Este trabalho de pesquisa apresenta uma nova abordagem para calibrar uma sonda helicoidal TDR, usada para medir o teor de umidade do solo. Foi empregada uma aproximação tomando em consideração a interpretação física dos valores de constantes dielétricas. As equações de calibração foram determinadas mediante um modelo dielétrico misto, quais relacionam a constante dielétrica da mistura multifase com a constante dielétrica e frações de volumes dessas componentes. Ensaios realizados em laboratório permitirem o desenvolvimento de duas equações de calibração para a avaliação de teor de umidade volumétrico e gravimétrico dos solos. A calibração foi executada com medições de constante dielétrica em diferentes líquidos e solos, usando uma sonda convencional TDR e a sonda helicoidal TDR. As leituras realizadas com as duas sondas foram depois comparadas. O modelo dielétrico das duas fases permitiu descrever a contribuição dos materiais dielétricos do corpo da sonda helicoidal e os materiais investigados. Mostrou-se que o conhecimento das características físicas e geométricas da sonda TDR usada nos ensaios é de crucial para garantir a qualidade das constantes dielétricas lidas, e conseqüentemente a determinação do teor de umidade in situ. / The objective of this work was to calibrate a coiled TDR probe used to measure the water content of soil. It was used an approach that takes into account a physical interpretation of the values of the dielectric constants. The calibration equations were determined by means of a mixed dielectric model, which relates the dielectric constant of a multi-phase mixture with the dielectric constants and volume fractions of its components. Tests carried out in the laboratory allowed development of two calibration equations for the assessment of the volumetric and gravimetric soil water content. Calibration was performed with measurements of dielectric constants in different liquids and soils, using a conventional TDR probe and a coiled TDR. The readings performed with the two probes were then compared. The dielectric model of two phases permitted describing the contribution of the dielectric material of the body of the probe coil and the materials investigated. It has been shown that knowledge of the physical and geometrical characteristics of the TDR probe used in the tests is crucial for the quality of the dielectric constant readings, and consequently the determination of water content in situ.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-06-19T18:59:30Z No. of bitstreams: 1 EvanildoLima.pdf: 4481585 bytes, checksum: 8fa0d16613f524e7afcc180f1e362073 (MD5) / Made available in DSpace on 2017-06-19T18:59:30Z (GMT). No. of bitstreams: 1 EvanildoLima.pdf: 4481585 bytes, checksum: 8fa0d16613f524e7afcc180f1e362073 (MD5) Previous issue date: 2015-06-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In Maranhão (northeast of Brazil), the “quilombolas”, African slaves descendants, match a significant part of state traditional communities. Although there are studies about them, few papersconsider and relate the pressure of this communities on the ecosystems. This study, using satellite remote sensing tools and ecology landscape elements, aimed to realize the forest cover percentage in different center of distances of the community area in the twenty "quilombolas" sites of Maranhão in 2006. The central hypothesis of this study be progressive decrease in vegetation clearance from the center of the community (negative correlation between distance and percentage of forest cover), however, was not confirmed (p = 0.272). The high variation observed in the forest cover of the different communities is a significant indication of the great variability in factors involved in this type of approach, which would involve a large number of replicates the data to minimize these differences. Data obtained through a Power analysis indicated that better results would be obtained at a distance of 10km from the center of community. However, the average coverage observed (38.5%) is within the range expected from forest cover to rural areas, higher in urban areas. In addition, five communities had more than 50% of that class in the first kilometer (SJB, FER, PAL, SI and FAI), while in three it was observed under 20% in the same range (COC COT and CUP). Thus, further studies are needed, not only using other image analysis routines and other landscape indexes, but also investigating the history of communities and their social aspects, as well as their relationship with other social actors in the area. / No Maranhão, os "quilombolas", descendentes de escravos africanos, correspondem a uma parte significativa das comunidades tradicionais do estado. Embora existam estudos sobre eles, poucos trabalhos consideram e relacionam a pressão dessas comunidades sobre os ecossistemas. Este estudo, usando ferramentas de sensoriamento remoto e elementos da ecologia de paisagens, teve o objetivo de analisar o percentual de cobertura florestal a diferentes distâncias do centro da comunidade em vinte áreas quilombolas do Maranhão, no ano de 2006. A hipótese central desse trabalho de haver diminuição progressiva na vegetação com o afastamento do centro das comunidades (correlação negativa entre distância e porcentagem cobertura florestal), entretanto, não foi corroborada (p=0.272). A alta variação observada na cobertura florestal das diferentes comunidades é um indicativo expressivo da grande variabilidade nos fatores envolvidos neste tipo de abordagem, o que implicaria em um grande número de replicações nos dados para minimizar estas diferenças. Dados obtidos através de uma Power análise indicaram que resultados mais consistentes seriam obtidos a uma distância de 10km do centro da comunidade. Entretanto, a cobertura média observada (38,5%) está dentro dos valores esperados de cobertura florestal para áreas rurais, superior às zonas urbanas. Além disso, cinco comunidades apresentaram mais de 50% dessa classe no primeiro quilômetro (SJB, FER, PAL, SI e FAI), enquanto que em apenas três observou-se menos de 20% no mesmo intervalo (COC, COT e CUP). Dessa forma, são necessários mais estudos, não apenas utilizando outras rotinas de análise de imagem e outros índices de paisagem, mas também investigando a história das comunidades e os seus aspectos sociais, bem como, a sua relação com outros atores sociais na área.

Halogen-driven ozone and nonmethane hydrocarbon losses in springtime Arctic boundary layer are investigated using a regional chemical transport model (CTM). Surface observation of O3 at Alert and Barrow and aircraft observations of O3 and hydrocarbons during the TOPSE experiment from February to May in 2000 are analyzed. We prescribe halogen radical distributions based on GOME BrO observations and calculated or observed other halogen radical to BrO ratios. GOME BrO shows an apparent anti-correlation with surface temperature over high BrO regions. At its peak, area of simulated near-surface O3 depletions (O3 LT 20ppbv) covers GT 50% of the north high latitudes. Model simulated O3 losses are in agreement with surface and aircraft O3 observations. Simulation of halogen distributions are constrained using aircraft hydrocarbon measurements. We find the currently chemical mechanism overestimate the Cl/BrO ratios. The model can reproduce the observed halogen loss of NMHCs using the empirical Cl/BrO ratios. We find that the hydrocarbon loss is not as sensitive to the prescribed boundary layer height of halogen as that of O3, therefore producing a more robust measure for evaluating satellite column measurement. Tropospheric tracer transport and chemical oxidation processes are examined on the basis of the observations at northern mid-high latitudes and over the tropical Pacific and the corresponding global 3D CTM (GEOS-CHEM) simulations. The correlation between propane and ethane/propane ratio is employed using a finite mixing model to examine the mixing in addition to the OH oxidations. At northern mid-high latitudes the model agrees with the observations before March. The model appears to overestimate the transport from lower to middle latitudes and the horizontal transport and mixing at high latitudes in May. Over the tropical Pacific the model reproduces the observed two-branch slope values reflecting an underestimate of continental convective transport at northern mid-latitudes and an overestimate of latitudinal transport into the tropics. Inverse modeling using the subsets of observed and simulated data is more reliable by reducing (systematic) biases introduced by systematic model transport model transport errors. On the basis of this subset we find the model underestimates the emissions of ethane and propane by 14 5%.

Este trabalho de pesquisa apresenta uma nova abordagem para calibrar uma sonda helicoidal TDR, usada para medir o teor de umidade do solo. Foi empregada uma aproximação tomando em consideração a interpretação física dos valores de constantes dielétricas. As equações de calibração foram determinadas mediante um modelo dielétrico misto, quais relacionam a constante dielétrica da mistura multifase com a constante dielétrica e frações de volumes dessas componentes. Ensaios realizados em laboratório permitirem o desenvolvimento de duas equações de calibração para a avaliação de teor de umidade volumétrico e gravimétrico dos solos. A calibração foi executada com medições de constante dielétrica em diferentes líquidos e solos, usando uma sonda convencional TDR e a sonda helicoidal TDR. As leituras realizadas com as duas sondas foram depois comparadas. O modelo dielétrico das duas fases permitiu descrever a contribuição dos materiais dielétricos do corpo da sonda helicoidal e os materiais investigados. Mostrou-se que o conhecimento das características físicas e geométricas da sonda TDR usada nos ensaios é de crucial para garantir a qualidade das constantes dielétricas lidas, e conseqüentemente a determinação do teor de umidade in situ. / The objective of this work was to calibrate a coiled TDR probe used to measure the water content of soil. It was used an approach that takes into account a physical interpretation of the values of the dielectric constants. The calibration equations were determined by means of a mixed dielectric model, which relates the dielectric constant of a multi-phase mixture with the dielectric constants and volume fractions of its components. Tests carried out in the laboratory allowed development of two calibration equations for the assessment of the volumetric and gravimetric soil water content. Calibration was performed with measurements of dielectric constants in different liquids and soils, using a conventional TDR probe and a coiled TDR. The readings performed with the two probes were then compared. The dielectric model of two phases permitted describing the contribution of the dielectric material of the body of the probe coil and the materials investigated. It has been shown that knowledge of the physical and geometrical characteristics of the TDR probe used in the tests is crucial for the quality of the dielectric constant readings, and consequently the determination of water content in situ.

Este trabalho apresenta uma metodologia de classificação de imagens multiespectrais aplicada a análise e mapeamento da evolução do uso da terra/cobertura vegetal em São Félix do Xingu, Sul do Pará. Imagens frações representando as proporções de sombra, vegetação e solo foram estimadas a partir das bandas 1 a 5 e 7 do Landsat-5 TM e relacionadas com as estruturas das classes de uso da terra/cobertura vegetal. As imagens frações geradas do modelo linear de mistura espectral foram importantes para reduzir a massa de dados e ao mesmo tempo realçar alvos de interesse na imagem. A banda do infravermelho próximo (TM-4) foi importante para realçar áreas de queimadas. A classificação adotada foi divida em etapas combinando técnica de segmentação por crescimento de regiões e uso de máscaras. Por meio da máscara foi possível restringir o processo de segmentação em regiões pré-estabelecidas com o intuito de adquirir um melhor particionamento da imagem. Adotando este procedimento, ao invés de realizar uma única segmentação para mapear todas as classes em uma única vez, foram realizadas várias segmentações ao longo das etapas. As regiões segmentadas foram agrupadas com um classificador não-supervionado batizado de ISOSEG. Os resultados mostram que a metodologia é bastante eficiente. A matriz de erro gerada para a classificação de 2008 apontou que as confusões mais freqüentes ocorreram entre as classes que apresentaram em certas localidades proporções de misturas parecidas: Capoeira e Campo/Pastagem-2; Campo/Pastagem-1 e Campo/Pastagem-2; Queimada-1 e Queimada-2; Solo Exposto e Campo/Pastagem-1. Considerando nove classes, o índice Kappa atingiu 0,58, o que representa um valor de concordância classificada como moderada. Quando o numero de classes foi reduzido para 6, agrupando as classes que apresentaram as maiores confusões, o índice Kappa subiu para 0,80, atingindo um valor de concordância quase perfeita. A comparação dos resultados das classificações de 1987, 1992, 2000 e 2008 juntamente com a analise de dados auxiliares permitiu traçar um modelo de evolução do desmatamento e do uso da terra para São Félix do Xingu. O intenso desmatamento observado principalmente a partir de 2000 foi relacionado com o incremento da atividade pecuária, sendo São Félix do Xingu o município que detém atualmente o segundo maior rebanho bovino do País. / In this work we present a methodological procedure for multi-spectral images classification to evaluate and map land-use and land-cover changes in São Félix do Xingu, Southern Pará (Brazilian Amazon). Fraction images representing shade, vegetation and soil abundance at the pixel scale were estimated using all six reflective bands of Thematic Mapper sensor (TM-1 to TM-5 and TM-7) and related to different types of land-use and land-cover classes. The linear spectral mixing analysis method was an alternative approach adopted to reduce the data-dimensionality while at the same time enhancing targets of interest. Also, the near-infrared band (TM-4) was employed to separate areas affected by burns (Queimadas in Portuguese). The classification routines were performed in stages by combining region-growing segmentation and use of masking techniques. For each stage, the segmentation process was directed to preselected areas by masking techniques in order to obtain a better image partitioning. This procedure resulted in more than one segmentation thereby reducing confusing errors during the classification routine. An unsupervised classifier by region named ISOSEG was employed to classify the segmented images. The analysis of classification results was mainly qualitative and visual except for the 2008 classification which was assessed through an error matrix. According to the error matrix analysis, misclassifications arose more frequently when a set of classes with similar mixture proportions were involved, such as: Capoeira and Campo/Pastagem-2; Campo/Pastagem-1 and Campo/Pastagem- 2; Queimada-1 and Queimada-2, and finally Bare Soil and Campo/Pastagem-1. As a robust measure of concordance for dichotomous data, the kappa statistic reached a value of 0.62 by considering nine land types of classes and it rose to 0.80 when the mapping classes were diminished to six. Theses kappa values represent moderate and strong agreements between the remotely sensed classification and the reference data, respectively. Making use of the classification results from 1987, 1992, 2000 and 2008 and auxiliary data, we tried to design a simple land evolution model to São Félix do Xingu. The deforestation process notably intensified since 2000 has been driven mainly by a continuous increase in cattle breeding, for wich São Félix do Xingu has the second-largest cattle herd of all Brazilian municipalities.

In this dissertation we aim to perform a multi-wavelength analysis of galaxy clusters. We discuss various methods for clustering in order to determine physical parameters of galaxy clusters required for this type of study. A selection of galaxy clusters was chosen from 4 papers, (Popesso et al. 2007b, Yoon et al. 2008, Loubser et al. 2008, Brownstein & Mo at 2006) and restricted by redshift and galactic latitude to reveal a sample of 40 galaxy clusters with 0.0 < z < 0.15. Data mining using Virtual Observatory (VO) and a literature survey provided some background information about each of the galaxy clusters in our sample with respect to optical, radio and X-ray data. Using the Kayes Mixture Model (KMM) and the Gaussian Mixing Model (GMM), we determine the most likely cluster member candidates for each source in our sample. We compare the results obtained to SIMBADs method of hierarchy. We show that the GMM provides a very robust method to determine member candidates but in order to ensure that the right candidates are chosen we apply a select choice of outlier tests to our sources. We determine a method based on a combination of GMM, the QQ Plot and the Rosner test that provides a robust and consistent method for determining galaxy cluster members. Comparison between calculated physical parameters; velocity dispersion, radius, mass and temperature, and values obtained from literature show that for the majority of our galaxy clusters agree within 3 range. Inconsistencies are thought to be due to dynamically active clusters that have substructure or are undergoing mergers, making galaxy member identi cation di cult. Six correlations between di erent physical parameters in the optical and X-ray wavelength were consistent with published results. Comparing the velocity dispersion with the X-ray temperature, we found a relation of T0:43 as compared to T0:5 obtained from Bird et al. (1995). X-ray luminosity temperature and X-ray luminosity velocity dispersion relations gave the results LX T2:44 and LX 2:40 which lie within the uncertainty of results given by Rozgacheva & Kuvshinova (2010). These results all suggest that our method for determining galaxy cluster members is e cient and application to higher redshift sources can be considered. Further studies on galaxy clusters with substructure must be performed in order to improve this method. In future work, the physical parameters obtained here will be further compared to X-ray and radio properties in order to determine a link between bent radio sources and the galaxy cluster environment. / MSc (Space Physics), North-West University, Potchefstroom Campus, 2013

In this dissertation we aim to perform a multi-wavelength analysis of galaxy clusters. We discuss various methods for clustering in order to determine physical parameters of galaxy clusters required for this type of study. A selection of galaxy clusters was chosen from 4 papers, (Popesso et al. 2007b, Yoon et al. 2008, Loubser et al. 2008, Brownstein & Mo at 2006) and restricted by redshift and galactic latitude to reveal a sample of 40 galaxy clusters with 0.0 < z < 0.15. Data mining using Virtual Observatory (VO) and a literature survey provided some background information about each of the galaxy clusters in our sample with respect to optical, radio and X-ray data. Using the Kayes Mixture Model (KMM) and the Gaussian Mixing Model (GMM), we determine the most likely cluster member candidates for each source in our sample. We compare the results obtained to SIMBADs method of hierarchy. We show that the GMM provides a very robust method to determine member candidates but in order to ensure that the right candidates are chosen we apply a select choice of outlier tests to our sources. We determine a method based on a combination of GMM, the QQ Plot and the Rosner test that provides a robust and consistent method for determining galaxy cluster members. Comparison between calculated physical parameters; velocity dispersion, radius, mass and temperature, and values obtained from literature show that for the majority of our galaxy clusters agree within 3 range. Inconsistencies are thought to be due to dynamically active clusters that have substructure or are undergoing mergers, making galaxy member identi cation di cult. Six correlations between di erent physical parameters in the optical and X-ray wavelength were consistent with published results. Comparing the velocity dispersion with the X-ray temperature, we found a relation of T0:43 as compared to T0:5 obtained from Bird et al. (1995). X-ray luminosity temperature and X-ray luminosity velocity dispersion relations gave the results LX T2:44 and LX 2:40 which lie within the uncertainty of results given by Rozgacheva & Kuvshinova (2010). These results all suggest that our method for determining galaxy cluster members is e cient and application to higher redshift sources can be considered. Further studies on galaxy clusters with substructure must be performed in order to improve this method. In future work, the physical parameters obtained here will be further compared to X-ray and radio properties in order to determine a link between bent radio sources and the galaxy cluster environment. / MSc (Space Physics), North-West University, Potchefstroom Campus, 2013

In recent years there has been an increasing awareness of the detrimental influence of diffuse sources of pollution on aquatic systems and of the integral role played by sediment in the mobilisation and transport of pollutants. The recognition of the environmental, societal and economic importance of the ecological health of aquatic environments has led to a change in emphasis regarding agricultural and environmental policy. To implement successful delivery of emerging policy requirements, there is a current need to have an enhanced understanding of the relationship between different forms of land use and sources of diffuse pollution, particularly sources of fine sediment. To understand the potential impacts of future land use changes, including environmental conservation measures on sources of sediment, it is useful to consider them within a longer-term context. This study has successfully applied the sediment source fingerprinting technique to floodplain overbank sediment cores in a retrospective study of six diverse UK river catchments with identified sediment problems. The varying estimates of relative sediment contributions from differing sources have been compared to known land use change in the study catchments over concurrent time periods, to explore any associations which might be apparent. Over the last 40 years, the increased cultivation of high erosion risk crops, such as those which are harvested late in the season (e.g. maize) and those which are sown in the autumn (e.g. winter wheat), has contributed disproportionately to the total sediment load relative to the area of land occupied by such cultivation. Increased stocking densities have resulted in increased relative sediment contributions from grassland sources, particularly intensively managed temporary grassland, but can have an even greater impact on sediment contributions derived from channel bank sources. The installation and maintenance of drainage for agriculture or for flood risk management has resulted in increased relative sediment loads from channel bank and associated sub-surface sources. Through the further development of such research, the efficacy of mitigation measures can be tested against evidence-based historic trends and those management approaches which provide identifiable improvements can be developed as best practice options for future land management targeted at reducing the negative impacts of excessive sediment ingress to river systems. The design of the source fingerprinting methodology used in this work was based on an established successful approach and this was developed further through the incorporation of a number of refinements designed to improve the robustness of the technique and expedite its implementation.

As interações tróficas de 31 espécies de peixes e 2 de lulas da Baía do Araçá, São Sebastião (SP), foram investigadas por meio dos isótopos estáveis de carbono (&#948;13C) e nitrogênio (&#948;15N). Os valores de &#948;13C das espécies variaram entre -17,2&#8240; e -12,1&#8240;, e os de &#948;15N, entre 10,0&#8240; e 14,5&#8240;. Os valores de &#948;13C dos produtores e consumidores permitiram indicar que as espécies analisadas participam das teias tróficas, pelágica e bentônica, e têm como base da cadeia alimentar o fitoplâncton, os microfitobentos e a matéria orgânica dos sedimentos. Maiores valores de &#948;13C nos peixes e lulas foram registrados no verão, associados a valores mais altos na base. As posições tróficas das espécies variaram entre 3,18 e 4,72, indicando que atuam como consumidores secundários e terciários. A composição da dieta dos peixes, avaliada pelo modelo de mistura isotópica, apontou elevada contribuição de presas como Polychaeta, Tanaidacea e Ophiuroidea, grupos com alta abundância na Baía do Araçá e no Canal de São Sebastião. A ingestão de presas disponíveis no interior da baía e no canal evidenciou a importância desses peixes e lulas como carreadores de nutrientes, realizando tanto acoplamento pelágico-bentônico, como entre as regiões sublitoral e entremarés da Baía do Araçá. / The trophic interactions of 31 fish species and 2 squid species of the Araçá Bay, São Sebastião (São Paulo, Brazil), were investigated through carbon (&#948;13C) and nitrogen (&#948;15N) stable isotopes. The &#948;13C of the species ranged from -17.2&#8240; to -12.1&#8240;, and the &#948;15N, from 10.0&#8240; to 14.5&#8240;. The &#948;13C data of the producers and consumers indicated that the species analysed are part of the pelagic and benthic trophic webs, and have phytoplankton, microphytobenthos and organic matter from the sediment as the base of the food web. Higher values of &#948;13C were registered in the summer, linked to the higher values at the base. The trophic positions of the species varied between 3.18 e 4.72, an indication that they act as secondary and tertiary-quaternary consumers. The diet composition of fish, evaluated trough the isotope mixing model, showed high contribution of prey, such as Polychaeta, Tanaidacea and Ophiuroidea, groups highly abundant in the Bay and the adjacent São Sebastião Channel. The intake of available prey in the intertidal region and in the Channel revealed the importance of the fish and squid as nutrient pathway links, coupling the pelagic-benthic systems and the sublittoral and intertidal regions of the Araçá Bay.

Ces travaux de thèse concernent le développement de nouvelles méthodes de séparation aveugle de mélanges linéaires instantanés pour des applications à des données hyperspectrales en astrophysique. Nous avons proposé trois approches pour effectuer la séparation des données. Une première contribution est fondée sur l'hybridation de deux méthodes existantes de séparation aveugle de source (SAS) : la méthode SpaceCORR nécessitant une hypothèse de parcimonie et une méthode de factorisation en matrices non négatives (NMF). Nous montrons que l'utilisation des résultats de SpaceCORR pour initialiser la NMF permet d'améliorer les performances des méthodes utilisées seules. Nous avons ensuite proposé une première méthode originale permettant de relâcher la contrainte de parcimonie de SpaceCORR. La méthode MASS (pour \textit{Maximum Angle Source Separation}) est une méthode géométrique basée sur l'extraction de pixels mono-sources pour réaliser la séparation des données. Nous avons également étudié l'hybridation de MASS avec la NMF. Enfin, nous avons proposé une seconde approche permettant de relâcher la contrainte de parcimonie de SpaceCORR. La méthode originale SIBIS (pour \textit{Subspace-Intersection Blind Identification and Separation}) est une méthode géométrique basée sur l'identification de l'intersection de sous-espaces engendrés par des régions de l'image hyperspectrale. Ces intersections permettent, sous une hypothèse faible de parcimonie, de réaliser la séparation des données. L'ensemble des approches proposées dans ces travaux ont été validées par des tests sur données simulées puis appliquées sur données réelles. Les résultats obtenus sur ces données sont très encourageants et sont comparés à ceux obtenus par des méthodes de la littérature. / This thesis deals with the development of new blind separation methods for linear instantaneous mixtures applicable to astrophysical hyperspectral data sets. We propose three approaches to perform data separation. A first contribution is based on hybridization of two existing blind source separation (BSS) methods: the SpaceCORR method, requiring a sparsity assumption, and a non-negative matrix factorization (NMF) method. We show that using SpaceCORR results to initialize the NMF improves the performance of the methods used alone. We then proposed a first original method to relax the sparsity constraint of SpaceCORR. The method called MASS (Maximum Angle Source Separation) is a geometric method based on the extraction of single-source pixels to achieve the separation of data. We also studied the hybridization of MASS with the NMF. Finally, we proposed an approach to relax the sparsity constraint of SpaceCORR. The original method called SIBIS (Subspace-Intersection Blind Identification and Separation) is a geometric method based on the identification of intersections of subspaces generated by regions of the hyperspectral image. Under a sparsity assumption, these intersections allow one to achieve the separation of the data. The approaches proposed in this manuscript have been validated by experimentations on simulated data and then applied to real data. The results obtained on our data are very encouraging and are compared with those obtained by methods from the literature.