WMO, and NWP centres, want radiosonde stations to move towards sending high-resolution reports in BUFR. Extra levels, and detailed position information, improves NWP forecasts.
For more details see Ingleby et al (2016, BAMS, http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-15-00169.1) 'Progress towards high-resolution, real-time radiosonde reports'.
There are various templates available, summarised here for convenience along with notes on when they should be used (these notes have no official standing).
Full documentation of the templates, and other doding coding issues, is at https://community.wmo.int/activity-areas/wis/wis-manuals
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These are sometimes written with spaces, eg. 3 09 057.
There should be no need to provide reports in multiple templates: if 309057 is provided then it is better to stop sending 309052.
It is important that there should be one report containing all data from the ascent, although there can be earlier partial reports (particularly up to 100 hPa) for timeliness reasons.
Usually these BUFR reports are produced by the software from the radiosonde manufacturers. (Attempts to convert alphanumeric TEMP reports to BUFR are very problematic, and do not provide the higher resolution that WMO GBON will require shortly.)
Ideally there should be an overlap of 2-6 months between good quality BUFR made available over the GTS and the withdrawal of TAC reports - with notification of these changes via https://community.wmo.int/news/operational-newsletter .
Following approval of the plans for the Global Basic Observing Network (GBON) in October 2021, radiosonde data should be reported at high vertical resolution from January 2023 and details of the horizontal/time sampling required were set out. See https://public.wmo.int/en/events/constituent-bodies/cg-ext2021 and https://meetings.wmo.int/Cg-Ext-2021/SitePages/Session%20Information.aspx .
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ECMWF provides a BUFR validator which can be used to check the content of BUFR messages.
It also provides EcCodes ecCodes including a customised program for reading/printing BUFR radiosonde reports (bufr_read_tempf, available in Python or Fortran - EcCodes ecCodes needs setting up first).
Example output is provided below. There is an option to print all levels or just standard levels.
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