Page History

This space is made available for a collaborative discussion on the status and challenges of the migration from Traditional Alphanumeric Codes (TAC) to BUFR. The aim is to share the information on the status of the BUFR data as seen by the users and to provide feedback to WMO and the producers to improve the usability of the data.

The latest version of the migration matrix as taken from the WMO page on migration to TDCF shows that the discontinuation of the category 1 data was planned by November 2014. Many of the reports are now available in BUFR and some TAC bulletins have ceased. 

Status on

4 June 2015

The UK, Eire and Netherlands SYNOPs were switched off in early November 2014 as advertised.  ASDE and ASEU TEMP SHIP reports ceased on 21 November (as did research ship DBLK), originally expected 10 November.  UK and Eire alphanumeric SHIP reports ceased on 3 March 2015 (the UK will still provide them bilaterally on request).  In May 2015 SYNOP data from New Zealand and Hungary ceased as did SHIP data from New Zealand.  In June 2015 we expect SYNOP and SHIP data from Spain and Portugal to cease, along with most Spanish TEMP reports.  For more details of such events see TAC GTS switch off .

Just The ASAP TEMP reports are available bilaterally for a limited period if you ask EUMETNET.  Around 16 December there were some reductions of SYNOPs from Romania and Estonia.  
On 18 December TEMPs, SYNOPs and SHIPs from New Zealand stopped, there was a METNO in November about this  but it had been overlooked by ECMWF and others, leaving a gap in our observation coverage.  The timing of the change was unfortunate - just before Christmas/New Year.  After representations from ECMWF and others the New Zealand TAC data was reinstated on 19 December (until 25 February 2015).  An aspect of particular concern is that the New Zealand BUFR radiosonde data is still as separate parts - it is not properly formatted BUFR - see https://software.ecmwf.int/wiki/display/TCBUF/Structure for notes about the problems with reformatted TEMP data.  (By coincidence ECMWF passed an example of errors in the reformatting to New Zealand on 12 December.)  We are in favour of moving to BUFR but not at the cost of data coverage or quality.  
The whole situation is rather a mess.  Just over 30% of radiosonde/surface stations aren't producing any BUFR at all (see https://software.ecmwf.int/wiki/display/TCBUF/Data+availability ) and the majority of US and Thai BUFR land surface reports disappeared for part of April/May 2015 but are now back; also there have been some problems with the US entries in WMO Publication 9A).  Many BUFR radiosonde reports are reformatted TEMP/PILOT - not proper BUFR.  As we have just seen there although the proportion of native (and high resolution) BUFR is gradually increasing (see https://software.ecmwf.int/wiki/display/TCBUF/Structure for notes about problems with reformatted TEMP data).  There is a risk of countries switching off TAC observations when the BUFR doesn't meet the coding regulations (or has other quality problems).  ECMWF started assimilating some subsets of BUFR radiosonde and surface data on 11 November 2014 but I am aware of three some other NWP centres that can't use BUFR radiosonde data from the GTS yet.  (Most centres don't process BUFR BUOY data yet, the templates have been in a state of flux, see E-SURFMAR for details of surface marine data.)  Some BUFR reports still have rather basic errors, such as wrong positions, and there are plenty of other more subtle errors/features in the data.  In one case both 00 and 12 UTC BUFR radiosonde reports were available within the country concerned, but only the 00 UTC reports were on the GTS.  ECMWF is taking the pragmatic approach of processing both TAC and BUFR data and gradually switching on more of the BUFR reports after they have been assessed.  Comparing different versions of the same reports is a very good way of finding problems, but it takes time and we can't look at lots of countries all at once.

In general we would like to see an overlap of several months between the TAC and BUFR reports (ideally six months but this may not always be possible) - and it should be the proper final version of BUFR (not radiosonde data still in parts; and for SHIPs the new template not the one that is being phased out).  There is a need for more coordination/information of TAC switch off dates via WMO (as described above a blanket switch off in November 2014 was unrealistic), two months warning via METNO of TAC cessation from a particular country would allow us to check and activate the BUFR data.  Developing countries in particular may need more time/help to produce acceptable BUFR reports (especially for radiosondes). 

High resolution data

New data have been released and NWP Centres have put a considerable effort in acquiring and processing new BUFR data which are expected to improve the forecast scores. The extra detail in the observations provided by the transition from TAC to BUFR can be visually represented by the temperature profile in the following figure where BUFR data are reported alongside the corresponding TAC values. For more information regarding the use of these data at ECMWF and their quality see ECMWF section of this wiki.