Differences in plots between DWD and Met Office

Information page on data availability monitoring setup and differences

This page supplies technical information on the data availability monitoring setups at the DWD and MetOffice that lead to systematic differences in the data coverage and timeliness monitoring results displayed. Details are listed following the data categories and types in the menues on the Data Coverage and Data Timeliness pages. Differences in the number of instruments currently included into the monitoring or the type of plots provided are not listed here and are generally related to internal implementation schedules at DWD and the Met Office.

General setup

DWD: The data availability monitoring is based on all the received data. I.e. all data stored in the data base within the respective observation time interval are retrieved and evaluated without applying any thinning, remapping or data quality control (each original lat/lon data position (FOV) constitutes one datum count).

Met Office: The data availability monitoring is set up as part of the data processing chain for the data assimilation. For several of the data types a thinning or remapping is applied leading to differences in data counts and data density compared to DWD, while the results of the timeliness statistics should generally not be affected since the overall data counts are large.

DBNet data and data reception routes: The Met Office has its own two polar receivers included in its monitoring which are not part of DBNet (and hence not part of the data received at and included in DWD monitoring). The actual routes used operationally for receiving different data types and instruments (e.g. via EUMETCast, GTS, ftp) may differ between DWD and the Met Office and information will be provided on the data reception routes page.

MW-T sounder

  • AMSU-A: The Met Office data are mapped to the HIRS grid as part of an ATOVS processing chain, resulting in 56 FOVs every 6.4 seconds versus 30 FOVs every 8 seconds for DWD, i.e. an expected factor of 2.3 more data in the Met Office monitoring.

MW-Hum sounder

  • MHS: The Met Office data are mapped to the HIRS grid as part of an ATOVS processing chain, resulting in 56 FOVs every 6.4 seconds versus 90 FOVs every 8/3 seconds for DWD, i.e. an expected factor of 0.139 (#Met Office / #DWD). The observed factor of 0.25 is likely due to the MetOffice reporting NOAA-18 which has a non-functioning MHS.
  • MWHS-2: The Met Office discards the outermost scans (i.e. counting 90 FOVs instead of 98 FOVs per scan line) and data are thinned to ~50 km comparable to AMSU-A.

MW-T+Hum sounder

  • ATMS / DBNet: currently merged with the globally received data for the coverage plots, but not for timeliness.

MW-Imager

  • MWRI: Data are thinned keeping 1 spot in 2 at the Met Office.

IR-sounder

  • HIRS: As data quality has degraded for the remaining instruments, these data have been taken out of the monitoring at the Met Office.

IR-hyperspectral

  • IASI: Storage of 1 spot in 4 (it varies which one is retained) at the Met Office.
  • CrIS: Storage of 1 spot in 9 (taking the central position) at the Met Office.
  • IASI/DBNet: Only the Exeter reception station is displayed (also thinned 1 in 4 FOVs) as most other stations are not stored at the Met Office.
  • CrIS/DBNet: Data are merged with the global in the Met Office processing (resulting in the double peak with very short and longer data delays in Met Office timeliness plots) and no seperate DBNet plots for the coverage.

GEO radiances

  • No systematic differences in data monitoring setup.

Scatterometer

  • ASCAT: Global and DBNet data are currently merged in the Met Office processing (resulting in the double peak with very short and longer data delays in Met Office timeliness plots and higher data counts in the coverage plots compared to the DWD plots).

Altimeter

  • Currently only monitored at DWD.

AMVs geo / polar

  • No systematic differences in data monitoring setup.