[Cosmic_announce] Edition 4 BUFR files expected soon!

[Josep Aparicio]

Doug,

I doubt the differences are only single/double precision.
All impact parameters are shifted by a constant -3m in the new version,
-2.5m in some levels. I would expect single vs double precision to produce
a random jitter.

Bending angles look compatible between versions, though, as they are larger
in the new version by a factor of ~(1+1/2000), which is compatible with the
3m systematic shift and the atmospheric vertical scale height of ~6.5 km.
3m/6.5km ~ 1/2000

However, the entire thing looks puzzling, as if something else, beyond the
BUFR edition was changed, and probably upstream of the BUFR encoding.

Josep

On 11/21/12 11:41, Doug Hunt wrote:
> Hi Harald:  I did notice a few small differences in the data values.
> These are due to the fact that I am using a different BUFR library that
> uses double precision rather than single precision.  So, if anything the
> new values ought to be more accurate.
>
> As to the 175 'originating center' value, we have contacted NOAA to apply
> to the WMO about getting 175 reserved for 'UCAR' rather than using 60
> ('NCAR').
>
> Regards,
>
>     Doug
>
> dhunt at ucar.edu
> Software Engineer
> UCAR - COSMIC, Tel. (303) 497-2611
>
> On Wed, 21 Nov 2012, Harald Anlauf wrote:
>
>> Hi Doug!
>>
>> On Tuesday, 20. November 2012 21:06:28 Doug Hunt wrote:
>>> Greetings:
>>>
>>> The current version of BUFR files available from CDAAC and the
>>> GTS is edition 3.  By the end of November, the WMO wants all edition 3
>>> files to be phased out in favor of the more recent edition 4 BUFR files.
>>>
>>> The change is only a small difference in the header--all the values
>>> remain the same.  Attached are sample edition 4 BUFR files from the COSMIC
>>> and C/NOFS missions.
>> the attached data actually do show small differences to the data
>> disseminated via GTS (usually a few meters in impact parameter, and
>> also small differences in the bending angles), but the obs-model check
>> shows that the effective differences are much smaller than the
>> observation errors we apply operationally.
>>
>> While running these data through our assimilation system, I noticed
>> that the field "originating center" is set to 175 (i.e. reserved for
>> other centers).  Is there a reason that you do not use the value 60
>> there, or is it an oversight?
>>
>>> Next week we plan to start delivering these files.  Note that the version
>>> will change from the current '0001.0006' to '0001.0007'.
>>>
>>> Please let me (dhunt at ucar.edu) know if you see a problem with these
>>> files or need extra time!
>> Cheers,
>> Harald
>>
>> -- 
>> Dr. Harald Anlauf
>> Deutscher Wetterdienst (DWD)           | Phone:  +49 69 8062 4941
>> FE12 / Datenassimilation               | Fax:    +49 69 8062 3721
>> Frankfurter Str. 135                   | e-Mail: harald.anlauf at dwd.de
>> 63067 Offenbach                        | Web:    http://www.dwd.de
>>
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-- 
Dr. Josep Maria APARICIO
Data Assimilation and Satellite Meteorology
Environment Canada
2121 Transcanada
H9P 1J3 Dorval, QC, Canada

Tel: (+1)-514-421-4687
Fax: (+1)-514-421-2106
Josep.Aparicio at ec.gc.ca