WorldCat Identities

Ribstein, Pierre

Overview
Works: 56 works in 76 publications in 4 languages and 115 library holdings
Genres: Conference papers and proceedings 
Roles: Thesis advisor, Other, Author, Opponent, Contributor, Editor
Publication Timeline
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Most widely held works by Pierre Ribstein
Modèles de crues et petits bassins versants au Sahel by Pierre Ribstein( Book )

6 editions published in 1990 in French and held by 22 WorldCat member libraries worldwide

LES FORTES CRUES DES PETITS BASSINS SAHELIENS SE CARACTERISENT PAR UNE PREPONDERANCE DU RUISSELLEMENT SUPERFICIEL PAR RAPPORT AUX AUTRES TYPES D'ECOULEMENTS (ECOULEMENT RETARDE, ECOULEMENT DE BASE). CETTE CARACTERISTIQUE PEUT S'EXPLIQUER PAR L'HOMOGENEITE DES FORMES DES FORTES PLUIES, MAIS AUSSI PAR L'ABSENCE DE NAPPE SOUTERRAINE PROCHE DE LA SURFACE ET PAR LES PARTICULARITES DES ORGANISATIONS PELLICULAIRES DE L'HORIZON SUPERFICIEL DU SOL. CES DIFFERENTS FACTEURS FONT DU SAHEL UNE REGION IDEALE POUR L'APPLICATION DU CONCEPT D'HYDROGRAMME UNITAIRE, AVEC COMME OBJECTIF L'ANALYSE ET LA PREDETERMINATION DES FORTES CRUES. PLUSIEURS MODELES FONDES SUR LA TECHNIQUE DE L'HYDROGRAMME UNITAIRE SONT PRESENTES. ILS SE DIFFERENCIENT PAR L'EXPRESSION ANALYTIQUE DE LA FONCTION DE PRODUCTION ET PAR LA METHODE D'IDENTIFICATION DE LA FONCTION DE TRANSFERT. CES MODELES SONT APPLIQUES AUX DONNEES DE HUIT PETITS BASSINS VERSANTS DE SUPERFICIE INFERIEURE A 100 KM#2. CETTE APPLICATION PERMET DE DELIMITER LE DOMAINE DE VALIDITE DE CE TYPE DE MODELISATION. UNE METHODE DE PREDETERMINATION DE CRUES SUR DES BASSINS NON JAUGES EST PROPOSEE. LES HYPOTHESES DE BASE DE CETTE METHODE SONT CONFIRMEES PAR DES RESULTATS DE LA MODELISATION
Eaux, glaciers & changements climatiques dans les Andes tropicales( Book )

3 editions published in 1995 in Spanish and held by 6 WorldCat member libraries worldwide

"Une grande partie des communications faites lors du séminaire: Eaux, glaciers et changements climatiques dans les Andes tropicales, organisé a La Paz (Bolivie) les 13-16 juin 1995."
Crues des hauts bassins de la Loire : modélisation géographiquement distribuée, Mike SHE : évaluation et perspectives by Delphine Grelat( Book )

2 editions published in 2002 in French and held by 4 WorldCat member libraries worldwide

Interprétation de la varaibilité climatique.enregistrée dans les carottes de glace à partir des isotopes stables de l'eau : cas des Andes tropicales by Edson Ramirez( Book )

2 editions published in 2003 in French and held by 4 WorldCat member libraries worldwide

Quels apports hydrologiques pour les modèles hydrauliques ? : vers un modèle intégré de simulation des crues by Julien Lerat( Book )

2 editions published in 2009 in French and held by 3 WorldCat member libraries worldwide

Les modèles hydrauliques sont couramment utilisés pour l'aménagement des rivières et la prévention des dommages liés aux inondations. Ces modèles calculent les hauteurs d'eau et débits sur un tronçon de rivière à partir de sa géométrie et des conditions aux limites du système: débit à l'amont du tronçon, débits d'apport latéraux provenant du bassin intermédiaire et hauteurs d'eau à l'aval. Lorsque le tronçon est long (plusieurs dizaines de kilomètres), les apports latéraux deviennent conséquents tout en demeurant rarement mesurés car provenant d'un ensemble d'affluents secondaires. Leur évaluation constitue alors une étape essentielle dans la simulation des crues sur le tronçon sous peine de fortes sous ou surestimations des variables hydrauliques. Cette thèse a pour objectif principal d'identifier une méthode de complexité minimale permettant de reconstituer ces apports. Nos travaux s'appuient sur un échantillon de 50 tronçons de rivière situés en France et aux Etats-Unis sur lesquels les apports latéraux ont été estimés à l'aide d'un modèle hydrologique semi-distribué. Ce modèle scinde le bassin intermédiaire en un ensemble de sous-bassins sur lesquels a été appliqué le modèle pluie-débit GR4H développé au Cemagref
Eaux, glaciers et changements climatiques dans les Andes tropicales( Book )

2 editions published in 1995 in Spanish and Multiple languages and held by 3 WorldCat member libraries worldwide

Hydrogéologie des séries sédimentaires de la dépression piézométrique du Gondo (bassin du Sourou) : Burkina Faso / Mali by Youssouf Koussoube( Book )

2 editions published in 2010 in French and held by 3 WorldCat member libraries worldwide

The Gondo Plain belongs to the Cenozoic intra-continental basins of sahelian Africa. It lies between Mali and Burkina Faso with an area of about 30 000 km². It has aquifer systems: an unconfined aquifer and a deeper confined one. The unconfined groundwater level shows a piezometric depression and the roof of the confined groundwater is more and more deep toward the centre of the Gondo basin. The present study deals in general with the natural context of the Gondo Plain and particularly with the Sourou Basin at Léry before dwelling on the lithology and the geometry of the aquifer system of the Gondo Plain. Then the results of the various investigations using an interdisciplinary approach (remote sensing, geophysics, major ions chemistry, isotopic geochemistry, pumping test modelling) allowed to better understanding of the groundwater recharge and their hydrodynamic working. The preferential recharge occurs under the Sourou reservoir and under the spreading cones of the border of Gondo basin. This recharge is up from 0,9 to 5 meters by year. A recharge model of the groundwater has been in permanent regime. This model takes into account exfiltration by evaporation and additional infiltration in the spreading cones of the border of the Gondo basin
Apport de l'imagerie radar pour la connaissance spatio-temporelle des champs de pluie : utilisation pour une modélisation prédictive des crues by Stéphanie Diss( Book )

2 editions published in 2009 in French and held by 3 WorldCat member libraries worldwide

Le but de cette étude est de vérifier l'apport d'une information spatialisée de la pluie, en particulier avec l'imagerie radar, dans une modélisation hydrologique opérationnelle, le modèle GR3H. Deux radars étaient placés près de Collobrières dans le Sud Est de la France. Le premier est un radar en bande X à double polarisation (Hydrix®) associé à l'algorithme ZPHI®. Le second est un radar en bande S (Météo France). La pertinence des lames d'eau obtenue avec les radars en bande S et en bande X diminue de manière significative à plus de 60 km des radars, en particulier pour le radar en bande X. Pour des distances entre 30 et 60 km, les radars en bande S et en bande X donnent des résultats similaires lorsque l'on considère un pas de temps horaire. Le radar en bande X ne nécessite pas de recalage avec les mesures au sol, ce qui est utile pour des zones sans réseau de pluviomètres. L'influence d'une information spatialisée de la pluie sur le modèle GR3H simplifié est étudiée. L'imagerie radar ne permet pas d'avoir une chronique de pluie assez ancienne pour réaliser raisonnablement un calage du modèle. Les données de pluie sont donc interpolées avec les 17 pluviographes du bassin du Réal Collobrier. Les calages les plus pertinents sont obtenus avec une modélisation distribuée, les paramètres de transfert sont distribués en fonction de la distance, couplée à une information spatialisée de la pluie. La comparaison, en validation, de ces calages optimums et de la modélisation distribuée calée avec des paramètres de transfert fixes (méthode opérationnelle d'AIGA) montre des similarités pour la mise en alerte des crues sur le bassin du Réal Collobrier
Etude des paramétrisations hydrologiques d'un modèle de surface continentale : des aquifères jusqu'aux premiers centimètres du sol by Simon Gascoin( Book )

2 editions published in 2009 in French and held by 3 WorldCat member libraries worldwide

Les modèles de surface continentale (Land Surface Models, LSM) ont été développés pour calculer les bilans d'eau et d'énergie à la surface des continents dans les modèles de climat, ou modèles de circulation générale. Depuis le simple « bucket » de Manabe (1969), la représentation des processus hydrologiques dans les LSM n'a cessé d'évoluer, si bien que les LSM de dernière génération sont employés comme des modèles hydrologiques à part entière. Le travail effectué au cours de cette thèse vise a`évaluer les paramétrisations hydrologiques d'un LSM de ce type, le Catchment LSM (CLSM), qui utilise l'information topographique pour calculer le ruissellement de surface et le flux souterrain, ainsi que la variabilité sous-maille de l'humidité du sol. Pour cela, nous présentons trois applications de CLSM : une application au bassin de la Somme (France) qui a permis d'améliorer la prise en compte des écoulements souterrains, une application à la moraine du Glacier Zongo (Bolivie) pour analyser la relation entre l'albedo et l'humidité du sol nu, une application dans le cadre du projet ALMIP (Afrique de l'Ouest) pour l'intercomparaison régionale de LSM. La diversité de ces contextes jette un éclairage varié sur les forces et les faiblesses de CLSM, et offre la possibilité de mieux appréhender les interactions complexes qui gouvernent les échanges d'eau et d'énergie à la surface des continents. On montre l'importance de considérer l'intégralité du domaine souterrain, depuis les premiers centimètres du sol jusqu'aux aquifères
Interactions ruissellement-système climatique en climats froids et chauds by Ramdane Alkama( Book )

2 editions published in 2007 in French and held by 3 WorldCat member libraries worldwide

Dans le cadre de cette thèse, on s'est intéressé aux interactions fleuves-système climatique dans des contextes climatiques plus froid ou plus chaud qu'actuellement. Une première étape a été de modéliser le climat du Dernier Maximum Glaciaire (DMG), en prenant en compte une modification du tracé des fleuves liée à la présence d'énormes calottes de glaces, touchant plus particulièrement les fleuves nordiques atteignant l'Océan Arctique, les Mers Nordiques et l'Océan Atlantique Nord, régions-clefs pour la circulation océanique. La deuxième étape consiste à comprendre et à quantifier les mécanismes qui peuvent influencer le débit des fleuves. En fait, trois éléments majeurs peuvent induire ce changement: le climat, l'effet stomatique, et enfin les variations de la surface foliaire. En forçant le modèle de surface ORCHIDEE par un climat issu simulé par le modèle couplé de l'IPSL et des concentrations de gaz à effet de serre pour les 20e et 21e siècle, on a pu montrer que le ruissellement augmentera 2 fois plus vite au cours du 21 siècle qu'au cours du 20e et que cette augmentation est largement pilotée par le climat. Le rôle des stomates et de surface foliaire est mineur
How to simulate radiative inputs in complex topographic areas, an analysis on 115 Swiss Alps weather stations by Philippe Riboust( )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

Etats de surface et fonctionnement hydrodynamique multi-échelles des bassins sahéliens ; études expérimentales en zones cristalline et sédimentaire by Moussa Malam Abdou( )

1 edition published in 2014 in French and held by 2 WorldCat member libraries worldwide

This work aims at characterizing and comparing the hydrodynamical functioning at several spatial scales within the granitic-basement and sedimentary zones of Western Niger. Then, a simple hydrological model that could be suitable for use at larger scales is proposed and tested.Qualitatively, the two geological domains have common and specific surface features.The experimental work carried out onto common surface features (biological crust, BIOL; erosion crust, ERO; fallow structural surface, ST and cultivated, C) shows that, at the point scale, ERO has the same hydraulic conductivity K value in both contexts. On the other hand, surfaces features C and especially ST have lower K values in granitic context.Monitoring of the ST and C sites along the rainy season proved the stationarity of the ST conductivity value. On the contrary, K varies widely with the amount of rain received from an initial value of 170 mm/h after weeding down to 20 mm/h (i.e. the ST measured value) after 70 mm of rain and even 10 mm/h after 180 mm of rain. This variation shows the short-term benefit of weeding onto infiltration but a degradation of the soil surface on the long term.At the plot scale (10 m2), runoff measurements are consistent with point measurements. ERO has the same runoff coefficient (Kr) in granitic and sedimentary zones while ST and C surfaces have a higher Kr in granitic context.Runoff monitoring of the granitic site cultivated plots showed that from a total of 63 rain events between 2011 and 2013, 22 had a Kr value higher than the average value (0.25) from which 2/3 are observed after the surface had received more than 70 mm rain after weeding.Results obtained at the two scales (point and 10-m2 plot) are thus consistent and show that the cultivated surface gets crusted and may produce runoff more than fallow ST sites and as much as ERO features.At the basin scale (5 ha), Kr values are higher in the granitic site, not only because of the higher Kr value for a given surface feature but also because of the specific low-infiltrating surfaces which are granite outcrops and gravel crusts (Kr = 0.58).At the three previous scales (point, plot and small basin), runoff volume was found independent of soil initial moisture.Using the previous point-scale results in a Green-Ampt infiltration model led to calibrate the wetting front pressure head for each surface feature and to satisfactorily describe runoff volumes obtained at the plot scale.By estimating runoff with the Green-Ampt infiltration model at any given point, basin-scale hydrograms were obtained by adding the contribution of all elementary surfaces. Assuming no re-infiltration of runoff water within the basins, a simple transfer function was chosen accounting for the distance of each surface to the hydrological network, a constant water velocity of 0.05 m.s-1 and a volume of 3-4 mm of water necessary to fill the kori sand cover, which is much less than that in the sedimentary context. Finally, simulated hydrograms reproduce nicely the measured ones, which offers the perspective of applying some principles of the model to larger basins
Sensibilité du bilan de masse des glaciers alpins aux variables atmosphériques et topographiques : Observations et simulations by Marion Réveillet( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

Glaciers naturally record hydrological and energetic information into varied climatic regions of the world, and are sensitive to small changes in their surface energy balance. The glacier surface mass balance is directly linked to the atmospheric variables which control accumulation and ablation processes. Many models, with different complexities, enable simulations of mass balance evolution, but some questions arise about the best approach to use, especially over long time periods. Based on long measurement series on four glaciers in the French Alps (GLACIOCLIM observatory), this thesis aims at studying the mass balance sensitivity to climatic variations, to identify relevant meteorological variables for modelling. Based on an empirical approach performed on each glacier, temperature was found to be the main driver of temporal ice/snow ablation variability while solar radiations strongly influence the spatial distribution of summer mass balance. However, at glacier scale, to include solar radiation in melt models does not improvethe performances and a classical degree-day model is sufficient to simulate glacier-wide mass balance.The snowpack model SURFEX-ISBA-Crocus was then used to study summer mass balance sensitivity to all surface energy balance fluxes. Results indicate good performances of the model to simulate mass balance at each stake, but it requires accurate meteorological forcing. In particular wind, generally difficult to assessby atmospheric models, appears as a key factor for an accurate ablation modelling. Our work emphasizes that both physical and empirical approaches are very efficient for ablation modeling when forced with accurate meteorological data. Yet, annual mass balances remain very sensitive to wintermass balance due to the surface albedo feedback. For this reason, simulating accumulation processes remainsas important as ablation modelling. Using GLACIOCLIM data measurements, our study failed to find relevant relationship between winter mass balance and topographical variables such as slope, aspect, elevation, due to insufficient spatio-temporal resolution. To fill this gap of measurements, we set up a dedicated field campaign to improve our understanding of the spatio-temporal variability of the snow depth distribution on Alpineglaciers. This year-round campaign was performed using LiDAR acquisitions at Col du Midi (Mont Blancmassif). Results underline the complexity of accurate accumulation measurements from DEM differences due to submergence/emergence velocities
Couplage des processus hydrologiques reliant parcelles agricoles drainées, collecteurs enterrés et émissaire à surface libre : intégration à l'échelle du bassin versant by Hocine Henine( Book )

2 editions published between 2010 and 2015 in French and held by 2 WorldCat member libraries worldwide

Estimation des valeurs extrêmes de débit par la méthode Shyreg : réflexions sur l'équifinalité dans la modélisation de la transformation pluie en débit by Yoann Aubert( Book )

2 editions published in 2012 in French and held by 2 WorldCat member libraries worldwide

Since 1995, French law has been requesting municipalities to achieve flood prevention plans thanks to flood frequency analysis (FFA). For hydraulic works (like bridges or dams spillways), the French legislation requires the building companies to design their infrastructure by taking into account the vulnerability of the surrounding and downstream areas for different return periods. The Cemagref, now IRSTEA - French National Research Institute of Science and Technology for Environment and Agriculture - has developed an original flood prediction method based upon simulation. It implements: - a hourly rainfall generator which consists of a stochastic rainfall model (based upon the geometric description of temporal rainfall signals), - a lumped conceptual rainfall-runoff model. The parameters of the rainfall generator and the rainfall runoff model are regionalized at the spatial resolution of 1 km2 thus allowing the implementation of both models in each 1 km2 pixel in the regionalized version, called Shyreg. Frequency distributions are then derived in each pixel from the simulated events. The results can be shown as maps of statistical estimates of rainfall and flood discharge of various duration (up to 72 hours) and return periods (from 2 to 1000 years). In order to estimate the flood discharge quantiles at the outlet of catchment, we need to aggregate this distributed statistical hydrological data thanks to a Discharge Areal Reduction Factor (DARF) function. This aggregation combines two distinct hydrological phenomena: the areal reduction of rainfall and the discharge attenuation in the channel network. The aim of this PhD thesis was to test different hypothesis on the hydrological model and to make improvement in the rainfall-runoff modelling. Two questions are discussed: - what is the geographical validity domain of the method? - what is the validity of the method in flood frequency extrapolation? Several assumptions used in the method have interaction with each other, making their study difficult. So, we have dispatched the hypotheses on the parameters in function of their link to the catchment: independent or dependant of catchment. The independent parameters mean we don't need to calibrate the method on each catchment. The dependent parameters mean we must determine their values on each catchment. Our work has enabled to improve the method on the following points: - the first improvement was to assess the DARF function for all sizes of French watersheds. We have calibrated this function with sizes of catchment ranging from 2 km² to 110 000 km². - the second improvement consisted of taking account the base flow in the hydrological modelling. - our third improvement goal was to study and reduce the problem of equifinality, i.e. to determine the parameters able to modelise the catchments behaviours for current events as well as for extreme ones. As no observation data are available for such low frequency events, we used two validation criteria. The first criterion is based on statistical tests (reliability and robustness) and the second criterion is based on the model saturation for extreme events. We have used in the thesis, two set of data. The first set is a large sample of catchments evenly located over the French metropolitan territory, with sizes ranging from 2 km² and 110 000 km². The second set of data consists of discharge quantiles (from current to extreme frequency) derived from the application of other methods (QdF, Gradex), which we have compared with the Shyreg discharge quantiles
Amélioration des méthodes de prédétermination des débits de référence d'étiage en sites peu ou pas jaugés by Clotaire Catalogne( )

1 edition published in 2012 in French and held by 2 WorldCat member libraries worldwide

Estimating water availability along the river network is a pre-requirement for water management purposes before defining water allocation at catchment scale. In France, rules for water allocation is partly based on QMNA5, the annual minimum monthly flow with a return period of 5 years ; QMNA5 is derived from time series with extended records of natural or naturalized discharges at gauged sites. In most cases, data is not warranted. Three contexts can be identified: (i) gauged site with short records, (ii) site with spot gauging data and (iii) no data available.This thesis aims at developing a general framework for estimating QMNA5 by using all the hydrological data available in the neighbouring of the location of interest (including short discharge records and spot gauging data). Different methods and strategies were adapted to data availability and tested on a large dataset. Their efficiency and sensitivity to the data collection strategy, the definition of neighbouring,... were assessed by cross validation and uncertainties were provided through a confidence interval. Lastly the most efficient methods for deriving QMNA5 are used to draw a national map with estimates along the main river network.In conclusion, one of most significant result can be illustrated by comparing the efficiency of the estimates according to the quantity of information available on the target location. Results show that a significant gain in accuracy in the estimated QMNA5 values, even when using only a few sporadic measurements to supplement regional information. The improvement depends on the amount of available data and the use of short record is logically more advantageous than the valuation of spot gauging data. Nevertheless, spot gauging data may offer obvious advantages in terms of monitoring at locations where embedment of a permanent gauging station is uneasy. Therefore using spot gauging data can be seen as a possible cost-effective trade-off to supply a reliable enough estimation for particular location of interest
Modelisation hydrologique distribuée du bassin versant nivo-pluvial de Sarennes : validation des données d'entrée et développement d'un module de fonte nivale sous forêt by Katia Durot( Book )

2 editions published between 1999 and 2006 in French and held by 2 WorldCat member libraries worldwide

CETTE ETUDE EST CONSACREE A LA MODELISATION HYDROLOGIQUE DISTRIBUEE D'UN BASSIN VERSANT NIVO-PLUVIAL DES ALPES FRANCAISES. ELLE EST PRESENTEE EN 3 PARTIES : DANS LA PREMIERE PARTIE, SONT PRESENTES LE BASSIN VERSANT DE RECHERCHE EXPERIMENTALE DE SARENNES ET LES OUTILS NUMERIQUES UTILISES POUR SIMULER LES DEBITS. CETTE MODELISATION EST REALISEE PAR L'INTERMEDIAIRE DU COUPLAGE D'UNE CHAINE DE MODELISATION DU MANTEAU NEIGEUX, ELABOREE PAR LE CENTRE D'ETUDE DE LA NEIGE (SAFRAN-CROCUS), AVEC UN MODELE HYDROLOGIQUE CONCEPTUEL A BASE TOPOGRAPHIQUE (TOPMODEL). ELLE EST REALISEE EN 3 ETAPES QUI FONT L'OBJET DE LA SECONDE PARTIE ET PERMETTENT L'ETUDE DE LA SENSIBILITE DU MODELE HYDROLOGIQUE A LA VARIABILITE SPATIALE DE LA LAME D'EAU DE FONTE FOURNIE PAR CROCUS. UNE PREMIERE MODELISATION DE REFERENCE EST FAITE AVEC UNE VERSION GLOBALE DE TOPMODEL ACCEPTANT UNE ENTREE MOYENNE UNIFORME. PUIS LA COMPLEXITE DU MODELE EST PROGRESSIVEMENT DEVELOPPEE (TOPBAND) D'ABORD PAR UNE PREMIERE SPATIALISATION DE L'ENTREE PAR BANDES D'ALTITUDE. FINALEMENT, UN MODELE TOTALEMENT DISTRIBUE ET DYNAMIQUE (TOPODYN) PERMET DE TENIR COMPTE DE LA VARIABILITE SPATIALE DE L'ENTREE AVEC L'ALTITUDE ET L'ORIENTATION DES VERSANTS. LE RAPPORT COMPLEXITE/PERFORMANCE EST SOIGNEUSEMENT ANALYSE. ENFIN, LA TROISIEME PARTIE S'INTERESSE PLUS PARTICULIEREMENT AUX ENTREES : TOUT D'ABORD, UNE REDISTRIBUTION DE LA CHRONOLOGIE HORAIRE DE LA PLUIE SAFRAN NOUS PERMET D'AMELIORER NOS SIMULATIONS. PUIS UNE VALIDATION DU MANTEAU NEIGEUX SIMULE PAR CROCUS EST EFFECTUEE GRACE AU SUIVI DE LA FONTE NIVALE PAR PHOTOGRAPHIES TERRESTRES. UN TRAITEMENT D'IMAGE ADAPTE PERMET ENSUITE DE DETERMINER L'ENNEIGEMENT REEL. FINALEMENT, DANS LA PERSPECTIVE DE MODELISATIONS HYDROLOGIQUES SUR DES BASSINS BOISES, UN MODULE DE FONTE SOUS FORET EST PROPOSE POUR COMPLETER LA CHAINE SAFRAN-CROCUS EXISTANTE
Estimation du bilan masse de surface du Glacier San Rafael et du Champ du Glace Nord de Patagonie par diverses approches by Gabriela Collao Barrios( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

The Northern Patagonia Icefield (NPI) have been losing mass at an accelerated rate during the last decades compared to the mean losses recorded since the Little Ice Age. Here we look for accurate estimates of the mean climate variables, surface mass balance (SMB) and ice dynamics of NPI. Due to the lack of available data in the area, the approach is based on physical models for both the atmosphere and the ice dynamics, in order to properly attribute the components of the glacial mass budget (mass balance, surface mass balance and ice discharge).First, the San Rafael Glacier (SRG) ice dynamics are modelled using the full-Stokes model Elmer/Ice. The flow model is initialised and constrained using the most up-to-date observations of surface velocities and bedrock elevation. The model is forced with several parametrisations of thealtitudinal SMB distribution to obtain consistency between the changes in SMB and ice dynamics. We show that previous studies have proposed excessive accumulation values on the icefield plateau, and that SRG imbalance is largely controlled by a large ice discharge (-0.83 +- 0.08 Gt/a compared to a slightly positive glacier-wide SMB (0.08 +- 0.06 Gt/a). This allows for an estimation of a committed mass loss of 0.34 +- 0.03 Gt/a for the next century. This value likely constitutes a minimum wastage in the future global climate change situation.Second, we model the SMB of the SRG and the NPI using the regional circulation model MAR (Modèle Atmosphérique Regional). This model is forced by the ERA-Interim reanalysis outputs and adapted to accurately reproduce accumulation on the icefield. In addition to accumulation, attention is paid to estimating accurate ablation and albedo values on the plateau. The modelled temperature and precipitation are also validated using data from weather stations in the valleys around the icefield. For the period 1980-2014, the modelled mean SMB of the SRG and the NPI are 0.86 Gt/a and -1.84 Gt/a, respectively, with a large inter-annual variability of 1.4 Gt/a and 6.1 Gt/a, which is induced by temperature and snowfall variability. Due to the hypsometry of the SRG, small changes in the punctual SMB around the ELA have impacts over large areas and have significant consequences on the final glacier-wide SMB. However, in-situ data above the ELA are lacking, leading to important uncertainty in accumulation. Nevertheless, our SMB estimates for the 3 largest non-calving glaciers of the icefield are similar to mass balance values given by geodetic techniques. This validation shows that our estimate of SMB, which is the first negative proposed at the scale of NPI, is accurate. Combined with the ice discharge proposed in the first section of this study, this SMB could have contributed to the observed mass loss from the 1980s.Finally, the study of the surface energy balance given by MAR reveals the key role of the albedo and the shortwave radiation budget in the variations of the SMB. Albedo variations indirectly justify the existing correlations between temperature and melting as air temperature controls the phase of precipitation on the plateau. Thus, changes in solid precipitation explain most of the SMB variations. Consequently, past conditions with higher solid precipitation may have explained larger glaciers in Patagonia. The current instability is possibly a result from the location of glacier fronts which are well below the necessary altitude for equilibrium in the current icefield topography.This study allows us to conclude that well constrained atmospheric and ice dynamic modelling leads to SMB values which are in better agreement with the mass balance of the icefield. Nevertheless, new field data is necessary to better constrain SMB estimates of the SRG and the NPI in order to improve our understanding of past and future climate change impacts on these glaciers
Tailor-made spatial patterns for hydrological model parameters combining regionalisation methods by Laura Rouhier( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Changement climatique et risque hydrologique : évaluation de la méthode SCHADEX en contexte non-stationnaire by Pierre Brigode( Book )

2 editions published between 2013 and 2015 in French and held by 2 WorldCat member libraries worldwide

Depuis 2006, Électricité de France (EDF) applique une nouvelle approche hydroclimatologique de prédétermination des pluies et crues extrêmes, la méthode SCHADEX, pour le dimensionnement des évacuateurs de crues de ses barrages. Dans un contexte de changement climatique global, l'application de la méthode SCHADEX en conditions non-stationnaires est un sujet d'intérêt majeur pour les hydrologues d'EDF. Aussi, l'objectif scientifique des travaux de thèse entrepris a été d'évaluer la capacité de la méthode SCHADEX à prendre en compte l'information contenue dans les simulations du climat futur, pour estimer les crues extrêmes du futur. Une analyse de sensibilité menée en temps présent sur plusieurs bassins versants a, dans un premier temps, révélé la grande sensibilité des estimations SCHADEX à l'aléa pluie forte et à la transformation pluie-débit réalisée par le modèle hydrologique utilisé. Des sorties récentes de modèles climatiques ont été analysées, et ont permis de déterminer des fréquences d'occurrences futures d'épisodes pluvieux, ainsi que des conditions futures de saturation des bassins versants. L'exercice final consistant à incorporer ces différentes évolutions futures au sein de la méthode SCHADEX a montré la difficulté de quantifier l'impact du changement climatique sur les crues extrêmes, du fait de processus qui s'additionnent (diminution des débits extrêmes due à la fois à l'évolution des fréquences d'occurrences d'épisodes pluvieux et à l'évolution des conditions de saturation des bassins versants) et d'autres qui s'opposent (augmentation des débits extrêmes due à l'augmentation de l'intensité future des épisodes pluvieux)
 
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