314 research outputs found
Flash floods in the french mediterranean region ; toward transfer methodologies for ungauged catchments
No full textD’un point de vue climatique la région méditerranéenne est propice aux évènements pluvio-orageux intenses, particulièrement en automne. Ces pluies s’abattent sur des bassins versants escarpés. La promptitude des crues ne laisse qu’un temps très court pour la prévision. L’amplitude de ces crues dépend de la grande variabilité des pluies et des caractéristiques des bassins versants. Les réseaux d'observations ne sont habituellement pas adaptés à ces petites échelles spatiales et l'intensité des événements affecte souvent la fiabilité des données quand elles existent d’où l’existence de bassin non jaugés. La régionalisation en hydrologie s’attache à la détermination de variables hydrologiques aux endroits où ces données manquent. L’objectif de cette thèse est de contribuer à poser les bases d’une méthodologie adaptée à la transposition des paramètres d'un modèle hydrologique distribué dédié aux crues rapides de bassins versants bien instrumentés à des bassins versants non jaugés, et ce sur une large zone d’étude. L’outil utilisé est le modèle hydrologique distribué MARINE [Roux et al., 2011] dont l’une des originalités est de disposer d’un modèle adjoint permettant de mener à bien des calibrations et des analyses de sensibilité spatio-temporelles qui servent à améliorer la compréhension des mécanismes de crue et à l’assimilation de données en temps réel pour la prévision. L’étude des sensibilités du modèle MARINE aborde la compréhension des processus physiques. Une large gamme de comportements hydrologiques est explorée. On met en avant quelques types de comportements des bassins versants pour la région d’étude [Garambois et al., 2012a]. Une sélection des évènements de calibration et une technique de calibration multi évènements aident à l’extraction d’un jeu de paramètres par bassin versant. Ces paramétrisations sont testées sur des évènements de validation. Une méthode de décomposition de la variance des résultats conduit aux sensibilités temporelles du modèle à ses paramètres. Cela permet de mieux appréhender la dynamique des processus physiques rapides en jeu lors de ces crues [Garambois et al., 2012c]. Les paramétrisations retenues sont transférées à l’aide de similarités hydrologiques sur des bassins versants non jaugés, à des fins de prévision opérationnelleClimate and orography in the Mediterranean region tend to promote intense rainfalls, particularly in autumn. Storms often hit steep catchments. Flood quickness only let a very short time lapse for forecasts. Peak flow intensity depends on the great variability of rainfalls and catchment characteristics. As a matter of facts, observation networks are not adapted to these small space-time scales and event severity often affects data fiability when they exist thus the notion of ungauged catchment emerges. Regionalization in hydrology seeks to determine hydrological variables at locations where these data lack. This work contributes to pose the bases of a methodology adapted to transpose parameterizations of a flash flood dedicated distributed hydrologic model from gauged catchments to ungauged ones, and for a large study area. The MARINE distributed hydrologic model is used [Roux et al., 2011], its originality lies in the automatically differentiated adjoint model able to perform calibrations and spatial-temporal sensitivity analysis, in order to improve understanding in flash flood generating mechanisms and real time data assimilation for hydrometeorological forecasts. MARINE sensitivity analysis addresses the question of physical process understanding. A large panel of hydrologic behaviours is explored. General catchment behaviours are highlighted for the study area [Garambois et al., 2012a]. Selected flood events and a multiple events calibration technique help to extract catchment parameter sets. Those parameterizations are tested on validation events. A variance decomposition method leads to parameter temporal sensitivity analysis. It enables better understanding in catching dynamics of physical processes involved in flash floods formation [Garambois et al., 2012c]. Parameterizations are then transfered from gauged catchments with hydrologic similarity to ungauged ones with a view to develop real time flood forecastin
Étude régionale des crues éclair de l'arc méditerranéen français ; élaboration de méthodologies de transfert à des bassins versants non jaugés
No full textD'un point de vue climatique la région méditerranéenne est propice aux évènements pluvio-orageux intenses, particulièrement en automne. Ces pluies s'abattent sur des bassins versants escarpés. La promptitude des crues ne laisse qu’un temps très court pour la prévision. L'amplitude de ces crues dépend de la grande variabilité des pluies et des caractéristiques des bassins versants. Les réseaux d'observations ne sont habituellement pas adaptés à ces petites échelles spatiales et l'intensité des événements affecte souvent la fiabilité des données quand elles existent d'où l'existence de bassin non jaugés. La régionalisation en hydrologie s'attache à la détermination de variables hydrologiques aux endroits où ces données manquent. L'objectif de cette thèse est de contribuer à poser les bases d’une méthodologie adaptée à la transposition des paramètres d'un modèle hydrologique distribué dédié aux crues rapides de bassins versants bien instrumentés à des bassins versants non jaugés, et ce sur une large zone d’étude. L'outil utilisé est le modèle hydrologique distribué MARINE [Roux et al., 2011] dont l'une des originalités est de disposer d'un modèle adjoint permettant de mener à bien des calibrations et des analyses de sensibilité spatio-temporelles qui servent à améliorer la compréhension des mécanismes de crue et à l'assimilation de données en temps réel pour la prévision. L'étude des sensibilités du modèle MARINE aborde la compréhension des processus physiques. Une large gamme de comportements hydrologiques est explorée. On met en avant quelques types de comportements des bassins versants pour la région d'étude [Garambois et al., 2012a]. Une sélection des évènements de calibration et une technique de calibration multi évènements aident à l'extraction d'un jeu de paramètres par bassin versant. Ces paramétrisations sont testées sur des évènements de validation. Une méthode de décomposition de la variance des résultats conduit aux sensibilités temporelles du modèle à ses paramètres. Cela permet de mieux appréhender la dynamique des processus physiques rapides en jeu lors de ces crues [Garambois et al., 2012c]. Les paramétrisations retenues sont transférées à l'aide de similarités hydrologiques sur des bassins versants non jaugés, à des fins de prévision opérationnelle
Learning river properties and infering river discharge from SWOT-like data time-series
No full textNew generations of satellites and sensors offer promising possibilities to overcome the lack of in situ data for hydrological sciences, with increasing spatio-temporal coverage and accuracy ([1, 2]). Nevertheless, inverse problems in hydraulics such as the estimation of river discharges from space are still open questions. Remotely sensed measurements of hydrosystems can provide valuable information but adequate methods are still required to take maximum advantage of it. Lots of studies have shown the possibility of retrieving discharge given the river bathymetry or roughness and/or in situ time series. The new challenge is to use SWOT-type data (that is to say water surface elevation, free surface slope and top width) to inverse the triplet formed by the roughness, the bathymetry and the discharge (A0,K,Q) ([3]). We show that the most complete shallow-water like model allowing to separate the roughness and bathymetry terms is the so-called low Froude model. The few inverse models elaborated for inferring (A0,K,Q) are analyzed in two contexts: 1) only remotely sensed observations of the water surface (surface elevation, width and slope) are available ; 2) one additional water depth measurement (or estimate) is available. Results of hydraulic parameters inversions will be presented for a large dataset of rivers with contrasted properties, in the context of the PEPSI challenge that is an intercomparison project of several discharge inversion methods using SWOT-like data ([4, 5, 3]). Considering effective hydraulic parameterizations (e.g. [6, 7]), depending on observation scale, several perspectives are discussed for data assimilation into 1D and 2D hydraulic models. The temporal sampling of a mission such as SWOT will offer new possibilities in terms of hydraulic visibility for describing and learning river reaches, floodplains, and hydrosystems behaviours. References [1] S. Calmant, F. Seyler, and J. Cretaux, Monitoring continental surface waters by satellite altimetry, Surveys in Geophysics, vol. 29, no. 4-5, pp. 247-269, 2008. [2] D. E. Alsdorf and D. P. Lettenmaier, Tracking fresh water from space, Science, vol. 301, no. 5639, pp. 1491-1494, 2003. [3] P.-A. Garambois and J. Monnier, Inference of effective river properties from remotely sensed observations of water surface, Advances in Water Resources, vol. 79, pp. 103-120, 2015. [4] M. Durand, J. Neal, E. Rodriguez, K. M. Andreadis, L. C. Smith, and Y. Yoon, Estimating reach-averaged discharge for the river severn from measurements of river water surface elevation and slope, Journal of Hydrology, vol.-, no. 0, pp., 2014. [5] C. J. Gleason, L. C. Smith, and J. Lee, Retrieval of river discharge solely from satellite imagery and at-many-stations hydraulic geometry: Sensitivity to river form and optimization parameters, Water Resources Research, vol. 50, no. 12, pp. 9604-9619, 2014. [6] P.-A. Garambois, S. Calmant, H. Roux, A. Paris, J. Monnier, and J. Santos da Silva, Hydraulic visibility and effective cross sections based on hydrodynamical modeling of flow lines gained by satellite altimetry,(submitted), 2015. [7] A. Paris, R. C. Paiva, J. Santos Da Silva, D. Moreira, S. Calmant, P.-A. Garambois, W. Collischonn, M.-P. Bonnet, and F. Seyler, Stage-discharge rating curves based on satellite altimetry and modelled discharge in the amazon basin, Water Ressources Research, revised
Retrieving river discharge from SWOT-like data time-series : a sample of rivers types
No full textThe future SurfaceWater and Ocean Topography (SWOT) mission would provide new cartographic measurements of ocean surface and inland water surfaces dynamics, and especially river height, width and slope. The highlight of SWOT will be its almost global coverage and temporal revisits on the order of 1 to 4 times per 22 - days repeat cycle [1]. The estimation of hydraulic parameters from water surface observations is still an open question. Several methods have recently been proposed for retrieving river discharge from SWOT data ([2, 3, 4]). The method introduced by [2] and used in the present study is based on Manning equation. The first step consists in retrieving an equivalent bathymetry profile for a river given one in situ depth measurement and SWOT like data of the water surface, that is to say water elevation, free surface slope and width. From this equivalent bathymetry, the second step consists in solving mass and Manning equation in the least square sense. Nevertheless, for cases where no in situ measurement of water depth is available, it is still possible to solve a system formed by mass and Manning equations in the least square sense (or with other methods such as Bayesian ones, see e.g. [3]). The approach is tested with synthetic data generated from hydraulic models for several river reaches around the world (cf. [5]). We show that a good a priori knowledge of bathymetry and roughness is required for such methods. The identifiability of the roughness geometry couple is also investigated for different space time sampling and hydraulic regimes. Indeed, the knowledge of effective hydraulic representation and limitations might be a cornerstone in identifications of hydraulic or hydrologic variables through data assimilation chains. References : [1] E. Rodriguez, “SWOT science requirements document,” JPL document, JPL, 2012. [2] P. A. Garambois and J. Monnier, “Inference of river properties from remotly sensed observations of water surface,” (minor revisions) Advances in Water Ressources, 2014. [3] M. Durand, J. Neal, E. Rodriguez, K. M. Andreadis, L. C. Smith, and Y. Yoon, “Estimating reach-averaged discharge for the river severn from measurements of river water surface elevation and slope,” Journal of Hydrology,vol. -, no. 0, pp. –, 2014.[4] C. J. Gleason, L. C. Smith, and J. Lee, “Retrieval of river discharge solely from satellite imagery and atmanystations hydraulic geometry: Sensitivity to river form and optimization parameters,” Water Resources Research, pp. n/a–n/a, 2014. [5] M. Durand, L. Smith, C. Gleason, D. Bjerklie, P.-A. Garambois, and H. Roux, “Assessing swot discharge algorithms performance across a range of river types,” in AGU fall meeting, H51S-02, 201
Flash flood prediction at the regional scale and methodology for ungauged catchments
No full textClimate and orography in the Mediterranean region tend to promote intense rainfalls, particularly in autumn. Storms often hit steep catchments and flood quickness only let a very short time lapse for forecasts. Peak flow intensity depends on the great variability of rainfalls and catchment characteristics. As a matter of facts, observation networks are not adapted to these small space-time scales and event severity often affects data reliability when they exist thus the notion of ungauged catchment emerges. Regionalization in hydrology seeks to determine hydrological variables at locations where these data lack. This work contributes to pose the bases of a methodology adapted to transpose parameterizations of a flash flood dedicated distributed hydrologic model from gauged catchments to ungauged ones, and for a large study area. The MARINE distributed hydrologic model is used (Roux et al. 2011), its originality lies in the automatically differentiated adjoint model able to perform calibrations and spatial-temporal sensitivity analysis, in order to improve understanding in flash flood generating mechanisms and real time data assimilation for hydrometeorological forecasts. The first step for MARINE model regionalization is sensitivity analysis which addresses the question of physical process understanding. A large panel of hydrologic behaviours is explored. General catchment behaviours are highlighted for the study area (Garambois, Larnier, et al. 2013). Selected flood events and a multiple events calibration technique help to extract catchment parameter sets. Those parameterizations are tested on validation events and ensemble predictions are performed for a recent flood event. A variance decomposition method leads to parameter temporal sensitivity analysis. It enables better understanding in catching dynamics of physical processes involved in flash floods formation (Garambois, Roux, et al. 2013). Parameterizations are then transferred from gauged catchments with hydrologic similarity to ungauged ones with a view to develop real time flood forecasting
Parameter Regionalization for a Process Oriented Distributed Model Dedicated to Flash Floods
No full textFlash flood is a very intense and quick hydrologic response of a catchment to rainfall. This phenomenon has a high spatial-temporal variability as its generating storm, often hitting small catchments (few km ² ). Consequently their prediction remains a hard exercise with the necessary data being often scarce. As defined by Sivapalan et al. (2003) prediction on ungauged catchments is one of the challenges of hydrological modelling, especially for flash flood. Several studies have been headed up with the MARINE model (Modélisation de l’Anticipation du Ruissellement et des Inondations pour des évèNements Extrêmes) for the Gard region (France), (Braud et al. 2010), (Castaings et al. 2009). This physically based spatially distributed rainfall runoff model is dedicated to flash flood prediction. The present contribution is a study about parameter sets regionalization for process oriented hydrological models in the case of flash floods. MARINE model performances are tested on 117 flash floods from the last two decades which is a large catalogue of hydrology and landscapes from Pyrenean, Mediterranean, Cévennes-Vivarais and Provence regions. Encouraging results are obtained with two similarity approaches. Only a small decrease of performances from calibration/ validation to regionalization is detected for these two methods. This study sheds more light on the importance of hydrological information that is available in calibration events for a gauged catchment or from donor catchment(s) for regionalization. It can also be shown that the most sensitive parameter of MARINE model (Garambois et al 2013) which is controlling the soil volume and water balance, is rather well constrained by the two similarity approaches thanks to bedrock descriptors.Garambois Pierre-André, Douinot Audrey, Roux Hélène, Dartus Denis. Parameter Regionalization for a Process Oriented Distributed Model Dedicated to Flash Floods. In: SimHydro 2014. New Trends in Simulation. 11-13 June 2014 Ecole Polytech’ Nice (France) 2014
Variational Assimilation of SWOT Altimetry into a 1D-2D Porosity-based Hydraulic River Model with Upstream Hydrology: Toward Integrated Hydrological-Hydraulic Discharge Estimation from SWOT
No full textInternational audienceThe high spatial density of SWOT data products enables unprecedented access to small scale variations of watersurface elevation (WSE) of worldwide rivers. The informative content carried by such observations has greatpotential for the calibration of high resolution basin-scale hydraulic-hydrological (H&H) models of river networksand could allow the estimation of reach and cross-section scale geometry parameters and distributed inflows.However, estimating river discharge solely from WSE altimetry data remains a notoriously ill-posed inverseproblem if bathymetry-friction are unknown (see Larnier et al., 2020). In this context, H&H modeling frameworksthat integrate variational data assimilation (VDA) have shown promise in providing hydrologic closure to thisunder-constrained problem and also enable the estimation of high-dimensional spatio-temporal H&H parameters.To address these challenges, we employ a robust H&H variational data assimilation (VDA) framework proposedin Pujol et al. (2022), consisting in 1D-2D effective hydraulic model (DassFlow) integrating the GR4H state-spacehydrological model (Santos et al. 2018), to assimilate SWOT altimetry for (i) optimizing sequentially orsimultaneously effective hydraulic parameters and hydrological parameters and (ii) improving model realism andfinally discharge estimation.To model sub-cell cross-sectional variability in a 1Dlike model (Pujol et al. (2022)), an effective depth-independent porosity parameter was implemented based on Guinot and Soares-Frazão (2006). This parameter iskey to the effective modelling of hydraulic controls and signal propagation through a river network hydraulicmodel based on the 1Dlike modelling approach. It can be estimated from local bathymetry surveys, channelgeometry databases, but remains model-dependent and must be calibrated.Our methodological framework enables the simultaneous inference of distributed hydraulic parameters(bathymetry, friction coefficients, longitudinal riverine porosity) and upstream hydrological parameters or inflowtime series. Notably, the H\&H model is integrated into the VDA framework such that information feedback fromhydraulic observables to the hydrological model can be achieved. This is key for integrated H&H dischargeestimation based on SWOT observations.The approach was tested on the Garonne river between Tonneins and La Réole (around 50km of river length).Knowledge on the real geometric variabilities of the minor bed is provided by a high-resolution expertised DEM. A1Dlike hydraulic model of the river was built based on this accurate bathymetry data.10 SWOT passes over the 2024-02-16 and 2024-04-21 period (65 days) provide snapshots of the waterline for arange of non-flooding upstream discharges. Assimilated SWOT data is in the format of single WSE observationpoints every 200m at the centerline (RiverObs algorithm output) and covers the whole reach.A series of inference experiments were designed to evaluate the capability of the VDA method to extractinformative content from SWOT WSE. Sought parameters are distributed friction and porosity, as well ashydrological parameters of the lumped upstream hydrological model. Results show improvement of the fit of themodeled waterlines to altimetry observations thanks to the calibration of finely distributed parameters andestablishes a robust H&H approach for SWOT discharge estimation.Low computation costs achieved through the 1Dlike modeling approach make it clear that this method could bescaled to larger river networks, opening the way toward leveraging the full informative content of basin-scaleSWOT altimetry through our H&H VDA framework.References:Guinot, V., Soares-Frazão, S. (2006). Flux and source term discretization in two‐dimensional shallow watermodels with porosity on unstructured grids. International Journal for Numerical Methods in Fluids, 50(3), 309-345.269 / 348Larnier, K., Monnier, J., Garambois, P.-A., Verley, J. (2020) River discharge and bathymetry estimation fromSWOT altimetry measurements, Inverse Problems in Science and Engineering (IPSE).Pujol, L., Garambois, P.-A., Monnier, J. (2022) Multi-dimensional hydrological-hydraulic model with variationaldata assimilation for river networks and floodplains, Geoscientific Model Development.Santos, L., Thirel, G., Perrin, C. (2018). Continuous state-space representation of a bucket-type rainfall-runoffmodel: a case study with the GR4 model using state-space GR4 (version 1.0). Geoscientific Model Development,11(4), 1591-1605
Variational Assimilation of SWOT Altimetry into a 1D-2D Porosity-based Hydraulic River Model with Upstream Hydrology: Toward Integrated Hydrological-Hydraulic Discharge Estimation from SWOT
No full textInternational audienceThe high spatial density of SWOT data products enables unprecedented access to small scale variations of watersurface elevation (WSE) of worldwide rivers. The informative content carried by such observations has greatpotential for the calibration of high resolution basin-scale hydraulic-hydrological (H&H) models of river networksand could allow the estimation of reach and cross-section scale geometry parameters and distributed inflows.However, estimating river discharge solely from WSE altimetry data remains a notoriously ill-posed inverseproblem if bathymetry-friction are unknown (see Larnier et al., 2020). In this context, H&H modeling frameworksthat integrate variational data assimilation (VDA) have shown promise in providing hydrologic closure to thisunder-constrained problem and also enable the estimation of high-dimensional spatio-temporal H&H parameters.To address these challenges, we employ a robust H&H variational data assimilation (VDA) framework proposedin Pujol et al. (2022), consisting in 1D-2D effective hydraulic model (DassFlow) integrating the GR4H state-spacehydrological model (Santos et al. 2018), to assimilate SWOT altimetry for (i) optimizing sequentially orsimultaneously effective hydraulic parameters and hydrological parameters and (ii) improving model realism andfinally discharge estimation.To model sub-cell cross-sectional variability in a 1Dlike model (Pujol et al. (2022)), an effective depth-independent porosity parameter was implemented based on Guinot and Soares-Frazão (2006). This parameter iskey to the effective modelling of hydraulic controls and signal propagation through a river network hydraulicmodel based on the 1Dlike modelling approach. It can be estimated from local bathymetry surveys, channelgeometry databases, but remains model-dependent and must be calibrated.Our methodological framework enables the simultaneous inference of distributed hydraulic parameters(bathymetry, friction coefficients, longitudinal riverine porosity) and upstream hydrological parameters or inflowtime series. Notably, the H\&H model is integrated into the VDA framework such that information feedback fromhydraulic observables to the hydrological model can be achieved. This is key for integrated H&H dischargeestimation based on SWOT observations.The approach was tested on the Garonne river between Tonneins and La Réole (around 50km of river length).Knowledge on the real geometric variabilities of the minor bed is provided by a high-resolution expertised DEM. A1Dlike hydraulic model of the river was built based on this accurate bathymetry data.10 SWOT passes over the 2024-02-16 and 2024-04-21 period (65 days) provide snapshots of the waterline for arange of non-flooding upstream discharges. Assimilated SWOT data is in the format of single WSE observationpoints every 200m at the centerline (RiverObs algorithm output) and covers the whole reach.A series of inference experiments were designed to evaluate the capability of the VDA method to extractinformative content from SWOT WSE. Sought parameters are distributed friction and porosity, as well ashydrological parameters of the lumped upstream hydrological model. Results show improvement of the fit of themodeled waterlines to altimetry observations thanks to the calibration of finely distributed parameters andestablishes a robust H&H approach for SWOT discharge estimation.Low computation costs achieved through the 1Dlike modeling approach make it clear that this method could bescaled to larger river networks, opening the way toward leveraging the full informative content of basin-scaleSWOT altimetry through our H&H VDA framework.References:Guinot, V., Soares-Frazão, S. (2006). Flux and source term discretization in two‐dimensional shallow watermodels with porosity on unstructured grids. International Journal for Numerical Methods in Fluids, 50(3), 309-345.269 / 348Larnier, K., Monnier, J., Garambois, P.-A., Verley, J. (2020) River discharge and bathymetry estimation fromSWOT altimetry measurements, Inverse Problems in Science and Engineering (IPSE).Pujol, L., Garambois, P.-A., Monnier, J. (2022) Multi-dimensional hydrological-hydraulic model with variationaldata assimilation for river networks and floodplains, Geoscientific Model Development.Santos, L., Thirel, G., Perrin, C. (2018). Continuous state-space representation of a bucket-type rainfall-runoffmodel: a case study with the GR4 model using state-space GR4 (version 1.0). Geoscientific Model Development,11(4), 1591-1605
Jacques MOIREAU, L’Étna des SégusiavesAETNA SEGVSIANORVM, 1663: Suivi d’extraits de l’ouvrage de Marcellin ALLARD (1605), de l’ouvrage de Papire MASSON (1618)et de sa libre interprétation par Louis COULON (1644) surles Ségusiaves, le Forez et les « montagnes de feu » de Saint-Étienne.Présentation : Pierre HABIG avec la collaboration d’Aline CANELLISTranscription des textes et réalisation du fascicule : Aline CANELLISTraduction des textes latins : Aline CANELLIS et Florence GARAMBOIS-VASQUEZNotes : Aline CANELLIS avec la collaboration de Pierre HABIGDocumentation et iconographie : Pierre HABIG avec la collaboration d’Aline CANELLIS
No full textPremière traduction française annotée de l'Etna des Ségusiaves de Jacques Moireau (1663) avec les témoignages sur les "montagnes de feu" de Saint-Étienne (Loire)
Jacques MOIREAU, L’Étna des SégusiavesAETNA SEGVSIANORVM, 1663: Suivi d’extraits de l’ouvrage de Marcellin ALLARD (1605), de l’ouvrage de Papire MASSON (1618)et de sa libre interprétation par Louis COULON (1644) surles Ségusiaves, le Forez et les « montagnes de feu » de Saint-Étienne.Présentation : Pierre HABIG avec la collaboration d’Aline CANELLISTranscription des textes et réalisation du fascicule : Aline CANELLISTraduction des textes latins : Aline CANELLIS et Florence GARAMBOIS-VASQUEZNotes : Aline CANELLIS avec la collaboration de Pierre HABIGDocumentation et iconographie : Pierre HABIG avec la collaboration d’Aline CANELLIS
No full textPremière traduction française annotée de l'Etna des Ségusiaves de Jacques Moireau (1663) avec les témoignages sur les "montagnes de feu" de Saint-Étienne (Loire)
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