Use of multi-sources 10-years quantitative precipitation estimation re-analyses in a lumped rainfall-runoff model

International audienceL'objectif principal de ce projet est de produire une base de donnée de référence couvrant une période de 10 ans pour l'estimation quantitative de lames d'eaux précipitées (LEP). L'objectif est d'utiliser de façon optimale l'ensemble des informations disponibles (radars, pluviomètres horaires et journaliers, données atellite....) afin d'obtenir la meilleure estimation possible de la pluie précipitée. La base de données résultante sera une série de LPE horaire, de 1km2, associée a une estimation des incertitudes sur l'ensemble du territoire français. Cela sera une référence commune pour les hydrologues, permettant des applications telles que le calage des paramètres de modèles, l'evaluation de la valeur ajoutée d'une entrée spatio-temporelle haute résolution pour les modèles hydrologiques ect... / This project main objective is to produce a 10-year reference database of Quantitative Precipitation Estimations (QPE). The objective is to make use optimally at any time of all the available information (radars, hourly and daily rain gauges, satellite data, etc) to obtain the best possible surface precipitation estimation. The resulting data base, will consist of hourly, 1km² gridded QPE and associated estimation uncertainties over the entire French territory. This will represent a common reference for hydrologists useful for various applications such as the calibration of the hydrological model parameters, the assessment of the the added value of high space-time resolution input for hydrological models, etc

Evaluation of hydrological models on small mountainous catchments: impact of the meteorological forcings

Hydrological modelling of small mountainous catchments is particularly challenging because of the high spatio-temporal resolution required for the meteorological forcings. In situ measurements of precipitation are typically scarce in these remote areas, particularly at high elevations. Precipitation reanalyses propose different alternative forcings for the simulation of streamflow using hydrological models. In this paper, we evaluate the performances of two hydrological models representing some of the key processes for small mountainous catchments (&lt; 300 km2), using different meteorological products with a fine spatial and temporal resolution. The evaluation is performed on 55 small catchments of the northern French Alps. While the simulated streamflows are adequately reproduced for most of the configurations, these evaluations emphasize the added value of radar measurements, in particular for the reproduction of flood events. However, these better performances are only obtained because the hydrological models correct the underestimations of accumulated amounts (e.g. annual) from the radar data in high-elevation areas.</p

High-resolution precipitation re-analysis system for climatological purposes

In this article, we describe the design and the validation of the Mescan precipitation analysis system developed for climatological purposes under the EURO4M project. The system is based on an optimal interpolation algorithm using the 24-h aggregated gauge measurements from the surface network. The background fields are the total accumulated precipitation forecasts at different resolutions from the ALADIN or HIRLAM mesoscale models, downscaled to 5.5 km grid spacing, chosen to match the time period of the climatological gauge reports. The validation of the Mescan system is carried out over the French territory employing various metrics and by providing forcing to a hydrological model to produce river discharges. The investigations have shown that the precipitation analyses have almost the same quality as the well-validated SAFRAN analysis system. In addition, the analysis of the precipitation variance spectra computed on the same horizontal domain has indicated that at short wavelengths the downscaled fields have significantly lower variability than a field produced by time integrating a forecast model. The Mescan precipitation analysis system has successfully been used to produce 24-h total accumulated precipitation re-analyses on a 5.5 km grid over Europe for the period 2007–2010