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| Titel |
Improving QPF by blending techniques at the Meteorological Service of Catalonia |
| VerfasserIn |
A. Atencia, T. Rigo, A. Sairouni, J. Moré, J. Bech, E. Vilaclara, J. Cunillera, M. C. Llasat, L. Garrote |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 10, no. 7 ; Nr. 10, no. 7 (2010-07-07), S.1443-1455 |
| Datensatznummer |
250008304
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| Publikation (Nr.) |
 copernicus.org/nhess-10-1443-2010.pdf |
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| Zusammenfassung |
| The current operational very short-term and short-term quantitative
precipitation forecast (QPF) at the Meteorological Service of Catalonia (SMC)
is made by three different methodologies: Advection of the radar reflectivity
field (ADV), Identification, tracking and forecasting of convective
structures (CST) and numerical weather prediction (NWP) models using
observational data assimilation (radar, satellite, etc.). These precipitation
forecasts have different characteristics, lead time and spatial resolutions.
The objective of this study is to combine these methods in order to obtain a
single and optimized QPF at each lead time. This combination (blending) of
the radar forecast (ADV and CST) and precipitation forecast from NWP model is
carried out by means of different methodologies according to the prediction
horizon. Firstly, in order to take advantage of the rainfall location and
intensity from radar observations, a phase correction technique is applied to
the NWP output to derive an additional corrected forecast (MCO). To select
the best precipitation estimation in the first and second hour (t+1 h and
t+2 h), the information from radar advection (ADV) and the corrected outputs
from the model (MCO) are mixed by using different weights, which vary
dynamically, according to indexes that quantify the quality of these
predictions. This procedure has the ability to integrate the skill of
rainfall location and patterns that are given by the advection of radar
reflectivity field with the capacity of generating new precipitation areas
from the NWP models. From the third hour (t+3 h), as radar-based forecasting
has generally low skills, only the quantitative precipitation forecast from
model is used. This blending of different sources of prediction is verified
for different types of episodes (convective, moderately convective and
stratiform) to obtain a robust methodology for implementing it in an
operational and dynamic way. |
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