The first part of this thesis deals with studying the effect of the specified bathymetric resolution and ideal bathymetric form parameters on the output from the wave and hydrodynamic modules of Delft-3D. This thesis then describes the use of an optimization to effectively reduce the required bathymetric sampling for input to a numerical forecast model, by using the model’s sensitivity to this input. A genetic algorithm is developed to gradually evolve the survey path for a ship, AUV, or other measurement platform to an optimum, with the resulting effect of the corresponding measured bathymetry on the model, used as a metric. Starting from an initial simulated set of possible random or heuristic sampling paths over the given bathymetry using certain constraints like limited length of track, the algorithm can be used to arrive at the path that would provide the best possible input to the model under those constraints. This suitability is tested by a comparison of the model results obtained by using these new simulated observations, with the results obtained using the best available bathymetry. Two test study areas were considered, and the algorithm was found to consistently converge to a sampling pattern that best captured the bathymetric variability critical to the model prediction.

The first part of this thesis deals with studying the effect of the specified bathymetric resolution and ideal bathymetric form parameters on the output from the wave and hydrodynamic modules of Delft-3D. This thesis then describes the use of an optimization to effectively reduce the required bathymetric sampling for input to a numerical forecast model, by using the model’s sensitivity to this input. A genetic algorithm is developed to gradually evolve the survey path for a ship, AUV, or other measurement platform to an optimum, with the resulting effect of the corresponding measured bathymetry on the model, used as a metric. Starting from an initial simulated set of possible random or heuristic sampling paths over the given bathymetry using certain constraints like limited length of track, the algorithm can be used to arrive at the path that would provide the best possible input to the model under those constraints. This suitability is tested by a comparison of the model results obtained by using these new simulated observations, with the results obtained using the best available bathymetry. Two test study areas were considered, and the algorithm was found to consistently converge to a sampling pattern that best captured the bathymetric variability critical to the model prediction.

A deriva litorânea é estudada no litoral sul do Espírito Santo através de diferentes técnicas: distribuição de Minerais Pesados (MP); modelo conceitual Análise de Transport de Sedimento (Sediment Trend Analysis - STA), através da variação de parâmetros texturais do sedimento; dados de clima de onda entre 1997 e 2010 do modelo global WaveWatch III propagados para a zona costeira através do modelo Delft-3D, fornecendo parâmetros necessários para as equações de deriva; e imagens de satélite e fotografias aéreas para avaliar a variação espaço-temporal da morfologia costeira. O modelo STA mostrou-se confiável apenas nos dois setores ao norte, enquanto nos demais os resultados foram mascarados por altos teores de MP e/ou carbonato e a entrada de outras fácies no sistema; as equações representaram bem a variação da morfologia costeira na área de estudos. De maneira geral, os setores ao sul apresentaram transporte longitudinal para sul, e os setores ao norte, para norte, fato relacionado à batimetria local. A orientação da linha de costa auxiliou na compreensão dos fenômenos erosivos, pois em sua maioria estão orientados no sentido NEN, formando 45º com as ondas dos setores de ESE e SE. / Longshore drift is studied in the southern portion of Espírito Santo through different techniques: Heavy Minerals (HM) distribution; the conceptual model Sediment Trend Analysis (STA) by sediment textural parameters fluctuation; wave climate data between 1997 and 2010 from WaveWatch III propagated to the coastal zone through Delft-3D model, providing the required data for longshore drift equations; and satellite images and aerial photograph to survey time-space coastline variations. The STA model appears to be trustworthy only within the northern sectors, as high HM and/or carbonate content and different facies input into the system may mask the results. Broadly speaking, the southern sectors showed longshore transport southward, while northern sectors showed northward longshore transport, which is related to local bathymetry. Shoreline azimuth helped understanding the location of erosive zones, since most of them are turned NEN, 45o with ESE and SE wave sectors.

Orientador: Roberto Fioravanti Carelli Fontes / Resumo: Estuários são ambientes aquáticos de transição entre o continente e o oceano com características únicas, ecológica e economicamente importantes. São condicionados por diversas forçantes naturais e compartilham contribuições terrestres e marinhas. Os principais métodos para estudo hidrodinâmico desses ambientes baseiam-se na análise dos processos de advecção e de mistura das massas de água, gerados pela dinâmica das marés e das descargas dos rios. O presente estudo visa a caracterização hidrodinâmica do estuário do rio Guaratuba (Bertioga, SP) durante as marés de sizígia e de quadratura, a partir de levantamentos hidrográficos realizados com ADCP e CTD e o desenvolvimento de um modelo hidrodinâmico computacional capaz de explicar e simular os processos oceanográficos deste estuário. Os resultados apontaram que, tanto a maré quanto a descarga fluvial têm a capacidade de alterar as vazões e os padrões de salinidade e temperatura no estuário. Em condições de precipitação médias ou na ausência de precipitações, a maré é a forçante dominante do sistema. Durante os períodos de sizígia ocorrem o aumento da turbulência e da mistura vertical. Nas quadraturas, quando as velocidades de corrente são menores, a estratificação vertical é mais estável, e a água salina incursiona até pontos mais internos do estuário. Precipitações na sub-bacia tem relação direta e imediata com o aumento da vazão, afetando a dinâmica e intensificando a estratificação vertical do estuário. O estuário do rio Gua... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Estuaries are transitional aquatic environments, with unique characteristics, ecologically and economically important. They are conditioned by several natural forcings and share land and marine contributions. The main methods to study these environments are based on the analysis of the water masses advection and mixing processes, that are generated by tides and river discharges. The purposes of this study are the hydrodynamic characterization of the Guaratuba’s estuary (Bertioga, SP) during spring and neap tides, based on ADCP and CTD hydrographic surveys, and the development of a computational hydrodynamic model using Delft-3D software, that helps to explain and simulate the main estuarine oceanographic processes. We observed that both, tide and river discharges, have the capacity to alter water flow, as well as salinity and temperature patterns in the estuary. Under mean precipitation conditions or in its absence, tide forces dominate the system. During the spring tide floods, turbulence and vertical mixing increase. During the neap tide floods, when current speed decreases, vertical stratification remains more stable, and saline water penetrates more along the upper estuary. Precipitation episodes in the sub-basin are direct and immediate related to water flow increase, and affect currents dynamics intensifying vertical stratification in the estuary. The Guaratuba estuary is classified as type A, B or D; depending on tidal and river flow conditions. The models we generated... (Complete abstract click electronic access below) / Mestre

A deriva litorânea é estudada no litoral sul do Espírito Santo através de diferentes técnicas: distribuição de Minerais Pesados (MP); modelo conceitual Análise de Transport de Sedimento (Sediment Trend Analysis - STA), através da variação de parâmetros texturais do sedimento; dados de clima de onda entre 1997 e 2010 do modelo global WaveWatch III propagados para a zona costeira através do modelo Delft-3D, fornecendo parâmetros necessários para as equações de deriva; e imagens de satélite e fotografias aéreas para avaliar a variação espaço-temporal da morfologia costeira. O modelo STA mostrou-se confiável apenas nos dois setores ao norte, enquanto nos demais os resultados foram mascarados por altos teores de MP e/ou carbonato e a entrada de outras fácies no sistema; as equações representaram bem a variação da morfologia costeira na área de estudos. De maneira geral, os setores ao sul apresentaram transporte longitudinal para sul, e os setores ao norte, para norte, fato relacionado à batimetria local. A orientação da linha de costa auxiliou na compreensão dos fenômenos erosivos, pois em sua maioria estão orientados no sentido NEN, formando 45º com as ondas dos setores de ESE e SE. / Longshore drift is studied in the southern portion of Espírito Santo through different techniques: Heavy Minerals (HM) distribution; the conceptual model Sediment Trend Analysis (STA) by sediment textural parameters fluctuation; wave climate data between 1997 and 2010 from WaveWatch III propagated to the coastal zone through Delft-3D model, providing the required data for longshore drift equations; and satellite images and aerial photograph to survey time-space coastline variations. The STA model appears to be trustworthy only within the northern sectors, as high HM and/or carbonate content and different facies input into the system may mask the results. Broadly speaking, the southern sectors showed longshore transport southward, while northern sectors showed northward longshore transport, which is related to local bathymetry. Shoreline azimuth helped understanding the location of erosive zones, since most of them are turned NEN, 45o with ESE and SE wave sectors.