WorldCat Identities

Delrieu, Guy

Overview
Works: 25 works in 32 publications in 3 languages and 40 library holdings
Roles: Thesis advisor, Other, Author, Contributor, Opponent
Publication Timeline
.
Most widely held works by Guy Delrieu
Integrated high-resolution dataset of high-intensity European and Mediterranean flash floods by William Amponsah( )

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

Evaluation et développement de la méthode IRIP de cartographie du ruissellement. Application au contexte ferroviaire by Lilly-Rose Lagadec( )

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

Surface runoff is the source of severe hazards such as floods, erosion or mudflows. Railways can disturb natural surface water flow path, which can generate accelerated deterioration of the infrastructure, or the destruction of railway elements, such as the roadbed or the embankments. The IRIP method 'Indicator of Intense Pluvial Runoff' (French acronym) allows mapping surface runoff through three maps, generation, transfer and accumulation. The IRIP method aims to be simple and reliable, in order to be used on all types of lands, without calibration stage. As for others surface runoff models, the IRIP method evaluation faces the lack of data. However, evaluation is a crucial stage for the development of models. In the perspective of an operational use, or simply for the model development, it is essential to estimate the value and the reliability of the model outputs. The thesis objective is to provide an evaluation method using surface runoff impacts on railways. Difficulties lie in the fact that data to be compared differ in terms of form and content. Moreover, the infrastructure vulnerability must be characterized. The proposed evaluation method is based on the computation of contingency tables and of verification indicators, together with detailed analysis of specific impacts. After an estimation of the IRIP method performance, further developments can be tested and evaluated thanks to the proposed evaluation method. Finally, maps comprehensibility is enhanced, while preserving satisfying performance scores. By applying the IRIP method to operational contexts, it has been shown how the IRIP method can be used as a tool in expert appraisals. Different tasks of the risk management process have been studied such as risk analysis on railways, post-event investigation or the realisation of regulatory zonings. More generally, this thesis contributes to improve knowledge about surface runoff and provide methods for improving the risk management
Ground-based remote sensing of Antarctic and Alpine solid precipitation by Claudio Durán Alárcon( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

Solid precipitation plays an important role in the Earth's climate system, as well as for the maintenance of ecosystems and the development of human society. The large uncertainty in precipitation estimates and the discrepancies within climate model projections make this component of the hydrological cycle important as a research topic. Remote sensing allows to monitor precipitation and clouds in regions where in-situ observations are scarce and scattered, but with limited temporal resolution and a blind zone close to the ground level for spaceborne sensors, and limited visibility in the lower atmosphere in complex terrain for ground-based radars. The objectives of this dissertation are the following: 1) to characterize cloud and precipitation in Antarctica, detecting the presence of supercooled liquid and ice particles near the ground level using a ground-based 532-nm depolarization lidar; 2) to characterize the vertical structure of the precipitation in two contrasted but important regions of the cryosphere, Antarctica and the Alps, in the low troposphere using ground-based radars.In this study, a cloud and precipitation hydrometeor detection method is proposed using lidar data, complemented with a K-band micro rain radar (MRR) to improve the detection of precipitation, both instruments deployed at the Dumont d'Urville (DDU) station in East Antarctica. A method based on lidar depolarization and attenuated backscattering coefficient and the use of k-means clustering is developed for the particle classification. The classification of cloud and precipitation particles provides the vertical distribution of supercooled liquid water, as well as planar oriented ice and randomly oriented ice particles. The comparison between ground-based and satellite-derived classifications shows consistent patterns for the vertical distribution of supercooled liquid water in clouds.The vertical structure of precipitation near the surface is analyzed using the Doppler moments derived from three MRR profiles at DDU, the Princess Elisabeth (PE) station, at the interior of East Antarctica, and at the Col de Porte (CDP) station, in the French Alps. These analyses demonstrate that local climate plays an important role in the vertical structure of the precipitation. In Antarctica, the strong katabatic winds blowing from the high plateau down to the coast decrease the radar reflectivity factor near the surface due to the sublimation of the snowfall particles. Doppler moments also provide rich information to understand precipitation processes, such as aggregation and riming, as observed at DDU and CDP.The results also show that in the interior of the Antarctic continent a significant part (47%) of the precipitation profiles completely sublimate before reaching the surface, due to the dry atmospheric conditions, while in the coast of Antarctica it corresponds to about the third part (36%). In the Alps, this percentage is reduced to 15%. The major occurrence of particle sublimation is observed below the altitude where CloudSat profiles are contaminated by ground clutter. Therefore, this phenomenon cannot be fully captured from space with the current generation of sensors.This dissertation contributes to the study of the vertical structure of snowfall in the low troposphere, useful for the evaluation of precipitation remote sensing products, which may have severe limitations in the vicinity of the surface
Visibilité hydrologique de radars météorologiques opérant en régions montagneuses : application au bassin versant de l'Ardèche by Thierry Pellarin( Book )

2 editions published between 2001 and 2006 in French and held by 2 WorldCat member libraries worldwide

L'utilisation du radar météorologique pour des applications hydrologiques est encore assez peu répandue. Si l'aspect qualitatif de la mesure radar représente un atout pour l'hydrologie, la mesure quantitative des précipitations bute en revanche sur l'existence de nombreuses sources d'erreurs inhérente à la physique de la mesure radar. En régions montagneuses, le relief constitue une limitation évidente de l'utilisation de cet appareil et le site d'implantation ainsi que le choix du protocole d'exploration apparaissent déterminants dans la qualité des mesures radar. Un objectif de ce travail consiste à prédéterminer la qualité de couverture d'un radar météorologique sur une région donnée. L'influence de trois sources d'erreurs prépondérantes de la mesure radar est modélisée permettant de quantifier et de visualiser la distribution spatiale des erreurs commises sur les intensités pluvieuses. L'intégration de ces cartes d'erreurs simulées dans un modèle hydrologique permet d'observer la répercussion sur la reconstitution des débits à l'exutoire d'un bassin versant de l'Ardèche (Vogué, 640kms2). Une évaluation de la qualité de mesure de deux radars du réseau ARAMIS de Météo France est proposée ainsi qu'une analyse des besoins en terme de corrections.Une partie de ce travail consiste par ailleurs à tirer parti de la présence d'échos de sol pour tester la stabilité temporelle de l'étalonnage électronique d'un radar en analysant le signal rétrodiffusé par un relief
Expérimentation Marseille 92-93 : mesure des précipitations en hydrologie urbaine à l'aide d'un radar bande X : le relief comme cible utile pour l'étalonnage et la correction d'atténuation, tests de cohérence des données issues des divers capteurs disponibles by Sophie Caoudal( Book )

2 editions published in 1996 in French and held by 2 WorldCat member libraries worldwide

LA MESURE EN TEMPS REEL ET LA PREVISION A COURTE ECHEANCE DES PRECIPITATIONS SONT DES PREOCCUPATIONS QUOTIDIENNES POUR UNE VILLE COMME MARSEILLE OU LE RISQUE HYDROLOGIQUE EST ELEVE (REGIME DES PRECIPITATIONS, FORTE IMPERMEABILISATION DES SOLS, RELIEF MARQUE). L'EXPERIENCE MARSEILLE 92-93 A ETE MENEE DANS LE BUT D'AMELIORER LES TECHNIQUES DE MESURE DES PLUIES AUX ECHELLES DE TEMPS ET D'ESPACE DE L'HYDROLOGIE URBAINE. AINSI, UN RADAR DE CONFIGURATION LEGERE EN BANDE X A ETE INSTALLE A PROXIMITE DE LA VILLE POUR UN RAFFINEMENT LOCAL DE LA MESURE EN COMPLEMENT DU RESEAU DE PLUVIOGRAPHES DE LA VILLE DE MARSEILLE ET DU RADAR BANDE S DE NIMES (RESEAU ARAMIS DE METEO FRANCE). CET APPAREIL, PETIT ET MOINS COUTEUX QUE LES APPAREILS CONVENTIONNELS EST CEPENDANT SENSIBLE AU PROBLEME DE L'ATTENUATION. DANS CE TRAVAIL QUI CONTRIBUE A UNE MEILLEURE DEFINITION DES CONDITIONS D'UTILISATION DE CE RADAR, NOUS AVONS TENTE DE TIRER LE MEILLEUR PROFIT DU SIGNAL RETRODIFFUSE PAR LES MONTAGNES POUR AMELIORER LE TRAITEMENT DES DEUX ERREURS PREPONDERANTES: L'ERREUR D'ETALONNAGE ET L'ATTENUATION. AINSI, NOUS AVONS MONTRE QUE, PAR TEMPS SEC, CE SIGNAL PERMET DE CONTROLER LA STABILITE DE L'ETALONNAGE. PAR TEMPS DE PLUIE, L'ETUDE DE LA CONTRAINTE D'ATTENUATION TOTALE NOUS A PERMIS DE PROPOSER UNE METHODE D'ETALONNAGE ABSOLU DU RADAR NE DEPENDANT QUE DES MESURES DE CET APPAREIL. LA COMPARAISON DES RESULTATS DE CETTE APPROCHE AVEC CELLE, CLASSIQUE, REPOSANT SUR L'UTILISATION DES MESURES PLUVIOGRAPHIQUES EN CONFIRME L'INTERET. DE PLUS, TROIS ALGORITHMES DE CORRECTION D'ATTENUATION ONT ETE MIS EN UVRE, COMPARES ET VALIDES A L'AIDE DE MESURES PLUVIOGRAPHIQUES INTEGREES A DIFFERENTES ECHELLES SPATIALES ET TEMPORELLES. GRACE A LA MAITRISE DE LA PARAMETRISATION DE CES ALGORITHMES, NOUS AVONS MONTRE QUE LES DIVERSES FORMULATIONS (FAISANT OU NON UN USAGE EXPLICITE DES MESURES D'ATTENUATION TOTALES DEDUITES DU RELIEF) CONDUISENT A DES RESULTATS EQUIVALENTS ET SATISFAISANTS POUR LA GAMME D'ATTENUATION OBSERVEE
Estimation quantitative des précipitations par radar météorologique : inférence de la structure verticale des pluies, modélisation des erreurs radar-pluviomètres by Pierre-Emanuel Kirstetter( Book )

2 editions published between 2008 and 2013 in French and held by 2 WorldCat member libraries worldwide

THE CÉVENNES-VIVARAIS MEDITERRANEAN HYDROMETEOROLOGICAL OBSERVATORY IS A RESEARCH INITIATIVE AIMED AT IMPROVING THE RAINFALL OBSERVATION. A NUMBER OF INNOVATIVE QUANTITATIVE PRECIPITATION ESTIMATION (QPE) ALGORITHMS AIMED AT A SPACE-TIME ADAPTIVE RADAR DATA PROCESSING WERE DEVELOPED USING THE DATASET OF THE BOLLÈNE 2002 EXPERIMENT. THE LAST INVOLVED THE OPERATIONAL WEATHER RADAR OF BOLLÈNE, WHICH IS PART OF THE ARAMIS NETWORK.OUR CONTRIBUTION IN THE PRESENT THESIS DEALS WITH THE VERTICAL HETEROGENEITY OF RAINFALL. WE CONSIDER THE VERTICAL PROFILE OF REFLECTIVITY INVERSION METHOD PROPOSED BY ANDRIEU ET CREUTIN (1995). IT IS ADAPTED TO THE CASE OF TIME-VARYING GEOGRAPHICAL SUPPORTS DESIGNED WITH PRELIMINARY RAIN TYPING. CHARACTERIZING THE ERROR STRUCTURE OF RADAR QUANTITATIVE PRECIPITATION ESTIMATES IS RECOGNIZED AS A MAJOR ISSUE. WE ASSESS THE RADAR QPE WITH RESPECT TO REFERENCE RAIN ESTIMATES DERIVED FROM RAIN GAUGE NETWORKS. A GEOSTATISTICAL FRAMEWORK IS PROPOSED FOR THE ESTABLISHMENT OF SUCH REFERENCE ESTIMATES. ASSUMING THE RESIDUAL BETWEEN RADAR AND REFERENCE VALUE TO BE A RANDOM VARIABLE, WE DESCRIBE RADAR ERROR BY MEAN OF PROBABILITY DISTRIBUTIONS. THE MODEL CONSISTS IN AN ADDITIVE RANDOM ERROR, DESCRIBED BY A RANDOM DISTRIBUTION. SOME ELEMENTS OF SPACE-TIME ERROR STRUCTURE ARE GIVEN. A NEW APPROACH TO DETERMINE THE VERTICAL PROFILE OF REFLECTIVITY (VPR) IS PROPOSED. IT IS BASED ON A SIMPLIFIED MICROPHYSICS IN SYNERGY WITH RADAR OBSERVATIONS TO SIMULATE THE VPR. A VPR IS DESCRIBED WITH A REDUCED NUMBER OF PHYSICAL PARAMETERS. THE NEW IDENTIFIED VPRS ARE THUS LESS REFINED BUT MORE VALID AND ROBUST THAN THE INITIAL METHOD
On the relationship between total differential phase and pathintegrated attenuation at X-band in an Alpine environment by Guy Delrieu( )

1 edition published in 2020 in English and held by 2 WorldCat member libraries worldwide

Impact de la résolution spatiale et temporelle des entrées pluviométriques pour la modélisation hydrologique en Afrique de l'Ouest et implication dans l'utilisation des produits satellitaires : Etude de cas sur le Bassin de l'Ouémé au Benin by Tania Gascon( )

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

Les zones intertropicales sont caractérisées par des précipitations très variables dans l'espace et le temps qui peuvent produire sur une même région des conditions de sécheresse prolongées entrecoupées d'événements pluviométriques intenses. Ces extrêmes secs et humides peuvent provoquer des pénuries d'eau ou des inondations, mettant en péril des populations souvent très vulnérables aux aléas climatiques. C'est particulièrement le cas de l'Afrique de l'Ouest qui, dans un contexte de conditions sèches dominantes depuis les années 1970, subit ces deux dernières décennies un nombre croissant d'inondations. Face à un réchauffement climatique déjà bien réel, mais qui va se renforcer avec des conséquences sur le cycle de l'eau encore très incertaines, il est nécessaire de mieux comprendre comment la variabilité climatique - et en l'occurrence plus spécifiquement la variabilité pluviométrique, impacte la variabilité hydrologique. On dispose pour cela de modèles numériques de surface qui représentent de façon explicite les principaux processus intervenant dans les bilans d'eau. Ils doivent être alimentés par des champs de forçage pluviométrique à des résolutions suffisamment fines pour bien représenter les variabilités de petite échelle qui caractérisent les précipitations tropicales (résolution spatiale de quelques kilomètres et pas de temps horaire ou inférieur). De telles résolutions sont la plupart du temps incompatibles avec les échelles des données issues des réseaux pluviométriques nationaux en Afrique de l'Ouest (densité moyenne de 1 pluviomètre pour 10.000 km² au pas de temps journalier). Il existe de surcroît des zones entières qui sont peu ou mal couvertes du fait de conditions climatiques difficiles ou du manque de moyens des services météorologiques nationaux. Dans ce contexte, la télédétection satellite s'avère très utile, mais elle ne permet pas encore d'atteindre les résolutions mentionnées plus haut. Compte tenu de cette situation, la question de la sensibilité des modèles hydrologiques à la résolution des champs pluviométriques utilisés pour les forcer constitue un sujet important, assez peu abordé en tant que tel dans la littérature consacrée à l'utilisation des données satellitaires pour forcer des modèles hydrologiques.Cette thèse s'attache donc à traiter séquentiellement deux questions distinctes, mais souvent confondues : i) quel est l'impact de la dégradation de la résolution spatio-temporelle des champs de forçages pluviométriques sur la réponse d'un modèle hydrologique, et ce en supposant que ces champs sont dépourvus d'erreur en moyenne ; ii) comment les champs de pluie estimés par satellite, qui présentent de façon combinée des problèmes de résolution et de biais, influencent-ils la réponse hydrologique simulée?Le jeu de données utilisé pour l'étude est celui du site soudanien de l'observatoire AMMA-CATCH au Benin (bassin de l'Ouémé, 13150 km2). Le réseau de pluviographes de cet observatoire permet de calculer des champs de référence à très fine résolution (0.05° et 30 minutes), utilisés pour forcer le modèle hydrologique DHSVM et constituer ainsi des débits simulés de référence. A partir de là il est possible de procéder à des études de sensibilité dans les deux directions mentionnées ci-dessus
Précipitations méditerranéennes intenses -caractérisation microphysique et dynamique dans l'atmosphère et impacts au sol by Nan Yu( )

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

This study offers a unified formulation for the single- and multi-moment raindrop size distributions (DSD), which were proposed in the framework of scaling analysis in the literature. The key point is to consider the DSD scaled by drop concentration (Nt, 0th order DSD moment), as a probability density function (pdf) of raindrop diameter scaled by characteristic diameter (D/Dc). The Dc is defined as the ratio of the 4th to the 3rd DSD moment. A two-parameter gamma pdf model, with a self-consistency relationship, is found to be suitable for representing the scaling DSD formulation. For the purpose of parameter estimation, two different methods, based on three DSD moments (0th, 3rd and 4th moments) and multiple DSD moments (from 0th to 6th moments), are proposed and then evaluated through the 3-year DSD observations, collected at Alés within the activities of the Cévennes-Vivarais Mediterranean Hydrometeorological Observatory (CVMHO). The results reveal that: 1) the scaled DSD model parameterized by three moments (0th, 3rd and 4th moments) possesses a similar performance compared to that constructed by multiple DSD moments; 2) regardless the application of scaled technique, large variation is still exhibited in this climatological DSD scaled dataset. The scaled DSD formulation is, in a second step, adapted to the one- and two-moment scaling DSD formulations by introducing single and dual power-law models between the reference moments (e.g. rain rate R and/or radar reflectivity factor Z) and the explained moments (total concentration Nt, characteristic diameter Dc). Compared with previous DSD formulations presented in the literature, the presented approach explicitly accounts for the prefactors of the power-law models to produce a uniform and dimensionless scaled distribution, whatever the reference moment(s) considered. In the same manner, two methods based on 1) single or dual power-law models and 2) multiple DSD moments (from 0th to 6th moments), are proposed to estimate the climatological parameters in the one- and two-moment scaling DSD formulations. The results show that: 1) the estimation method has a significant impact on the climatological DSD formulation scaled by one moment; 2) the choice of the reference moment to scale DSD depends on the objectives of the research: e.g. the DSD model scaled by high order moment produces a good performance for large drops at the cost of a poor performance for the small ones; 3) using two scaling moments improves significantly the model performance to represent the natural DSD, compared to the one-moment DSD formulation. In terms of applications of scaling DSD model, the analysis of the inter-event variability is performed on the basis of the scaling formulation containing three parameters (Nt, Dc and µ describing the shape of the gamma function). Different rain phases can be identified by the sudden shifts of moments and parameters in DSD time series. It is found that these rain phases are well linked to different weather processes. And a preliminary relationship is established between the radar observations and DSD parameters. The climatological scaling DSD formulations are also used for the DSD reconstitutions and for rainfall kinetic energy flux density estimations by rain intensity and/or radar reflectivity factor. The results confirm that the application of two scaling moments (R and Z) improves significantly the performance of these models, regardless the different sampling characteristics between radar and raingauge
Modélisation hydrologique distribuée des crues en région Cévennes-Vivarais : impact des incertitudes liées à l'estimation des précipitations et à la paramétrisation du modèle by Rafael Navas Nunez( )

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

It is known that having a precipitation observation system at high space - time resolution is crucial to obtain good results in rainfall - runoff modeling. Radar is a tool that offers quantitative precipitation estimates with very good resolution. When it is merged with a rain gauge network the advantages of both systems are achieved. However, radars estimates have different uncertainties than those obtained with the rain gauge. In the modeling process, uncertainty of precipitation interacts with uncertainty of the hydrological model. The objective of this work is: To study methods used to quantify the uncertainty in radar - raingauge merge precipitation estimation and uncertainty in hydrological modeling, in order to develop a methodology for the analysis of their individual contributions in the uncertainty of rainfall - runoff estimation.The work is divided in two parts, the first one evaluates: How the uncertainty of radar precipitation estimation can be quantified? To address the question, the geostatistical approach by Kriging with External Drift (KED) and Stochastic Generation of Precipitation was used, which allows to model the spatio - temporal structure of errors. The method was applied in the Cévennes - Vivarais region (France), where there is a very rich observation system. The second part explains: How can it be quantified the uncertainty of the hydrological simulation coming from the radar precipitation estimates and hydrological modeling process? In this point, the hydrological mesoscale computation tool was developed; it is distributed hydrological software in time continuous, within the basis of the Curve Number and the Unit Hydrograph. It was applied in 20 spatio-temporal resolutions ranging from 10 to 300 km2 and 1 to 6 hours in the Ardèche (~ 1971 km2) and the Gardon (1810 km2) basins. After a sensitivity analysis, the model was simplified with 4 parameters and the uncertainty of the chain of process was analyzed: 1) Precipitation estimation; 2) Hydrological modeling; and 3) Rainfall - runoff estimation, by using the coefficient of variation of the simulated flow.It has been shown that KED is a method that provides the standard deviation of the precipitation estimation, which can be transformed into a stochastic estimation of the local error. In the chain of processes: 1) Uncertainty in precipitation estimation increases with decreasing spatio-temporal scale, and its effect is attenuated by hydrological modeling, probably due by storage and transport properties of the basin; 2) The uncertainty of hydrological modeling depends on the simplification of hydrological processes and not on the surface of the basin; 3) Uncertainty in rainfall - runoff treatment is the result of the amplified combination of precipitation and hydrologic modeling uncertainties
Evaluation d'un radar météorologique pour la mesure des précipitions : validation et étalonnage par technique géostatique : application au bassin parisien by Guy Delrieu( Book )

3 editions published between 1986 and 2006 in French and held by 2 WorldCat member libraries worldwide

LE PRINCIPE DE LA MESURE DES PRECIPITATIONS PAR RADAR METEOROLOGIQUE EST BRIEVEMENT RAPPELE. LES AVANTAGES DE CE DISPOSITIF, LIES A LA SOUPLESSE DE L'ACQUISITION DES DONNEES, MAIS AUSSI SES LIMITES POUR L'ESTIMATION QUANTITATIVE DES PRECIPITATIONS SONT SOULIGNES. LES DONNEES DE REFLECTIVITE ENREGISTREES AU RADAR MELODI DE DAMMARTIN-EN-GOELLE ET LES MESURES PLUVIOGRAPHIQUES DES RESEAUX SOL EXISTANTS EN REGION PARISIENNE ONT SERVI DE SUPPORT A CETTE ETUDE: -L'ANALYSE GEOSTATIQUE DU SIGNAL RADAR NOUS PERMET DE PRECISER LE CHOIX DES CARACTERISTIQUES D'ECHANTILLONAGE DU RADAR REQUISES POUR LES APPLICATIONS HYDROLOGIQUES. LES DIFFICULTES DE L'EVALUATION DE LA MESURE RADAR SONT MISES EN EVIDENCE A PARTIR DE COMPARAISONS PONCTUELLES RADAR-PLUVIOGRAPHES AU PAS DE TEMPS HORAIRE; -UN PROTOCOLE DE VALIDATION, FONDE SUR L'ESTIMATION DE LARMES D'EAU SPATIALES DE REFERENCE PAR KRIGEAGE DES MESURES PLUVIOMETRIQUES D'UN RESEAU DENSE NOUS PERMET DE MIEUX POSER CE PROBLEME. LES PERFORMANCES DU RADAR SONT COMPAREES AU PAS DE TEMPS JOURNALIER A CELLES FOURNIES PAR DES RESEAUX DE DIFFERENTES DENSITES; -ENFIN, UNE PROCEDURE GEOSTATIQUE DE COMBINAISON DES MESURES RADAR ET SOL EST DECRITE ET EVALUEE PAR COMPARAISON AUX METHODES D'ETALONNAGE PROPOSEES DANS LA LITTERATURE. L'INTERET ET LES LIMITES DE L'ETALONNAGE DU RADAR SONT APPRECIES PAR RAPPORT AUX ESTIMATIONS DU RESEAU D'ETALONNAGE SEUL
Etude des pluies intenses dans la région Cévennes-Vivarais à l'aide du radar météorologique : régionalisation des traitements radar et analyse granulométrique des pluies au sol by Benoît Chapon( Book )

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

We have studied in the present thesis the development of an automated rainfall typing procedure into convective and stratiform regions based on the use of 3D weather radar data. First, we have shown the strong influence of the radar sampling properties for two algorithms already proposed in the literature by Steiner et al. (1995) and Sanchez-Diezma et al. (2000) for the detection of convective and stratiform precipitation, respectively. This problem was partially overcome by a decision tree and a coupling of the rain typing and the vertical profile of reflectivity (VPR) identification. The final algorithm is shown to significantly improve the raintyping at long ranges (e.g., greater than 60 km). On the other hand, we have conducted an experiment in Alès during the autumn 2004 to document the Cévennes drop size distributions (DSD) at ground level by using an optical disdrometer. We have first implemented various methods to establish the reflectivity - rain rate relationship (Z-R relationship). Their respective merits were assessed through a self-consistency procedure based on DSD data alone. Then we have studied the seasonal, inter-storm and inner-storm variability of the Z-R relationship and shown the major influence of the inner-storm variability. Finally, we have performed a preliminary study of the link between the 3D radar data and the ground-based DSD data through a comparison of DSD-based and radar-based rain typing
Précipitations méditerranéennes intenses en milieu urbain : interprétation physique et analyse statistique de mesures à fines échelles spatio-temporelles, impact de la variabilité spatiale sur la réponse de bassins versants by Alexis Berne( Book )

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

Les régions du pourtour méditerranéen sont fréquemment soumises à des pluies violentes qui euvent engendrer des crues aux bilans humains et matériels catastrophiques. Ces récipitations onstituent l'objet d'étude de ce travail, qui s'appuie sur les données collectées à l'automne 998 à Marseille dans le cadre de l'expérimentation HIRE 98. L'analyse de mesures de deux adars locaux bande X a fourni des informations sur la pluie dans le plan vertical, notamment ar le profil vertical de réflectivité (PVR). Les structures spatiales et temporelles moyennes aractéristiques des précipitations méditerranéennes intenses sont ensuite estimées à l'aide des esures pluviométriques et radar bande S et bande X, par analyse géostatistique avec le ariogramme en 1 et 2 dimensions. Enfin, la simulation du fonctionnement hydrologique d'un nsemble de 8 bassins versants urbains et péri-urbains permet de quantifier l'impact de la ariabilité spatiale de la pluie sur les débits générés
Integrated high-resolution dataset of high intensity Euro-Mediterranean flash floods by William Amponsah( )

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

Prototype de re-analyses pluviometriques pour la region Cevennes-Vivarais( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

Attenuation in rain for X- and C-band weather radar systems sensitivity with respect to the drop size distribution by Guy Delrieu( )

1 edition published in 1999 in English and held by 1 WorldCat member library worldwide

Hydrologic visibility of weather radar systems operating in mountainous regions case study for the Ardèche catchment (France)( )

1 edition published in 2002 in English and held by 1 WorldCat member library worldwide

Temporal and spatial resolution of rainfall measurements required for urban hydrology( )

1 edition published in 2004 in English and held by 1 WorldCat member library worldwide

Interactions entre le champ de vapeur d'eau et les systèmes précipitants by Laurent Labbouz( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

This thesis focuses on the links between the evolution of atmospheric water vapour content and precipitation formation. The general goal of the works presented is to improve the understanding of the precipitation formation mechanisms using water vapour measurements, primarily made by GPS. An original statistical study based on 5 years of data (from GPS, rain gauge, and other meteorological probes collocated on a platform in Clermont-Ferrand, France) shows that the increase of integrated water vapour amount (IWV) is, on average, a precursor for rain formation. We also show that the IWV evolution is primarily disconnected from the variations in water vapour mixing ratio measured at the surface. Indeed, unlike moisture at the surface, the IWV reaches its maximum on average 20 minutes before the precipitation peak. This could indicate that the condensation dominates in the whole column, while at the surface there is a strong evaporation. The detailed study of convective precipitations which occurred on 18th of July 2007 (Intensive Operation Period 9a of the Convective and Orographically- induced Precipitation Study COPS) on the lee side of the Vosges Mountains shows the significant contribution of GPS measurement for the study of convective precipitations in mountainous areas. Indeed, Thanks to a synergic use of radars, surface meteorological analysis and GPS receivers (which allow the observation of small scale water vapour field features, with a high temporal resolution), we show that the moisture accumulation occurs several hours before convective initiation and we also show that the triggering of the convection is favoured by moisture flux convergence (MFC). This MFC is associated with surface wind convergence leading to a substantial vertical transport of water vapour, which is observed by the GPS tomography. The wind direction on the windward side of the mountains appears to control the location of this convergence zone. The role of local forcing due to small scale orography (< 5km) is also shown, complementing the observations by the results from high resolution numerical model simulations
 
moreShow More Titles
fewerShow Fewer Titles
Audience Level
0
Audience Level
1
  Kids General Special  
Audience level: 0.95 (from 0.86 for Estimation ... to 0.98 for Attenuatio ...)

Languages