Re: GEMPAK5.8.3a: Problems with Canadian METAR and dcmetr

Christian,

does the SFPARM=text output from SFLIST for the file on the SGI
show that both the SA and METAR bulletins were processed?

The $GEMPAK/source/bridge/ra/raptnd.f routine that decodes the
pressure tendency hadn't been modified in structure since 1995, so
the 3 or 5 digit field for pressure tendency should still have a problem
in decoding the pressure tendency in th 5.7.4 version. So, if
the SA was received on the SGI, and the order was the same, and then
the metar data was allowed to overwrite the previously decoded data
wihout the bulletin being labeled as a correction, then that would
have been a bug in 5.7.4.

The reason that decoded data is not overwritten without being
a correction is that corrected reports do not have to restransmit the
entire report, but just those fields that were changed. If a later
received bulletin were allowed to overwrite without being a correction,
reporting errors could be reintroduced (which did happen when metars
were received from both local bulletins as well ad national
collectives).

Steve Chiswell
Unidata User Support

On Tue, 2005-11-08 at 20:16, Christian Pagé wrote:
> Steve,
> 
> The data was received in the same order on the SGI server running the
> older version of GEMPAK... so I don't understand why on the SGI it
> doesn't do exactly the same thing...?!?
> 
> Christian
> 
> 08 Nov 2005 11:29:47 -0700, Steve Chiswell <address@hidden>:
> > Christian,
> >
> > The pressure tendency is decoded from the metar report. However, since
> > the metar bulletin is not marked as a correction, the decoder will not
> > attempt to overwrite the already stored values from the SA report.
> > If you use SFPARM=text, you will see that the metar bulletin was
> > received and stored.
> >
> > The problem you have is that the SA report is arriving first, and the
> > pressure tendency is not being decoded since it is not either the 3 or 5
> > character group representation that is expected in the airways format.
> >
> > The behavior to not overwrite data without the correction flag has not
> > changed. This feature does prevent corrected bulletins from being
> > overwritten!
> >
> > Steve Chiswell
> > Unidata User Support
> >
> >
> >
> > On Tue, 2005-11-08 at 06:47, Christian Pagé wrote:
> > > Hello everyone,
> > >
> > > I am transitioning between GEMPAK 5.7.3 (SGI IRIX) and 5.8.3a (Linux
> > > FC4). I have noticed that on my surface plots, many stations from the
> > > Montreal mesonet transmitted in METAR format in the DDS/IDS feed are
> > > not decoded the same way. In 5.8.3a, I am missing the parameters in
> > > the RMK section, though that in the WMO ascii data the data is the
> > > same (in that particular case only P03C is missing, along with no
> > > tenth precision on temperatures):
> > > 368
> > > SACN90 KWBC 081309
> > > METAR CWEW 081300Z AUTO 25007KT 02/M01 RMK AO1 SLP164 T00231012
> > > 52017=
> > >
> > > It is also transmitted in old SAO format, but before (in time) the METAR 
> > > report:
> > > 332
> > > SACN90 CWAO 081300
> > > WEW SA 1300 AUTO8 M M M 164/02/-01/2507/M/ 2017 32MM=
> > >
> > > The P03C group is 52017 in METAR format in the RMK section. I get in 
> > > SFLIST:
> > >     WEW    051108/1300   1016.40 -9999.00     2.00    -1.00     7.00   
> > > 250.00
> > >                         -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 
> > > -9999.00
> > >                         -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 
> > > -9999.00
> > >                         -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 
> > > -9999.00
> > >                         -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 
> > > -9999.00
> > >                         -9999.00
> > > instead of:
> > >     WEW    051108/1300   1016.40 -9999.00     2.30    -1.20     7.00   
> > > 250.00
> > >                         -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 
> > > -9999.00
> > >                          2017.00 -9999.00 -9999.00 -9999.00 -9999.00 
> > > -9999.00
> > >                         -9999.00 -9999.00     1.70 -9999.00 -9999.00 
> > > -9999.00
> > >                         -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 
> > > -9999.00
> > >                         -9999.00
> > >
> > > What did change??
> > >
> > > --
> > > Christian Pagé
> > > UQAM
> >
> 
> 
> --
> Christian Pagé
> http://meteocentre.com/    http://meteoalerte.com/
> Etudiant au Doctorat en Sciences de l'environnement UQAM