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| Titel |
Precipitation forecasting by a mesoscale numerical weather prediction (NWP) model: eight years of experience |
| VerfasserIn |
P. Kaufmann, F. Schubiger, P. Binder |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 7, no. 6 ; Nr. 7, no. 6, S.812-832 |
| Datensatznummer |
250004857
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| Publikation (Nr.) |
 copernicus.org/hess-7-812-2003.pdf |
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| Zusammenfassung |
| The Swiss Model, a hydrostatic numerical weather prediction model, has been used
at MeteoSwiss for operational forecasting at the meso-beta scale (mesh-size 14 km) from
1994 until 2001. The quality of the quantitative precipitation forecasts is evaluated for
the eight years of operation. The seasonal precipitation over Switzerland and its
dependence on altitude is examined for both model forecasts and observations using the
Swiss rain gauge network sampling daily precipitation at over 400 stations for verification.
The mean diurnal cycle of precipitation is verified against the automatic surface
observation network on the basis of hourly recordings. In winter, there is no diurnal
forcing of precipitation and the modelled precipitation agrees with the observed values.
In summer, the convection in the model starts too early, overestimates the amount of
precipitation and is too short-lived. Skill scores calculated for six-hourly precipitation
sums show a constant level of performance over the model life cycle. Dry and wet seasons
influence the model performance more than the model changes during its operational period.
The comprehensive verification of the model precipitation is complemented by the discussion
of a number of heavy rain events investigated during the RAPHAEL project. The sensitivities
to a number of model components are illustrated, namely the driving boundary fields, the
internal partitioning of parameterised and grid-scale precipitation, the advection scheme
and the vertical resolution. While a small impact of the advection scheme had to be
expected, the increasing overprediction of rain with increasing vertical resolution in
the RAPHAEL case studies was larger than previously thought. The frequent update of the
boundary conditions enhances the positioning of the rain in the model.
Keywords: numerical weather prediction, quantitative precipitation forecast,
model verification |
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