Originating centre and sub centre incorrect in BUFR generated by wis2box

[david-i-berry]

Whilst the originating centre and sub centre in BUFR data generated by the wis2box (via synop2bufr and csv2bufr) can be set by configuring the csv2bufr mapping files this has not been done for the vast majority of wis2box's currently installed.

With the new configuration workflow this could be done via an environment variable and then using this environment variable via the API and event driven workflows.

[tomkralidis]

2023-11-09 wis2box standup

• we should ensure the value is null/missing rather than incorrect (in BUFR tools)

[tomkralidis]

1. check BUFR regulations on centre id requirements (@david-i-berry)
2. default is null
3. in BUFR tools, check for centre id environment variable; if exists, then set, else null/unset

[tomkralidis]

• default is null
  • template changes in synop2bufr/csv2bufr

[tomkralidis]

2024-01-17

• updated as part of csv2bufr-template refactor
• needs update in synop2bufr
• needs testing/release management

[david-i-berry]

wis2box docs need updating to instruct user how to update originating centre (some initial instructions provided as part of the Jakarta training material).

[tomkralidis]

2024-01-30

• @RoryPTB / @david-i-berry to update synop2bufr
• add docs in this issue for docs PR

[RoryPTB]

Update:
When the BUFR header centre and subcentre are not set in the mapping file, the default is not none but rather 98 and 0 respectively. So, it appears that ECMWF are setting the defaults to their own if it is missing. Hence the use of environment variables BUFR_ORIGINATING_CENTRE and BUFR_ORIGINATING_SUBCENTRE should be mandatory.

[tomkralidis]

Thanks @RoryPTB. Can we (in the BUFR handler) force unset these values in any way? Or is the result the same?

[RoryPTB]

Update:
It turns out it is possible to manually do this. Elements that are part of the data section can be set to MISSING. However, elements in the header section are set to missing by setting all of their respective bit values to 1. Since the originating centre and originating subcentre have a data width of 16, setting their default values to 65535 is equivalent to missing.

In this way, the environment variables are no longer mandatory. If they are not set however, synop2bufr will still present a warning to the user.
For the implementation of this, please see the latest commit of my PR.

[david-i-berry]

See also #546

[tomkralidis]

2024-03-05:

• fixed in API, will be fixed once API updates are merged/integrated to stack

[tomkralidis]

Closing. Will monitor as wis2box BUFR production circulates across WIS2.