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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.
The availability performance reports are generated by comparing the 6-hourly and daily totals against the respective expected values for each observed variable (Table 2). A performance report is generated individually for each NWP Centre and time interval. For the 6-hourly totals, four reports are generated daily for each of the NWP centres.
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Definition | Number of observations per station as received by each NWP Centre during a defined period. |
Calculation | For each observed variable, the sum of all valid data is computed |
Valid data | Data not flagged as missing value |
Math expression | Nj, where N is the total number of valid data for variable j. |
Table 2 - Availability performanceAnchor Table2 Table2
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