The SAFRAN-ISBA-MODCOU hydrometeorological model applied over France

An edited version of this paper was published by AGU. Copyright (2008) American Geophysical UnionThe hydrometeorological model SIM consists in a meterological analysis system (SAFRAN), a land surface model (ISBA) and a hydrogeological model (MODCOU). It generates atmospheric forcing at an hourly time step, and it computes water and surface energy budgets, the river ow at more than 900 rivergauging stations, and the level of several aquifers. SIM was extended over all of France in order to have a homogeneous nation-wide monitoring of the water resources: it can therefore be used to forecast flood risk and to monitor drought risk over the entire nation. The hydrometeorologival model was applied over a 10-year period from 1995 to 2005. In this paper the databases used by the SIM model are presented, then the 10-year simulation is assessed by using the observations of daily stream-flow, piezometric head, and snow depth. This assessment shows that SIM is able to reproduce the spatial and temporal variabilities of the water fluxes. The efficiency is above 0.55 (reasonable results) for 66 % of the simulated rivergages, and above 0.65 (rather good results) for 36 % of them. However, the SIM system produces worse results during the driest years, which is more likely due to the fact that only few aquifers are simulated explicitly. The annual evolution of the snow depth is well reproduced, with a square correlation coeficient around 0.9 over the large altitude range in the domain. The stream ow observations were used to estimate the overall error of the simulated latent heat ux, which was estimated to be less than 4 %

Modélisation des bilans de surface et des débits sur la France, application à la prévision d'ensemble des débits

The French coupled hydrometeorological model SIM (SAFRAN : interpolates atmospheric forcing over a 8 km regular grid; ISBA : surface scheme; MODCOU : distributed hydrological model) is first applied over the Seine basin. It is evaluated over a 10-year period, with a particular attention on the underground and the streamflows. The long duration floods of the Seine at Paris are also examined.A real-time ensemble streamflow prediction system over France, based on SIM, is then described. The ISBA and MODCOU models are forced by meteorological ensemble forecasts from ECMWF, downscaled to a 8 km resolution. A statistical study of the abilities of the system, especially for low flows and floods, is produced using nearly one year of forecasts. An analysis of ensemble forecasts for recent large flood events over France is also presented.Ce travail de thèse s'appuie sur l'utilisation du modèle couplé hydro-météorologique SAFRAN-ISBA-MODCOU.D'abord, la modélisation couplée du bassin de la Seine est mise en place, en utilisant une représentation détaillée des aquifères du bassin. La capacité de SIM à simuler les différentes composantes des bilans d'eau et d'énergie, le comportement du souterrain, et donc les débits, est présentée. En particulier, SIM est évalué pour la simulation des crues lentes de la Seine à Paris.Ensuite, une chaîne temps réel de prévision d'ensemble des débits sur la France, basée sur SIM, est construite, où ISBA et MODCOU sont forcés par les prévisions d'ensemble météorologiques du CEPMMT désagrégées. Une analyse statistique de la qualité des prévisions d'ensemble de précipitations désagrégées et des prévisions d'ensemble de débit est effectuée sur près d'un an de prévision. Enfin, une étude des prévisions d'ensemble de plusieurs cas de grandes crues du passé récent est présentée

On the Impact of Short-Range Meteorological Forecasts for Ensemble Streamflow Predictions

International audienceEnsemble streamflow prediction systems are emerging in the international scientific community in order to better assess hydrologic threats. Two ensemble streamflow prediction systems (ESPSs) were set up at Météo-France using ensemble forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) Ensemble Prediction System for the first one, and from the Prévision d'Ensemble Action de Recherche Petite Echelle Grande Echelle (PEARP) ensemble prediction system of Météo-France for the second. This paper presents the evaluation of their capacities to better anticipate severe hydrological events and more generally to estimate the quality of both ESPSs on their globality. The two ensemble predictions were used as input for the same hydrometeorological model. The skills of both ensemble streamflow prediction systems were evaluated over all of France for the precipitation input and streamflow prediction during a 569-day period and for a 2-day short-range scale. The ensemble streamflow prediction system based on the PEARP data was the best for floods and small basins, and the ensemble streamflow prediction system based on the ECMWF data seemed the best adapted for low flows and large basins

The New Operational Hydro-meteorological Ensemble Prediction System at Meteo-France and its representation interface for the French Service for Flood Prediction (SCHAPI)

International audienceThe coupled physically-based hydro-meteorological model SAFRAN-ISBA-MODCOU (SIM) is developed at Meteo-France for many years. This fully distributed catchment model is used in an operationnal real-time mode since 2005 for producing mid-range ensemble streamflow forecasts based on the 51-member 10-day ECMWF EPS. New improvements have been recently implemented in this forecasting chain. First, the new version of the forecasting chain includes new atmopheric products from the ECWMF (EPS at the resolution of 0,25 over France). Then an improvement of the physics of the ISBA model (a new physical representation of the soil hydraulic conductivity) is now used. And finally, a past discharges assimilation system has been implemented in order to improve the initial states of the ensemble streamflow forecasts. These developpement were first tested in the framework of a Phd thesis, and are now evaluated in real-time conditions. This study aims to assess the improvements obtained by the new version of the forecasting chain. Several experiments were performed ton assess the effects of i) the high resolution atmospheric forcing ii) the new representation of the hydraulic conductivity iii) the data assimilation method and iv) the real-time framework. Tested on a 18-month period of reforecasts, the new chain presents significantly improved ensemble streamflow forecasts compared to the previous version. Finally, this system provides ensemble 10-day streamflow prediction to the French National Service for Flood Prediction (SCHAPI). A collaboration between Meteo-France and SCHAPI led to the development of a new website. This website shows the streamflow predictions for about 200 selected river stations over France (selected regarding their interest for flood warning) , as well as alerts for high flows (two levels of high flows corresponding to the levels of risk of the French flood warning system). It aims at providing to the French hydrological forecaters a real-time tool for mid-range flood awareness

Le nouveau système opérationnel de prévisions d'ensemble hydro-météorologiques à Météo-France, et l'interface utilisateur pour le service français de prévision des crues (SCHAPI)

International audienceThe coupled physically-based hydro-meteorological model SAFRAN-ISBA-MODCOU (SIM) is developed at Meteo-France for many years. This fully distributed catchment model is used in an operationnal real-time mode since 2005 for producing mid-range ensemble streamflow forecasts based on the 51-member 10-day ECMWF EPS. New improvements have been recently implemented in this forecasting chain. First, the new version of the forecasting chain includes new atmopheric products from the ECWMF (EPS at the resolution of 0,25 ̊ over France). Then an improvement of the physics of the ISBA model (a new physical representation of the soil hydraulic conductivity) is now used. And finally, a past discharges assimilation system has been implemented in order to improve the initial states of the ensemble streamflow forecasts. These developpement were first tested in the framework of a Phd thesis, and are now evaluated in real-time conditions. This study aims to assess the improvements obtained by the new version of the forecasting chain. Several experiments were performed ton assess the effects of i) the high resolution atmospheric forcing ii) the new representation of the hydraulic conductivity iii) the data assimilation method and iv) the real-time framework. Tested on a 18-month period of reforecasts, the new chain presents significantly improved ensemble streamflow forecasts compared to the previous version. Finally, this system provides ensemble 10-day streamflow prediction to the French National Service for Flood Prediction (SCHAPI). A collaboration between Meteo-France and SCHAPI led to the development of a new website. This website shows the streamflow predictions for about 200 selected river stations over France (selected regarding their interest for flood warning) , as well as alerts for high flows (two levels of high flows corresponding to the levels of risk of the French flood warning system). It aims at providing to the French hydrological forecaters a real-time tool for mid-range flood awareness

Suivi en temps réel des sécheresses : de l'analyse à la prévision saisonnière

Météo-France opère en temps réel depuis 2003 la chaîne de modélisation hydro-météorologique SIM, composée du module d'analyse des conditions atmosphériques en surface (SAFRAN), d'une modélisation détaillée des interactions sol-biosphère-atmosphère (ISBA) et du modèle hydrogéologique MODCOU. Cette chaîne a connu une évolution majeure en 2016 afin d'améliorer certains de ses composants. Cette application temps-réel, complétée par une réanalyse depuis 1958 permet de caractériser la situation par rapport aux années antérieures pour plusieurs variables du cycle hydrologique (précipitations, humidité du sol, enneigement). Les épisodes de sécheresse, l'évolution du stock nival, etc. peuvent ainsi être suivis au jour le jour sur l'ensemble de la France métropolitaine. Des applications de prévisions ont également été mises en place pour anticiper l'évolution de la situation hydrologique. L'initialisation des conditions hydrologiques provient de la chaîne d'analyse temps-réel et des données météorologiques prévues sont utilisées en entrée d'ISBA-MODCOU. Ainsi une application pour les échéances allant jusqu'à 10 jours utilise comme forçage météorologique les prévisions d'ensemble du CEPMMT (Centre Européen de Prévision Météorologique à Moyen Terme). Chaque jour des prévisions sont produites sur différentes zones (départements, bassins versants, etc.), l'ensemble de prévision fournit des informations pour les différentes variables hydrologiques au pas de temps quotidien. De plus la visualisation de la dispersion des prévisions renseigne sur l'incertitude associée à chaque prévision. Pour des échéances plus lointaines (jusqu'à 6 mois), deux applications de prévisions sont opérées tous les mois. La première utilise en entrée des scénarios météorologiques issus de la climatologie, alors que la seconde utilise des données issues du modèle de prévisions saisonnières atmosphériques de Météo-France. Malgré l'incertitude des prévisions, l'exploitation complémentaire des prévisions climatologique et saisonnière est un outil pour la gestion des ressources en eau. Les débits moyens mensuels prévus pour chacune des applications comparés aux débits des années précédentes permettent en effet de caractériser la situation pour les mois à venir et l'incertitude associée

Multicentre study of laparoscopic or open assessment of the peritoneal cancer index (BIG-RENAPE)

International audienceBackgroundThe peritoneal cancer index (PCI) is a comparative prognostic factor for colorectal peritoneal metastasis (CRPM). The ability of laparoscopy to determine the PCI in consideration of cytoreductive surgery remains undetermined, and this study was designed to compare it with laparotomy. MethodsA prospective multicentre study was conducted for patients with no known CRPM, but at risk of peritoneal disease. Surgery began with laparoscopic exploration followed by open exploration to determine the PCI. Concordance between laparoscopic and open assessment was evaluated for the diagnosis of CRPM and for the PCI. ResultsAmong 50 patients evaluated, CRPM recurrence was found in 29 (58 per cent) and 34 (68 per cent) at laparoscopic and open surgery respectively. Laparoscopy was feasible in 88 per cent (44 of 50) and deemed satisfactory by the surgeon in 52 per cent (26 of 50). Among the 25 evaluable patients with satisfactory laparoscopy, there was concordance of 96 per cent (24 of 25 patients) and 38 per cent (10 of 25) for laparoscopic and open assessment of CRPM and the PCI respectively. Where there were discrepancies, it was laparoscopy that underestimated the PCI. ConclusionLaparoscopy may underestimate the extent of CRPM. Underestimated by laparoscop

Impact de l'amélioration du forçage météorologique, du profil de la conductivité hydraulique dans le sol et de l'assimilation de données sur un système opérationnel de prévision hydrologique d'ensemble sur la France

International audienceA Hydrological Ensemble Forecasting System (HEFS) known as SIMPE has been run over France in real time by Météo-France since 2004. The system combines the 51-member, 10-day ECMWF EPS atmospheric forcing at a 1.5° resolution with the ISBA-MODCOU physically-based distributed hydrological model to provide streamflow forecasts over France. The initial conditions for all the HEFS runs are provided by SIM; i.e., the ISBA-MODCOU model forced by the outputs of the mesoscale meteorological analysis system SAFRAN. A previous study introduced and tested two improvements of this system over a past period. These modifications consisted of an improved representation of the profile of hydraulic conductivity and the implementation of a data assimilation subsystem. The purpose of the present study was to test the HEFS and its two modifications in operational mode, with the new higher-resolution ECMWF EPS atmospheric forcing at 0.25° resolution, available in real time on the Météo-France database, and with less observed discharge available for the data assimilation subsystem. The new ISBA physics scheme led to a notable improvement in the discharge simulation in western and northeastern France, where no aquifers were simulated by the MODCOU model. This improvement was not impacted by real-time conditions. Likewise, the improvement resulting from the data assimilation system applied over France was not significantly affected by real-time conditions. The propagation of the data assimilation correction to gauging stations located upstream or downstream of the assimilated stations limited the deterioration of forecasted streamflow due to real-time conditions. Finally, the ECMWF EPS high-resolution atmospheric forcing had a significant impact on the streamflow forecasts for small catchments, which increased with lead time