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| Titel |
Factors influencing skill improvements in the ECMWF forecasting system |
| VerfasserIn |
Erland Källén, Linus Magnusson |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072938
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| Zusammenfassung |
| During the past 30 years the skill in ECMWF numerical forecasts has steadily improved.
Three major factors contributing are (1) improvements in the forecast model both regarding
resolution and physical aspects, (2) improvements in the data assimilation and (3) the
increased number of available observations. In this study we are investigating the relative
contribution from these three components by using the simple error growth model introduced
in Lorenz (1982) and extended in Dalcher and Kalnay (1987), together with the results from
ERA Interim forecasts where the improvement is only due to an increased number of observations.
We are also applying the growth model on ”lagged”-forecast differences in order to
investigate the usefulness of the forecast jumpiness as a diagnostic tool for improvements in
the forecasts.
Our main findings are that the main contribution to the reduced error comes from model
improvements together with a large contribution from the initial conditions around year
2000. The changes in the available observations contributed to a lesser degree, but we have to
remember that the all the ERA Interim forecasts are from the satellite era and that we here
focus on the mid-troposphere in the extra-tropics. Regarding the jumpiness in the forecasts,
this is mainly a function of the error in the initial conditions and is therefore an insufficient
tool to investigate improvements in the full forecasting system. |
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