Teses / dissertações sobre o tema "Observations par satellite"
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Chen, Hong-Bin. "Simulation d'observations satellitaires passives en micro-onde : influence de la nébulosité et des précipitations sur les températures de brillance : inversion de paramètres nuageux à partir des mesures du sondeur micro-onde Météosat". Lille 1, 1991. http://www.theses.fr/1991LIL10029.
Texto completo da fonteArtru, Juliette. "Observations au sol ou par satellite et modélisation des signaux ionosphériques post-sismiques". Paris, Institut de physique du globe, 2001. http://www.theses.fr/2001GLOB0006.
Texto completo da fonteDartois, Emmanuel. "Les glaces interstellaires : interpretation par simulations en laboratoire des observations du satellite iso". Paris 6, 1998. http://www.theses.fr/1998PA066456.
Texto completo da fonteYaacoub, Rouba. "Résonance optique par effet tunnel en optique atmosphérique : application aux observations par satellite des gouttelettes de nuages". Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1R001.
Texto completo da fonteThe light interaction with a homogeneous dielectric spherical scatterer (e.g. cloud droplet) of known characteristics (diameter, optical index) is treated, in atmospheric optics, by the Mie's theory. This theory serves, also, in remote sensing to retrieve physical properties of scatterers (inverse problem). Recent studies have showed the importance of tunneling effects in atmospheric optics. They have attribute the implication of tunneling effects in the atmospheric glory which is the circular iridescence that form around the projected shadow of an object on a cloud of water droplets. Precisely, light can penetrate by tunneling into a droplet and produces sharp resonances. According to these studies, the Mie's theory , as used in atmospheric optic, seems to neglect such effects. We have called these resonances by the acronym TOR (Tunneling Optical Resonance). In this thesis, we show that TOR can be solved using a one-dimensional Schrödinger equation with an effective potential energy that characterizes the light-droplet interaction and that depends on the refractive index, diameter of the droplet and the incident light's energy. The first main purpose of this thesis is to identify the concept of tunneling and the necessity to introduce it in the Mie's theory. In order to reach this goal, a new method (called transfer matrix method -- TMM) is developed that takes into account the TOR, and allows the identification of the conditions for which TOR occur. The second main purpose, is to compare this method to the Mie's theory and illustrates the differences between them. Our findings show the similarity of the two methods in the case of non-TOR occurrences and disagreement otherwise. This study is performed upon two different cases: (1) a single droplet with a specific diameter and incident energy; (2) a cloud droplet population with a range of diameters from 5 microns to 30 micron for the incident energies of the nine channels (from IR to UV) of the POLDER sensor. For both (1) and (2), cross sections (scattering, extinction and absorption) and the angular distributions of ²the scattered intensity are compared when taking into account the TOR and without considering them. The results are promising and presents a new aspect for addressing light-droplet interaction in atmospheric optics that may affect the inversion problem treatments in remote sensing
Yaacoub, Rouba. "Résonance optique par effet tunnel en optique atmosphérique : application aux observations par satellite des gouttelettes de nuages". Electronic Thesis or Diss., Université de Lille (2018-2021), 2020. http://www.theses.fr/2020LILUR001.
Texto completo da fonteThe light interaction with a homogeneous dielectric spherical scatterer (e.g. cloud droplet) of known characteristics (diameter, optical index) is treated, in atmospheric optics, by the Mie's theory. This theory serves, also, in remote sensing to retrieve physical properties of scatterers (inverse problem). Recent studies have showed the importance of tunneling effects in atmospheric optics. They have attribute the implication of tunneling effects in the atmospheric glory which is the circular iridescence that form around the projected shadow of an object on a cloud of water droplets. Precisely, light can penetrate by tunneling into a droplet and produces sharp resonances. According to these studies, the Mie's theory , as used in atmospheric optic, seems to neglect such effects. We have called these resonances by the acronym TOR (Tunneling Optical Resonance). In this thesis, we show that TOR can be solved using a one-dimensional Schrödinger equation with an effective potential energy that characterizes the light-droplet interaction and that depends on the refractive index, diameter of the droplet and the incident light's energy. The first main purpose of this thesis is to identify the concept of tunneling and the necessity to introduce it in the Mie's theory. In order to reach this goal, a new method (called transfer matrix method -- TMM) is developed that takes into account the TOR, and allows the identification of the conditions for which TOR occur. The second main purpose, is to compare this method to the Mie's theory and illustrates the differences between them. Our findings show the similarity of the two methods in the case of non-TOR occurrences and disagreement otherwise. This study is performed upon two different cases: (1) a single droplet with a specific diameter and incident energy; (2) a cloud droplet population with a range of diameters from 5 microns to 30 micron for the incident energies of the nine channels (from IR to UV) of the POLDER sensor. For both (1) and (2), cross sections (scattering, extinction and absorption) and the angular distributions of ²the scattered intensity are compared when taking into account the TOR and without considering them. The results are promising and presents a new aspect for addressing light-droplet interaction in atmospheric optics that may affect the inversion problem treatments in remote sensing
Tournadre, Benoît. "Heliosat-V ˸ une méthode polyvalente d’estimation du rayonnement solaire au sol par satellite". Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM063.
Texto completo da fonteSolar irradiance at the surface of the Earth is recognized as an essential climate variable by the World Meteorological Organization. Its knowledge is as much important for climate sciences as for the development of energy alternatives to fossil fuels, like solar photovoltaic. Ground measurements of this radiation are very sparse on Earth, explaining the interest for satellite-based remote sensing to estimate it. Combining estimations from different satellites in orbit is a pathway to cover the information on the whole globe. Different generations of satellites also produced a multidecadal imagery of the Earth, making it conceivable to estimate long time series of solar radiation, or even to identify long-term variations, a recurrent objective in the study of climate change. For more than 30 years, Heliosat methods estimate surface solar irradiance from satellite imagery, but they have been designed to be applied to a specific sensor on a geostationary orbit, and have limitations in their scope : the need for a long archive of satellite imagery (Heliosat, Heliosat-2), or else the need for multispectral measurements (Heliosat-4). This work dedicated to the development of a Heliosat-V method brings elements of versatility to the satellite-based estimation from so-called "cloud-index" methods, with the ultimate goal to reach homogeneous data of solar radiation derived from measurements made by different satellite instruments. Two issues are in particular considered here to reach such an estimation: the diversity of sensors in terms of spectral sensitivities, and the influence of viewing and solar geometries on spaceborne measurements. The method extensively deals with radiative transfer modeling in the spectral range 400-1000 nm to simulate on one hand satellite measurements in clear-sky conditions, and on the other hand satellite measurements in the presence of an optically thick cloud. The method is tested on the imagery of a geostationary satellite instrument, Meteosat-9/SEVIRI, and in a more exploratory way, on the non geostationary sensor DSCOVR/EPIC. Results are compared to high quality ground-based measurements of irradiance, and show performances similar to operational satellite products. However, the quality of estimates depends on the spectral channel used, and especially of the presence of clear-sky atmospheric scattering or absorption in the signal measured by the satellite instrument. The accent is also put on the need for an accurate absolute calibration of satellite radiometric measurements in order to produce time series of surface solar irradiance with the smallest biases and temporal drift possible
Söhne, Nathalie. "Validation des prévisions de nuages et de précipitations à mésoéchelle par l'observation satellite". Toulouse 3, 2007. http://thesesups.ups-tlse.fr/102/.
Texto completo da fonteAn original methodology combining the model-to-satellite approach and skill score calculation has been developped in order to objectively evaluate mesoscale models. This method has been applied on three study cases using the Meso-NH model. The first case is about the validation of an ensemble of contrasted precipitating situations, at mid-latitude, used for a data base. It also shows the link between the forecast quality and the meteorological nature of the situation. The second, is an ensemble of forecasts done to quantify the influence on the predictibility of an extreme event when modifications were done on initial conditions and model configurations. The last case allowes to quantify the reliability of a series of AMMA previsions and its variability with synoptic factors
Ringard, Justine. "Estimation des précipitations sur le plateau des Guyanes par l'apport de la télédétection satellite". Thesis, Guyane, 2017. http://www.theses.fr/2017YANE0010/document.
Texto completo da fonteThe Guiana Shield is a region that is characterized by 90% of a primary rainforest and about 20% of the world’s freshwater reserves. This natural territory, with its vast hydrographic network, shows annual rainfall intensities up to 4000 mm/year; making this plateau one of the most watered regions in the world. In addition, tropical rainfall is characterized by significant spatial and temporal variability. In addition to climate-related aspects, the impact of rainfall in this region of the world is significant in terms of energy supply (hydroelectric dams). It is therefore important to develop tools to estimate quantitatively and qualitatively and at high spatial and temporal resolution the precipitation in this area. However, this vast geographical area is characterized by a network of poorly developed and heterogeneous rain gauges, which results in a lack of knowledge of the precise spatio-temporal distribution of precipitation and their dynamics.The work carried out in this thesis aims to improve the knowledge of precipitation on the Guiana Shield by using Satellite Precipitation Product (SPP) data that offer better spatial and temporal resolution in this area than the in situ measurements, at the cost of poor quality in terms of precision.This thesis is divided into 3 parts. The first part compares the performance of four products of satellite estimates on the study area and attempts to answer the question : what is the quality of these products in the Northern Amazon and French Guiana in spatial and time dimensions ? The second part proposes a new SPP bias correction technique that proceeds in three steps: i) using rain gauges measurements to decompose the studied area into hydro climatic areas ii) parameterizing a bias correction method called quantile mapping on each of these areas iii) apply the correction method to the satellite data for each hydro-climatic area. We then try to answer the following question : does the parameterization of the quantile mapping method on different hydro-climatic areas make it possible to correct the precipitation satellite data on the study area ? After showing the interest of taking into account the different rainfall regimes to implement the QM correction method on SPP data, the third part analyzes the impact of the temporal resolution of the precipitation data used on the quality of the correction and the spatial extent of potentially correctable SPP data (SPP data on which the correction method can be applied effectively). In summary, the objective of this section is to evaluate the ability of our method to correct on a large spatial scale the bias of the TRMM-TMPA 3B42V7 data in order to make the exploitation of this product relevant for different hydrological applications.This work made it possible to correct the daily satellite series with high spatial and temporal resolution on the Guiana Shield using a new approach that uses the definition of hydro-climatic areas. The positive results in terms of reduction of the bias and the RMSE obtained, thanks to this new approach, makes possible the generalization of this new method in sparselygauged areas
Avenas, Arthur. "Tropical cyclone dynamics revealed by satellite ocean surface wind speeds observations : the key contribution of the near-core surface wind structure". Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2024. http://www.theses.fr/2024IMTA0397.
Texto completo da fonteDespite advances in predicting the tropical cyclones (TCs) trajectory and outer-core wind speeds, the numerical representation of the strongest winds associated with the most intense events is still an open issue, essentially because of the small radial extent of the TC core and the difficulty in understanding and resolving turbulent air-sea exchanges. Observational limitations have for a long time hindered accurate measurements of the ocean surface near the core region in extreme wind conditions, while geostationary satellites help characterizing the cloud patterns but lack direct information on the air-sea interface. Recently, synthetic aperture radar (SAR) has emerged as a promising satellite technology capable of producing high-resolution two dimensional measurements of the ocean surface wind speeds, thanks to new acquisition modes and algorithmic developments. Given these new observational opportunities, we investigate the contribution of near-core structural features, exclusively discernible through high-resolution instruments, to the TC dynamics. Using a simple theoretical framework and examining its consistency with SAR measurements, we demonstrate that the near-core surface winds modulate the evolution of the TC wind structure. The developed framework allows to illustrate how future measurements of ocean-atmosphere boundary layer characteristics could benefit the short- and long-term monitoring of TCs
El-Alaoui, Mostafa. "Etude des faisceaux d'ions détectés en région aurorale par le satellite AUREOL-3 : synthèse des observations et apport de la modélisation numérique". Toulouse 3, 1994. http://www.theses.fr/1994TOU30037.
Texto completo da fonteBerthier, Sébastien. "Complémentarité et représentativité des observations atmosphériques effectuées par instrumentation active et passive sur les nouvelles plates-formes spatiales". Phd thesis, Université de Versailles-Saint Quentin en Yvelines, 2007. http://tel.archives-ouvertes.fr/tel-00327231.
Texto completo da fonteKacem, Issaad. "Structure et dynamique de l'interface entre des tubes de flux entrelacés observés à la magnétopause terrestre par la mission MMS". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30163/document.
Texto completo da fonteMagnetic reconnection is a ubiquitous and fundamental process in space plasma physics. The NASA's Magnetospheric Multiscale mission (MMS) launched on 12 March 2015 was designed to provide in-situ measurements for analyzing the reconnection process at the Earth's magnetosphere. In this aim, four identically instrumented spacecraft measure fields and particles in the reconnection regions with a time resolution which is one hundred times faster than previous missions. MMS allows for the first time to study the microscopic structures associated with magnetic reconnection and, in particular, the thin electron diffusion region. At the Earth's magnetopause, magnetic reconnection governs the transport of energy and momentum from the solar wind plasma into the Earth's magnetosphere through conversion of magnetic energy into kinetic and thermal energies after a rearrangement of magnetic field lines. Flux Transfer Events (FTEs) are considered to be one of the main and most typical products of magnetic reconnection at the Earth's magnetopause. However, more complex 3D magnetic structures with signatures akin to those of FTEs might also occur at the magnetopause like interlaced flux tubes resulting from magnetic reconnection at multiple sites. The first part of the work presented in this thesis consisted of the investigation of one of these events that was observed, under unusual and extreme solar wind conditions, in the vicinity of the Earth's magnetopause by MMS. Despite signatures that, at first glance, appeared consistent with a classic FTE, this event was interpreted to be the result of the interaction of two separate sets of magnetic field lines with different connectivities. The high time resolution of MMS data allowed to resolve a thin current sheet that was observed at the interface between the two sets of field lines. The current sheet was associated with a large ion jet suggesting that the current sheet was submitted to a compression which drove magnetic reconnection and led to the formation of the ion jet. The direction, velocity and scale of different structures were inferred using multi-spacecraft data analysis techniques. This study was completed with a plasma wave analysis that focused on the reconnecting current sheet
Guihou, Karen. "Étude de la dynamique du Courant Nord au large de Toulon, à l’aide de modèle, observations in-situ et données satellites". Electronic Thesis or Diss., Toulon, 2013. http://www.theses.fr/2013TOUL0004.
Texto completo da fonteThe main objective of this work is to improve our knowledge of the Northern Mediterrranean Current (NC) variability and its interactions with coastal dynamics, using high-resolution modelling of the North-Western Mediterranean Sea, based on the NEMO code and nammed GLAZUR64.The configuration has been validated using all available observations for the period of study (CTD, gliders, ARGO, HF radar, ADCP, satellite altimetry and SST), in order to assess the realism of the simulations and their parameterisations. The contribution of the high-resolution for the simulation of the mesoscale dynamics, compared to 1/12° configurations used at the boundaries is shown.Finally, the use of an operationnal oceanic boundary forcing allowed us to use a combined data-model approach to study the generation and advection of an anticyclonic eddy trapped at the coast and associated to a NC meander, flowing off Toulon in April 2011 [Guihou et al., 2013]
Guihou, Karen. "Étude de la dynamique du Courant Nord au large de Toulon, à l’aide de modèle, observations in-situ et données satellites". Thesis, Toulon, 2013. http://www.theses.fr/2013TOUL0004/document.
Texto completo da fonteThe main objective of this work is to improve our knowledge of the Northern Mediterrranean Current (NC) variability and its interactions with coastal dynamics, using high-resolution modelling of the North-Western Mediterranean Sea, based on the NEMO code and nammed GLAZUR64.The configuration has been validated using all available observations for the period of study (CTD, gliders, ARGO, HF radar, ADCP, satellite altimetry and SST), in order to assess the realism of the simulations and their parameterisations. The contribution of the high-resolution for the simulation of the mesoscale dynamics, compared to 1/12° configurations used at the boundaries is shown.Finally, the use of an operationnal oceanic boundary forcing allowed us to use a combined data-model approach to study the generation and advection of an anticyclonic eddy trapped at the coast and associated to a NC meander, flowing off Toulon in April 2011 [Guihou et al., 2013]
Kurzrock, Frederik. "Assimilation de données satellitaires géostationnaires dans des modèles atmosphériques à aire limitée pour la prévision du rayonnement solaire en région tropicale". Thesis, La Réunion, 2019. https://elgebar.univ-reunion.fr/login?url=http://thesesenligne.univ.run/19_13_FKurzrock.pdf.
Texto completo da fonteThe variability of solar irradiance necessitates to limit the instantaneous feed-in of solar power to electricity grids. An improvement of solar irradiance forecasts would allow to increase the defined threshold limits, especially in non-interconnected zones such as Reunion Island. Achieving higher forecast accuracy is particularly challenging in the case of tropical islands due to pronounced convection and local thermal circulations. Limited-area numerical weather prediction (NWP) models allow to forecast cloud processes and solar irradiance at high spatio-temporal resolutions of a few kilometres and minutes. Nevertheless, they often fail to accurately predict cloudiness evolution and thus tend to overestimate solar irradiance. Refining the initial conditions of regional models in terms of clouds is an efficient means for improving short-term cloud cover and irradiance forecasts. The assimilation of geostationary meteorological satellite observations can achieve this improvement. Nevertheless, a variety of satellite data assimilation (DA) approaches exist and research has focused on mid-latitudes so far. This thesis deals with the assimilation of geostationary satellite observations with limited-area models in the southwestern Indian Ocean. In a first step, the state of the art in terms of existing approaches for radiance and cloud property retrieval assimilation with regional-scale models is reviewed. In consequence, one of the most promising approaches is identified and applied to the southwestern Indian Ocean. In the performed experiments, multi-phase cloud water path retrievals from NASA Langley's SatCORPS cloud products are assimilated with an ensemble Kalman filter using the Weather Research and Forecasting model. A 41-member ensemble at 12 km grid spacing is applied with a DA cycling interval of 6 hours. The Data Assimilation Research Testbed and its forward operator for cloud water path are used to assimilate gridded cloud water retrievals in the ice, supercooled liquid, and liquid phase. The impact of this assimilation approach on forecasts of global horizontal irradiance (GHI) is evaluated for austral summer 2017/2018 using pyranometer observations on Reunion Island. A distinct positive impact of the applied method on the first 14 hours of GHI forecasts is found. Different aspects of the forecast improvement due to DA are analysed by means of control experiments without DA, experiments with a nested domain at 4 km grid spacing, and a comparison with operational NWP models. As the utilised gridded cloud products are available globally, the method offers a portable and globally applicable approach that may also be evaluated for other regions of the Earth
Pislar, Vincent. "Étude d'amas de galaxies observés avec le satellite ROSAT". Paris 6, 1998. http://www.theses.fr/1998PA066594.
Texto completo da fonteCheruy, Frédérique. "Variations diurnes du flux ondes-longues sortant determinees par observation satellitaire". Paris 7, 1990. http://www.theses.fr/1990PA077121.
Texto completo da fonteBeaudoin, Laurent. "Sélection de données satellitales optiques pour la photo-interprétation". Paris, ENST, 2001. http://www.theses.fr/2001ENST0042.
Texto completo da fonteCabanes, Cécile. "Les variations du niveau moyen global et régional de la mer : observation par altimétrie satellitale et marégraphie, analyse et interprétation physique". Toulouse 3, 2003. http://www.theses.fr/2003TOU30237.
Texto completo da fonteMemier, Michel. "Stéréophotogrammétrie numérique : calcul de M.N.T. par corrélation automatique d'images SPOT". Université Joseph Fourier (Grenoble), 1991. http://www.theses.fr/1991GRE10083.
Texto completo da fonteJourdain, Elisabeth. "Résultats récents sur les sursauts Gamma : les observations réalisées par les expériences satellites LILAS et APEX". Toulouse 3, 1990. http://www.theses.fr/1990TOU30108.
Texto completo da fonteChailleux, Yohann. "Observation satellitaire de la pollution à l’ozone par synergie multispectrale à trois bandes Ultraviolet+Visible+Infrarouge". Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1033/document.
Texto completo da fonteAir quality is a major environmental issue for our society. This PhD thesis focuses on space borne observation of the major gaseous pollutant. Tropospheric ozone. New generation satellite instruments allow measuring it daily at regional to global scales. However, single spectral domain measurements do not provide enough information for quantifying ozone concentrations at the atmospheric boundary layer, where the air we breathe is located. Synergism of measurements from multiple spectral domains offers a great potential for better characterizing ozone pollution. The first 2-band multispectral approach combining infrared (IR) measurements of IASI and the ultraviolet (UV) of GOME-2 was developed at LISA laboratory, where I conducted my thesis. The goal of my thesis is to go a step further in the quantification of ozone pollution by including the visible (VIS) Chappuis band, in order to develop an unprecedented 3-band multispectral synergism UV+VIS+IR. First, I developed a approach for extracting ozone information from GOME-2 VIS spectra, by selecting the wavelengths mostly affected by ozone absorption and rejecting those with absorptions from other gases, as well as determining the joint adjustment variables of the approach (vertical ozone profile, surface albedo, spectral shifts, etc) and the databases needed to simulate the spectra VIS (surface albedo, spectroscopy).Then, I implemented the multispectral method with three bands UV+VIS+IR, first on simulated low-orbit and geostationary observations from respectively IASI and GOME-2 and MAGEAQ to estimate the improvement in terms of sensitivity and precision, as compared to existing methods. Last, I applied the 3-band multispectral approach to real satellite observations of IASI and GOME-2. Comparisons with other data shows enhanced performances of the new UV+VIS+IR observations to characterize ozone pollution events, with respect to the 2-band approach
Gohin, Francis. "Analyse geostatistique des champs thermiques de surface de la mer". Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0095.
Texto completo da fonteCloarec, Marc. "Estimation de la bathymétrie par observation de la terre pour les énergies marines renouvelables". Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM071.
Texto completo da fonteBathymetry is a key parameter for marine renewable energies development. The current acquisition these data is made by acoustic sounders on board ships. Synthetic Aperture Radar (SAR) images can be used to acquire bathymetric maps whose resolution could satisfy the actors of the MRE. The objective of the thesis is the evaluation of the potential of new satellites carrying radar imagers for bathymetry estimation and mapping. Repetition of measurements of the Sentinel-1 mission provides Synthetic Aperture Radar (SAR) images of the same area every 6 days. This ability to capture images with sea states very different from one to another allows increasing the probability of capturing favorable conditions to estimate bathymetry with methods exploiting the swell bottom interaction. The approach proposed in this thesis is the use of wave propagation for the purpose of estimating depth. First, the use of a phase-resolved wave propagation model (Boussinesq Ocean & Surf Zone model) allowed establishing, testing and developing a method of bathymetry estimation on several free surfaces of the ocean. With favorable conditions, SAR images of the ocean can be considered as a linear representation of the sea state. Secondly, we adapted and apply the method implemented on the model to SAR images. Simple approaches of data fusion have been applied to exploit of the repetitiveness of the Sentinel-1 mission. Results obtained are able to satisfy the needs of actors in the domain of MRE. The prospects of this work are presented in this document
Bourdarie, Sébastien. "Modélisation de la dynamique des ceintures de radiations à l'échelle de l'orage magnétique". Toulouse, ENSAE, 1996. http://www.theses.fr/1996ESAE0020.
Texto completo da fonteBallabrera, Poy Joaquim. "Assimilation de données avec un filtre de Kalman évolutif de rang réduit dans un modèle aux équations primitives". Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10019.
Texto completo da fonteCherpeau, Aline. "Télédétection et agroécologie : un essai de cartographie destinée à la gestion des milieux herbacés de haute montagne : application au Parc national des Ecrins". Grenoble 1, 1996. http://www.theses.fr/1996GRE10106.
Texto completo da fonteMoine, Pascale. "Analyse tri-dimensionnelle de la structure de l'atmosphère à partir d'observations satellitaires : classification des masses d'air observées et extension à la haute stratosphère (30-50 km)". Paris 6, 1986. http://www.theses.fr/1986PA066329.
Texto completo da fonteAligné, Thomas. "Assimilation variationnelle des observations de sondeurs infrarouges hyperspectraux : correction de biais et la détection nuageuse". Toulouse 3, 2007. http://www.theses.fr/2007TOU30038.
Texto completo da fonteBaverez-Puech, Aline. "Assimilation variationnelle et impact dynamique des colonnes d'ozone observées par l'instrument HIRS". Toulouse 3, 2004. http://www.theses.fr/2004TOU30167.
Texto completo da fonteTotal ozone columns variability depends on the flux in the lower stratosphere. Total ozone observations measured by the HIRS sounder have been assimilated with the four-dimensional variational (4D-Var) assimilation system of the ARPEGE meteorological model, in order to assess the possible impact of these data upon numerical weather prediction. First, some Observing-System Simulation Experiments have confirmed in an idealized context the potential interest of ozone column measurements. In order to assimilate real data, an analysis of the ozone field has been introduced in the 4D-Var system. Some Observing-System Experiments have then shown that assimilating ozone columns, ARPEGE provides total ozone fields of good quality. However, the impact on meteorological forecasts is generally neutral ; the origin of this result seems to be related to the insufficient quality of ozone observations and of the ozone forecast model
Atteia, Jean Luc. "Profils temporels et origine des sursauts gamma : l'apport du programme signe". Toulouse 3, 1987. http://www.theses.fr/1987TOU30283.
Texto completo da fonteVincent, Patrick. "Modélisation aux éléments finis des marées océaniques : [thèse en partie soutenue sur un ensemble de travaux]". Grenoble 1, 1987. http://www.theses.fr/1987GRE10033.
Texto completo da fonteWajeman, Nathalie. "Observation des discontinuités du manteau terrestre par des méthodes sismologiques : Etude des phases de la coda de l'onde P directe". Toulouse 3, 1989. http://www.theses.fr/1989TOU30212.
Texto completo da fonteBeaudoin, André. "Observation de la terre par radar imageur : estimation de la biomasse forestière : [thèse soutenue sur un ensemble de travaux]". Toulouse 3, 1992. http://www.theses.fr/1992TOU30244.
Texto completo da fonteSiefridt, Laure. "VValidation des données de vent ERS-1 et des flux de surface du CEPMMT dans le contexte de la modélisation des circulations océaniques à l'échelle d'un bassin". Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10242.
Texto completo da fonteLyard, Florent. "Modélisation de la marée océanique : application à l'océan indien". Grenoble 1, 1992. http://www.theses.fr/1992GRE10157.
Texto completo da fonteLassoued, Khaoula. "Localisation de robots mobiles en coopération mutuelle par observation d'état distribuée". Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2289/document.
Texto completo da fonteIn this work, we study some cooperative localization issues for mobile robotic systems that interact with each other without using relative measurements (e.g. bearing and relative distances). The considered localization technologies are based on beacons or satellites that provide radio-navigation measurements. Such systems often lead to offsets between real and observed positions. These systematic offsets (i.e, biases) are often due to inaccurate beacon positions, or differences between the real electromagnetic waves propagation and the observation models. The impact of these biases on robots localization should not be neglected. Cooperation and data exchange (estimates of biases, estimates of positions and proprioceptive measurements) reduce significantly systematic errors. However, cooperative localization based on sharing estimates is subject to data incest problems (i.e, reuse of identical information in the fusion process) that often lead to over-convergence problems. When position information is used in a safety-critical context (e.g. close navigation of autonomous robots), one should check the consistency of the localization estimates. In this context, we aim at characterizing reliable confidence domains that contain robots positions with high reliability. Hence, set-membership methods are considered as efficient solutions. This kind of approach enables merging adequately the information even when it is reused several time. It also provides reliable domains. Moreover, the use of non-linear models does not require any linearization. The modeling of a cooperative system of nr robots with biased beacons measurements is firstly presented. Then, we perform an observability study. Two cases regarding the localization technology are considered. Observability conditions are identified and demonstrated. We then propose a set-membership method for cooperativelocalization. Cooperation is performed by sharing estimated positions, estimated biases and proprioceptive measurements. Sharing biases estimates allows to reduce the estimation error and the uncertainty of the robots positions. The algorithm feasibility is validated through simulation when the observations are beacons distance measurements with several robots. The cooperation provides better performance compared to a non-cooperative method. Afterwards, the cooperative algorithm based on set-membership method is tested using real data with two experimental vehicles. Finally, we compare the interval method performance with a sequential Bayesian approach based on covariance intersection. Experimental results indicate that the interval approach provides more accurate positions of the vehicles with smaller confidence domains that remain reliable. Indeed, the comparison is performed in terms of accuracy and uncertainty
Membrive, Olivier. "Caractérisation de la distribution verticale des gaz à effet de serre CO2 et CH4 par mesures sous ballons. Application à la validation d'observations satellites". Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066509.
Texto completo da fonteMonitoring and understanding the evolution of the two most important anthropogenic greenhouse gases(carbon dioxide (CO2) and methane (CH4)) are some of the major challenges in climate science. Over the past decades,the increased availability and diversity of observations (surface networks, aircraft campaigns, satellite observations)and the improvement of atmospheric transport models has allowed to increase our understanding of biogeochemicalcycles of CO2 and CH4. Nevertheless, precise vertical observations are still very rare. However, these become crucialto both properly characterize the vertical transport of the gases, as well as to fully evaluate total or partial columnsof gases retrieved from space observations.In this thesis, we present an innovative instrument called “AirCore” allowing to collect a continuous air samplealong an atmospheric column while descending from high altitude. The analysis of CO2 and CH4 mole fractions inthe collected sample combined with the measurements of an ambient parameters (Pressure, temperature...) allows toretrieve vertical profiles from the surface up to 30 km. Initially invented at NOAA, several new AirCores giving accessto various vertical resolutions have been developed at LMD and flown with success during the CNES Strato-Sciences2014, 2015, and 2016 balloon campaigns. Excellent agreement was found between profiles acquired with differentAirCores during the same flights demonstrating the repeatability of the measurements and allowing to validate thecalculation of the vertical resolution. Comparisons with measurements from independent laser diode spectrometersflown on the same gondola have confirmed that AirCore profiles capture the vertical variability of CO2 and CH4.The vertical profiles retrieved from AirCores have been allowed to validate the CH4 partial columns retrieved fromIASI/Metop at LMD and revealed that the information on the full atmospheric column is required. Comparisons havebeen performed with tropospheric profiles obtained during aircraft campaigns (HIPPO) as well as vertical profilesextracted from atmospheric transport models (LMDz,TM5) and forecast systems (CAMS). Results demonstrated theimportance of a good characterization of the stratosphere for satellite
LE, TEXIER-COULOMB HELENE. "Etude des composes de l'hydrogene, ch4, h2o, h2 et hox dans la stratosphere et la mesosphere : photochimie et transport". Paris 7, 1987. http://www.theses.fr/1987PA077275.
Texto completo da fonteFlorenchie, Pierre. "La circulation de l'océan Atlantique Sud : expériences de simulation avec un modèle quasi-géostrophique et l'assimilation des données altimétriques des satellites TOPEX/POSEIDON et ERS1". Grenoble INPG, 1996. http://www.theses.fr/1996INPG0198.
Texto completo da fonteGalle, Sylvie. "Analyse des champs spatiaux par utilisation de la télédétection : estimation de la durée quotidienne d'insolation en France à l'aide d'images du satellite Météosat et de mesures sol". Phd thesis, Grenoble INPG, 1987. http://tel.archives-ouvertes.fr/tel-00694114.
Texto completo da fonteGuerbette, Jérémy. "Modélisation et assimilation d’observations satellitaires micro-ondes dans les systèmes dépressionnaires tropicaux". Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/16003/1/Guerbette.pdf.
Texto completo da fonteGreiner, Eric. "Mise en oeuvre de méthodes de contrôle optimal pour l'assimilation de données in situ et satellitaires dans les modèles océaniques". Paris 6, 1993. http://www.theses.fr/1993PA066108.
Texto completo da fonteMuller, Etienne. "Dynamique saisonnière des paysages fluviaux par télédétection spatiale : application à la vallée de la Garonne avec Spot et Thematic Mapper : [thèse en partie soutenue sur un ensemble de travaux]". Toulouse 3, 1993. http://www.theses.fr/1993TOU30265.
Texto completo da fonteBoër, Michel. "Contribution a l'etude des sursauts gamma cosmiques : recherche de contreparties permanentes x et optiques, resultats de l'experience signe 2 mp 9". Toulouse 3, 1988. http://www.theses.fr/1988TOU30107.
Texto completo da fonteTestut, Charles-Emmanuel. "Assimilation de données satellitales avec un filtre de Kalman de rang réduit dans un modèle aux équations primitives de l'océan Atlantique". Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10257.
Texto completo da fonteMembrive, Olivier. "Caractérisation de la distribution verticale des gaz à effet de serre CO2 et CH4 par mesures sous ballons. Application à la validation d'observations satellites". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066509/document.
Texto completo da fonteMonitoring and understanding the evolution of the two most important anthropogenic greenhouse gases(carbon dioxide (CO2) and methane (CH4)) are some of the major challenges in climate science. Over the past decades,the increased availability and diversity of observations (surface networks, aircraft campaigns, satellite observations)and the improvement of atmospheric transport models has allowed to increase our understanding of biogeochemicalcycles of CO2 and CH4. Nevertheless, precise vertical observations are still very rare. However, these become crucialto both properly characterize the vertical transport of the gases, as well as to fully evaluate total or partial columnsof gases retrieved from space observations.In this thesis, we present an innovative instrument called “AirCore” allowing to collect a continuous air samplealong an atmospheric column while descending from high altitude. The analysis of CO2 and CH4 mole fractions inthe collected sample combined with the measurements of an ambient parameters (Pressure, temperature...) allows toretrieve vertical profiles from the surface up to 30 km. Initially invented at NOAA, several new AirCores giving accessto various vertical resolutions have been developed at LMD and flown with success during the CNES Strato-Sciences2014, 2015, and 2016 balloon campaigns. Excellent agreement was found between profiles acquired with differentAirCores during the same flights demonstrating the repeatability of the measurements and allowing to validate thecalculation of the vertical resolution. Comparisons with measurements from independent laser diode spectrometersflown on the same gondola have confirmed that AirCore profiles capture the vertical variability of CO2 and CH4.The vertical profiles retrieved from AirCores have been allowed to validate the CH4 partial columns retrieved fromIASI/Metop at LMD and revealed that the information on the full atmospheric column is required. Comparisons havebeen performed with tropospheric profiles obtained during aircraft campaigns (HIPPO) as well as vertical profilesextracted from atmospheric transport models (LMDz,TM5) and forecast systems (CAMS). Results demonstrated theimportance of a good characterization of the stratosphere for satellite
Eisenbeis, Julian. "Ionospheric Dynamics by GNSS total electron content observations : the effect of Solar Eclipses and the mystery of Earthquake precursors". Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7027.
Texto completo da fonteThis thesis focuses mainly on two topics: one is the ionospheric signature of solar eclipses, the second is the Hole vs Enhancement debate about earthquake precursors. On the 21st August 2017 the shadow of a total eclipse drastically changed the state of the ionosphere over the USA. This effect is visible in the total electron content (TEC) measured by ~3000 GNSS stations seeing multiple GPS and GLONASS satellites. This tremendous dataset allows high-resolution characterization of the frequency content and wavelengths -using an omega-k analysis based on 3D Fast-Fourier-Transform (FFT)- of the eclipse signature in the ionosphere in order to fully identify traveling ionospheric disturbances (TIDs). We confirm the generation of TIDs associated with the eclipse including TIDs interpreted as bow waves in previous studies. Additionally we reveal, for the first time, short (50-100 km) and long (500-600 km) wavelength TIDs with periods between 30 and 65 min (Eisenbeis et al., 2019). On 2nd July 2019 another total solar eclipse happened across the South American continent at magnetic conjugate latitudes as the Great American Eclipse, and consequently useful to visualize the difference response. Although for the South American eclipse we have only data from more than hundred GNSS stations and located in a zone close to the sunset, we can show the clear evidence of the ionospheric signature of the eclipse (Eisenbeis & Occhipinti in prep.a).The second major topic in this work is the still ongoing debate about the possibility of earthquake precursors. Heki (2011) sparked this debate when he published results of the Tohoku earthquake showing a TEC enhancement before the earthquake. The enhancement claimed by Heki (2011) has been interpreted as a decrease in the background TEC after the seismic event, the so called ionospheric hole in literature. The existence of the enhancement has been promoted by several papers (e.g. He & Heki, 2017) extending the observation to several events with moderate magnitude (M> 7.5) and proposes a new vision of the rupture dynamics. By trying to reproduce their results we show that the reference curve used by Heki (2011) to define the TEC background is strongly affected by the order of polynomial fit as well as the selected time windows. This shows that the TEC enhancement could be, in fact, just an artifact, subjectively selected to create the presumed precursor (Eisenbeis & Occhipinti in prep.b)
Yassine, Manal. "The prompt emission of Gamma-Ray Bursts : analysis and interpretation of Fermi observations". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS006/document.
Texto completo da fonteGamma-Ray Bursts (GRBs) are very energetic and brief flashes of high-energy radiations which are emitted in a short time scale (fraction of a second to several minutes). The GRB bright emission is thought to be powered by a newly formed stellar-mass black hole that is accompanied by a collimated outflow (i.e. a jet) moving at a relativistic speed. The emission is observed as two successive phases: the highly variable “prompt” phase and the late and less luminous “afterglow” phase. The two instruments on board the Fermi space telescope, the Gamma-ray Burst Monitor (GBM) and the Large Area Telescope (LAT), allow the study of GRB prompt emission over a broad energy range (from ~10 keV to ~100 GeV). In June 2015, a new set of LAT data (Pass 8) was publicly released, which were generated using improved algorithms of reconstruction and classification of gamma-ray events. The main goal of my thesis is the analysis and interpretation of the spectral and temporal properties of the prompt emission phase of the GRBs observed by Fermi, especially using LAT Pass8 data.In the first part of my work, I performed a detailed time-resolved spectral analysis of the prompt phase of GRB 090926A with GBM and LAT data. My results confirm with a greater significance the spectral break at ∼400 MeV that is observed during a fast variability pulse, and they also reveal the presence of a spectral attenuation throughout the GRB prompt emission, as well as an increase of the break energy up to the GeV domain. I interpreted the spectral break in terms of gamma-ray absorption or as a natural curvature of the inverse Compton (IC) emission in the Klein-Nishina regime. Strong constraints on the jet Lorentz factor were obtained in both scenarios. My results lead also to emission radii R ∼10^14 cm, which are consistent with an internal origin of both the keV-MeV and GeV prompt emissions above the jet photosphere.The second part of my work is an exploration of the internal shock model that has been developed by collaborators at the "Institut d'Astrophysique de Paris" (IAP). This model simulates the GRB jet dynamics and the radiations (synchrotron and IC processes) from a population of shock-accelerated electrons. I simulated the response of the Fermi instruments to the synthetic GRB spectra provided by this numerical code. From these simulations, I built a new parametric function that can be used to fit the keV-MeV spectra of GRBs with the model. I applied successfully this function to a sample of 64 GBM bright GRBs. I confronted also the IAP model to the prompt emission spectrum of GRB 090926A. I obtained a relatively good agreement and I identified a couple of solutions that may improve it. The synthetic spectra are wider than any GRB spectra in the GBM sample. I present some theoretical developments that could improve the data-model agreement in the future, and I discuss possible advances from future GRB missions as well
Hernandez, Fabrice. "Comparaison et combinaison de données altimétriques et lagrangiennes. Application à la campagne SEMAPHORE-93". Toulouse 3, 1995. http://www.theses.fr/1995TOU30295.
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