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All targets regarding availability refer to the number of observations received by NWP centres from the network (Table 1). For each station, 6-hourly totals (section 4.1) and daily totals (section 4.2) are computed based on the quality monitoring information received from all the NWP Centres (section 5) and stored in the WDQMS Database. This task is performed on a daily basis, so that availability information of the observing network is accessible in near-real time. It is worth noting that in the WDQMS context “observations received” means the observations that were made available to the assimilation system of each NWP centre and are considered as a good proxy for the observations disseminated on the GTS. Moreover the results are aggregated across NWP centres (section 5.2) to help reduce potential differences between the number of observations available on the GTS and the number of the observations seen by the individual assimilation systems.
Number of Expected Observations (based on OSCAR/Surface)
For each station, the expected 6-hourly and daily totals (i.e. the number of observations the station should exchange internationally via GTS/WIS during the defined period) are extracted from OSCAR/surface and used as a reference (Table 2). In this context, the schedule of observations is obtained for all the stations recorded in OSCAR/Surface that meet the following criteria: stations that are declared operational or partially operational on the level of the GOS/Regional Basic Synoptic Network (RBSN) affiliation; have an observation of the variable of interest; have the “international exchange” field set to “yes” (currently only for surface); are valid at the date of the defined period. For the upper-air, the schedule is obtained for all stations that are of station class Upper-air/Radiosonde. In case an observation has no entry in "Deployments" in OSCAR/Surface, a default schedule is assumed, which is 3 hourly observations for surface and 2 observations per day for upper-air stations, one in each interval, the 00 and 12 UTC interval. All the metadata used in WDQMS is updated daily, which means that any update on the station metadata recorded in OSCAR/surface will be reflected on the performance maps the next day.
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