Within the framework of the European Interreg IIIb Medocc program, the
HYDROPTIMET project aims at the optimization of the hydrometeorological
forecasting tools in the context of intense precipitation within complex
topography. Therefore, some meteorological forecast models and hydrological
models were tested on four Mediterranean flash-flood events. One of them
occured in France where the South-eastern ridge of the French "Massif
Central", the Gard region, experienced a devastating flood on 8 and 9 September 2002.
24 people were killed during this event and the economic damage was
estimated at 1.2 billion euros.
To built the next generation of the hydrometeorological forecasting chain
that will be able to capture such localized and fast events and the resulting
discharges, the forecasted rain fields might be improved to be relevant for
hydrological purposes.
In such context, this paper presents the results of the evaluation
methodology proposed by Yates et al. (2005) that highlights the relevant
hydrological scales of a simulated rain field. Simulated rain fields of 7
meteorological model runs concerning with the French event are therefore
evaluated for different accumulation times. The dynamics of these models are
either based on non-hydrostatic or hydrostatic equation systems. Moreover,
these models were run under different configurations (resolution, initial
conditions). The classical score analysis and the areal evaluation of the
simulated rain fields are then performed in order to put forward the main
simulation characteristics that improve the quantitative precipitation
forecast.
The conclusions draw some recommendations on the value of the quantitative
precipitation forecasts and way to use it for quantitative discharge
forecasts within mountainous areas.
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