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Titel |
Verification of intense precipitation forecasts from single models and ensemble prediction systems |
VerfasserIn |
F. Atger |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 8, no. 6 ; Nr. 8, no. 6, S.401-417 |
Datensatznummer |
250005885
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Publikation (Nr.) |
copernicus.org/npg-8-401-2001.pdf |
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Zusammenfassung |
The performance of
single models and ensemble prediction systems has been investigated with
respect to quantitative precipitation forecasts. Evaluation is based on
the potential economic value of + 72 h/ + 96 h forecasts. The verification
procedure consists of taking into account all precipitation amounts that
are predicted in the vicinity of an observation in order to compute
spatial, multi-event contingency tables. A probabilistic forecast from an
ensemble can thus be compared to a probabilistic forecast from a single
model run. The main results are the following: (1) The performance of the
forecasts increases with the precipitation threshold. High levels of
potential value reflect high hit rates that are obtained at the expense of
a high frequency of false alarms. (2) The ECMWF ensemble performs better
than a single forecast based on the same model, even when the resolution
of the ensemble is lower. This is true for the NCEP ensemble as well, but
only for morning precipitations. (3) The ECMWF ensemble performs better
than the 5-member NCEP ensemble running at 12:00 UTC, even when the
population of the former is reduced to 5 members. (4) The impact of
reducing the population of the ECMWF ensemble is rather small. Differences
between 51 members and 21 members are hardly significant. (5) A 2-member
poorman ensemble consisting of the control forecasts of the ECMWF and the
NCEP ensembles performs as well as the ECMWF ensemble for afternoon
precipitations. |
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