[Datastream #KEJ-427580]: Duplicate GRIB messages over NOAAPORT

Hi Kevin,

re:
> We have noticed that some GRIB messages are duplicated over NOAAPORT.

We have noticed that NOAAPort contains numerous duplicated products
** as indicated by their WMO IDs **.  The NOAAPort ingest software and
LDM itself do not try to distinguish between duplicate products other
than to reject them IF/WHEN their MD5 signatures are the same.  If the
contents of the products differ at all, then their MD5 signatures will
be different, and, so, they will look different to the LDM.

re:
> Going into the raw data, we did find one difference.
> As an example, in the attached CAPE_180mb_2019311_0Z_GFS.grib2 file that
> came in today at 329Z, the message starts with GRIB and ends with 7777.
> In the attached CAPE_180mb_2019311_0Z_GFS_YWPB86_KWBC.070000.grib2 file
> that came in today at 337Z, the message has the start sequence, then WMO
> Header, then GRIB, then 7777, and then the end sequence.
> If you remove the start/header/end, both GRIB messages are the same as
> determined by their md5sum.
> It seems like the 2 messages are coming from 2 sources, so an upstream
> issue?

Yes, but not an upstream LDM since the LDM doesn't know or care about
the content of the products it moves.  It is probable that the site
that preps products for broadcast in NOAAPort had a hiccup of some
sort, and that hiccup resulted in more than one copy of the same
product being sent.

re:
> There are many of these duplicates and it would be nice just to have one
> source if possible.

There is one source, and that is NWS/NOAA, not us.  The problem is in systems
over which we have no control, so there is not much, if anything, we can do
to correct the situation.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: KEJ-427580
Department: Support Datastream
Priority: Normal
Status: Closed
===================
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