1.1\xThis study proposed a particle-set distributed hydrological model for the dynamic simulation of rainfall-runoff process. With the supports of remote sensing, GIS, terrain analysis and distributed computing techniques, a representation-simplified and physically-based high-performance watershed framework has been developed. It simplifies the underlying watershed with a flow path network model, and represents the moving surface flow with independent runoff particles.;1.2\xThe original idea was to investigate a real-time modeling system for the space-time dynamics of increasingly frequent extreme rainfall events. Short-term heavy rains may cause further damages by spawning floods and landslides. It is quite essential to understand how the rainfall water moves across the watershed surface as early as possible. A modelling system with high-performance in simulation efficiency and space-time prediction accuracy would be very desirable.;1.3\xWatershed modeling is the primary way to explore the hydrological cycle at a local scale. Existing models are classified as empirical lumped, conceptual semi-distributed and physically-based distributed models. The first two types of models have focused more on predicting outlet discharges rather than estimating spatiotemporal flow dynamics. The application of physically-based models has always been hampered by some common shortcomings like over-parameterization, inflexibility and computational burden. With the increasing support from terrain analysis and parallel computing techniques, a number of previous studies have made some efforts to improve the performance in dynamic and real-time simulation. However, research gaps still exist in realistic representation, physical description and real-time simulation.;1.4\xThis study, therefore, developed the particle-set modeling system on the basis of flow path network model. This one-dimensional topological structure was created beforehand to represent the three-dimensional watershed, and a series of particle beams were dynamically generated to simulate the surface flow. Under the control of flow velocities, these runoff particles would keep on moving along with the flow paths, which can represent the spatial distributions of surface water in time.;1.5\xTo validate the proposed particle-set framework, a prototype of particle-set system was implemented by programming methods with the assistance of third-party platforms. Three experiments were undertaken to respectively evaluate the performance in prediction accuracy, simulation efficiency and parameter sensitivity. More specifically, a total of 10 rainfall events and up to 128 computer processors were tested. In addition, the influences of underlying spatial scale and source sampling density on hydrological responses were explored with comparative tests.;1.6\xThe accuracy validation comes in two parts, the representation loss in terrain analysis, and the discharge error in hydrological modeling. The experimental results indicate that the TIN-based flow path network has maintained the terrain features at a very high level with much less data storage, and the particle-set framework has achieved quite acceptable predictions of outlet discharges. Besides, the efficiency evaluation concerns with two aspects, parallel portion and parallel efficiency. The speed-up results indicate that about 99% of the computational workloads can be computed in parallel, and the particle-based scheme can achieve almost the ideal parallel efficiency. In addition, the sensitivity test focuses also on two parameters, underlying spatial scale and source sampling density. The preliminary results show that the particle-set model has shown a good reliability and stability as scale gets coarser or density becomes sparser.;1.7\xThis study will contribute to the understanding of short-term rainfall-runoff events at a basin scale. The particle-set distributed hydrological model has been proven to provide real-time spatio-temporal dynamics of surface flow. Further studies would still be required to apply it to real world scenarios.;1.8\xKeywords: terrain analysis, watershed hydrology, rainfall-runoff process, flow path network, particle system, parallel computing

Call number: LD2668 .T4 1946 L5 / Master of Science

Este trabalho objetivou analisar a suscetibilidade à erosão linear da região do Médio Rio Grande (MG), que abrange uma área de 9794,12 km², através de documentos cartográficos interpretativos. Utilizando técnicas de geoprocessamento e sensoriamento remoto associadas a levantamentos de campo e ensaios de laboratório, foram produzidos os seguintes documentos cartográficos: Carta de Declividade, Mapa de Landforms, Mapa de Materiais Inconsolidados e Inventário de Feições Erosivas. O produto final do trabalho, a Carta de Suscetibilidade à Erosão em escala 1:100.000, foi elaborada utilizando informações referentes ao substrato rochoso, formas do terreno, materiais inconsolidados e declividade. Cada documento cartográfico utilizado foi analisado de forma individual, para observar a potencialidade de cada um de seus atributos internos (ou classes) em desenvolver processos erosivos, assim, foram atribuídos pesos através do Processo Analítico Hierárquico (AHP). A Carta de Suscetibilidade à Erosão obtida conseguiu retratar bem a suscetibilidade da área, pois dos 78 processos erosivos de grande porte (boçorocas), identificados no inventário, em torno de 80% estão situados nas classes de alta e muito alta suscetibilidade à erosão. Portanto, esta Carta indica quais são as áreas em que se deve ter um controle mais rígido do uso e ocupação do solo para prevenir o desencadeamento de processos erosivos de grande porte, ou seja, auxilia no planejamento ambiental e na definição de medidas a serem tomadas. / This study aimed to analyze the susceptibility to linear erosion of the region of the Middle Rio Grande (Minas Gerais - Brazil) that covers an area of 9794.12 km², through interpretive cartographic documents. Using geoprocessing techniques and remote sensing associated with field surveys and laboratory tests, the following cartographic documents were produced: Chart of Slope, Landforms Map, Map of Unconsolidated Material and Inventory of Erosive Features. The final product of this work is the Chart of Erosion Susceptibility in scale 1:100,000. It was prepared using information relating to the bedrock, forms of terrain, unconsolidated materials and slope. Each cartographic document used was analyzed individually in order to observe the potential of each of its internal attributes (or classes) to develop erosive processes, thus were assigned weights using the Analytic Hierarchy Process (AHP). The Chart of Erosion Susceptibility obtained could well portray the susceptibility of the area because analyzing a total of 78 large erosion processes (gully erosion) identified in the inventory, about 80% are located in the classes of high and very high susceptibility to erosion. Therefore, this Chart indicates which areas in which to have a tighter control of the use and occupation of land to prevent large erosion triggering, ie assists in environmental planning and defining actions to be taken.

Este trabalho consiste no estudo sistemático dos fenômenos erosivos em áreas urbanas, tendo como objetivo a avaliação e identificação das causas destes fenômenos no município de Ouro Preto - MG. Como ferramenta principal utilizou-se o mapeamento geotécnico, na escala de detalhe 1:5.000 em uma área de aproximadamente 6 Km2, com o objetivo de fazer uma caracterização geotécnica das feições erosivas existentes na área. Buscou-se também fazer um levantamento de dados geológicos, geomorfológicos e de influência antrópica. Os resultados obtidos através deste mapeamento possibilitaram a elaboração do mapa de susceptibilidade à erosão. Como ferramenta auxiliar utilizou-se a sistemática da Técnica de Compartimentação do Terreno proposta por LOLLO (1995) e o Sistema de Informação Geográfica IDRISI. A compartimentação do terreno baseou-se no estudo das formas de relevo (landforms), que foram divididas a nível de elementos, procurando sempre respeitar os limites naturais do meio físico. O SIG-IDRISI possibilitou a atualização e o tratamento das diversas informações levantadas e analisadas, além da agilidade em se gerar as cartas. Os documentos cartográficos gerados foram: mapa de documentação, modelo digital do terreno, mapa do substrato rochoso, mapa de landforms, carta de declividade e carta de susceptibilidade à erosão. / This work presents a systematic study on the erosion processes in urban areas, with the aim of evaluation and identification of its causes in the municipal district of Ouro Preto - MG. As the main tool, the engineering geological mappping procedures have been used, scale 1:5.000, covering on area of about 6 Km2. These procedures were particulary used for the geothecnical characterization of the erosion features present in the area. lt was intended also to get, as much as possible, all the geological, geomorphological and human interference. The results obtained from the mapping procedures have been used as a base for the erosion susceptibility chart. The sistematic of the terrain landforms division, proposed by LOLLO (1995) and the GIS - IDRISI were used as auxiliary tools. These landforms have been divided in elements, obeing environmental constraints. The use of the GIS - IDRISI, has promoted the updating and manilulation of the several information obtained, besides the agility in generating the charts. The chartographycal documents produced were digital terrain model, documentation map, bedrock map, landforms map, declivity chart, erosion susceptibility chart.

Este trabalho objetivou analisar a suscetibilidade à erosão linear da região do Médio Rio Grande (MG), que abrange uma área de 9794,12 km², através de documentos cartográficos interpretativos. Utilizando técnicas de geoprocessamento e sensoriamento remoto associadas a levantamentos de campo e ensaios de laboratório, foram produzidos os seguintes documentos cartográficos: Carta de Declividade, Mapa de Landforms, Mapa de Materiais Inconsolidados e Inventário de Feições Erosivas. O produto final do trabalho, a Carta de Suscetibilidade à Erosão em escala 1:100.000, foi elaborada utilizando informações referentes ao substrato rochoso, formas do terreno, materiais inconsolidados e declividade. Cada documento cartográfico utilizado foi analisado de forma individual, para observar a potencialidade de cada um de seus atributos internos (ou classes) em desenvolver processos erosivos, assim, foram atribuídos pesos através do Processo Analítico Hierárquico (AHP). A Carta de Suscetibilidade à Erosão obtida conseguiu retratar bem a suscetibilidade da área, pois dos 78 processos erosivos de grande porte (boçorocas), identificados no inventário, em torno de 80% estão situados nas classes de alta e muito alta suscetibilidade à erosão. Portanto, esta Carta indica quais são as áreas em que se deve ter um controle mais rígido do uso e ocupação do solo para prevenir o desencadeamento de processos erosivos de grande porte, ou seja, auxilia no planejamento ambiental e na definição de medidas a serem tomadas. / This study aimed to analyze the susceptibility to linear erosion of the region of the Middle Rio Grande (Minas Gerais - Brazil) that covers an area of 9794.12 km², through interpretive cartographic documents. Using geoprocessing techniques and remote sensing associated with field surveys and laboratory tests, the following cartographic documents were produced: Chart of Slope, Landforms Map, Map of Unconsolidated Material and Inventory of Erosive Features. The final product of this work is the Chart of Erosion Susceptibility in scale 1:100,000. It was prepared using information relating to the bedrock, forms of terrain, unconsolidated materials and slope. Each cartographic document used was analyzed individually in order to observe the potential of each of its internal attributes (or classes) to develop erosive processes, thus were assigned weights using the Analytic Hierarchy Process (AHP). The Chart of Erosion Susceptibility obtained could well portray the susceptibility of the area because analyzing a total of 78 large erosion processes (gully erosion) identified in the inventory, about 80% are located in the classes of high and very high susceptibility to erosion. Therefore, this Chart indicates which areas in which to have a tighter control of the use and occupation of land to prevent large erosion triggering, ie assists in environmental planning and defining actions to be taken.

published_or_final_version / Geography and Geology / Master / Master of Arts

Este trabalho consiste no estudo sistemático dos fenômenos erosivos em áreas urbanas, tendo como objetivo a avaliação e identificação das causas destes fenômenos no município de Ouro Preto - MG. Como ferramenta principal utilizou-se o mapeamento geotécnico, na escala de detalhe 1:5.000 em uma área de aproximadamente 6 Km2, com o objetivo de fazer uma caracterização geotécnica das feições erosivas existentes na área. Buscou-se também fazer um levantamento de dados geológicos, geomorfológicos e de influência antrópica. Os resultados obtidos através deste mapeamento possibilitaram a elaboração do mapa de susceptibilidade à erosão. Como ferramenta auxiliar utilizou-se a sistemática da Técnica de Compartimentação do Terreno proposta por LOLLO (1995) e o Sistema de Informação Geográfica IDRISI. A compartimentação do terreno baseou-se no estudo das formas de relevo (landforms), que foram divididas a nível de elementos, procurando sempre respeitar os limites naturais do meio físico. O SIG-IDRISI possibilitou a atualização e o tratamento das diversas informações levantadas e analisadas, além da agilidade em se gerar as cartas. Os documentos cartográficos gerados foram: mapa de documentação, modelo digital do terreno, mapa do substrato rochoso, mapa de landforms, carta de declividade e carta de susceptibilidade à erosão. / This work presents a systematic study on the erosion processes in urban areas, with the aim of evaluation and identification of its causes in the municipal district of Ouro Preto - MG. As the main tool, the engineering geological mappping procedures have been used, scale 1:5.000, covering on area of about 6 Km2. These procedures were particulary used for the geothecnical characterization of the erosion features present in the area. lt was intended also to get, as much as possible, all the geological, geomorphological and human interference. The results obtained from the mapping procedures have been used as a base for the erosion susceptibility chart. The sistematic of the terrain landforms division, proposed by LOLLO (1995) and the GIS - IDRISI were used as auxiliary tools. These landforms have been divided in elements, obeing environmental constraints. The use of the GIS - IDRISI, has promoted the updating and manilulation of the several information obtained, besides the agility in generating the charts. The chartographycal documents produced were digital terrain model, documentation map, bedrock map, landforms map, declivity chart, erosion susceptibility chart.

In this study four different aspects of primary successions on glacier forelands in South-Central Norway are investigated. First, general vegetation and environment trends, which have been observed by other scientists, were studied on two forelands. It is shown that the two selected forelands (one low- and one high-altitude foreland, Nigardsbreen and Storbreen, respectively) differ in the speed of vegetation cover change and in the overall species richness developed over the last 250 years since deglaciation. This is attributed to differences in the severity of the environment between the two forelands. Some support for an early peak in the number of species was found for the Nigardsbreen foreland, whereas the Storbreen foreland shows no significant trend in the development of species richness. Life-forms and soil-depth change on both forelands in the predicted manner. A novel approach for the use of Ellenberg indicator values for the estimation of pH-values from the existent vegetation shows highly significant correlations between predicted pH values and trends measured for similar terrain ages from a study by Messer (1988). Investigation at two different scales indicated that small-scale disturbances (< 100 m) may influence the mosaic of the environment, which affects the results of the chronosequence approach. By using a strict geometrical sampling design more variable conditions entered the analyses than with the stratified random sampling schemes adopted by others, such as Matthews (1979b). Some loss in the power of analysing the data occurred, but the results are still consistent with hypotheses about primary succession on glacier forelands. Second, new aspects of the temporal development and successional change of plant communities were investigated on the same two forelands. There is some evidence of succession from a pioneer community to the local climax community of the surrounding area for both forelands. There is also support for the correlation of timedependent environmental variables with the successional development of plant communities. A new application of Ellenberg indicator values in ordinations was assessed for its value in estimating average environmental conditions derived from the vegetation. As with the previous analyses, investigation of community development at two different scales supported the importance of sampling scale on the analysis of succession data. Third, spatially explicit analyses of distribution patterns of dominant woody species was developed as a means to investigate processes and formulate hypotheses about primary succession on glacier forelands. The data for this part of the study was collected on five glacier forelands, three low-altitude (Nigardsbreen, Austerdalsbreen and Bødalsbreen) and two high-altitude (Storbreen and Høgvaglbreen). Pattern descriptors including perimeter/area index, autocorrelation measures and fractal dimensions, support the hypothesis of differential colonisation of wind and animaldispersed species. Even more convincing is the result that low- and high-altitude forelands show significant differences in the patterns exhibited by wind and animals dispersed species. This result is thought to be related to the differences in environmental severity affecting the establishment of colonising species. Finally, logit modelling of the distributions of dominant woody species provides insights into the sampling effort needed to gather enough data for meaningful analyses. It also leads to the identification of important factors influencing the distribution of those species.

The influence of seasonal influx of supraglacial meltwater on basal water pressures and consequent changes in ice surface velocity has been a focus of research spanning over three decades. With a need to better include glacial hydrology within models of ice sheet evolution, the ability to predict where and when meltwater reaches the subglacial system is paramount for understanding the dynamics of large Arctic ice masses. The response of ice velocities to melt production suggests efficient transmission of meltwater from the supraglacial to subglacial hydrologic systems, and it has been shown that build-ups of stored meltwater in supraglacial lakes can force crevasse penetration through hundreds of metres of ice. This thesis presents a new modelling routine for prediction of moulin formation and delivery of meltwater to the ice-bed interface. Temporal and spatial patterns of moulin formation and drainage of supraglacial lakes are presented, and quantitative controls on crevasse propagation are investigated through a series of sensitivity tests. _J .' . The model is applied to two glacial catchments: the Croker Bay catchment of the Devon Ice Cap in High Arctic Canada; and the Leverett glacier catchment of the Greenland Ice Sheet. Through model application to these sites, sensitivities to crevasse surface dimensions, ice tensile strength, ice fracture toughness and air temperatures are investigated. Model predictions of moulin formation and melt transfer are compared with field observations and remotely sensed data, including ice surface velocities, proglacial discharge, dynamic flow regimes, and visible surface features. The inclusion of spatially distributed points of meltwater delivery to the 'subglacial system is imperative to fully understand the behaviour of the subglacial drainage system. Furthermore, dynamic response to future climatic change and melt scenarios, and the evolution of ice masses, cannot be fully understood without first understanding the glacial hydrologic processes driving many of these changes.

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