").  Is it really stored
as dewpoint depression?

2)  In regards to the time, the AWIPS CDL has synTime and relTime.
I just want to confirm that synTime would be the synoptic time
(00, 03, 06, etc) and that relTime would be the time listed
in the bulletin.  

Do you have any upper air netCDF files that use the AWIPS raob.cdl
that we could take a look at?

Thanks for your help.

Don 
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Don Murray                               UCAR Unidata Program
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(303) 497-8628                              Boulder, CO 80307
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