[Cosmic_announce] Change in BUFR file header

[Sean Healy]

Hi Doug,

I am unclear whether this change will be made to the bufr files we 
currently get via ftp from UCAR or are they changes to a new, parallel 
data stream?

Do you really have to make the changes on a Friday? Could
we not see a few sample files first, and then make the changes
next week?

Thanks

Sean.









Doug Hunt wrote:
> Hi all:  In order to get cosmic BUFR files (bfrPrf) on the GTS, we need 
> to make a small change to the header bytes at the beginning of the 
> bfrPrf files.
> 
> Currently, the header of a "WMO message" is being sent, which starts with:
> 
> 00000000: 010d 0d0a 2d2d 2d0d 0d0a 4955 5446 3134  ....---...IUTF14
> 00000010: 204b 5742 4320 3131 3030 3131 0d0d 0a42   KWBC 110011...B
> 00000020: 5546 5200 2104 0300 0012 0000 3c00 0003  UFR.!.......<...
> 
> In order to get the NESDIS DDS system to accept these files,
> they need to have the WMO starting line:
> 
> [SOH][cr][cr][lf]nnn  Where nnn is 0-999 sequence number
> 
> replaced by a 'Flag Field Separator':
> 
> ####018008476####[lf]
> 
> where 018 is the flag field separator length and 008476 is the BUFR 
> message length.
> 
> So, the new files will start like this:
> 
> 00000000: 2323 2323 3031 3830 3038 3437 3623 2323  ####018008476###
> 00000010: 230a 0d0d 0a49 5554 4a31 3420 4b57 4243  #....IUTJ14 KWBC
> 00000020: 2031 3032 3335 390d 0d0a 4255 4652 0021   102359...BUFR.!
> 
> My understanding is that any good BUFR decoder will skip past
> these initial bytes.
> 
> The new files will have a 0001.0006_bufr suffix.  They will start being 
> produced tomorrow.
> 
> Regards,
> 
>   Doug Hunt
> 
> dhunt at ucar.edu
> Software Engineer III
> UCAR - COSMIC, Tel. (303) 497-2611
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