Inhaltsverzeichnis
Auswahl der wissenschaftlichen Literatur zum Thema „Système convectif de mésoéchelle“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit den Listen der aktuellen Artikel, Bücher, Dissertationen, Berichten und anderer wissenschaftlichen Quellen zum Thema "Système convectif de mésoéchelle" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Zeitschriftenartikel zum Thema "Système convectif de mésoéchelle"
Didier, Ricard. „Modélisation à haute résolution : des pluies intenses dans les Cévennes Le système convectif Des 13 et 14 octobre 1995“. La Météorologie 8, Nr. 48 (2005): 28–38. http://dx.doi.org/10.4267/2042/56316.
Der volle Inhalt der QuelleDissertationen zum Thema "Système convectif de mésoéchelle"
Arnould, Gabriel. „Approche objet pour la détection, le suivi et la prévision à très courte échéance des systèmes convectifs de mésoéchelle“. Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEP082.
Der volle Inhalt der QuelleMesoscale convective systems (MCSs) can produce floods and severe wind gusts. Although their size exceeds 100 km, their predictability is limited by convective instability. This thesis provides keys to improving the monitoring and 6-hour forecasting of MCSs in France and to making progress in our understanding of the physical processes involved. Two types of data are used: radar and satellite observations, and numerical forecasts from the AROME model at kilometre resolution. The MCSs are identified as "objects" to which attributes are attached concerning convective activity, the trend and the environment interacting with the system.A U-Net convolutional neural network was first developed to identify the MCSs in meteorological images, whether observed or simulated from the AROME prognostic variables. These are radar reflectivity and infrared brightness temperature measured by satellite. The U-Net is trained on more than 1,200 hand-annotated images. Evaluated on objective scores and case studies, the method proves to be more robust than less complex algorithms based on thresholding.Understanding the life cycle of MCSs in France is essential to anticipating them. More than 150 MCSs are being studied in severe convective situations between 2018 and 2022. Most of them evolve from May to October, in a wide band from the south-west to the north-east of the country. On average, their size follows a parabolic trend, peaking in the second third of their life cycle. The same applies to convective activity, which peaks earlier. AROME simulations, run on the same situations, realistically reproduce the life cycle of the objects observed. The AROME 3D fields are then used to understand the influence of the environment on the evolution of MCSs. Two methods are used: (1) calculating average ambient values within a 100 km radius, (2) creating composite annular maps to display averaged fields, projected onto a grid adapted to the geometry of each object. MCSs generally form in a dynamic, unstable environment, with low-level convergence. Their displacement is well approximated by the mid-level wind. The drying and cooling at low-level ahead of the system are mainly responsible for its weakening. Studied separately, the quasi-stationary Mediterranean MCSs are driven by the warm, moist low-level flow, which tends to weaken at the end of their life cycle.The last part of the thesis measures the contribution of numerical weather prediction. At Météo-France, the AROME-NWC configuration updates the forecasts of the AROME production chain every hour by assimilating the latest observations, mainly from radar. The "object" scores calculated with observed MCSs as ground truth show that, when an MCS is present in the AROME background, AROME- NWC corrects its location errors. Moreover, the latest available AROME- NWC run is not always the best performing. However, the Lagrangian extrapolation of observed objects remains better than the numerical forecast up to almost 4 hours ahead. Over this period, the most relevant forecasting strategy is therefore based on the extrapolation and trend of object attributes, possibly supplemented by numerical forecast data to describe the environment and anticipate convective activity. Beyond 4 h, numerical forecasting becomes essential, and the sets of forecasts from successive AROME- NWC runs valid at the same times can be used to estimate the probability of occurrence of the phenomenon. Practical methods based on a synergy between observation and numerical forecasting are introduced at the end of the thesis
Nguyen, Thi Thuy Hanh. „Analyses des perturbations synoptiques et de la modulation diurne des systèmes convectifs sur l'Afrique centrale“. Paris 6, 2007. http://www.theses.fr/2007PA066638.
Der volle Inhalt der QuelleMathon, Vincent. „Etude climatologique des systèmes convectifs de meso-échelle en Afrique de l'Ouest“. Paris 7, 2001. http://www.theses.fr/2001PA077099.
Der volle Inhalt der QuellePenide, Guillaume. „Mise en place de simulateurs d'instruments de télédétection dans un modèle méso-échelle (BRAMS): Application à l'étude d'un système convectif observé pendant la campagne AMMA“. Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2010. http://tel.archives-ouvertes.fr/tel-00532834.
Der volle Inhalt der QuellePenide, Guillaume. „Mise en place de simulateurs d'instruments de télédétection dans un modèle méso-échelle (BRAMS) : application à l'étude d'un système convectif observé durant la campagne AMMA“. Clermont-Ferrand 2, 2010. http://www.theses.fr/2010CLF22047.
Der volle Inhalt der QuelleFresnay, Simon. „Prévisibilité des épisodes météorologiques à fort impact : sensibilité aux anomalies d'altitude“. Phd thesis, Université Paul Sabatier - Toulouse III, 2014. http://tel.archives-ouvertes.fr/tel-00986467.
Der volle Inhalt der QuelleTaufour, Marie. „Validation et amélioration du schéma microphysique à deux moments LIMA à partir des observations de la campagne de mesures HyMeX“. Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30325/document.
Der volle Inhalt der QuelleThe triggering and growth of Convective systems is a complex process that extends from the synoptic scale, with the establishment of atmospheric circulations promoting convection, to the microscale, with the formation and growth processes of hydrometeors. This PhD focuses on these finest scales and investigates the contribution of complex cloud-microphysics to the occurrence and morphology of heavy precipitation events. The two-moment microphysical scheme LIMA evaluated in this study takes into account the evolution of a multimodal aerosol population and the prognostic treatment of its interaction with liquid and ice clouds and precipitation. First, the contribution of LIMA is evaluated in comparison to the ICE3 one-moment bulk microphysical scheme, which is less sophisticated and currently operational in the AROME model at Météo-France. In order to measure the performance of this new scheme, two case studies of the HyMeX campaign were simulated with the Meso-NH model and compared to a wide variety of available measurements. The assessment of cumulative precipitation shows a moderate impact of each of these microphysical schemes, but the difference is more pronounced in terms of convective systems composition and structure: the two moment microphysics develops a more realistic vertical structure and introduces more microphysical variability. The evaluation also identified biases in the scheme (such as an overestimation of rain drop diameters). Some improvements to the implementation of LIMA were proposed and evaluated on the same cases. Then, the scheme is used to perform a sensitivity test to the aerosol population on the same case studies. Tests on the concentration of idealized populations have shown that aerosols do not only affect primary production of cloud droplets and ice crystals but also precipitating hydrometeors, causing impacts on the development of simulated convective systems in terms of cloud composition and generated precipitation. Simulations based on a realistic aerosol population initialized from CAMS analyses also showed a moderate impact on cumulative precipitation, but a more significant improvement on the temporal evolution of the system (intensification, dissipation) and cloud composition, leading to a reduction of rain drop diameters in the studied cases
Crumeyrolle, Suzanne. „Impact des systèmes convectifs sur les propriétés hygroscopiques des aérosols : analyse de deux cas d'étude durant la campagne AMMA“. Toulouse 3, 2008. http://thesesups.ups-tlse.fr/320/.
Der volle Inhalt der QuelleIn West Africa, three types of aerosols prevail: desert dusts, biomass burning particles and sea salts. The mixing of these three types of particles may have consequences on atmospheric radiative properties and on cloud formation and precipitation. Within the framework of AMMA (African Monsoon Multidisciplinary Analyses) and to better characterize these particles, an isokinetic inlet as well as an instrumental platform were developed and deployed in the French research aircraft (ATR-42). Two study cases (July SOP1 and August SOP2 2006) illustrate the impact of the meso-scale convective systems (MCS) on the hygroscopic properties of particles. The observed results show an increase of particle hygroscopic properties due to the coating of soluble elements (sulfate, nitrate and chloride). Then, the simulation of the first study case shows the mixing of soluble elements and desert dusts in aqueous phase (i. E. Cloud droplets). After evaporation, dust particles coated with soluble elements are released in the atmosphere
Coutris, Pierre. „Analyse des propriétés dimensionnelles et massiques des cristaux de glace pour l’étude des processus microphysiques dans les systèmes convectifs à méso-échelle“. Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC007/document.
Der volle Inhalt der QuelleThe detailed characterization of ice cloud microphysics is key to understand their role in theEarth’s hydrological cycle and radiation budget. The developement of atmospheric models and remote sensingalgorithms relies on parametrisations derived from in situ measurements. These measurements are also usedby the aviation industry to handle the problem of ice crystal icing. This PhD work presents an analysis of themass and size properties of ice crystals observed in high ice water content areas embedded in tropical mesoscaleconvective systems (MCS) during two airborne field campaigns of the HAIC-HIWC international project.A new approach is developped to derive mass-size relationships (m - D) from size distributions and icewater contents. The retrieval is formulated as an inverse problem which waives the power law constraint, aclassical assumption that proves to be an oversimplification when applied to heterogeneous populations of iceparticules typical of MCS anvils.The horizontal variability of size distributions and the aging of MCS anvils is described in terms of microphysicalprocesses. The importance of the aggregation growth process is emphasized as it efficiently removessmall ice particles brought into the upper troposphere by deep convection and significantly contributes to theformation of large agregates, precusor of the stratiform precipitations. The analysis of mass properties revealsthat distinctive microphysical regimes may be identified from the m-D relationship retrieved in various conditions.It paves the way toward a statistical model of the effective density of ice particles as a function of environmentalparameters
Arnault, Joel. „Evolution cyclogénétique des perturbations convectives de l'Afrique de l'Ouest et de l'Atlantique tropical“. Phd thesis, Université Paul Sabatier - Toulouse III, 2009. http://tel.archives-ouvertes.fr/tel-00424219.
Der volle Inhalt der Quelle