The WIGOS monitoring Centres that are currently providing quality monitoring reports are: DWD, ECMWF, JMA and NCEP for surface land stations; ECMWF, JMA and, in future, DWD for upper-air land stations. Based on the feedback from the assimilation systems, the monitoring information provided by the NWP Centres reflect the main characteristics - strengths and weakness - of their own systems. Therefore, the tool also combines the information across Centres to exploit the strengths of each NWP assimilation system and provide a more robust statement regarding availability and quality.
5.1.Individual NWP CentresCentre
Regarding the generation of the monitoring performance reports for land surface stations, there are four NWP monitoring centres to choose from: DWD, ECMWF, NCEP and JMA. For the upper-air land stations only ECMWF and JMA are available (DWD will soon be implemented into de system). Note that the four 6-hourly reports provided by the participating WIGOS monitoring Centres are based on the observations that were made available to the assimilation system at each Monitoring Centre, which is used as a proxy to the observations available on the GTS. Therefore, the way the four different NWP data assimilation systems deal with the observations varies and may explain the differences seen on the performance reports across Centres. Below are highlighted some of the procedures used in the different NWP centres that should be taken into consideration when comparing the results between NWP centres. NCEP monitoring reports show only the data that pass a quality control step prior to DA, therefore, part of the data available that is deemed to be of poor quality or duplicate is filtered out and is not available to the DA. Another important aspect of its DA system is the assimilation of surface pressure observations provided by METAR reports - mainly over US - rather than from SYNOP reports when both reports are available in the same location, therefore some SYNOPs observations over this region may not show in NCEP maps.
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