https://repositorio.ufba.br/handle/ri/7275 2026-05-03T18:25:31Z https://repositorio.ufba.br/handle/ri/42779 Título: Controle hidrográfico-biogeoquímico do pCO2 no Oceano Atlântico Sudoeste. Autor(es): Matos, Maria Luíza Belmonte Bulcão de Primeiro Orientador: Mendonça, Luís Felipe Ferreira de Abstract: This study aims to understand and investigate the physical and biological processes that influence the variability of pCOff in the Southwestern Atlantic Ocean, using numerical model data provided by the Copernicus Marine Service. For this purpose, time series of SST, SSS, Chl-a, and pCOff were analyzed from late 2021 to 2024. During summer, the southern Brazilian coast and continental shelf exhibit higher pCOff values compared to winter, due to the absence of the La Plata River Plume and increased input of warm waters driven by the Brazil Current. The extent of the La Plata Plume is a key factor in this region, as it regulates seasonal variability in pCOff. Its spatial influence during summer and winter significantly affects the concentrations of local variables. Analyzing this seasonal effect, the current patterns modulate the distribution of nutrients, Chl-a, and consequently pCOff along the coast and shelf. This dynamic leads to enhanced coastal productivity during autumn and winter, as well as greater COff uptake and consumption, characterizing the region as one of low pCOff, positively correlated with SST and SSS. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 0006-06-17T00:00:00Z https://repositorio.ufba.br/handle/ri/42743 Título: Estimativa de parâmetros geoelétricos e gravimétricos através de inversão híbrida com os métodos Metropolis e Steepest Descent. Autor(es): Silva, Annie Gabrielle de Oliveira Primeiro Orientador: Dutra, Alanna Costa Abstract: The main objective of this dissertation was to test inversion methodologies applied to synthetic gravimetric and geoelectrical data, integrating the inversion and interpretation of these data for the study of a hydrogeological environment. Based on the theory of potential fields, both methods face inherent ambiguities in the interpretation of their anomalies, which can be caused by several possible sources. To mitigate these limitations, joint inversion was used, which simultaneously processes the data, generating models that represent the geometry of the density and resistivity interfaces and the distribution of these properties. The study was conducted in two main stages: the individual modeling of the geophysical data and the application of two joint inversions, a global one, using the Metropolis method, and a local one, using the Steepest Descent, both implemented through codes developed in Python. Four initial models were evaluated under three noise levels (no noise, 5% and 10%), generating 24 models using the Metropolis methodology, which served as input for the Steepest Descent, totaling 48 inverted models. The results allowed us to evaluate the quality of the inversion methodologies, identify the limitations of each geophysical method and visualize the geometry and distribution of properties in the geological environment, contributing to the understanding and development of more robust solutions for inverse problems. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 0002-02-27T00:00:00Z https://repositorio.ufba.br/handle/ri/40915 Título: Um algoritmo colônia de formigas aplicado à inversão de dados geofísicos. Autor(es): Jesus, Yan Carlos Viegas de Primeiro Orientador: Bassrei, Amin Abstract: Nonlinear inversion of geophysical data uses global and local optimization methods. These methods can be separately used, each with its own advantages and disadvantages. Local scope methods tend to have high convergence speed and usually produce very accurate results, but they are highly sensitive to the initial model, easily getting trapped in local optima closer to the starting point. Global scope methods have the ability to escape from local optima; on the other hand, they usually have high computational cost and low accuracy when compared to local scope methods. In order to overcome these negative attributes and fully exploit the positive ones, we propose a hybrid optimization method developed as a product of the combination of the Ant Colony (global search) and linearized inversion (local search). Then, through (1) the generation of 1-D vertical electrical sounding data from multilayer models; and (2) the generation of 2-D gravimetric data from prism models, a comparative study was carried out between the methods ant colony optimization, linearized inversion and the hybrid method resulting from the combination of these ones in data inversion experiments. Furthermore, among the several variants of the Ant Colony family methods, Ant Colony Optimization for Continuous Domains is the most popular and most robust variant, being the chosen one to be discussed in this study. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 0006-12-01T00:00:00Z https://repositorio.ufba.br/handle/ri/40681 Título: Caracterização geofísica multimétodos de aterros sanitários. Autor(es): Silva, Pablo Uale de Carvalho Primeiro Orientador: Batista, Joelson da Conceição Abstract: This dissertation presents the results of a geophysical investigation in two landfills: the Camaçari Landfill and the Metropolitano Centro Landfill. These two landfills have distinct characteristics regarding the planning, installation, and development of waste disposal activities. In the first, the construction information of the waste pit was lost. In contrast, a historical monitoring and characterization service of the waste and its structure was carried out in the second. The need to use an effective indirect method to delineate the bottom of the pit, as well as the internal volumes, motivated a multiphysical approach for this study, carried out using the geophysical methods of Electroresistivity, Ground Penetrating Radar (GPR) and Very Low Frequency Electromagnetic (VLF). The three methods present different investigation depths and spatial resolutions, acting in a complementary way in the mapping. The resistivity profiles allowed the partial delineation of the impermeable structure of compacted clay installed at the bottom of the pit during its construction. Furthermore, they highlighted resistive volumes possibly associated with biogas and conductive volumes produced by accumulated leachate and/or bioactive zones in deeper portions of the massif. They also allowed the delimitation of the final cover and waterproofing layers, the identification of the characteristics of old cells in the Aterro Metropolitano Centro, and the observation of distinct responses of the electromagnetic method for waste disposed of in different periods. The current density distributions obtained by the VLF allowed a partial extrapolation of the continuity of the bottom waterproofing structure, in addition to indicating increased conductivity in certain areas. The GPR method complemented the investigation by providing shallow information, up to approximately 5 meters deep, allowing the identification of pipes related to the landfill drainage network, zones of conductive soil on the sides of the waste pile, details about the final cover layer, and its waterproofing, as well as information about the most superficial solid waste. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2024-09-30T00:00:00Z