Below are plots of SYNOP/radiosonde BUFR coverage for February 2016 - reports as decoded at ECMWF, some reports not in standard BUFR are not decoded.
Please can data producers ensure that there is a reasonable overlap of TAC and BUFR data on the GTS (at least two months, EUMETNET recommendation is six months), any attempt to rush the change will result in more errors, extra work for NWP centres and possibly worse forecasts. Most countries give notice via METNOs or the WMO newsletter. Note also that reformatted TEMP reports still as separate parts are not regulation BUFR and cause problems for NWP centres (some more than others).
Surface coverage
Over 80% of stations now report in BUFR. (Iceland is reporting BUFR from almost 100 stations, compared to about 20 in TAC.) For some countries stations/reports designated for national use only are received in TAC but not in BUFR. Light blue markers indicate that fewer BUFR reports are received than SYNOP reports - in most cases the BUFR is six-hourly but the SYNOPs are three-hourly.
Countries that have ceased TAC SYNOP transmission on the GTS are shown green (most recently Germany in January 2016) and labelled 'Post SYNOP' (see SYNOP ). ECMWF is assimilating BUFR surface reports from these countries plus some others.
(Grey: TAC reports but no BUFR, Purple: BUFR reports but no TAC, Red *: position error. Light/dark blue indicates that there are less/more than 60% of the reports available in BUFR.)
Radiosonde coverage
Almost 70% of stations report in BUFR, about 20% report native BUFR with roughly 50% reporting reformatted TEMP (see "structure" page and plots below). Reports may be incomplete (eg data above 100 hPa missing). The UK has recently started sending high resolution BUFR from some stations in the standard template (it was using an alternate template before).
On 11 November 2014 ECMWF started assimilating a subset of the high resolution reports and has gradually added more BUFR reports after careful checking. After 21 November 2014 some of the ASAPs (those starting ASDE and ASEU) also research vessel DBLK stopped reporting in TEMP SHIP format, they are now only available in BUFR format. We understand that a few NWP centres are not yet in a position to assimilate BUFR radiosonde data, although they are working on this.
(Grey: TAC reports but no BUFR, Purple: BUFR reports but no TAC, Red *: position error. Blue: both BUFR and TAC, light blue indicates fewer ascents in BUFR. Triangle - ship report, X - wind-only report.)
It can be difficult to distinguish native BUFR from reformatted TEMP. The plot below (showing data received at the Met Office) shows stations reporting radiosonde drift with a red halo, some Australian stations started sending native BUFR in July. Of the native BUFR reports about half have 300 or more levels.
The maximum number of levels reported gives some information on the resolution of the reports (1-29 grey; 30-99 light blue; 100-299 dark blue; 300-999 green; 1000-2999 orange; over 3000 cyan.)
