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WIGOS Data Quality Monitoring System webtool retrieves metadata information from OSCAR/Surface on a daily basis. For example, the availability maps are generated in near-real time by comparing the observations received by the NWP Centers against the schedules retrieved from OSCAR/Surface. Therefore, if the metadata has been updated today, tomorrow's maps should reflect that change. In the case a new station is added in OSCAR/Surface, it should appear on the WDQMS availability map the next day. If that does not happen, it means that some fields may have not been correctly populated in OSCAR/Surface and this needs to be reported to the RWCs.
What is the cut off time in the different temporal categories (i.e, 6-hour, daily and alert)?
The interval categories are defined as follows. The 6-hourly intervals are centred on the main synoptic hours: 00 (21 UTC ≤ t < 03 UTC); 06 (03 UTC ≤ t < 09 UTC); 12 (09 UTC ≤ t < 15 UTC); and 18 (15 UTC ≤ t < 21 UTC), where t refers to observation time. The daily interval is the union of the four 6-hourly intervals as defined above, therefore is the 24-hour period within the interval 21 UTC ≤ t < 21 UTC, where t is the observation time and the lower “21UTC” limit is the day before. The alert maps represent a 5-day moving average, therefore rely on daily values for a 5-day period.
Do Centers consider TAC or BUFR bulletins to calculate the statistics displayed on the web tool?
The Centres are providing monitoring information based on their assimilation systems, which means that the statistics computed for each station, interval and variable, will include mainly the observations used in the assimilation system (either TAC or BUFR) because observation duplicates are not considered in WDQMS. On the quality maps for surface observations, the 6-hourly intervals for a particular monitoring centre allow you to see the details of individual observations that contribute for the average value displayed on the map. This means that it is possible to check the O-B value, the usage (Status, i.e., used or not used because it was rejected by/before the assimilation) and the type of report (Type, i.e., TAC or BUFR) of a particular observation (identified by date and time) by hovering the mouse over each dot in the time series. For the upper-air, this information is provided on the 6-hourly availability maps for a single NWP Centre. Clicking on a dot on the map shows a pop-up with detailed information about the station data availability over the selected period. For the 6-hourly periods, details of the observations received such as Layer (Trop - from surface up 100hPa- and Stra -from 100hPa up balloon burst), Variable and observation type (TAC or the new high resolution BUFR reports) and status (used / not used, “used” meaning that at least one level/variable was assimilated) are provided.
What bulletin type does NCEP assimilate, TAC, BUFR or both?
NCEP does not provide this information to WDQMS (that is why it is shown as Type: n/a) as they don't currently pass info into their DA database on whether the observation source was TAC or BUFR. However, most data NCEP uses is TAC.
Why does DWD surface availability maps always show less observations than ECMWF for example, with orange dots being the dominant feature?
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