Atmospheric motion vector observations in the ECMWF system: third year report

TitleAtmospheric motion vector observations in the ECMWF system: third year report
Publication TypeReport
Date Published11/2013
Series/CollectionEUMETSAT/ECMWF Fellowship Programme Research Reports
Document Number32
AuthorsSalonen, K, Bormann, N
Event Series/CollectionEUMETSAT/ECMWF Fellowship Programme
Place of publicationShinfield Park, Reading

The report summarises the recent changes in the operational use of AMVs in the ECMWF system, and the main results from research work carried out during 2013. The work on situation dependent observation errors and revising the quality control has reached maturity for operational implementation. The changes are included to the ECMWF integrated forecasting system (IFS) cycle 40r1. The aim of the changes is to ensure effective and realistic use of AMVs in data assimilation in order to improve their impact on model analyses and forecasts. Other operational changes include changeover from Meteosat-9 to Meteosat-10, changes in the EUMETSAT AMV processing at low levels, preparations for dissemination of hourly AMVs from GOES-13 and GOES-15 and increased use of AVHRR polar AMVs. The research focus is now on alternative interpretations of AMVs and the work is ongoing. A traditional single-level observation operator is currently used in the operational ECMWF system. A novel observation operator could interpret an AMV as a layer average. Single observation experiments reveal that layer averaging spreads the observation information more in vertical than a single-level observation operator. The choice where the layer is positioned determines where the maximum analysis increment is located. Thus, it is evident that the choice of the observation operator will have an impact on the resulting analysis and consequently on the forecasts.

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