Rozprawy doktorskie: „Remote-sensing maps”

1

Kannich, Rosene. "Automated selection of topographic base information for thematic maps". Thesis restricted. Connect to e-thesis to view abstract, 2007. http://theses.gla.ac.uk/544/.

Pełny tekst źródła

Streszczenie:

Thesis (MSc(R)) - University of Glasgow, 2007.
MSc(R) thesis submitted to the Faculty of Physical Sciences, Department of Geographical and Earth Sciences, University of Glasgow, 2007. Includes bibliographical references. Print version also available.

Style APA, Harvard, Vancouver, ISO itp.

2

Horstman, Kevin Charles. "Geological, remote sensing, and geophysical investigation of the greater Arivaca region, Pima and Santa Cruz counties, Arizona". Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/565552.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

3

Necsoiu, Dorel Marius. "A Data Fusion Framework for Floodplain Analysis using GIS and Remotely Sensed Data". Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2557/.

Pełny tekst źródła

Streszczenie:

Throughout history floods have been part of the human experience. They are recurring phenomena that form a necessary and enduring feature of all river basin and lowland coastal systems. In an average year, they benefit millions of people who depend on them. In the more developed countries, major floods can be the largest cause of economic losses from natural disasters, and are also a major cause of disaster-related deaths in the less developed countries. Flood disaster mitigation research was conducted to determine how remotely sensed data can effectively be used to produce accurate flood plain maps (FPMs), and to identify/quantify the sources of error associated with such data. Differences were analyzed between flood maps produced by an automated remote sensing analysis tailored to the available satellite remote sensing datasets (rFPM), the 100-year flooded areas "predicted" by the Flood Insurance Rate Maps, and FPMs based on DEM and hydrological data (aFPM). Landuse/landcover was also examined to determine its influence on rFPM errors. These errors were identified and the results were integrated in a GIS to minimize landuse / landcover effects. Two substantial flood events were analyzed. These events were selected because of their similar characteristics (i.e., the existence of FIRM or Q3 data; flood data which included flood peaks, rating curves, and flood profiles; and DEM and remote sensing imagery.) Automatic feature extraction was determined to be an important component for successful flood analysis. A process network, in conjunction with domain specific information, was used to map raw remotely sensed data onto a representation that is more compatible with a GIS data model. From a practical point of view, rFPM provides a way to automatically match existing data models to the type of remote sensing data available for each event under investigation. Overall, results showed how remote sensing could contribute to the complex problem of flood management by providing an efficient way to revise the National Flood Insurance Program maps.

Style APA, Harvard, Vancouver, ISO itp.

4

Umbert, Ceresuela Marta. "Exploiting the multiscale synergy among ocean variables : application to the improvement of remote sensing salinity maps". Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/321115.

Pełny tekst źródła

Streszczenie:

Les imatges de teledetecció de la superfície oceànica proporcionen una vista sinòptica de la complexa geometria de la circulació oceànica, dominada per la variabilitat de mesoescala. Estructures com filaments i vòrtex són presents en els diferents escalars advectats pel flux oceànic. L’origen més probable d’aquestes estructures és el caràcter turbulent dels corrents, aquestes estructures són persistents amb el temps i compatibles amb la dinàmica mesoscalar oceànica. A escales espacials de quilòmetres o més, la turbulència és principalment 2D, i una complexa geometria, plena de filaments i remolins de mides diferents, emergeix en les imatges superficials de teledetecció de concentració de clorofil·la-a, salinitat superficial, així com en altres escalars més coneguts com són la temperatura superficial i la topografia dinàmica. L’objectiu d’aquesta tesi és explorar i aplicar metodologies de mapatge que permeten millorar la qualitat de mapes de teledetecció oceànica en general, i en particular de la salinitat superficial del mar (SSS). Les diferents metodologies emprades en aquesta tesi han estat aplicades amb l’objectiu específic de millorar els mapes de teledetecció de salinitat superficial del mar proveïts per la missió SMOS de l’Agència Espaial Europea. SMOS és el primer satèl·lit capaç de mesurar la humitat del sol i salinitat oceànica des de l’espai a escala global. La primera part d’aquesta tesi se centra a analitzar les característiques dels productes de nivell 2 (L2) de salinitat de SMOS i produir mapes de nivell 3 (L3) de salinitat utilitzant aproximacions clàssiques: millora del filtratge, mitjana ponderada i Interpolació Òptima. En el curs de la nostra recerca obtenim un conjunt de recomanacions de com processar les dades de SMOS començant des del nivell L2. Aquesta tesi també presenta una nova tècnica de fusió de dades que permet explotar les estructures turbulentes comunes entre diferents variables oceàniques, representant un pas endavant en la cadena de processat per generar mapes de nivell 4 (L4). Aquesta tècnica de fusió es basa teòricament en les propietats geomètriques dels traçadors advectats per la dinàmica oceànica (Turiel et al., 2005a). Degut a l’efecte de forta cissalla als fluits turbulents, l’estructura espacial d’un traçador oceànic hereta algunes propietats del flux subjacent, i en particular el seu arranjament geomètric. Com a conseqüència, les diferents variables oceàniques mostren propietats d’escala similars a la cascada d’energia turbulenta (Seuront and Schmitt, 2005; Nieves et al., 2007; Nieves and Turiel, 2009; Isern-Fontanet et al., 2007). El mètode de fusió agafa un senyal de menor qualitat (afectat per soroll, forats de dades i/o de resolució més baixa) i en millora la seva qualitat. A més d’això, el mètode de fusió és capaç d’extrapolar les dades de forma geofísicament coherent. Aquesta millora del senyal s’aconsegueix utilitzant una altra variable oceànica adquirida amb major qualitat, cobertura espacial més gran i/o millor resolució. Un punt clau d’aquesta aproximació és la suposició de l’existència d’una estructura multifractal de les imatges de teledetecció oceànica (Lovejoy et al., 2001b), i que les línies de singularitat de les diferents variables de l’oceà coincideixen. Sota aquestes premises, els gradients de les dues variables a fusionar estan relacionats per una matriu suau. Com a primera i simple aproximació, s’assumeix que aquesta matriu és proporcional a la identitat; això porta a un esquema de regressió lineal local. Aquesta tesi mostra que aquesta aproximació senzilla permet reduir l’error i millorar la cobertura del producte de nivell 4 resultant. D’altra banda, s’obté informació sobre la relació estadística entre les dues variables fusionades, ja que la dependència funcional entre elles es determina per cada punt de la imatge.
Remote sensing imagery of the ocean surface provides a synoptic view of the complex geometry of ocean circulation, which is dominated by mesoscale variability. The signature of filaments and vortices is present in different ocean scalars advected by the oceanic flow. The most probable origin of the observed structures is the turbulent character of ocean currents, and those signatures are persistent over time scales compatible with ocean mesoscale dynamics. At spatial scales of kilometers or more, turbulence is mainly 2D, and a complex geometry, full of filaments and eddies of different sizes, emerges in remote sensing images of surface chlorophyll-a concentration and surface salinity, as well as in other scalars acquired with higher quality such as surface temperature and absolute dynamic topography. The aim of this thesis is to explore and apply mapping methodologies to improve the quality of remote sensing maps in general, but focusing in the case of remotely sensed sea surface salinity (SSS) data. The different methodologies studied in this thesis have been applied with the specific goal of improving surface salinity maps generated from data acquired by the European Space Agency's mission SMOS, the first satellite able to measure soil moisture and ocean salinity from space at a global scale. The first part of this thesis will introduce the characteristics of the operational SMOS Level 2 (L2) SSS products and the classical approaches to produce the best possible SSS maps at Level 3 (L3), namely data filtering, weighted average and Optimal Interpolation. In the course of our research we will obtain a set of recommendations about how to process SMOS data starting from L2 data. A fusion technique designed to exploit the common turbulent signatures between different ocean variables is also explored in this thesis, in what represents a step forward from L3 to Level 4 (L4). This fusion technique is theoretically based on the geometrical properties of advected tracers. Due to the effect of the strong shear in turbulent flows, the spatial structure of tracers inherit some properties of the underlying flow and, in particular, its geometrical arrangement. As a consequence, different ocean variables exhibit scaling properties, similar to the turbulent energy cascade. The fusion method takes a signal affected by noise, data gaps and/or low resolution, and improves it in a geophysically meaningful way. This signal improvement is achieved by using an appropriate data, which is another ocean variable acquired with higher quality, greater spatial coverage and/or finer resolution. A key point in this approach is the assumption of the existence of a multifractal structure in ocean images, and that singularity lines of the different ocean variables coincide. Under these assumptions, the horizontal gradients of both variables, signal and template, can be related by a smooth matrix. The first, simplest approach to exploit such an hypothesis assumes that the relating matrix is proportional to the identity, leading to a local regression scheme. As shown in the thesis, this simple approach allows reducing the error and improving the coverage of the resulting Level 4 product; Moreover, information about the statistical relationship between the two fields is obtained since the functional dependence between signal and template is determined at each point.

Style APA, Harvard, Vancouver, ISO itp.

5

Tyoda, Zipho. "Landslide susceptibility mapping : remote sensing and GIS approach". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79856.

Pełny tekst źródła

Streszczenie:

Thesis (MSc)--Stellenbosch University, 2013.
Landslide susceptibility maps are important for development planning and disaster management. The current synthesis of landslide susceptibility maps largely applies GIS and remote sensing techniques. One of the most critical stages on landslide susceptibility mapping is the selection of landslide causative factors and weighting of the selected causative factors, in accordance to their influence to slope instability. GIS is ideal when deriving static factors i.e. slope and aspect and most importantly in the synthesis of landslide susceptibility maps. The integration of landslide causative thematic maps requires the selection of the weighting method; in order to weight the causative thematic maps in accordance to their influence to slope instability. Landslide susceptibility mapping is based on the assumption that future landslides will occur under similar circumstances as historic landslides. The weight of evidence method is ideal for landslide susceptibility mapping, as it calculates the weights of the causative thematic maps using known landslides points. This method was applied in an area within the Western Cape province of South Africa, the area is known to be highly susceptible to landslide occurrences. A prediction rate of 80.37% was achieved. The map combination approach was also applied and achieved a prediction rate of 50.98%. Satellite remote sensing techniques can be used to derive the thematic information needed to synthesize landslide susceptibility maps and to monitor the variable parameters influencing landslide susceptibility. Satellite remote sensing techniques can contribute to landslide investigation at three distinct phases namely: (1) detection and classification of landslides (2) monitoring landslide movement and identification of conditions leading up to an event (3) analysis and prediction of slope failures. Various sources of remote sensing data can contribute to these phases. Although the detection and classification of landslides through the remote sensing techniques is important to define landslide controlling parameters, the ideal is to use remote sensing data for monitoring of areas susceptible to landslide occurrence in an effort to provide an early warning. In this regard, optical remote sensing data was used successfully to monitor the variable conditions (vegetation health and productivity) that make an area susceptible to landslide occurrence.

Style APA, Harvard, Vancouver, ISO itp.

6

Aleong-Mackay, Kathryn. "Landsat imagery and small-scale vegetation maps : data supplementation and verification : a case study of the Maralal area, northern Kenya". Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66182.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

7

Camacho, Mark A. "Depth analysis of Midway Atoll using Quickbird multi-spectral imaging over variable substrates". Thesis, Monterey California. Naval Postgraduate School, 2006. http://hdl.handle.net/10945/2674.

Pełny tekst źródła

Streszczenie:

Shallow water bathymetry is important for both safe navigation and natural resource management purposes. Extracting depth information from spectral imagery allows identification of benthic features and characterization of coral reef habitats, especially in remote islands. Techniques have been developed to extract water depth from multispectral imagery (Lyzenga, 1978; Philpot, 1989). These techniques can be difficult to apply in optically shallow waters with heterogeneous bottom types and varying albedo, and require tuning of multiple parameters. An improved algorithm to extract water depth from multispectral satellite imagery was proposed by Stumpf et al. (2003) to generate bathymetric maps with limited a priori information. The algorithm is based on the ratios of transformed reflectance values in the visible bands, retrieving greater depths than previous algorithms and compensating for variable bottom type and albedo. This method requires fewer tunable parameters and can be applied to low-albedo features. Although Stumpf et al. (2003) conclude that the method is robust and works well over variable bottom types, recent studies have pointed out limitations, mostly attributable to varying albedo (Clark, 2005; Densham, 2005). This research attempts to quantify the contribution of variable benthic substrates to the algorithmâ s accuracy by classifying the scene into its main bottom types and tuning the coefficients separately. The algorithm is evaluated using a QuickBird high resolution multispectral image of the remote Midway Atoll, in the Northwestern Hawaiian Islands. Classifying the image into two main bottom types and tuning the coefficients separately produced a small improvement in the accuracy of the bathymetric estimates when bottom reflectance is included as a factor. This result indicates that Stumpf et al. (2003)â s ratio method is not insensitive to variable bottom type, and that knowledge of the distribution and extent of different benthic substrates in optically shallow waters has the potential to improve bathymetric derivation in remote coastal areas such as coral reef environments in the Pacific.

Style APA, Harvard, Vancouver, ISO itp.

8

Park, Kyoung Jin. "Generating Thematic Maps from Hyperspectral Imagery Using a Bag-of-Materials Model". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366296426.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

9

Baxter, Katrina. "Linking seafloor mapping and ecological models to improve classification of marine habitats : opportunities and lessons learnt in the Recherche Archipelago, Western Australia". University of Western Australia. School of Plant Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0181.

Pełny tekst źródła

Streszczenie:

[Truncated abstract] Spatially explicit marine habitat data is required for effective resource planning and management across large areas, although mapped boundaries typically lack rigour in explaining what factors influence habitat distributions. Accurate, quantitative methods are needed. In this thesis I aimed to assess the utility of ecological models to determine what factors limit the spatial extent of marine habitats. I assessed what types of modeling methods were able to produce the most accurate predictions and what influenced model results. To achieve this, initially a broad scale marine habitat survey was undertaken in the Recherche Archipelago, on the south coast of Western Australia using video and sidescan sonar. Broad and more detailed functional habitats types were mapped for 1054km2 of the Archipelago. Broad habitats included high and low profile reefs, sand, seagrass and extensive rhodolith beds, although considerable variation could be identified from video within these broad types. Different densities of seagrass were identified and reefs were dominated by macroalgae, filter feeder communities, or a combination of both. Geophysical characteristics (depth, substrate, relief) and dominant benthic biota were recorded and then modelled using decision trees and a combination of generalised additive models (GAMs) and generalised linear models (GLMs) to determine the factors influencing broad and functional habitat variation. Models were developed for the entire Archipelago (n=2769) and a subset of data in Esperance Bay (n=797), which included exposure to wave conditions (mean maximum wave height and mean maximum shear stress) calculated from oceanographic models. Additional distance variables from the mainland and islands were also derived and used as model inputs for both datasets. Model performance varied across habitats, with no one method better than the other in terms of overall model accuracy for each habitat type, although prevalent classes (>20%) such as high profile reefs with macroalgae and dense seagrass were the most reliable (Area Under the Curve >0.7). ... This highlighted not only issues of data prevalence, but also how ecological models can be used to test the reliability of classification schemes. Care should be taken when mapping predicted habitat occurrence with broad habitat models. It should not be assumed that all habitats within the type will be defined spatially, as this may result in the distribution of distinctive and unique habitats such as filterfeeders being underestimated or not identified at all. More data is needed to improve prediction of these habitats. Despite the limitations identified, the results provide direction for future field sampling to ensure appropriate variables are sampled and classification schemes are carefully designed to improve descriptions of habitat distributions. Reliable habitat models that make ecological sense will assist future assessments of biodiversity within habitats as well as provide improved data on the probability of habitat occurrence. This data and the methods developed will be a valuable resource for reserve selection models that prioritise sites for management and planning of marine protected areas.

Style APA, Harvard, Vancouver, ISO itp.

10

Carmody, James Daniel Physical Environmental &amp Mathematical Sciences Australian Defence Force Academy UNSW. "Deriving bathymetry from multispectral and hyperspectral imagery". Awarded by:University of New South Wales - Australian Defence Force Academy. School of Physical, Environmental and Mathematical Sciences, 2007. http://handle.unsw.edu.au/1959.4/38654.

Pełny tekst źródła

Streszczenie:

Knowledge of water depth is a crucial for planning military amphibious operations. Bathymetry from remote sensing with multispectral or hyperspectral imagery provides an opportunity to acquire water depth data faster than traditional hydrographic survey methods without the need to deploy a hydrographic survey vessel. It also provides a means of collecting bathymetric data covertly. This research explores two techniques for deriving bathymetry and assesses them for use by those involved in providing support to military operations. To support this aim a fieldwork campaign was undertaken in May, 2000, in northern Queensland. The fieldwork collected various inherent and apparent water optical properties and was concurrent with airborne hyperspectral imagery collection, space-based multispectral imagery collection and a hydrographic survey. The water optical properties were used to characterise the water and to understand how they affect deriving bathymetry from imagery. The hydrographic data was used to assess the performance of the bathymetric techniques. Two methods for deriving bathymetry were trialled. One uses a ratio of subsurface irradiance reflectance at two wavelengths and then tunes the result with known water depths. The other inverts the radiative transfer equation utilising the optical properties of the water to derive water depth. Both techniques derived water depth down to approximately six to seven metres. At that point the Cowley Beach waters became optically deep. Sensitivity analysis of the inversion method found that it was most sensitive to errors in vertical attenuation Kd and to errors in transforming the imagery into subsurface irradiance reflectance, R(0-) units. Both techniques require a priori knowledge to derive depth and a more sophisticated approach would be required to determine water depth without prior knowledge of the area of interest. This research demonstrates that water depth can be accurately mapped with optical techniques in less than ideal optical conditions. It also demonstrates that the collection of inherent and apparent optical properties is important for validating remotely sensed imagery.

Style APA, Harvard, Vancouver, ISO itp.

11

Hollinger, David L. "Crop Condition and Yield Prediction at the Field Scale with Geospatial and Artificial Neural Network Applications". Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1310493197.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

12

Alkhadour, Wissam M. "Reconstruction of 3D scenes from pairs of uncalibrated images. Creation of an interactive system for extracting 3D data points and investigation of automatic techniques for generating dense 3D data maps from pairs of uncalibrated images for remote sensing applications". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4933.

Pełny tekst źródła

Streszczenie:

Much research effort has been devoted to producing algorithms that contribute directly or indirectly to the extraction of 3D information from a wide variety of types of scenes and conditions of image capture. The research work presented in this thesis is aimed at three distinct applications in this area: interactively extracting 3D points from a pair of uncalibrated images in a flexible way; finding corresponding points automatically in high resolution images, particularly those of archaeological scenes captured from a freely moving light aircraft; and improving a correlation approach to dense disparity mapping leading to 3D surface reconstructions. The fundamental concepts required to describe the principles of stereo vision, the camera models, and the epipolar geometry described by the fundamental matrix are introduced, followed by a detailed literature review of existing methods. An interactive system for viewing a scene via a monochrome or colour anaglyph is presented which allows the user to choose the level of compromise between amount of colour and ghosting perceived by controlling colour saturation, and to choose the depth plane of interest. An improved method of extracting 3D coordinates from disparity values when there is significant error is presented. Interactive methods, while very flexible, require significant effort from the user finding and fusing corresponding points and the thesis continues by presenting several variants of existing scale invariant feature transform methods to automatically find correspondences in uncalibrated high resolution aerial images with improved speed and memory requirements. In addition, a contribution to estimating lens distortion correction by a Levenberg Marquard based method is presented; generating data strings for straight lines which are essential input for estimating lens distortion correction. The remainder of the thesis presents correlation based methods for generating dense disparity maps based on single and multiple image rectifications using sets of automatically found correspondences and demonstrates improvements obtained using the latter method. Some example views of point clouds for 3D surfaces produced from pairs of uncalibrated images using the methods presented in the thesis are included.
Al-Baath University
The appendices files and images are not available online.

Style APA, Harvard, Vancouver, ISO itp.

13

Johnson, Adam Bradford. "THE USE OF REMOTE SENSING AND GEOGRAPHICAL INFORMATION SYSTEMS TO CREATE LAND USE AND LAND COVER MAPS AND TO DETERMINE THE CHANGES IN THE LAND USE AND LAND COVER OVER A TEN YEAR PERIOD". MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07072005-193332/.

Pełny tekst źródła

Streszczenie:

Construction of land use and land cover (LULC) maps was accomplished through the use of remote sensing and GIS. Remote sensing and GIS were used to classify 1990 Landsat 5 and 2000 Landsat 7 Mississippi Gulf Coast imagery into six LULC classes: urban, barren, forested vegetation, non-forested vegetation, marsh, and water. An accuracy assessment was performed on the 2000 LULC map to determine the reliability of the map. Finally, GIS software was used to quantify and illustrate the various LULC conversions that took place over the ten year span of time. The paper concludes that remote sensing and GIS can be used to create LULC maps. It also notes that the maps generated can be used to delineate the changes that take place over time.

Style APA, Harvard, Vancouver, ISO itp.

14

Alkhadour, Wissam Mohamad. "Reconstruction of 3D scenes from pairs of uncalibrated images : creation of an interactive system for extracting 3D data points and investigation of automatic techniques for generating dense 3D data maps from pairs of uncalibrated images for remote sensing applications". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4933.

Pełny tekst źródła

Streszczenie:

Much research effort has been devoted to producing algorithms that contribute directly or indirectly to the extraction of 3D information from a wide variety of types of scenes and conditions of image capture. The research work presented in this thesis is aimed at three distinct applications in this area: interactively extracting 3D points from a pair of uncalibrated images in a flexible way; finding corresponding points automatically in high resolution images, particularly those of archaeological scenes captured from a freely moving light aircraft; and improving a correlation approach to dense disparity mapping leading to 3D surface reconstructions. The fundamental concepts required to describe the principles of stereo vision, the camera models, and the epipolar geometry described by the fundamental matrix are introduced, followed by a detailed literature review of existing methods. An interactive system for viewing a scene via a monochrome or colour anaglyph is presented which allows the user to choose the level of compromise between amount of colour and ghosting perceived by controlling colour saturation, and to choose the depth plane of interest. An improved method of extracting 3D coordinates from disparity values when there is significant error is presented. Interactive methods, while very flexible, require significant effort from the user finding and fusing corresponding points and the thesis continues by presenting several variants of existing scale invariant feature transform methods to automatically find correspondences in uncalibrated high resolution aerial images with improved speed and memory requirements. In addition, a contribution to estimating lens distortion correction by a Levenberg Marquard based method is presented; generating data strings for straight lines which are essential input for estimating lens distortion correction. The remainder of the thesis presents correlation based methods for generating dense disparity maps based on single and multiple image rectifications using sets of automatically found correspondences and demonstrates improvements obtained using the latter method. Some example views of point clouds for 3D surfaces produced from pairs of uncalibrated images using the methods presented in the thesis are included.

Style APA, Harvard, Vancouver, ISO itp.

15

Gonçalves, Marcio Leandro. "Metodos de classificação não-supervisionada de imagens de sensoriamento remoto usando mapas auto-organizaveis de Kohonen". [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261035.

Pełny tekst źródła

Streszczenie:

Orientadores: Marcio Luiz de Andrade Netto, Jose Alfredo Ferreira Costa
Acompanha Anexo A: Midia com informações adicionais em CD-R
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-13T08:13:27Z (GMT). No. of bitstreams: 1 Goncalves_MarcioLeandro_D.pdf: 17165173 bytes, checksum: 5d69834b0b51b236f01317b4de54a2b3 (MD5) Previous issue date: 2009
Resumo: Esta tese propõe novas metodologias de classificação não-supervisionada de imagens de sensoriamento remoto que particularmente exploram as características e propriedades do Mapa Auto-organizável de Kohonen (SOM - Self-Organizing Map). O ponto chave dos métodos de classificação propostos é realizar a análise de agrupamentos das imagens através do mapeamento produzido pelo SOM, ao invés de trabalhar diretamente com os padrões originais das cenas. Tal estratégia reduz significativamente a complexidade da análise dos dados, tornando possível a utilização de técnicas normalmente consideradas computacionalmente inviáveis para o processamento de imagens de sensoriamento remoto, como métodos de agrupamentos hierárquicos e índices de validação de agrupamentos. Diferentemente de outras abordagens, nas quais o SOM é utilizado como ferramenta de auxílio visual para a detecção de agrupamentos, nos métodos de classificação propostos, mecanismos para analisar de maneira automática o arranjo de neurônios de um SOM treinado são aplicados e aprimorados com o objetivo de encontrar as melhores partições para os conjuntos de dados das imagens. Baseando-se nas propriedades estatísticas do SOM, modificações nos cálculos de índices de validação agrupamentos são propostas com o objetivo de reduzir o custo computacional do processo de classificação das imagens. Técnicas de análise de textura em imagens são aplicadas para avaliar e filtrar amostras de treinamento e/ou protótipos do SOM que correspondem a regiões de transição entre classes de cobertura terrestre. Informações espaciais a respeito dos protótipos do SOM, além das informações de distância multiespectral, também são aplicadas em critérios de fusão de agrupamentos procurando facilitar a discriminação de classes de cobertura terrestre que apresentam alto grau de similaridade espectral. Resultados experimentais mostram que os métodos de classificação propostos apresentam vantagens significativas em relação às técnicas de classificação não-supervisionada mais freqüentemente utilizadas na área de sensoriamento remoto.
Abstract: This thesis proposes new methods of unsupervised classification for remotely sensed images which particularly exploit the characteristics and properties of the Kohonen Self-Organizing Map (SOM). The key point is to execute the clustering process through a set of prototypes of SOM instead of analyzing directly the original patterns of the image. This strategy significantly reduces the complexity of data analysis, making it possible to use techniques that have not usually been considered computationally viable for processing remotely sensed images, such as hierarchical clustering methods and cluster validation indices. Unlike other approaches in which SOM is used as a visual tool for detection of clusters, the proposed classification methods automatically analyze the neurons grid of a trained SOM in order to find better partitions for data sets of images. Based on the statistical properties of the SOM, clustering validation indices calculated in a modified manner are proposed with the aim of reducing the computational cost of the classification process of images. Image texture analysis techniques are applied to evaluate and filter training samples and/or prototypes of the SOM that correspond to transition regions between land cover classes. Spatial information about the prototypes of the SOM, in addition to multiespectral distance information, are also incorporated in criteria for merging clusters with aim to facilitate the discrimination of land cover classes which have high spectral similarity. Experimental results show that the proposed classification methods present significant advantages when compared to unsupervised classification techniques frequently used in remote sensing.
Doutorado
Engenharia de Computação
Doutor em Engenharia Elétrica

Style APA, Harvard, Vancouver, ISO itp.

16

Pagliarani, Arianna. "Potenzialità di utilizzo di dati satellitari Sentinel-2 a supporto di procedure di Sensitivity Mapping in area costiera". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

Znajdź pełny tekst źródła

Streszczenie:

L'inquinamento da oil spill risulta una tra le principali cause dell'inquinamento marino. Esso può avere un grave impatto economico e biologico, causando danni sostanziali agli ecosistemi marini. Nel tempo, a seguito di grandi incidenti a petrolifere, si è affermata l'importanza della realizzazione di un quadro generale delle zone costiere sensibili e di conoscere tutti i fattori che permettono la previsione degli spostamenti delle quantità di idrocarburi sversate. A partire dagli anni '70, vari enti a livello nazionale e globale hanno sviluppato delle linee guida per la prevenzione, il monitoraggio e l’intervento in caso di oil spill, in particolare per la creazione delle cosidette Environmental Sensitivity Index (ESI) Maps. Esse forniscono un quadro generale della sensibilità delle coste agli sversamenti di idrocarburi in base al litorale, alle risorse biologiche e alle risorse per uso umano. Obiettivo dell'elaborato è esaminare la possibilità di utilizzare le immagini multispettrali gratuite fornite dalle piattaforme satellitari Sentinel-2 a supporto di procedure di generazione di Environmental Sensitivity index ESI maps. In particolare, si è valutata in una vasta area di studio la realizzazione della classificazione del litorale secondo l'indice ESI (che assegna alle varie tipologie di costa una classe in funzione della sensibilità agli sversamenti da petrolio) analoga a quella prodotta dalla National Oceanographic and Atmospheric Administration (NOAA).

Style APA, Harvard, Vancouver, ISO itp.

17

Wiggers, Kelly Lais. "ANÁLISE EM UMA IMAGEM ORBITAL DE ALTA RESOLUÇÃO PARA CLASSIFICAÇÃO DO USO E COBERTURA DA TERRA DE UMA ÁREA DA BACIA DO PITANGUI - PR". UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2014. http://tede2.uepg.br/jspui/handle/prefix/126.

Pełny tekst źródła

Streszczenie:

Made available in DSpace on 2017-07-21T14:19:23Z (GMT). No. of bitstreams: 1 Kelly Lais.pdf: 3909972 bytes, checksum: a9e068fb926de9ca233857005e400c84 (MD5) Previous issue date: 2014-12-16
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O Sensoriamento Remoto (SR) dispõe de tecnologias em constante crescimento e com grande potencial para a agricultura, tanto no gerenciamento de culturas, manejo de solo, bem como discriminações de feições da terra. Atualmente, há muitos métodos de análise e categorização de paisagens, que com a integração de dados de SR e técnicas de Sistemas de Informação Geográfica (SIG) apresentam alternativa promissora. Isto é, proporcionam maior facilidade na manipulação de dados geográficos, bem como otimização da validação a campo. Neste contexto, esta pesquisa foi realizada utilizando classificação digital não-supervisionada pela Rede Neural Artificial (RNA) Self-Organizing Maps (SOM) no reconhecimento de padrões de uso e cobertura da terra em um recorte de imagem orbital de alta resolução Rapideye pertencente à Bacia do Pitangui, o qual abrange o município de Ponta Grossa, localizado a centro-leste do Estado do Paraná. Primeiramente aplicouse a técnica NDVI (Índice de Vegetação por Diferença Normalizada) para estimular a separação das classes, principalmente os diferentes tipos de cultivos agrícolas, bem como cobertura florestal. A imagem orbital e NDVI foram segmentadas por meio de Análise de Imagem Baseada em Objeto (GEOBIA), gerando descritores com propriedades espaciais, espectrais e de textura, culminando no banco de dados relacional (BDR) com tais descritores. Mediante Análise de Componentes Principais (ACP) reduziu-se a dimensionalidade dos dados do BDR, selecionando os descritores mais significativos. A dimensionalidade foi reduzida, sem perda de informação, de 42 descritores para 21, a saber 6 espaciais, 12 espectrais e 3 de textura. Após esta preparação dos dados, utilizou-se a RNA SOM para o reconhecimento dos padrões pré-determinados a campo. As classes de uso e cobertura da terra discriminadas pela RNA SOM foram cultivos (cultivo 1, 2, 3 e 4), estradas e construções, cobertura florestal e corpos d’água. A RNA SOM culminou no agrupamento das classes cultivos inclusive em relação ao seu ciclo fenológico. A associação da banda artificial NDVI, com seus descritores às bandas espectrais, incrementou a separabilidade entre classes, tais como cobertura florestal e corpos d’água. As classes de uso e cobertura da terra foram validadas a campo, a exatidão global foi de 91% de acerto, com índice kappa de 0,9, considerado resultado excelente em valores de referência. Também foi realizado o teste estatístico F, o qual satisfez as hipóteses de nulidade nas áreas analisadas.Conclui-se que os métodos utilizados apresentaram eficácia, agilidade e baixo custo no mapeamento d o uso e cobertura da terra em escala detalhada.
Remote Sensing (RS) uses steadily growing technologies and presents great potential for agriculture, e.g. in crop and land management, as well as for discrimination of land features. Currently, there are many methods of analysis and landscape categorization that when integrated with RS data and Geographic Information Systems (GIS) techniques stage as promising alternatives. That is, they provide greater ease in handling spatial data as well as optimizing validation on the field. In this context, this study was carried out using unsupervised digital classification with Artificial Neural Network (ANN) Self- Organizing Maps (SOM), in order to recognize patterns of land cover and land use in part of a high-resolution Rapideye orbital image belonging to the Pitangui River Basin, which encompasses the city of Ponta Grossa, located in the Central-Eastern portion of the State of Paraná. Initially, NDVI (Normalized Difference Vegetation Index) technique was applied to stimulate the separation of classes, especially to evidence different types of agricultural crops and forest cover. The orbital image and the NDVI were segmented through Geographic Object-Based Image Analysis (GEOBIA), generating descriptors with spatial, spectral and textural properties, culminating in the relational database (RDB) with such descriptors. With Principal Component Analysis (PCA) dimensionality of the BDR data was reduced, selecting the most significant descriptors. Dimensionality was reduced without information loss, from 42 descriptors to 21, namely 6 spatial, 12 spectral and 3 textural. After this data preparation, ANN SOM was used to recognize predetermined patterns in the field. The classes of land cover and land use discriminated by ANN SOM were crops (crop 1, 2, 3 and 4), roads and buildings; forest cover and water bodies. The ANN SOM culminated in the grouping of crop classes including in relation to its phenological cycle. The association of the NDVI artificial band with descriptors to spectral bands, increased the separability between classes, such as forest cover and water bodies. Classes of land cover and land use were validated in the field, the global accuracy was 91%, with kappa index of 0.9 and considered to be excellent as reference values. F statistical test was also carried out and showed satisfiability in the analyzed areas. It is concluded that the methods used were effective, agile and low-cost in detailed scale mapping of land use and coverage.

Style APA, Harvard, Vancouver, ISO itp.

18

Myburgh, Gerhard. "The impact of training set size and feature dimensionality on supervised object-based classification : a comparison of three classifiers". Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71655.

Pełny tekst źródła

Streszczenie:

Thesis (MSc)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Supervised classifiers are commonly used in remote sensing to extract land cover information. They are, however, limited in their ability to cost-effectively produce sufficiently accurate land cover maps. Various factors affect the accuracy of supervised classifiers. Notably, the number of available training samples is known to significantly influence classifier performance and to obtain a sufficient number of samples is not always practical. The support vector machine (SVM) does perform well with a limited number of training samples. But little research has been done to evaluate SVM’s performance for geographical object-based image analysis (GEOBIA). GEOBIA also allows the easy integration of additional features into the classification process, a factor which may significantly influence classification accuracies. As such, two experiments were developed and implemented in this research. The first compared the performances of object-based SVM, maximum likelihood (ML) and nearest neighbour (NN) classifiers using varying training set sizes. The effect of feature dimensionality on classifier accuracy was investigated in the second experiment. A SPOT 5 subscene and a four-class classification scheme were used. For the first experiment, training set sizes ranging from 4-20 per land cover class were tested. The performance of all the classifiers improved significantly as the training set size was increased. The ML classifier performed poorly when few (<10 per class) training samples were used and the NN classifier performed poorly compared to SVM throughout the experiment. SVM was the superior classifier for all training set sizes although ML achieved competitive results for sets of 12 or more training samples per class. Training sets were kept constant (20 and 10 samples per class) for the second experiment while an increasing number of features (1 to 22) were included. SVM consistently produced superior classification results. SVM and NN were not significantly (negatively) affected by an increase in feature dimensionality, but ML’s ability to perform under conditions of large feature dimensionalities and few training areas was limited. Further investigations using a variety of imagery types, classification schemes and additional features; finding optimal combinations of training set size and number of features; and determining the effect of specific features should prove valuable in developing more costeffective ways to process large volumes of satellite imagery. KEYWORDS Supervised classification, land cover, support vector machine, nearest neighbour classification maximum likelihood classification, geographic object-based image analysis
AFRIKAANSE OPSOMMING: Gerigte klassifiseerders word gereeld aangewend in afstandswaarneming om inligting oor landdekking te onttrek. Sulke klassifiseerders het egter beperkte vermoëns om akkurate landdekkingskaarte koste-effektief te produseer. Verskeie faktore het ŉ uitwerking op die akkuraatheid van gerigte klassifiseerders. Dit is veral bekend dat die getal beskikbare opleidingseenhede ŉ beduidende invloed op klassifiseerderakkuraatheid het en dit is nie altyd prakties om voldoende getalle te bekom nie. Die steunvektormasjien (SVM) werk goed met beperkte getalle opleidingseenhede. Min navorsing is egter gedoen om SVM se verrigting vir geografiese objek-gebaseerde beeldanalise (GEOBIA) te evalueer. GEOBIA vergemaklik die integrasie van addisionele kenmerke in die klassifikasie proses, ŉ faktor wat klassifikasie akkuraathede aansienlik kan beïnvloed. Twee eksperimente is gevolglik ontwikkel en geïmplementeer in hierdie navorsing. Die eerste eksperiment het objekgebaseerde SVM, maksimum waarskynlikheids- (ML) en naaste naburige (NN) klassifiseerders se verrigtings met verskillende groottes van opleidingstelle vergelyk. Die effek van kenmerkdimensionaliteit is in die tweede eksperiment ondersoek. ŉ SPOT 5 subbeeld en ŉ vier-klas klassifikasieskema is aangewend. Opleidingstelgroottes van 4-20 per landdekkingsklas is in die eerste eksperiment getoets. Die verrigting van die klassifiseerders het beduidend met ŉ toename in die grootte van die opleidingstelle verbeter. ML het swak presteer wanneer min (<10 per klas) opleidingseenhede gebruik is en NN het, in vergelyking met SVM, deurgaans swak presteer. SVM het die beste presteer vir alle groottes van opleidingstelle alhoewel ML kompeterend was vir stelle van 12 of meer opleidingseenhede per klas. Die grootte van die opleidingstelle is konstant gehou (20 en 10 eenhede per klas) in die tweede eksperiment waarin ŉ toenemende getal kenmerke (1 tot 22) toegevoeg is. SVM het deurgaans beter klassifikasieresultate gelewer. SVM en NN was nie beduidend (negatief) beïnvloed deur ŉ toename in kenmerkdimensionaliteit nie, maar ML se vermoë om te presteer onder toestande van groot kenmerkdimensionaliteite en min opleidingsareas was beperk. Verdere ondersoeke met ŉ verskeidenheid beelde, klassifikasie skemas en addisionele kenmerke; die vind van optimale kombinasies van opleidingstelgrootte en getal kenmerke; en die bepaling van die effek van spesifieke kenmerke sal waardevol wees in die ontwikkelling van meer koste effektiewe metodes om groot volumes satellietbeelde te prosesseer. TREFWOORDE Gerigte klassifikasie, landdekking, steunvektormasjien, naaste naburige klassifikasie, maksimum waarskynlikheidsklassifikasie, geografiese objekgebaseerde beeldanalise

Style APA, Harvard, Vancouver, ISO itp.

19

De, Villiers Germari Marzen Luke J. King David T. "Remote sensing of shallow-marine impact craters on Mars". Auburn, Ala., 2007. http://hdl.handle.net/10415/1343.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

20

Milazzo, Moses Pollen. "Remote Sensing Of Thermally Induced Activity On Io And Mars". Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1363%5F1%5Fm.pdf&type=application/pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

21

Ashcraft, Ivan S. "Microwave Remote Sensing of the Greenland Ice Sheet: Models and Applications". Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd532.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

22

Bayoudh, Meriam. "Apprentissage de connaissances structurelles à partir d’images satellitaires et de données exogènes pour la cartographie dynamique de l’environnement amazonien". Thesis, Antilles-Guyane, 2013. http://www.theses.fr/2013AGUY0671/document.

Pełny tekst źródła

Streszczenie:

Les méthodes classiques d'analyse d'images satellites sont inadaptées au volume actuel du flux de données. L'automatisation de l'interprétation de ces images devient donc cruciale pour l'analyse et la gestion des phénomènes observables par satellite et évoluant dans le temps et l'espace. Ce travail vise à automatiser la cartographie dynamique de l'occupation du sol à partir d'images satellites, par des mécanismes expressifs, facilement interprétables en prenant en compte les aspects structurels de l'information géographique. Il s'inscrit dans le cadre de l'analyse d'images basée objet. Ainsi, un paramétrage supervisé d'un algorithme de segmentation d'images est proposé. Dans un deuxième temps, une méthode de classification supervisée d'objets géographiques est présentée combinant apprentissage automatique par programmation logique inductive et classement par l'approche multi-class rule set intersection. Ces approches sont appliquées à la cartographie de la bande côtière Guyanaise. Les résultats démontrent la faisabilité du paramétrage de la segmentation, mais également sa variabilité en fonction des classes de la carte de référence et des données d'entrée. Les résultats de la classification supervisée montrent qu'il est possible d'induire des règles de classification expressives, véhiculant des informations cohérentes et structurelles dans un contexte applicatif donnée et conduisant à des valeurs satisfaisantes de précision et de KAPPA (respectivement 84,6% et 0,7). Ce travail de thèse contribue ainsi à l'automatisation de la cartographie dynamique à partir d'images de télédétection et propose des perspectives originales et prometteuses
Classical methods for satellite image analysis are inadequate for the current bulky data flow. Thus, automate the interpretation of such images becomes crucial for the analysis and management of phenomena changing in time and space, observable by satellite. Thus, this work aims at automating land cover cartography from satellite images, by expressive and easily interpretable mechanism, and by explicitly taking into account structural aspects of geographic information. It is part of the object-based image analysis framework, and assumes that it is possible to extract useful contextual knowledge from maps. Thus, a supervised parameterization methods of a segmentation algorithm is proposed. Secondly, a supervised classification of geographical objects is presented. It combines machine learning by inductive logic programming and the multi-class rule set intersection approach. These approaches are applied to the French Guiana coastline cartography. The results demonstrate the feasibility of the segmentation parameterization, but also its variability as a function of the reference map classes and of the input data. Yet, methodological developments allow to consider an operational implementation of such an approach. The results of the object supervised classification show that it is possible to induce expressive classification rules that convey consistent and structural information in a given application context and lead to reliable predictions, with overall accuracy and Kappa values equal to, respectively, 84,6% and 0,7. In conclusion, this work contributes to the automation of the dynamic cartography from remotely sensed images and proposes original and promising perpectives

Style APA, Harvard, Vancouver, ISO itp.

23

LOUAHALA, SAM. "Signatures spectrales de roches en milieu tempere : valeurs reelles et valeurs percues par le satellite". Paris 7, 1988. http://www.theses.fr/1988PA077109.

Pełny tekst źródła

Streszczenie:

Etude automatique des donnees de teledetection multispectrale pour la cartographie en provence a partir de mesures spectroradiometriques qui donnent les caracteristiques spectrales de surfaces rocheuses naturelles. Le role de la rugosite sur les mesures de reflectance est mis en evidence a partir de mesures realisees sur des plages de galets de granulometrie differentes, il est confirme par simulation numerique. Une comparaison entre mesures au sols et mesures satellitaires est effectuee afin d'evaluer les corrections atmospheriques necessaires pour des petites cibles. Une methode de reduction des variations d'eclairement des cibles est testee. Des ameliorations de resolution spectrale ne peuvent etre envisagee sans amelioration de resolution spatiale

Style APA, Harvard, Vancouver, ISO itp.

24

McLay, Nicholas Ross. "Ice Velocity and Mass Balance Study of the Skelton Glacier, Antarctica, Using Remote Sensing and GIS Techniques". Thesis, University of Canterbury. Gateway Antarctica, 2013. http://hdl.handle.net/10092/7883.

Pełny tekst źródła

Streszczenie:

The Skelton Glacier is one of the many smaller outlet glaciers located in the Transantarctic Mountains, where it drains ice into the Ross Ice Shelf. These outlet glaciers are important when determining the past, present, and future state of the mass balance of the East Antarctic Ice Sheet. This research uses satellite imagery acquired over a period of 15 years to obtain a high resolution velocity field for the Skelton Glacier which is then used to calculate the mass flux and mass balance at ten flux gates along the glacier using the input-output method. The high resolution velocity field is combined with ice thickness data and accumulation data from other sources to obtain the total mass balance. The high resolution velocity field of the Skelton Glacier was created using European Remote-Sensing Satellite 1 and 2 (ERS-1/2) Synthetic Aperture Radar (SAR) data acquired in 1996 with the processing technique of SAR interferometry (InSAR). Because of the lack of differential InSAR pairs, new auxiliary data from the ICESat and TanDEM-X mission were included into the analysis. A velocity field was created at a spatial resolution of 50m which was validated with in situ GPS measurements from 2011/12, and compared to lower resolution velocity fields of the Skelton Glacier. The ice velocity field is at improved accuracy for this area compared to previous studies and is thought to be representative for the mean ice velocity. The analysis of ice flux at several flux gates allowed an improved error estimation of the applied technique to estimate the overall mass balance. Mass flux estimates along the glacier were calculated using the new velocity field and additional thickness data, which was then compared to two accumulation datasets to give mass balance estimates along the glacier at selected flux gates. The mass flux through the grounding line was found to be 1.2165 Gt a⁻¹, which needs to be balanced in a state of mass balance equilibrium by a mean annual snow accumulation of about 185 mm a⁻¹ water equivalent over the total catchment area determined with 6569 km². The mass balance at the grounding line is slightly negative, but the second flux gate is thought to be more representative of the mass balance, which is estimated to be 0.0441 Gt a⁻¹. Error analysis of the mass balance estimates found uncertainties in this data to be approximately 0.110 Gt a⁻¹. It is concluded from the analysis that further improvements in the overall mass balance estimate can be primarily obtained by a better knowledge of ice thickness and snow accumulation.

Style APA, Harvard, Vancouver, ISO itp.

25

Allender, Elyse J. "Automated Tools and Techniques for Mars Forward Exploration". University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1480328341223151.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

26

Chee, Yenlai. "Remote sensing analysis of cratered surfaces Mars landing hazard assessment, comparison to terrestrial crater analogs, and Mars crater dating models /". To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2007. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

27

Willame, Yannick. "Aerosol and ozone retrieval in the Martian atmosphere using the SPICAM/UV instrument and algorithm preparation for future missions". Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/219965.

Pełny tekst źródła

Streszczenie:

Mars is the fourth planet of the Solar System starting from the Sun. Compared to Earth, Mars has an atmosphere that is significantly thinner and undergoes also a seasonal cycle that is more marked. A Martian year lasts about two terrestrial years. One of the particularity of the Martian atmosphere is the continuous presence of an airborne dust layer.SPICAM is an instrument on board the Mars-Express satellite orbiting around Mars since the end of 2003. This instrument is divided in two modules: SPICAM/IR, a infrared spectrometer (1.0 - 1.7 µm) and SPICAM/UV, a spectrometer working in the ultraviolet range (106 - 317 nm). In this work, we have analysed the SPICAM/UV measurements that have been recorded in nadir viewing and in the spectral interval between 220 and 290 nm.The analysis of this spectral domain allows to study different species and constituents of the Martian atmosphere such as ozone, dust and ice clouds. In the frame of this work, we have developed a method capable of inverting the SPICAM spectra obtained in nadir viewing in order to simultaneously retrieve the integrated quantities of these different species i.e. the ozone total column, and the integrated optical depths of dust and ice clouds. The method is based on a radiative transfer code that allows to take into account the scattering of light by the different molecules and aerosols of the Martian atmosphere. The surface reflectivity is also considered and is retrieved in the cases where no ice clouds are present in the observed scenes, ice clouds reducing the sensitivity in the surface albedo. Therefore, a cloud detection algorithm has been developed and its results were compared with results obtained with other methods and instruments for validation.Our method has been used to invert the data measured by SPICAM/UV over more than four Martian years which allowed to obtain climatologies of the different studied species: the spatial and seasonal distributions of the ozone column, the optical depths of dust and ice clouds and also the surface albedo are presented in this work. These distributions are discussed and compared to those obtained in previous works obtained with other instruments.This work is also a preparation for the future measurement analysis of the NOMAD/UVIS, an instrument that will be on board the ExoMars Trace Gas Orbiter which is planned to be launched in the beginning of 2016. The algorithm developed in this thesis has also been used to assess performances of NOMAD/UVIS such as the detection limits of particular gases (O3, SO2 et NH3) and the values of the signal-to-noise ratio.
Mars est la quatrième planète du Système Solaire en partant du Soleil. Comparée à la Terre, Mars se caractérise par une atmosphère significativement plus ténue, et possède également un cycle annuel des saisons plus marqué. Une année martienne dure environ deux années terrestres. Une des particularités de l'atmosphère de Mars réside en la présence persistante d'une couche de poussière en suspension.SPICAM est un instrument embarqué à bord du satellite Mars-Express qui orbite autour de Mars depuis fin 2003. Il comprend deux modules: SPICAM/IR, un spectromètre infrarouge (1.0 - 1.7 µm) et SPICAM/UV, un spectromètre opérant dans le domaine ultraviolet (106 - 317 nm). Dans le cadre de ce travail, nous avons analysé les mesures de SPICAM/UV obtenues en visée nadir dans l'intervalle spectral s'étendant de 220 à 290 nm.L'analyse de ce domaine spectral permet d'étudier différentes espèces ou constituants de l'atmosphère martienne telles que l'ozone, les poussières ainsi que les nuages de glace. Dans le cadre de ce travail, nous avons développé une méthode capable d'inverser les spectres SPICAM/UV en visée nadir afin de restituer simultanément les quantités intégrées de ces différentes espèces, à savoir la colonne totale d'ozone ainsi que l'opacité intégrée des poussières et des nuages. Cette méthode est basée sur un code de transfert radiatif, permettant de tenir compte de la diffusion de la lumière par les particules en suspension dans l'atmosphère martienne. La réflectivité de la surface martienne est également étudiée et restituée pour les cas où aucun nuage n'est présent dans les scènes observées, les nuages réduisant la sensibilité en l'albédo de surface. Pour ce faire, un algorithme de détection des nuages a été développé et ses résultats ont été comparés avec les résultats obtenus par d'autres méthodes et instruments afin de le valider.Notre méthode d'inversion a été utilisée pour analyser les données recueillies par SPICAM/UV pendant plus de 4 années martiennes, permettant d'obtenir une climatologie des différentes espèces étudiées: des distributions spatiales et saisonnières de la colonne d'ozone, de l'opacité des poussières et nuages de glace ainsi que de l'albédo de surface sont présentées dans ce travail. Ces distributions sont discutées et comparées à celles obtenues dans des travaux antérieurs à l'aide d'autres instruments.Ce travail constitue également une préparation en vue de l'analyse des données de l'instrument NOMAD/UVIS, supervisé par l'IASB-BIRA, et qui sera lancé à bord de la sonde ExoMars Trace Gas Orbiter en direction de Mars au début de l'année 2016. L'algorithme développé dans ce travail a notamment été utilisé pour l'estimation de performances de NOMAD/UVIS telles que les limites de détection de certains gaz (O3, SO2 et NH3) ou encore les valeurs du rapport de signal-sur-bruit.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Style APA, Harvard, Vancouver, ISO itp.

28

Filho, Osmar Bazaglia. "Comparação entre mapas de solos obtidos pelos métodos convencional e digital numa área complexa". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-24042012-102912/.

Pełny tekst źródła

Streszczenie:

Mapas de solos são essenciais para o desenvolvimento de áreas agrícolas de maneira economicamente viável e ambientalmente correta. Até o momento, o Brasil conta apenas com mapas de solos de escala pequena (1:250.000 a 1:1.000.000), cuja utilização é limitada para planejamento agrícola e ambiental a nível de propriedade rural. Apesar de sua importância, no Brasil poucos mapeamentos têm sido realizados pelos órgãos públicos competentes, principalmente por restrições orçamentárias e falta de pedólogos. Além disso, o 5º e 6º níveis categóricos do Sistema Brasileiro de Classificação de Solos (SiBCS), que devem ser utilizados em levantamentos detalhados, não estão definidos. Dessa forma, pouco se sabe a respeito da qualidade/similaridade dos mapas desse nível que vem sendo executados no país. Os principais motivos para essa situação são: elevado custo, mão-de-obra e tempo requeridos nos trabalhos de mapeamento. Uma alternativa para redução desses entraves é o mapeamento digital de solos (MDS). Sendo assim, objetivou-se: (i) comparar quatro mapas de solos convencionais de uma mesma área complexa, de mesma escala (1:10.000), elaborados por diferentes pedólogos de maneira independente, e (ii) comparar estes com um mapa de solos obtido por técnica de MDS. Para tanto, utilizou-se uma área de estudo de 182 ha, cultivada com cana-de-açúcar, localizada no município de Rafard (SP). Foram fornecidas aos pedólogos as mesmas informações: mapas geológico e pedológico semidetalhado (ambos escala 1:100.000), mapa planialtimétrico e fotografias aéreas (ambos escala 1:10.000). Viagens a campo, resultados de análise e exame de perfis foram realizados conforme estes julgaram necessário. Para o mapa digital de solos foram utilizados atributos de terreno (elevação, declividade, poder de fluxo dágua, fator LS, plano e perfil de curvatura), calculados a partir do modelo digital de elevação gerado com base no mapa planialtimétrico, e informação espectral superficial do solo de uma imagem de satélite Landsat 5 (sensor TM) obtida em período que a superfície do solo estava desnuda. Tais informações foram sintetizadas através da análise por componentes principais, sendo posteriormente feita uma compartimentação da área com auxílio da análise Fuzzy K-médias. Nos compartimentos foram realizadas observações para classificá-los como unidades de mapeamento. Os mapas foram então comparados dois a dois, sendo medida a correspondência espacial para cada um dos quatro níveis categóricos estabelecidos no SiBCS, e além destes acrescida a informação textural. Tanto para as comparações entre mapas convencionais, quanto para comparações com o mapa digital, houve redução da correspondência espacial para os níveis categóricos mais detalhados. A maior correspondência final (4º nível + textura) entre mapas convencionais se deu entre os mapas A e B (24,3 %). As maiores correspondências espaciais em relação ao mapa digital se deram entre este e o mapa A (35,2 %) e o mapa B (28,7 %). Portanto confirma-se que os mapas de solos convencionais variam conforme critérios subjetivos do executor, cuja mensuração é impraticável. O mapa de solos digital gerado pela metodologia proposta obteve índices de correspondência aos mapas convencionais semelhantes aos obtidos entre estes, sendo uma boa opção no processo de otimização dos trabalhos de mapeamento.
Soil maps are essential for the development of agricultural areas in an economically viable and environmentally friendly manner. So far, Brazil only has soil maps of small scale (1:250,000 to 1:1,000,000), whose use is limited to agricultural and environmental planning at the farm. Despite its importance, in Brazil a few mappings have been carried out by public authorities, primarily because budget constraints and lack of soil scientists. In addition, 5 and 6 categorical levels of the Brazilian System of Soil Classification (SiBCS), which should be used for detailed surveys, are not defined. Thus, little is known about the quality and level of similarity of the maps that have been undertaken in the country. The main reasons for this situation are: high cost, manpower and time required of mapping. An alternative to reducing these barriers is the digital soil mapping (DSM). Therefore, the objectives were to: (i) compare four conventional soil maps of the same complex area of the same scale (1:10,000), prepared by different independent soil scientists independently, and (ii) compare these with a soil map obtained by the DSM technique. For this purpose, we used a study area of 182 ha cultivated with sugar cane in the municipality of Rafard (SP). The same information was provided to the soil scientists: a geological map anda a semi-detailed pedological map (both scale 1:100,000), planialtimetric map and aerial photographs (both scale 1:10,000). Field trips, results of analysis and examination soil profiles were performed as deemed necessary. The information for the digital soil map included terrain attributes (elevation, slope, stream power, LS factor, plan and profile curvature), calculated from the digital elevation model generated based on the topographic map, and data reflectance of the surface soil of a satellite image Landsat 5 (TM sensor) obtained in the period that ground was bare. Such information has been summarized by principal component analysis, and subsequently made a subdivision of the area using Fuzzy K-means analysis. Observations were made in each compartment to classify them as a mapping unit. The maps were then compared two by two, the spatial correspondence being measured for each of the four levels established in the Brazilian System of Soil Classification, and beyond the increased textural information. Both for comparisons between conventional maps, and for comparisons to the digital map, there was a reduction of spatial correspondence to the more detailed categoric levels. The longest match final (4th level + texture) occurred between conventional maps A and B (24.3%). The highest spatial correlation in relation to the digital map that occurred was between it and the map A (35.2%) and the map B (28.7%). Therefore it is confirmed that the conventional soil maps vary according to subjective criteria of the soil scientist, whose measurement is impractical. The digital soil map generated by the proposed method achieved similar rates of correspondence with the conventional maps as those obtained among these, being a good choice in the optimization process of mapping work.

Style APA, Harvard, Vancouver, ISO itp.

29

Smeda, Braden William. "Area and Volume Changes of Adams Icefield from 1948 to 2019, Axel Heiberg Island, Nunavut, Canada". Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/41602.

Pełny tekst źródła

Streszczenie:

There has been a marked increase in melt season length over the past two decades on glaciers and ice caps within Canada’s Queen Elizabeth Islands (QEI). Prior to the year ~2000 land ice was in a state of slightly negative mass balance (-11 +/- 11.5 Gt yr⁻¹ over 1958-1995), but recent GRACE measurements suggest that mass losses averaged -33 +/- 5 Gt yr⁻¹ between 2003-2015. These losses have primarily been attributed to meltwater runoff, making the QEI one of the largest recent contributors to sea level rise outside of the ice sheets. Despite these losses, there is a lack of information concerning how a warming climate is affecting small (<1 km²) ice bodies, which are considered sensitive indicators of change due to their short response time. In this study, historical and contemporary aerial photographs, high resolution optical satellite imagery, and ground penetrating radar (GPR) surveys are used to determine area, thickness, mass and volume changes of Adams Icefield within Expedition Fiord, Axel Heiberg Island, Nunavut, over the past seven decades (1948/59-2019). Area changes are determined from a comparison of air photos acquired in 1948/59 with satellite images acquired since 1979. Contemporary (2001, 2012, 2019) digital elevation models (DEMs) were either collected or created from stereo satellite images, and via aerial photo surveys using Structure from Motion photogrammetry. DEM of Difference maps calculated from these DEMs provide volume and mass changes. Results illustrate a steady reduction in glacier area, thickness, and volume prior to the year ~2000, followed by a rapid increase in losses over the past two decades. As a result, Adams Icefield is now rapidly declining and is likely to completely disappear early in the twenty-second century.

Style APA, Harvard, Vancouver, ISO itp.

30

El, Hourany Roy. "Télédétection du phytoplancton par méthode neuronale : du global au régional, de la composition pigmentaire aux biorégions". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS095.

Pełny tekst źródła

Streszczenie:

Cette thèse présente une approche novatrice d’analyse et d’observation de la structure de la communauté de phytoplancton à l'échelle mondiale et régionale à l'aide de données satellitaires (couleur de l‘océan et température de surface) et d'observations in-situ. L'approche est basée sur des méthodes neuronales de classification, telles que les cartes auto-organisatrices (SOM) calibrées sur une grande base de données globale formée de mesures satellitaires collocalisées avec des mesures in-situ. Nous avons d’abord développé une méthode d’estimation des pigments phytoplanctoniques secondaires appliquée à l’océan global à partir de mesures satellitaires. Ensuite nous avons réalisé une étude fine de la Méditerranée où les groupes phytoplanctoniques (PFTs) ont été identifiés. En se servant des mesures de profondeur de la couche de mélange (MLD) fournies par les flotteurs ARGO, de la température de surface de la mer (SST) et de la concentration en chlorophylle-a (Chla) satellitaire, nous avons déterminé sept bio-régions basées sur le cycle annuel de ces variables en utilisant une SOM modifiée. Enfin ces bio-régions ont été caractérisées en termes de PFTs. Les méthodes utilisées nous ont permis d’évaluer les incertitudes sur les pigments et sur les PFTs. L’ensemble des méthodes proposées dans la thèse permettent d’effectuer des études similaires dans d’autres régions
This thesis presents a novel approach to analyze and observe the phytoplankton community structure at global and regional scale using satellite data (Ocean colour and Sea surface temperature) and in-situ observations. The approach is based on neural network classification methods, such as Self-Organizing Maps (SOM) trained on a large global database composed of satellite observations collocated with in-situ measurements. First, we developed a method to estimate secondary phytoplankton pigments from satellite measurements in the global ocean. Then we focused our studies on the Mediterranean Sea. Phytoplankton groups (PFTs) were identified from the secondary pigments estimated in the first phase. We then characterized seven bio-regions by clustering annual cycles MLD obtained from Argo floats, SST and Chla by using an advanced SOM. At last, these bio-regions were characterized in terms of PFTs. The methods developed in this thesis allowed us to estimate uncertainties on secondary pigments and PFTs. The applicability of these methods are broad and can be used to investigate other oceanic areas

Style APA, Harvard, Vancouver, ISO itp.

31

Fongaro, Caio Troula. "Mapeamento granulométrico do solo via imagens de satélite e atributos de relevo". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-09032016-133136/.

Pełny tekst źródła

Streszczenie:

O planeta terra tem grande dimensão, e seus recursos naturais precisam ser mapeados e conhecidos para nortear políticas públicas. O solo é um destes importantes recursos. O seu conhecimento passa pela caracterização e mapeamento pedológico e/ou de seus atributos. Para o adequado monitoramento, é necessário o conhecimento em escala detalhadas. Isto demanda recursos humanos, altos custos financeiros e de logística. Fato este ainda difícil de se atingir. Logo, é preciso investir em tecnologias que auxiliem na rápida obtenção de informações de qualidade, à baixo custo. Tendo em vista as áreas agrícolas da região de estudo, os objetivos deste trabalho foram: (i) definir uma metodologia que identifique em imagens de satélite, locais de o solo exposto; (ii) Mapear os teores granulométricos através de imagens de satélite e atributos do relevo, utilizou-se das imagens compostas do tópico (i). A área de estudo localiza-se na região de Araraquara, São Paulo, Brasil, com dimensão de 14.614 km2. Dentro desta área foram demarcados 952 pontos para coleta de amostras de terra na camada superficial, as quais foram georreferenciadas e analisadas granulometricamente em laboratório. Sua demarcação seguiu os preceitos do método da topossequência com o intuito de representar a variabilidade da região. Foram obtidas imagens do satélite Landsat 5 (sensor TM) multitemporais as quais foram processadas e transformadas em reflectância. As amostras de terra coletadas em campo passaram por sensor em laboratório (400-2500 nm), os espectros laboratoriais foram utilizados para validar aqueles obtidos nas imagens de satélite. Para tanto, nos locais onde foram coletadas as amostras, foram extraídos os dados espectrais dos pixels perfazendo os gráficos das curvas espectrais. Estas foram comparadas com os dados de obtidos em laboratório simulados. Feita a correlação, as imagens passaram por processos de eliminação de objetos que não fossem solo. Todas as imagens multitemporais foram finalizadas contendo apenas solo exposto, as quais dentro do software R foram sobrepostas e gerou-se uma imagem composta, com apenas solo exposto. Os resultados mostraram que as curvas espectrais de laboratório foram extremamente semelhantes aos das imagens de satélite, seguindo a lógica das variações texturais. Além disso, as técnicas de componentes principais e relação entre bandas 3-4, 5-7, e correlação entre bandas (sendo a mais expressiva com r de 0,87 entre TM7), comprovaram que a imagem apresentou solo exposto. Se um usuário utilizar-se somente uma imagem para estudar solos, teria na faixa de 4% de solo exposto, porém utilizando a técnica de composição de imagens, atingiria 43%. Não obstante, se a área de estudo fosse 100 % com agricultura poderia atingir 95% de solo exposto. Num segundo momento, o trabalho comprova, com o modelo Cubist, que tanto por imagens de satélite quanto por relevo foi possível quantificar os teores de argila da área da camada superficial, atingindo R2 de ≈0,65. No entanto, a qualidade visual do mapa gerado por relevo é ruim. Porém, quando se integra dados de imagens, relevo e geomorfologia, este resultado é de 0,72 e apresenta o melhor resultado visual.
Planet Earth has great dimension, and its natural resources has to be mapped and monitored, looking towards correct decisions. Soil is one of these important resources. Know soils is related with its caracterization and mapping by pedological and attributes recognition. For soil monitoring, its necessary maps in large scale, which demand man power and high cost. Thus, its necessary to invest in geotechnologies, to reach the goal faster and low cost. The objective of this work was to determine a method to determine exposed soils in satellite images, even when have vegetation, taking in account a multitemporal dataset, in agricultural areas, where as in a given season will have exposed soils. b. quantify clay and sand contents by satellite images and relief attributes. The area is located in Araraquara, SP, Brazil, with a 14.614 km2 dimension. We collected soil samples all over the area with a total of 952 points and 0-20 cm depth, georeferenced, representative of the area. Samples were granulometric analysed and afterwards passed throgh a vis-nir-swir sensor (400-2500 nm). We collected multitemporal images from landsat satellite from september and october n the last 15 years. Images were atmospheric corrected and transformed into reflectance. Laboratory spectral data was used to validate pixels spectra information from satellite. We extracted all objects which were not soils from all images. Using R software, we merged the multitemporal images and performed a unique bare soil image. Also, we made processing on the DEM of the área reaching several soil attribute factors. Results indicated as follows: a. labortory spectral curves validated satellite data; b) principal componentes and relation between bands ¾ and 5/7 reached great R2 until 0,87 between laboratory and satellite data; d) a user could reach 1,21% of na image with bare soil, while with our method could reach 43% in the entire image. On the other hand, if the user have only agriculture area, could reach until 95% with bare soil. In a second step of this work, we prove that by regression tree statistics, clay and sand content can be quantified by satellite images with a 0,62 of R2, as also with terrain atributes. On the other hand, when we associate image spectral data with terrain atributes, we can reach 0,72 on clay quantification. Despite this, the visual aspecto of data, is better using image data than relief , which presented more noise. Another conclusion, is that images could substitute geology information in the models. This work can considerably assist pedologists, farmers and environment professionals on soil monitoring.

Style APA, Harvard, Vancouver, ISO itp.

32

Demchuk, Robert W. "Detailed Mapping of Lava Flows in Syrtis Major Planum, Mars". Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1617806602421614.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

33

Burström, Annika. "Trends in mass balance indexes connected to spatial location and precipitation : Remote sensing of 111 glaciers in the Everest region". Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-77138.

Pełny tekst źródła

Streszczenie:

Studies of Himalayan glacial response to climatic forcing are few and a more comprehensive understanding of the relationship between the two is needed. This has been highlighted by recent controversies over future glacier change in this area. This study has therefore reviewed if there is a connection between glacier mass balance indexes and precipitation pattern in the Everest region. 111 glaciers were mapped in ArcGIS through remote sensing. Glacial total area, accumulation area as well as snowline altitudes and aspect were mapped. From this, the two mass balance indexes Accumulation Area Ratio, AAR and Area-Altitude Balance Ratios, AABR were derived. The intention was to search for patterns. In addition to this, an expedition to parts of the study area was conducted in March to April 2011. Hundreds of photographs of snow stratigraphy, debris cover ice snouts, accumulation etc were taken. The expedition also led to an understanding of the environment and of the glaciers which was helpful for the assessment of the remote sensing results. No pattern in glacier size, ELA, AAR or AABR was found that suggests a connection between mass balance and local precipitation pattern. The glaciers instead appear to be more sensitive to elevation. The largest glaciers and highest AAR and AABR are found at high - although not the highest - elevations.

Style APA, Harvard, Vancouver, ISO itp.

34

Kaiser, Stefan. "Legal implications of satellite based communication navigation and surveillance systems for civil aviation". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22385.

Pełny tekst źródła

Streszczenie:

This thesis deals with the legal problems arising from the introduction of satellite based communication, navigation and surveillance systems for civil aviation. The technical innovations are asking for an international institutional implementation, which has not yet started.
After a brief look at the technical aspects of the new systems (Chapter II), existing institutional arrangements of international satellite systems, air-navigation infrastructure and air traffic control are outlined (Chapter III). A legal analysis presents the obstacles and alternatives future institutional arrangements will be confronted with, and leads to a definition of the institutional problem (Chapter IV).
The core of the thesis is a proposal for regional intergovernmental organizations, which coordinate the operation of aeronautical satellite communications and air traffic control as an intermediary between the States and service providers (Chapter V). Among other problems financing, user charges, and liability are discussed. Legal problems of navigation systems are discussed on the base of the emerging global systems (Chapter VI).

Style APA, Harvard, Vancouver, ISO itp.

35

Wolfinger, Doug C. "Geologic Characterization of Ladon Valles, Mars and the Surrounding Area". Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1398291492.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

36

Marchiorato, Ivo Aurélio [UNESP]. "Mapas de variabilidade do potencial de produtividade obtidos por satélites como instrumentos auxiliares às decisões sobre o manejo de nematóides na cultura da soja". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/105237.

Pełny tekst źródła

Streszczenie:

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-18Bitstream added on 2014-06-13T19:44:35Z : No. of bitstreams: 1 marchiorato_ia_dr_jabo.pdf: 517282 bytes, checksum: f2d40c2e6db9d7a211f668d69642bc62 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O conhecimento da distribuição espacial dos nematóides nas lavouras é imprescindível para adoção de práticas de manejo. Nas grandes fazendas do Mato Grosso, pelo fato de não se ter uma informação precisa sobre as áreas infestadas dentro dos talhões, os produtores preferem não adotar nenhuma medida de manejo, já que, em função do custo e do ponto de vista operacional, seria inviável fazê-lo em toda a área. Com os mapas de variabilidade do potencial de produtividade dos talhões ou partes deles, cujo potencial de produtividade está abaixo da expectativa, em função do nível da tecnologia de produção adotado, o produtor pode, na safra atual, certificar-se se os nematóides, problemas de fertilidade, combinações desses ou outras causas estão sendo os fatores limitantes à realização do potencial de produtividade do talhão. O presente estudo foi conduzido numa parceria entre o Laboratório de Nematologia da UNESP/FCAV, Câmpus de Jaboticabal-SP e a Empresa Globalsat Monitoramento Agrícola com sede em Rondonópolis-MT, com objetivo de avaliar a eficácia dos mapas de variabilidade do potencial de produtividade obtido com imagens de satélite como instrumento auxiliar às decisões sobre o manejo de nematóides na cultura da soja. O mapa de variabilidade do potencial de produtividade da Fazenda Aimi, no Município de Rondonópolis, foi utilizado no estudo. As médias do potencial de produtividade nas áreas correspondentes às diferentes classes de potencial foram negativamente correlacionadas com as populações de Pratylenchus. brachyurus obtidas nas amostras de solo e raízes coletadas nessas áreas, confirmando que os mapas em questão são instrumentos auxiliares valiosos para a tomada de decisão sobre o manejo de nematóides.
The knowledge of the spatial distribution of nematodes in crops is essential to adoption of management practices. In big farms of Mato Grosso, because of not have accurate information on infested areas within the plots, producers prefer not adopt any measure of management because, depending on the cost and operational point of view, it would be impracticable make it across the area. With maps of variability of the potential of productivity of the plots or parts of them, whose potential productivity is below the expectations, depending on the level of technology used in production, the producer may, in the current crop, make sure that the nematodes, problems of fertility, or combinations of both or other causes are the limiting factors to the achievement of the potential productivity of the plot. This study was carried out in a partnership between the Laboratorio de Nematologia of UNESP/FCAV, Câmpus de Jaboticabal-SP, and Globalsat Monitoramento Agrícola Company based in Rondonópolis-MT, to evaluate the effectiveness of maps of the potential variability in productivity achieved with satellite imagery as a tool to assist decisions on the management of nematodes on soybean. The map of variability of the potential of productivity from of Fazenda Aimi in the county of Rondonópolis was used in the study. The averages of the potential for productivity in the areas corresponding to different classes of potential were negatively correlated with the population of P. brachyurus obtained in samples of soil and roots collected in those areas, confirming that the maps in question are valuable auxiliary instruments for decision on the management of nematodes.

Style APA, Harvard, Vancouver, ISO itp.

37

De, Berardinis Pierluigi. "Analisi di morfologie carsiche o crio-carsiche in relazione alla mobilizzazione di fluidi nella regione di Arabia Terra, Marte". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10129/.

Pełny tekst źródła

Streszczenie:

This thesis tries to interpret the origin and evolution of karst-like forms present in Arabia Terra, a region of Mars that develops in the equatorial zone of the planet. The work has been carried out specifically in the craters Crommelin (4o 91’ N-10o 51’ E), 12000088 (3o 48’ N-1o 30’ E), NE 12000088 (4° 20’ N-2° 50’ E), C "2" (3° 54’ N-1° W), and in their surrounding areas. These craters contain layered deposits characterized by a high albedo and on which erosion is very pronounced. The area containing the craters is a plateau that has the same characteristics of albedo and texture. The preliminary morphological study has made use of instrumentation such as the Mars Reconnaissance Orbiter (MRO), in particular HiRISE images (High Resolution Imaging Science Experiment), CTX (Context Camera) and CRISM (Compact Reconnaissance Imaging Spectrometers for Mars). A regional geomorphological map has been drawn up containing the main morphotypes, and detailed geomorphological maps were prepared for different karst-like morphologies. The analysis of spectral data collected from CRISM instrumentation has allowed to identify the footprint of sulphate minerals in the external area. Data were collected for morphometric negative forms (karst-like) and positive forms (mud volcanoes, dikes and pingos). For the analysis of the relief forms DTMs (Digital Terrain Models) produced by the union of stereographic CTX couples or HiRISE were used. From the analysis of high-resolution images morphological footprints similar to periglacial environments have been identified, including the presence of patterned ground and polygonal cracks found all over the area of investigation, and relief structures similar to pingos present in the crater C "2". These observations allow us to imagine a geological past with a cold climate at the equator able to freeze the few fluids present in the Martian arid terrain. The development of karst-like landforms, on the other hand, can be attributed to a subsequent improval of the weather conditions that led to a normal climate regime for the equatorial areas, resulting in the degradation of the permafrost. The melt waters have thus allowed the partial dissolution of the sulphate layers. The karst-like forms look rather fresh suggesting them to be not that old.

Style APA, Harvard, Vancouver, ISO itp.

38

Marchiorato, Ivo Aurélio. "Mapas de variabilidade do potencial de produtividade obtidos por satélites como instrumentos auxiliares às decisões sobre o manejo de nematóides na cultura da soja /". Jaboticabal : [s.n.], 2008. http://hdl.handle.net/11449/105237.

Pełny tekst źródła

Streszczenie:

Orientador: Jaime Maia dos Santos
Banca: Arlindo Leal Boiças Júnior
Banca: Clélia Aparecida Iunes Lapera
Banca: Maria Amélia dos Santos
Banca: Júlio Cesar Galli
Resumo: O conhecimento da distribuição espacial dos nematóides nas lavouras é imprescindível para adoção de práticas de manejo. Nas grandes fazendas do Mato Grosso, pelo fato de não se ter uma informação precisa sobre as áreas infestadas dentro dos talhões, os produtores preferem não adotar nenhuma medida de manejo, já que, em função do custo e do ponto de vista operacional, seria inviável fazê-lo em toda a área. Com os mapas de variabilidade do potencial de produtividade dos talhões ou partes deles, cujo potencial de produtividade está abaixo da expectativa, em função do nível da tecnologia de produção adotado, o produtor pode, na safra atual, certificar-se se os nematóides, problemas de fertilidade, combinações desses ou outras causas estão sendo os fatores limitantes à realização do potencial de produtividade do talhão. O presente estudo foi conduzido numa parceria entre o Laboratório de Nematologia da UNESP/FCAV, Câmpus de Jaboticabal-SP e a Empresa Globalsat Monitoramento Agrícola com sede em Rondonópolis-MT, com objetivo de avaliar a eficácia dos mapas de variabilidade do potencial de produtividade obtido com imagens de satélite como instrumento auxiliar às decisões sobre o manejo de nematóides na cultura da soja. O mapa de variabilidade do potencial de produtividade da Fazenda Aimi, no Município de Rondonópolis, foi utilizado no estudo. As médias do potencial de produtividade nas áreas correspondentes às diferentes classes de potencial foram negativamente correlacionadas com as populações de Pratylenchus. brachyurus obtidas nas amostras de solo e raízes coletadas nessas áreas, confirmando que os mapas em questão são instrumentos auxiliares valiosos para a tomada de decisão sobre o manejo de nematóides.
Abstract: The knowledge of the spatial distribution of nematodes in crops is essential to adoption of management practices. In big farms of Mato Grosso, because of not have accurate information on infested areas within the plots, producers prefer not adopt any measure of management because, depending on the cost and operational point of view, it would be impracticable make it across the area. With maps of variability of the potential of productivity of the plots or parts of them, whose potential productivity is below the expectations, depending on the level of technology used in production, the producer may, in the current crop, make sure that the nematodes, problems of fertility, or combinations of both or other causes are the limiting factors to the achievement of the potential productivity of the plot. This study was carried out in a partnership between the Laboratorio de Nematologia of UNESP/FCAV, Câmpus de Jaboticabal-SP, and Globalsat Monitoramento Agrícola Company based in Rondonópolis-MT, to evaluate the effectiveness of maps of the potential variability in productivity achieved with satellite imagery as a tool to assist decisions on the management of nematodes on soybean. The map of variability of the potential of productivity from of Fazenda Aimi in the county of Rondonópolis was used in the study. The averages of the potential for productivity in the areas corresponding to different classes of potential were negatively correlated with the population of P. brachyurus obtained in samples of soil and roots collected in those areas, confirming that the maps in question are valuable auxiliary instruments for decision on the management of nematodes.
Doutor

Style APA, Harvard, Vancouver, ISO itp.

39

Flahaut, Jessica. "Minéralogie de Valles Marineris (Mars) par imagerie hyperspectrale : histoire magmatique et sédimentaire de la région". Thesis, Lyon, École normale supérieure, 2011. http://www.theses.fr/2011ENSL0642/document.

Pełny tekst źródła

Streszczenie:

Les processus internes et externes qui ont formé et structuré la croûte de la planète Mars au début de son histoire sont actuellement mal connus. Le canyon de Valles Marineris représente la plus grande coupe naturelle à la surface de Mars, où affleure la croûte moyenne et supérieure. L'étude de cette région clé a été abordée minéralogiquement et morphologiquement à partir de données hyperspectrales CRISM, et des images à haute résolution HiRISE de la mission MRO (NASA, 2006). La base du canyon est constituée de roches massives, fracturées, à fort albédo, riches en pyroxènes pauvres en calcium, pénétrées par des dikes verticaux riches en olivine. Ces roches sont interprétées comme des affleurements de croûte primitive, préservée et exposée dans son contexte originel. Les plateaux bordant le canyon sont couverts d’une formation de 100m d’épaisseur d’argiles ferromagnésiennes, recouvertes d’argiles alumineuses. Cette formation géologique visible sur plus de 106km2 traduit un niveau d’altération de la croûte sous un climat humide. Enfin, les dépôts stratifiés centraux de la région de Capri Chasma, d'épaisseur plurikilométrique, sont riches en sulfates monohydratés et polyhydratés, corrélés à des groupes de strates distincts. Ces sédiments se sont déposés durant l’Hespérien et ont ensuite été érodés par des processus fluviatiles. Ces résultats permettent de reconstituer la succession d’événements suivants : I) formation de la croûte primitive témoin d’un océan magmatique primitif, II) recouvrement de cette croûte primitive par un empilement volcanique, III) Altération de surface à grand échelle, IV) Ouverture du canyon de Valles Marineris, V) dépôts et érosion de niveaux stratifiés riches en sulfates
Valles Marineris is a unique vertical section through the uppermost kilometers of the martian crust; its location, east of Tharsis bulge, and its water-related history suggest a great diversity of rock types in this area. High resolution morphologic (HiRISE) and mineralogic (CRISM) data from the MRO mission (NASA, 2006) available over the area were investigated. A typical succession of horizontal units of distinct morphologies and mineralogies was observed in the Eastern part of Valles Marineris, including basaltic lavas, phyllosilicate-rich boulders and a LCP (Low-Calcium Pyroxene)-rich basement. This basement, interpreted as being a uniquely preserved outcrop of pristine Noachian crust, is intruded by olivine-rich dikes, which are valuable witnesses of early magmatic and tectonic processes. A thin light-toned formation, enriched in Fe/Mg smectites at its base, and Al-phyllosilicates at its top, is draping the Noachian plateaus around the canyons. This widespread unit could have formed by alteration under a wet climate, and is akin to pedogenesis. Finally, kilometer-thick layered deposits that are filling most of the canyons were analyzed in the area of Capri Chasma, at the outlet of Valles Marineris. These Hesperian-aged deposits are enriched in monyhydrated and polyhydrated sulfates and appear to have been eroded by younger fluvial processes. Both spectral types are associated with different units of distinct morphologies, at different elevations. All these observations were combined to propose the following succession of events: I- Formation of the pristine crust by crystallization in a magma ocean, II- Piling of lava flows on the top of this crust and dike activity, III- Widespread surficial alteration, IV- Opening of Valles Marineris, V- deposition and erosion of the sulfate-rich layered deposits

Style APA, Harvard, Vancouver, ISO itp.

40

Fernando, Jennifer. "Caractérisation des propriétés physiques de la surface de Mars à partir de mesures spectro-photométriques orbitales". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112293/document.

Pełny tekst źródła

Streszczenie:

Depuis leur formation, les surfaces des corps de notre Système Solaire montrent une diversité étonnante. Cette diversité est le reflet des processus géologiques qui ont modelé les surfaces planétaires au cours du temps. Parmi les objets du Système Solaire, Mars constitue un objet particulièrement intéressant car il présente de nombreuses similitudes avec notre planète. La minéralogie de la surface de Mars est bien documentée. Cependant, on dispose de peu d'information sur les paramètres physiques des matériaux qui sont également des traceurs des processus géologiques. Un des objectifs de cette thèse est de développer et de valider un outil permettant leur détermination à partir de techniques d'investigation spatiale depuis l'orbite et d’interpréter les résultats. Pour cela, une approche basée sur la photométrie, qui étudie les propriétés de diffusion des matériaux de surface, a été développée et validée. Ces propriétés de diffusion dépendent de la composition mais aussi des propriétés physiques des matériaux comme la taille, la forme, la structure interne, la rugosité des grains et la rugosité de la surface. Les données hyperspectrales multi-angulaires CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) à bord de la sonde Mars Reconnaissance Orbiter (11 images prises à des angles d'émergence variés) ont été utilisées, permettant de contraindre le comportement de diffusion des matériaux de surface. Tout d'abord, les données sont corrigées de la contribution atmosphérique à l'aide de l'algorithme nommée MARS-ReCO (Multi-angle Approach for Retrieval of Surface Reflectance for CRISM Observations), développé en collaboration avec Xavier Ceamanos et Sylvain Douté (IPAG) au cours de la thèse. Puis, les données de réflectance de surface à différentes géométries sont analysées en inversant à l’aide d’une approche bayésienne le modèle photométrique de Hapke qui décrit le transfert radiatif en milieu granulaire. Ce modèle dépend de six paramètres photométriques de surface (e.g., albédo de diffusion, fonction de phase, rugosité macroscopique de la surface), reliés aux propriétés physiques des matériaux comme la taille, la structure interne, la forme, la rugosité des grains, et la rugosité de la surface.Une première application a été menée au niveau des sites d'atterrissage des rovers de la mission Mars Exploration Rover, où des données orbitales et in situ sont disponibles. Ces dernières sont utilisées comme «vérité terrain» pour valider les interprétations des paramètres photométriques estimés. Dans ce travail, des cartes des paramètres photométriques ont été fournies le long et autour du trajet des rovers permettant d'avoir accès aux informations des propriétés des matériaux sur une étendue plus importante que les données in situ. Une interprétation de chacun des paramètres et un lien aux propriétés physiques et aux processus géologiques ont été fournis. Les résultats montrent des propriétés de diffusion variés au sein d'une observation CRISM (10x10km) suggérant que les surfaces sont contrôlées par des processus géologiques plus locaux (e.g., processus éoliens, fragmentation de la croûte par impact).Une dernière partie se focalise sur la détermination des propriétés de diffusion des matériaux de surface de différents terrains géologiques formés dans des contextes différents. Le but est d'identifier les variabilités des propriétés de diffusion à travers Mars
The PhD work focuses on the characterization of geological processes on planetary surfaces. Due to the lack of broad scale in situ information about the surface physical properties of the Martian materials (recording the geological processes), my work centers on the development and validation of an approach for their estimation from orbital spaceborne datasets. In addition, determining the physical properties has an implication for the spectroscopic interpretation notably for the mineral abundances. More specifically, I developed an approach for the determination and the analysis of the Martian surface scattering properties using CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) observations [Murchie et al., 2007] on-board MRO (Mars Reconnaissance Orbiter). CRISM provides multi-angular (varied emission angles) hyperspectral images which allow the characterization of the surface scattering behavior at ∼200m/pixel. The scattering behavior depends on the material composition but also the physical properties such as the grain size, shape, internal structure, and the surface roughness / porosity. The main objective is to observe the spatial variations of the surface scattering properties and the photometric parameters as a function of geological units.The methodology I employ is based on the estimation of the surface photometric parameters in term of surface physical properties. After an atmospheric correction (aerosols) by the Multi-angle Approach for Retrieval of the Surface Reflectance from CRISM Observations (MARS-ReCO) [Ceamanos et al., 2013] developed in collaboration with X. Ceamanos and S. Douté (IPAG, France), I analyze the surface reflectance taken at varied geometries by inverting the Hapke photometric model [Hapke, 1993] depending on six parameters (single scattering albedo, 2-term phase function, macroscopic roughness and 2-term opposition effects parameters) in a Bayesian framework [Fernando et al., 2013]. The algorithm for the correction for the aerosols and the methodology for the estimates of surface photometric parameters have been validated by comparing the results from orbit to the in situ photometric measurements from Mars Exploration Rover (MER) rovers [Fernando et al. 2013].The MER landing sites located at Gusev Crater and Meridiani Planum provide an excellent opportunity to ground truth and validate the interpretation of derived Hapke photometric parameters as both orbital and in situ data are readily available over numerous geological terrains. Orbital results are consistent with the in situ observations. In my work, I mapped the surface scattering properties in and around the rover path, providing extended information over a wider area. Significant variations in the scattering properties are observed inside a CRISM observation (10x10km) suggesting that the surfaces are controlled by local geological and climatic processes [Fernando et al., in revision].The last part of this work focuses on the determination of the surface photometric parameters of different Martian geological terrains under different contexts in order to identify variabilities of the scattering properties

Style APA, Harvard, Vancouver, ISO itp.

41

Nixdorf, Erik. "Combining measurements, remote sensing and numerical modelling to assess multi-scale flow dynamics in groundwater-dependent environmental systems". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-236485.

Pełny tekst źródła

Streszczenie:

Groundwater flow modelling provides an important quantitative instrument for addressing issues related to the quantity and quality of groundwater and the connected water resources. Consequently, groundwater flow models have been developed and used ubiquitously in science to deepen the understanding of subsurface processes and their drivers as well as management and planning tools. The present work investigates how numerical models can be linked to field investigations and public databases to quantitatively approach questions in the area of groundwater research. The primary goal is to develop new, efficient ways to overcome limitations of the individual hydrological concepts for solving specific hydrological problems and to increase the understanding of practical applicability of different methods. For this purpose, tailor-made approaches were developed for different study areas covering diverse spatial scales: the hydrology of a small mining lake, the riparian aquifer at the scale of a single meander as well as the aquifer systems of a large-scale river basin in China. The first part of the work deals with the physical and mathematical modelling of water constituents balance in a meromictic mining lake in Lusatia. The capability of using a rather simple mass-balance model based on a sufficient dataset of field data to evaluate lake stratification and lake-groundwater interaction were shown. In the second part, a transient numerical groundwater flow model was developed for the riparian aquifer of a stream meander and was calibrated by three different salt tracer tests. The model was used to proof the reliability of subsurface travel times derived from time series analysis and to give insights in the riparian zone dynamics during changing hydraulic gradients. The third part of the work describes the methodology to conduct risk assessment of groundwater contamination on the large catchment scale of the Songhua River in China. A comprehensive literature study was conducted to get an overview about measurement data on water quality data in China. A three-dimensional numerical flow and mass transport model was applied to access the flow and matter transport dynamics in the aquifer system of a sub-basin considering changing groundwater exploitation scenarios. Consequently, numerical groundwater modelling was combined with processed remote sensing and web mapping service data to overcome field data limitations and to derive groundwater vulnerability, groundwater hazard and groundwater risk maps for the entire Songhua River Basin. Summarizing, this doctoral thesis could develop new methods of combining field measurements, data assimilation and aggregation from various sources and groundwater modelling strategies and successfully apply these methods to find solutions on problems of multiple scales and across water systems
Die Grundwassermodellierung stellt eine wichtige wissenschaftliche Methode zur quantitativen Analyse von Fragestellungen zum Schutz der Menge und Güte der Grundwasserressourcen sowie der angeschlossenen Wasserkörper dar. Dementsprechend werden Grundwassermodelle sowohl für Planungs- und Bewertungszwecke im Wasserressourcenmanagement als auch zur wissenschaftlichen Erforschung der Prozesse im Untergrund entwickelt und angewendet. Die vorliegende Arbeit untersucht in diesem Rahmen, wie numerische Modelle, Feldmessungen und Daten generiert aus Fernerkundungsdaten und Webplattformen systematisch verknüpft werden können, um Fragestellungen im Bereich der Grundwasserforschung quantitativ zu beantworten. Das Ziel der Arbeit ist es neue effiziente Abläufe zu entwickeln, die die Limitierung der einzelnen Methoden überwinden und diese auf deren Anwendbarkeit für die Lösung spezifischer hydrologischer Probleme zu analysieren. Zu diesem Zweck wurden in dieser Doktorarbeit fallspezifische Lösungen für verschiedene Untersuchungsgebiete entwickelt, die sowohl in der räumlichen Skale als auch in den zu untersuchenden hydrologischen Fragestellungen eine große Diversität aufweisen. Im ersten Teil der Arbeit wurde die Massenbilanz von Wasserinhaltsstoffen in einem meromiktischen Tagebaurestsee im Lausitzer Revier durch physikalische und mathematische Modellierungsmethoden untersucht. Dabei konnte gezeigt werden, dass auf Basis einer gewonnenen mehrjährigen Zeitreihe von Messdaten ein einfaches Massenbilanzmodell in der Lage ist, sowohl Seeschichtungs- als auch Grundwasseraustauschdynamiken quantitativ zu beschreiben. Der zweite Teil der Arbeit umfasst die Entwicklung eines transienten numerischen Grundwassermodells für den quartären Uferaquifer im Bereich eines Flussmäanders der Selke welches anhand von Daten aus mehreren Salztracertests kalibriert wurde. Das Modell wurde dafür verwendet die transienten Verweilzeiten in der gesättigten Zone des Mäanderbogens unter dem Einfluss dynamischer hydraulischer Bedingungen zu untersuchen. Die Ergebnisse wurden im Anschluss mit Verweilzeiten verglichen, die aus der Analyse der zeitlichen Verschiebung von gemessenen elektrischen Leitfähigkeitszeitreihen zwischen Fluss und Grundwassermessstellen gewonnen wurden. Durch dieses kombinierte Verfahren konnten sowohl die Beschränkungen der zeitreihenbasierten Verweilzeitberechnung aufgezeigt als auch ein tieferes Systemverständnis für die Interaktionsdynamiken zwischen Grund- und Flusswasser auf der Mäanderskala gewonnen werden. Der dritte Teil der Arbeit beschreibt die Vorgehensweise für die Bewertung des Grundwasserkontaminationsrisikos im Einzugsgebiet des Songhua Flusses in China. Eine umfassende Literaturstudie wurde durchgeführt, um einen Überblick über die Verfügbarkeit von Messdaten zur Belastung der Wasserressourcen Chinas mit organischen Schadstoffen zu erhalten. Danach wurde für ein Teileinzugsgebiet ein dreidimensionales numerisches Grundwassermodell auf Basis der vorhandenen hydrogeologischen Daten aufgebaut. Dieses wurde dazu verwendet die Änderungen im Stofftransports und den Schadstoffkonzentrationen innerhalb des Aquifersystems unter steigenden Entnahmeraten zu analysieren. Basierend auf diesen Studien wurden auf der Skale des Gesamteinzugsgebiets, um die beschränkte Verfügbarkeit von Felddaten auszugleichen, die Ergebnisse der numerischen Grundwassermodellierung mit Fernerkundungsdaten und Webdatenbanken in einem Indexsystem kombiniert mit dem für die oberflächennahen Aquifere Vulnerabilität, Gefährdungspotential und Verschmutzungsrisiko in einer räumlichen Auflösung von 1 km² bestimmt wurden. Zusammenfassend konnten durch die vorliegende Doktorarbeit neue passgenaue Methoden zur effektiven Kombination von in-situ Messungen, der Datenerhebung und Datenintegration aus vielfältigen Datenquellen sowie numerischen Grundwassermodellierungsstrategien entwickelt und zur Lösung der untersuchten hydrologischer Fragestellen auf den verschiedenen Skalen und über die Grenzen der einzelnen hydrologischen Teilsysteme hinaus erfolgreich angewandt werden

Style APA, Harvard, Vancouver, ISO itp.

42

Audouard, Joachim. "Propriétés thermo-physiques et hydratation de la surface de Mars". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112304/document.

Pełny tekst źródła

Streszczenie:

Ce travail de thèse est consacré à la caractérisation physique de la surface de Mars et à l'étude des facteurs dynamiques la modifiant. Deux aspects sont étudiés. Le premier concerne les propriétés thermo-physiques qui sont un moyen de contraindre les actions que les forces érosives et sédimentaires cumulées sur les temps géologiques ont joué à la surface de Mars. Le second est l'hydratation de la surface de Mars qui est une donnée importante du système climatique martien en tant que réservoir d'eau.Afin de caractériser ces deux propriétés physiques de la surface de Mars, nous avons combiné l'approche orbitale permettant une couverture globale, l'approche in situ qui fournit une interprétation locale robuste et l'utilisation d'outils de simulation des processus physiques. Les données des instruments OMEGA, un spectro-imageur à bord de Mars Express en orbite autour de Mars depuis 2004, et le capteur de température de surface de l'instrument REMS, embarqué à bord de Curiosity et en opération dans le cratère Gale depuis 2012 ont été analysées en détail. Les mesures de température de surface de ces deux instruments ont été inversées pour caractériser les propriétés thermo-physiques de la surface au moyen d'un modèle climatique. Nous présentons la première carte globale de l'inertie thermique de la surface de Mars calculées à partir des données OMEGA et nous mettons en évidence de manière inédite des comportements thermiques spécifiques d'assemblages hétérogènes à la surface de Mars ou de processus physiques négligés.Les informations relatives à l'hydratation de la surface ont pu être extraites des données OMEGA grâce à la prise en compte de mesures en laboratoire et ont été interprétées de concert avec les résultats de plusieurs missions autour ou à la surface de Mars et des simulations climatiques du cycle de l'eau afin de reconstruire l'histoire de cette hydratation. Nous trouvons que l'hydratation est stable tout au long de l'année martienne et qu'elle augmente avec la latitude de manière asymétrique entre les deux hémisphères. La distribution spatiale de l'hydratation coincide avec les zones en contact régulier avec des dépôts de givre, qui apparaît ainsi être à l'origine du processus responsable de l'implémentation de l'eau dans le régolite martien
This thesis work is devoted to the physical characterization of the Martian surface and to the study of dynamic processes modifying it. Two aspects are addressed. The first concerns the thermo-physical properties which are a mean to putting constraints on to the erosive and sedimentary actions summed over the geologic history. The second is the hydration of the Martian surface which plays, as a planetary reservoir of water, an important role on the Martian climate.In order to characterize these two physical parameters of the Martian surface, we have combined the orbital view which allows a global coverage with in situ measurements, which provides a robust local interpretation, and we have used tools allowing numerical simulations of physical processes. Data from OMEGA, an imaging spectrometer onboard Mars Express orbiting Mars since 2004, and from the ground temperature sensor of the REMS instrument onboard Curiosity have been analyzed in details. Surface temperature measurements from these two instruments have been inverted using a climate model for characterizing the thermo-physical properties of the Martian surface. We present the first global map of the Martian surface thermal inertia constructed from OMEGA data and we directly highlight for the first time some thermal behavior caused by heterogeneous mixtures or neglected physical processes at the surface of Mars.Information regarding the hydration of the Martian surface have been extracted from OMEGA data using a large set of laboratory experiments. This information has been interpreted together with scientific results from multiple mission orbiting or at the surface of Mars and with numerical simulations of the Martian water cycle in order to reconstruct the history of this hydration. We find that the hydration remains stable throughout the whole Martian year and that it increases with latitude with an asymetry between the two hemispheres. The spatial distribution of the hydration fits areas that are in regular contact with water frost, which therefore seems to be involved in the process of water implementation in the Martian regolith

Style APA, Harvard, Vancouver, ISO itp.

43

Séjourné, Antoine. "Formation et évolution des structures périglaciaires en contexte de réchauffement climatique : comparaison Terre-Mars". Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00713531.

Pełny tekst źródła

Streszczenie:

Sur Terre, les régions périglaciaires ayant un pergélisol riche en glace peuvent enregistrer les changements climatiques globaux. Ce pergélisol contenant 50-80 % de glace en volume s'est formé lors des grandes périodes glaciaires du Pléistocène. Par la suite, ce pergélisol riche en glace a subi une dégradation intense lors de réchauffements climatiques globaux au début de la période interglaciaire de l'Holocène.La planète Mars comporte un pergélisol à l'échelle planétaire dont la formation serait associée à des changements climatiques globaux provoqués par des variations chaotiques de son orbite durant les derniers millions d'années. La région d'Utopia Planitia située dans les moyennes latitudes nord de Mars présente différents modelés de surface (" scalloped depressions ", polygones, cavités à la jonction des polygones) interprétés comme s'étant formés à partir d'un pergélisol contenant potentiellement une grande quantité de glace. De la même manière que sur Terre, ce pergélisol a pu enregistrer les derniers changements climatiques globaux survenus sur Mars.Cette thèse propose d'étudier comparativement l'impact des changements climatiques sur le paysage des régions périglaciaires sur Terre et sur Mars. Dans ce but, nous avons conduit des études sur le terrain des processus et des modelés périglaciaires en Yakoutie Centrale (Sibérie) et dans le delta du Mackenzie (Canada) associées à une étude géomorphologique à haute résolution des modelés d'Utopia Planitia.Notre étude montre que l'ensemble des modelés d'Utopia Planitia est similaire en morphologie, taille et association spatiale à celui de la Yakoutie Centrale et du delta du Mackenzie (lacs thermokarstiques, polygones, mares à la jonction des polygones) indiquant que la région présenterait un pergélisol riche en glace. Le pergélisol serait composé de sédiments stratifiés et dont l'âge de formation minimale est estimé entre ~ 5 et 100 Ma. Le pergélisol contiendrait un volume de glace important (≥ 50 % en volume) sur une épaisseur de ~ 70 m.De part ses caractéristiques, ce pergélisol aurait une origine syngénétique : sa formation serait le résultat d'une accumulation importante de sédiments au sein du bassin d'Utopia Planitia sous des conditions froides permettant le gel in-situ des sédiments. Les sédiments peuvent avoir été déposés par des vallées de débâcles provenant d'Elysium Mons et/ou par une activité éolienne importante. Par ailleurs, la formation synchrone d'une calotte de glace régionale près d'Utopia Planitia lors de périodes de moyenne obliquité (~ 35°) de Mars pourrait avoir induit un dépôt éolien préférentiel dans Utopia Planitia.Par la suite, le pergélisol riche en glace aurait subi une dégradation régionale importante entre ~ 5 et 10 Ma. Ce thermokarst aurait été déclenché par une insolation accrue lors de périodes de haute obliquité (~ 45°) de Mars. L'augmentation des températures aurait provoqué une déstabilisation thermique du pergélisol entraînant une sublimation de la glace, modifiant profondément le paysage de la région.Ainsi, les variations importantes de l'obliquité de Mars ont généré des changements climatiques globaux qui ont permis la formation et la dégradation du pergélisol riche en glace d'Utopia Planitia entre ~ 5 et 10 Ma.

Style APA, Harvard, Vancouver, ISO itp.

44

Abou, Karaki Najib. "Synthese et carte sismotectonique des pays de la bordure orientale de la mediterranee : sismicite du systeme de failles du jourdain-mer morte". Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13067.

Pełny tekst źródła

Streszczenie:

Realisation d'une carte sismotectonique (echelle 1:1 000 000) fondee sur la sismicite historique et instrumentale, la tectonique active, le volcanisme et les aspects geophysiques. Cette carte, concue sur support numerique, est evolutive et modifiable en temps reel. Les premiers mecanismes focaux de la zone du golfe d'aquaba et des failles du carmel sont proposes, accompagnes des relocalisations des trois crises recentes dans cette zone. Une distribution epicentrale en anneau de sismicite est mise en evidence dans la partie centrale de la vallee du jourdain. Les taux de recurrence pour les segments de la faille du jourdain sont calcules. On met l'accent sur les erreurs chronologiques, de localisation et d'interpretation de la sismicite

Style APA, Harvard, Vancouver, ISO itp.

45

Andrieu, François. "Caractérisation des surfaces glacées de Mars par imagerie hyperspectrale : inversion du transfert radiatif". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS178/document.

Pełny tekst źródła

Streszczenie:

La planète Mars est le siège d'un climat complexe, caractérisé par des cycles du dioxyde de carbone et de l'eau, ainsi qu'un transport de poussière à toutes les échelles. Ces cycles se manifestent par la condensation saisonnière aux pôles de dépôts de glace de CO₂ et d'eau pendant la nuit polaire, et leur sublimation pendant le printemps local. Les cycles du CO₂ , de l'eau et des poussières sur Mars sont intimement liés. Un processus saisonnier actif illustre bien ces liens : les jets de gaz froid, déclenchés par la sublimation saisonnière des dépôts de CO₂ , pouvant mettre en suspension des poussières du régolite de manière durable dans l'atmosphère, et dont l'activité semble être modulée par les échanges d'eau à la surface.L'objectif de cette thèse est de permettre l'utilisation des données d'imagerie hyperspectrale disponibles au maximum de leur potentiel, pour apporter de nouvelles contraintes sur les échanges saisonniers entre surface et atmosphère et sur les interactions entre les différents cycles (CO₂ , eau, poussières), en se focalisant sur les jets de gaz froid. Pour cela, un modèle semi-analytique de transfert radiatif dans les glaces compactes, ainsi qu'une méthode efficace d'inversion ont été développés et validés.Le modèle de transfert radiatif permet de décrire l'interaction de la lumière avec une couche de glace de manière quantitative d'après les paramètres suivants : épaisseur de la couche, proportions volumiques et tailles des impuretés, rugosité de la surface. Il repose sur plusieurs hypothèses majeures : optique géométrique, milieux continus par morceaux, inclusions quasi-sphériques. L'approximation des deux flux est utilisée pour le transfert au sein de la couche mais la réflexion spéculaire en surface est estimée en tenant compte de la variabilité des facettes de la rugosité surfacique. Ce modèle a été validé numériquement et sur des données de laboratoire et des tests numériques. La méthode d'inversion consiste à créer des bases de données synthétiques d’après le modèle de transfert radiatif pour déterminer les jeux de paramètres les plus probables pour reproduire une mesure donnée. L'inversion repose sur le formalisme bayésien : les grandeurs manipulées sont décrites par des densités de probabilités. Ceci permet la prise en compte de manière réaliste des incertitudes sur la donnée et le calcul d'une incertitude a posteriori sur le résultat de l'inversion.Une étude ciblée d'un site d'intérêt a été menée pour tester et démonter l'applicabilité de cette démarche à l'inversion massive de données de spectro-imagerie.Nous avons déterminé l’état de surface du champ de dunes du cratère de Richardson (72°S, 180°W), choisi car il présente de fortes interactions entre cycle de l'eau et du CO₂ , une important activité saisonnière de jets froids mais aussi une grande quantité de données disponible et une haute qualité du suivi temporel. Le suivi des caractéristiques de surface sur ce site montre une diminution de l'épaisseur de la couche de glace pendant le printemps cohérente avec les estimations des modèles de climat. Nous avons pu estimer et faire le suivi du contenu en eau et en poussière pour discuter le scénario de formation des jets froids. Nous avons proposé un nouveau mécanisme de mise en suspension des petits grains d’eau
Mars has a complex climate, characterized by carbon dioxide and water cycles, and dust transport at all scales. These cycles are mainly controlled by the seasonal condensation of CO₂ and water ice deposits at high latitudes during the polar night and their sublimation during the local spring. There are a lot of interactions between the CO₂ , water and dust cycles on Mars and they influence each other. An active seasonal process illustrates particularly well these links: the cryoventing, cold CO₂ gas jets triggered by seasonal sublimation of CO₂ deposits, which can put dust from the regolith in suspension into the atmosphere durably, and whose activity seems to be modulated by the exchange of water at the surface.The purpose of this thesis is to allow the use of the available hyperspectral imaging data to their full potential, to bring new constraints on seasonal exchanges between surface and atmosphere and the interactions between the different cycles (CO₂ , water , dust), focusing on cold gas jets. To achieve this, a semi-analytical radiative transfer model in compact ices and an effective inversion method were developed and validated.The radiative transfer model describes the interaction of light with a surface quantitatively, using the following parameters: thickness of the layer, volume proportions and grain-sizes of impurities, surface roughness. It is based on several key assumptions: geometrical optics, piecewise-continuous media quasi-spherical inclusions. The two-stream approximation is used for the radiative transfer inside the layer, but the surface specular reflectance is estimated taking into account the variability of the facets orientations from the surface roughness. This model was validated both numerically and on laboratory data.The inversion method consists in exploring synthetic databases generated by the radiative transfer model and determining the most likely sets of parameters to reproduce a given measure. The inversion is based on the Bayesian formalism: the manipulated variables are described by probability density functions. This allows to take into account realistic uncertainties on the data and enables to calculate a posteriori uncertainties on the result of the inversion.A focused study was conducted on a area of particular interest, to test and prove the applicability of this approach to the massive inversion of spectro-imaging data. The dune-field of Richardson Crater (72°S, 180°W) was chosen because it shows strong interactions between the water and CO₂ cycles, a major seasonal cryoventing activity, but also a large amount of data available and a high quality temporal monitoring. The monitoring of surface characteristics on this site shows a decrease in the thickness of the ice during the spring consistently with climate models simulations. We were able to estimate and monitor the content of water and dust in order to discuss the formation scenario of cold jets

Style APA, Harvard, Vancouver, ISO itp.

46

Wendling, Ademir. "SENSORIAMENTO REMOTO PARA IDENTIFICAÇÃO DAS CAUSAS DA VARIABILIDADE NO ÍNDICE DE MASSA DA SOJA". Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/3621.

Pełny tekst źródła

Streszczenie:

Remote sensing is the use of sensors to capture electromagnetic energy reflected by objects. The quantification and qualification of the reflected energy can help the diagnosis of plant development and the presence of anomalies. The presence of nematodes has been observed in several areas of Rio Grande do Sul state. The most frequent species are the Meloidogyne sp. (root-knot nematode) and Heterodera glycines (cyst nematode). All species can reduce productivity. In order to establish control programs, is essential to know the spatial distribution of nematodes species. The present study aims to evaluate the remote sensing tools to help in the detection of variability in soybeans and diagnosis of possible causes. Spectroradiometer, active sensor and satellite image were used to diagnose areas with different mass indexes. It was analyzed the presence of nematodes, soil fertility, soil compaction, land declivity and number of plants, in order to understand the causes of indices variation. The active sensor showed good performance in the detection of mass indexes. No correlation between index mass, soil fertility and soil compaction. When mass index grouped into classes, it was related to the presence of nematodes. The land declivity and the number of plants are correlated with mass indexes.
O sensoriamento remoto é a utilização de sensores para captação da energia eletromagnética refletida pelos objetos. Sua quantificação e qualificação tem auxiliado no diagnóstico de desenvolvimento de plantas e presença de anomalias. A presença de nematóides vem sendo diagnosticada em várias áreas do Rio Grande do Sul. As espécies mais encontradas são os nematóides de galhas (Meloidogyne sp.) e cisto (Heterodera glycines). O ataque de qualquer espécie reduz a produtividade, dependendo do número de indivíduos. Para elaboração de um plano de controle, é importante conhecer a distribuição espacial e identificação das espécies. O presente estudo teve por objetivo avaliar a potencialidade das ferramentas de sensoriamento remoto no auxílio da detecção da variabilidade da produtividade da soja e diagnóstico das possíveis causas. Espectroradiômetro, sensor ativo e imagem de satélite foram utilizadas para diagnosticar as manchas de índices de massa. Nessas áreas foram analisadas a presença de nematóides, a fertilidade do solo, os índices de compactação, a declividade do terreno e o número de plantas, a fim de compreender a variação dos índices. Dentre as ferramentas de sensoriamento remoto o sensor ativo apresentou o melhor resultado. Não foi encontrada correlação entre os índices de massa e fertilidade do solo e compactação do solo. Quando agrupado em classes de índice de massa, foi encontrada relação com a presença de nematóides. A declividade do terreno e o número de plantas se correlacionaram com os índices de massa.

Style APA, Harvard, Vancouver, ISO itp.

47

Samecima, Junior Elcio Hissagy. "Índice de vegetação por diferença normalizada e caracteres agronômicos em genótipos de milho". Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153547.

Pełny tekst źródła

Streszczenie:

Submitted by Elcio Hissagy Samecima Júnior (elciosamecimajr@hotmail.com) on 2018-04-16T17:43:05Z No. of bitstreams: 1 Dissertação_Elcio_Hissagy_Samecima_Junior.pdf: 1068541 bytes, checksum: 75dddd77d07a71a9442232dc1cc0fcde (MD5)
Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-16T18:28:37Z (GMT) No. of bitstreams: 1 samecimajunior_eh_me_jabo.pdf: 1068541 bytes, checksum: 75dddd77d07a71a9442232dc1cc0fcde (MD5)
Made available in DSpace on 2018-04-16T18:28:37Z (GMT). No. of bitstreams: 1 samecimajunior_eh_me_jabo.pdf: 1068541 bytes, checksum: 75dddd77d07a71a9442232dc1cc0fcde (MD5) Previous issue date: 2018-02-27
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
RESUMO – O melhoramento vegetal, além de buscar as características de interesse, busca também otimizar o processo. Sendo assim, quando há correlação entre as características de interesse e uma de fácil avaliação, abre-se a vertente para a seleção indireta. A utilização de sensores na agricultura possibilita a avaliação sem contato físico, podendo ser uma nova ferramenta na seleção indireta, visando otimizar tempo, mão de obra, custo e o processo. Objetivou-se estudar a relação entre o Índice de Vegetação por Diferença Normalizada (NDVI) e os caracteres agronômicos, na seleção indireta em milho e selecionar os genótipos superiores utilizando técnicas multivariadas. O experimento foi conduzido na segunda safra de 2016, sendo realizadas as medições de NDVI via sensor ativo terrestre, a cada 15 dias após a emergência das plântulas e as avaliações agronômicas de campo considerando os caracteres: altura de planta, altura da espiga principal, acamamento, quebramento, estande e produtividade. O conjunto de variáveis obtidas foram submetidas as análises multivariadas de fatores e de componentes principais. A análise de fatores detectou, no primeiro fator, correspondências positivas entre as variáveis, altura de planta, altura de espiga e produtividade, no segundo fator NDVI-80, NDVI-95 e acamamento mais quebramento e no terceiro fator NDVI-15 e estande. Os gráficos biplots gerados pelos componentes principais, juntamente com análise de ganho de seleção permitiram identificar o genótipo 3 como o mais promissor, por apresentar baixo acamamento mais quebramento, baixo valor de NDVI-80 e NDVI-95 e alta produtividade em relação a este experimento. A partir de todos os resultados concluise que é possível usar o NDVI, via sensor ativo terrestre, como técnica promissora na seleção indireta, para acamamento, quebramento e predição do estande em milho.
ABSTRACT - The plant breeding look beyond the characteristics of interest, look to optimize process, so when there is a correlation between the characteristics of interest and one of easy evaluation, a strand is opened for indirect selection. The use of sensors in agriculture makes possible to evaluate without physical contact and it can be a new tool in the indirect selection, aiming to optimize time, work, cost and optimize process. The objective of this study was to analyse the relationship between Normalized Difference Vegetation Index (NDVI) and agronomic traits, in the indirect selection and to select superior genotypes of maize by multivariate analyse. The experiment was conducted in the second crop of 2016, and NDVI was measurements by an active sensor every 15 day after seedling and field agronomic traits were evaluated considering the following characteristics: plant height, ear height, stalk lodging, stalk breakage, stand and yield. With these data were processed the factor analyzes, principal component and gain selection. The factor analysis detected positive correspondences between the variables, plant height, ear height and yield with factor 1; NDVI-80, NDVI-95 and stalk lodging plus stalk breakage with factor 2; NDVI- 15 and stand with factor 3. The graphics biplots generated by the principal components with gain selection analyze allowed to identify the best genotype, where we could identify the genotype 3 as the most promising, because it present lower lodging plus breakage stalk, low value of NDVI-80 and 95, and high yield in relation to this experiment. From all results it is concluded that it is possible to use the NDVI, by active sensor, as a promising technique in the indirect selection, for stalk lodging, breakage and stand in maize.

Style APA, Harvard, Vancouver, ISO itp.

48

Charpentier, Stanislas. "Du périurbain au périurbanisme : analyse des (bonnes et mauvaises) pratiques de lutte contre l'étalement urbain dans l'aire urbaine du Mans". Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA3014.

Pełny tekst źródła

Streszczenie:

Le périurbain est souvent décrié, notamment en raison des formes urbaines produites par un étalement urbainspatiophage et polymorphe. Depuis les lois relatives à la Solidarité et au Renouvellement Urbains (2000) et Grenelle II (2010), le législateur a fait de la lutte contre l‘étalement urbain une priorité nationale. Pour la première fois en France, des outils de planification urbaine tels que les Plans Locaux d’Urbanisme (PLU) ou les Schémas de Cohérence Territoriale (SCoT) sont « officiellement » chargés de lutter contre la consommation excessive des terres agricoles. Au delà de la lutte contre l’étalement urbain se pose la question de la mesure du phénomène. Cette thèse propose d’analyser la morphologie urbaine produite par le processus de périurbanisation à partir d’une méthodologie originale et reproductible à d’autres territoires, reposant sur la télédétection et la photointerprétation et élaborée à l’échelle de l’aire urbaine duMans. Cette recherche mobilise deux approches complémentaires : l’analyse spatiale – diachronique etmultiscalaire – est utilisée pour quantifier le phénomène d’étalement urbain ; l’analyse des entretiens menés auprès des élus permettant de confronter les discours aux pratiques d’urbanisation identifiées grâce à l’analyse spatiale. Les études menées à l’échelle communale révèlent que la délimitation morphologique du périurbain est l’une des conditions sine qua non pour envisager une reprise en main urbanistique de cet espace. Au même titre que l’évolution accélérée de laville contemporaine a donné naissance à l’urbanisme au début du XXe siècle, nous posons ici l’hypothèse que lanotion de périurbanisme pourrait qualifier la mise en ordre nécessaire du périurbain
Suburbia is often criticized, especially because urban forms produced by urban sprawl and spatiophage multiforme. Since the laws Solidarity and Urban Renewal (2000) and Grenelle II (2010), the legislature has made the fight against urban sprawl a national priority. For the first time in France, the urban planning tools such as Plan Local d’Urbanisme (PLU) orSchémas de Cohérence Territoriale (SCoT) are "officially" in charge of the fight against the excessive consumption of agricultural land. Beyond the fight against urban sprawl is the question of the extent of the phenomenon. This thesis proposes to analyze urban morphology produced by the process of suburbanization from an original and reproduciblemethodology to other territories, based on remote sensing and photo interpretation and developed across the urban area Le Mans. This research uses two complementary approaches: spatial analysis - diachronic and multiscale - is used toquantify the phenomenon of urban sprawl; analysis of interviews with elected officials to compare the speech to urbanization practices identified through spatial analysis. Studies conducted at the municipal level show that the morphological delimitation of peri is a condition sine qua non to consider a recovery in hand urban space. As well as the accelerated evolution of the contemporary city gave birth to urban planning in the early twentieth century, we pose the hypothesis that the concept of périurbanisme might call the ordering of suburban necessary

Style APA, Harvard, Vancouver, ISO itp.

49

Davaze, Lucas. "Quantification du bilan de masse des glaciers de montagne à l'échelle régionale par télédétection spatiale optique". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU022/document.

Pełny tekst źródła

Streszczenie:

Au-delà de leur rôle d’icône du changement climatique, les glaciers de montagne sont une composante essentielle de notre planète. Ils sont, de plus, de véritables « climat-mètres » naturels. Malgré leur faible superficie (0.5% des terres émergées), les glaciers de montagne contribuent à hauteur de 30% à la hausse du niveau des mers. Dans certaines régions, ils constituent de véritables enjeux quant à l’eau potable, l’agriculture, la production hydroélectrique ou les aléas glaciaires. Peu sont en revanche instrumentés (<0.0025%) et leurs fluctuations à l’échelle de régions entières sont mal connues.Grâce au développement de capteurs satellitaires à haute résolution spatiale (métrique à décamétrique), le développement de méthodes automatisées permet aujourd’hui d’augmenter considérablement le nombre de glaciers observés. Après avoir dressé un état de l’art des méthodes existantes et identifié les verrous méthodologiques, nous avons développé deux méthodes en particulier.La première se base sur la détection automatique de l’altitude de la limite glace/neige (i.e. ligne de neige) à la surface du glacier, à partir d’images satellites optiques. Cette altitude, lorsque mesurée à la fin de l’été, est un marqueur du changement de masse à la surface du glacier ayant eu lieu au cours de l’année (appelé bilan de masse de surface). Cette approche nous a permis d’estimer le bilan de masse de surface annuel de 239 glaciers dans les Alpes européennes et de 82 glaciers dans les Andes tropicales pour la période 2000-2016 et 2000-2018, respectivement. La perte moyenne annuelle observée est de -0.74 et de -1.29 m équivalent eau par an pour les deux régions respectivement. A notre connaissance, cette approche a permis d’établir le premier jeu de données de bilans de masse de surface annuels pour des glaciers individuels à échelle régionale à partir d’images satellites optiques. Une dépendance du bilan de masse de surface moyen par glacier à des caractères morpho-topographiques (e.g. pente, altitude médiane …) a été observée, où plus les glaciers sont pentus et hauts en altitude, moins leur perte de masse est importante. Une comparaison avec des mesures in situ dans les Alpes Européennes révèle une surestimation de la perte de masse par ces dernières si on les extrapole spatialement, notamment à cause de la faible représentation de glaciers à forte pente (>20°) dans les mesures in situ. Notre étude sur les Alpes Européennes a de plus permis d’identifier une variabilité interannuelle hétérogène sur cette région, en partie expliquée par des contextes climatiques différents grâce à l’utilisation de données issues de ré-analyses.Le développement d’une autre méthode a permis, à partir de l’analyse de carte d’albédo issues du capteur MODIS, de caractériser le bilan de masse de surface annuel et estival de 30 glaciers dans les Alpes françaises. Cette étude ouvre la porte à l’utilisation de cette méthode pour l’analyse du bilan annuel et saisonnier à l’échelle régionale.Ce travail a permis, à travers des applications dans différentes régions englacées, de développer et valider des méthodes capables, à partir d’images satellites optiques, d’estimer le bilan de masse de surface annuel et saisonnier de glaciers de montagne à l’échelle de régions entières. Ces estimations peuvent ensuite être utilisées pour : (1) étudier l’impact du climat local sur les glaciers de montagne ; (2) d’investiguer de possibles conditions météorologiques favorisant les fluctuations observées ; (3) calibrer et valider les modèles glacio-hydrologiques utilisés pour estimer les contributions actuelles et futures des glaciers de montagne au fonctionnement hydrologique des bassins versants et à l'élévation du niveau des mers
Beyond their iconic role of climate change, mountain glaciers can be considered as Earth’ essential component and natural “climate-meter”. Despite their small spatial coverage (0.5% of emerged land), mountain glaciers contribute as high as 30% of the observed sea-level rise. In some regions, they are considered as essential issues because of their importance in terms of potable water, agriculture, hydroelectricity or natural hazards. A small share is however monitored in situ (<0.0025%) and their fluctuations at regional scale are poorly known.Thanks to the development of high spatial resolution satellite sensors (metric to decametric), new methods are today available to significantly increase the number of monitored glaciers. After a state of the art of the existing methods and an identification of the limitations, we focused our attention on the development of two methods.The first one is based on the automatic detection of the snow/ice interface altitude (i.e. snowline) at the glacier surface from optical satellite images. This altitude, when estimated at the end of summer, is a proxy of the annual glacier-wide mass change at the glacier surface (called surface mass balance, SMB). Using this approach, we estimated the annual SMBs of 239 glaciers in the European Alps and 82 glaciers in the tropical Andes for the period 2000-2016 and 2000-2018, respectively. The mean mass loss are -0.74 and -1.29 m water equivalent per year for the two regions, respectively. This approach allowed to derive the first dataset of annual SMBs for individual glaciers at regional scale from optical remote sensing. We found significant relationships between the computed SMBs and the glacier morpho-topographic features (e.g. slope, median altitude, …), with steeper and higher glaciers, experiencing less mass losses. Comparison with in situ monitored SMBs revealed an overestimation of mass losses from in situ estimates, due to a low representativeness of steep glaciers (>20°) in the in situ datasets. Our study also revealed heterogeneous inter-annual variability across the European Alps, partially explained by the climatic context of the studied sub-regions, thanks to the analysis of climate reanalysis data.We developed a second method to derive the annual and summer SMBs from albedo maps, computed from MODIS images. With an application on 30 glaciers in the French Alps, this work opened the way toward a regional application of this method, in order to estimate both annual and summer SMBs.By performing regional applications on different glacierized regions, we developed and validated methods capable of deriving the annual and summer SMBs of individual mountain glaciers at regional scale, from optical remote sensing data. These data could then be used to (1) assess the impact of peculiar climatic conditions onto mountain glaciers; (2) investigate possible meteorological conditions driving the documented glacier fluctuations; (3) calibrate and validate glacio-hydrological models used to estimate the current and future contributions of mountain glaciers to the hydrological functioning of mountain catchments and to sea level rise

Style APA, Harvard, Vancouver, ISO itp.

50

Faria, Bruno Guedes. "Identificação dinamica longitudinal de um dirigivel robotico autonomo". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260166.

Pełny tekst źródła

Streszczenie:

Orientadores: Paulo Augusto Valente Ferreira, Ely Carneiro de Paiva
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-04T03:59:44Z (GMT). No. of bitstreams: 1 Faria_BrunoGuedes_M.pdf: 2340545 bytes, checksum: 440ff7a9aa46f5a39514e81423363750 (MD5) Previous issue date: 2005
Resumo: Nos últimos anos tem-se observado um crescente interesse de empresas e instituições de pesquisa pelo desenvolvimento de veículos robóticos, dotados de diferentes níveis de capacidade de operação autônoma, objetivando a execução de diversas tarefas. Dentro deste contexto o CenPRA, Centro de Pesquisas Renato Archer, propôs o Projeto AURORA. O Projeto AURORA (Autonomous Unmanned Remote mOnitoring Robotic Airship) tem como seu principal objetivo o desenvolvimento de protótipos de veículos aéreos tele-operados, e a obtenção de veículos telemonitorados, através do desenvolvimento de sistemas com graus de autonomia crescentes. Para que se possam agregar níveis crescentes de autonomia ao veículo, é essencial incrementar seu sistema de controle e navegação de maneira gradativa. Por esse motivo o aprimoramento das estratégias de controle do sistema é essencial. Assim, é primordial possuir um modelo fidedigno do sistema físico em questão, pois somente dessa forma é possível elaborar leis de controle e testá-las imediatamente em simulação antes de partir para os ensaios práticos no veículo real. Além disso, um modelo adequado é essencial para a simulação do vôo do dirigível de forma a permitir a análise preliminar de seu comportamento diante de uma nova missão. O principal objetivo deste trabalho é a implementação e validação de metodologias para a identificação do modelo dinâmico longitudinal do dirigível. Foram abordadas três metodologias para a identificação do modelo dinâmico do dirigível: a identificação estacionária, que identifica os coeficientes aerodinâmicos do dirigível a partir de um vôo estacionário, a identificação dinâmica, que identifica esses coeficientes e a dinâmica linearizada do veículo a partir de um vôo com entradas de perturbação conhecidas e, finalmente, a identificação por meio de estratégias evolutivas, que procura otimizar alguns parâmetros do modelo dinâmico. As três metodologias foram testadas, validadas e comparadas através de ensaios de simulação, utilizando-se o simulador do dirigível AS800 do Projeto AURORA
Abstract: In recent years many research institutions and companies have been demonstrating a growing interest in the development of unmanned aerial vehicles with different autonomous operation levels in order to allow for the performance of many types of tasks. Within this context, CenPRA (Renato Archer Research Center) proposed the Project AURORA. Project AURORA (Autonomous Unmanned Remote Monitoring Robotic Airship) aims at the development of unmanned airships remotely operated with a view to the creation of an autonomous flight airship by the incorporation of increasing levels of autonomy. In order to increase the vehicle autonomy level, the development of a proportionally enhanced control and navigation systems is essential. It is extremely important to have a very accurate model of the physical airship system, given that this is the only way to design control laws for the vehicle and test them in simulation before performing actual flight tests. Moreover, an accurate model is essential to predict the vehicle behavior in simulation before any real flight demanding a new type of mission. The definition of identification methodologies for the AS800 airship system identification is the main scope of this work. Three methodologies were considered to allow the airship dynamic model identification: stationary identification, which identifies aerodynamic coefficients from stationary stabilized flight conditions; dynamic identification, which identifies these coefficients and the vehicle linear dynamics from the application of known inputs into the system; and, finally, through evolution strategies, which uses an evolutionary approach for the optimization of the aerodynamic coefficients of the dynamic model. All the methodologies were tested, validated and compared through simulation experiments by using the AS800 airship simulator of the Project AURORA
Mestrado
Automação
Mestre em Engenharia Elétrica

Style APA, Harvard, Vancouver, ISO itp.

Rozprawy doktorskie na temat „Remote-sensing maps”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych