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In the near-real-time NWP module, the monitoring of data availability is based on performance figures obtained from comparing the observations received from the network to those required and expected to be ingested into the WMO Information System (WIS) according to the schedule determined from OSCAR/Surface metadata. In the Global Basic Observing Network (GBON) module, the monitoring of data availability performance is obtained by comparing the observations received from the GBON-affiliated stations to those expected in accordance with the GBON standard requirements (the shall provisions on Table 2.1 of EC-76/Doc. 3.2(3), ANNEX), where the expected frequency of observations is hourly for surface-based and 12-hourly for upper-air observations.The GBON list of stations is based on the current tentative GBON composition, which will be finalized in June 2023 at the nineteenth World Meteorological Congress (Cg-19)list of stations assigned to GBON by WMO Members in OSCAR/Surface.
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), daily totals (section 4.2), and monthly totals (section 4.3) 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.
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