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Below are plots of SYNOP/radiosonde BUFR coverage for 2 1 - 8 March 5 May 2015 - reports as decoded at ECMWF, some reports not in standard BUFR are not decoded.
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Almost 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. Since early March (shown below) BUFR reports from USA, Thailand and some western Pacific islands have disappeared, BUFR reports from some Canadian stations have appeared and Tanzanian stations have started reporting BUFR six-hourly (Ethiopian reports were not received in either format in early May). There have been other fluctuations over this time, partly because some countries started using new BUFR tables that ECMWF could not introduce immediately.
Three countries (UK, Eire and Netherlands, shown green) ceased TAC SYNOP transmission on the GTS on 3rd or 4th November 2014 (see SYNOP ). ECMWF is now assimilating BUFR surface reports from these countries (plus Germany).
(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, only about 10% report proper BUFR with almost 60% reporting reformatted TEMP (see "structure" page and plots below). Reports may be incomplete (eg data above 100 hPa missing). The numbers have recovered from a dip (affecting several countries) seen at ECMWF in mid-November (due partly to slightly non-standard BUFR reports).
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(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 proper 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 in eary May 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.)
