Below are plots of SYNOP/radiosonde BUFR coverage for 1 - 7 June 2015 - 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
About 70% of stations now report in BUFR. Iceland is now reporting BUFR from almost 100 stations, compared to about 20 in TAC, there are also extra stations from Brazil. For some countries (eg Japan) stations/reports designated for national use only are received in TAC but not in BUFR. For part of March and April BUFR reports from USA, Thailand and some western Pacific islands were missing, in recent months BUFR reports from some Canadian stations have appeared and Tanzanian stations have started reporting BUFR six-hourly. There were other fluctuations about two months ago, partly because some countries started using new BUFR tables that ECMWF could not introduce immediately.
Countries that have ceased TAC SYNOP transmission on the GTS are shown green 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 15% report native BUFR with roughly 55% 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 (about 16 stations from Europe plus some ASAP ships). After 21 November 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 some 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. Light/dark blue indicates low/high vertical resolution BUFR data. Black ring - ship report, or identifier error!)
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, there are a few extra island stations reporting native BUFR compared to early March.
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.)
