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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Beach-dune morphodynamics and climatic variability in Gwaii Haanas National Park and Haida Heritage Site, British Columbia, Canada

Cumming, Rebecca Miville 27 July 2007 (has links)
This thesis describes the geomorphology and morphodynamics of two embayed, sandy, macrotidal beach-dune systems in the Cape St. James region of Gwaii Haanas National Park Reserve and Haida Heritage Site. Gilbert Bay beach is a small embayment with a southwest aspect that exhibits prograding dune ridges. Woodruff Bay beach, a larger system with a SE aspect, is characterized by large erosional scarps on the established foredune. Aspect to erosive conditions and embayment size control the distinct morphologic responses of these beach-dune systems. The morphodynamic regime at Cape St. James consists of high onshore sediment transport potential combined with an increasingly erosive water level regime that is forced by PDO and ENSO climatic variability events. Conceptual models of potential future responses of these beaches to sea level rise show a possible landward migration of up to 3.5 m at Gilbert Bay beach and up to 4 m at Woodruff Bay beach.
32

Caracteriza??o geomorfol?gica e modelagem de dados espaciais na plataforma continental rasa do RN nos limites da folha Touros

Ara?jo Filho, Lino Pedro de 28 February 2011 (has links)
Made available in DSpace on 2015-03-13T17:08:32Z (GMT). No. of bitstreams: 1 LinoPAF_DISSERT.pdf: 3570938 bytes, checksum: 9f6e2a321c5dc93388c87d95193a12d6 (MD5) Previous issue date: 2011-02-28 / Universidade Federal do Rio Grande do Norte / This work focuses the geomorphological characterization and spatial data modeling in the shallow continental shelf within the Folha Touros limits (SB-25-CV-II), based on bathymetric data analysis and remote sensing products interpretation. The Rio Grande do Norte state is located in northeastern Brazil and the work area is located at the transition region between the eastern and northern portions of their coast. The bathymetric surveys were conduced between march and may 2009, using a 10 meters long vessel and 0.70 meters draught, equipped with global positioning system and echo sounder (dual beam, 200KHz , 14?). The fieldwork resulted in 44 bathymetric profiles espaced 1.5 km and 30 km average length. The bathymetric data amount were 111,200 points and were navigated 1395.7 km within na area about 1,850 km2. The bathymetric data were corrected for the tide level, vessel draught and were subsequently entered into a geographic information system for further processing. Analysis of remote sensing products was carried out using Landsat 7/ETM + band 1, from november 1999. The image was used for visualization and mapping submerged features. The results showed the presence of geomorphological features within the study area. Were observed, from the analysis of local bathymetry and satellite image, seven types of geomorphological features. The channels, with two longitudinals channels (e. g. San Roque and Cioba channels) and other perpendicular to the coast (e. g. Touros, Pititinga and Barretas). Coastal reef formations (Maracaja?, Rio do Fogo and Cioba). Longitudinal waves, described in the literature as longitudinal dunes. The occurrence of a transverse dune field. Another feature observed was the oceanic reefs, an rock alignment parallel to the coast. Were identified four riscas , from north to south: risca do Liso, Gameleira, Zumbi, Pititinga (the latter being described for the first time). Finally, an oceanic terrace was observed in the deepest area of study. Image interpretation corroborated with the in situ results, enabling visualization and description for all features in the region. The results were analysed in an integrating method (using the diferent methodologies applied in this work) and it was essential to describe all features in the area. This method allowed us to evaluate which methods generated better results to describe certain features. From these results was possible to prove the existence of submerged features in the eastern shallow continental shelf of Rio Grande do Norte. In this way, the conclusions was (1) this study contributed to the provision of new information about the area in question, particularly with regard to data collection in situ depths, (2) the method of data collection and interpretation proves to be effective because, through this, it was possible to visualize and interpret the features present in the study area and (3) the interpretation and discussion of results in an integrated method, using different methodologies, can provide better results / O objetivo deste trabalho ? apresentar uma caracteriza??o geomorfol?gica e a modelagem de dados espaciais na plataforma continental rasa nos limites da Folha Touros (SB-25-V-C-II), com base na an?lise/interpreta??o de dados batim?tricos e produtos de sensores remotos orbitais. O Estado do Rio Grande do Norte est? localizado na regi?o nordeste do Brasil e a ?rea de trabalho situa-se na regi?o de transi??o entre as por??es oriental e setentrional de sua plataforma. Para o desenvolvimento das an?lises foram realizados levantamentos batim?tricos entre os meses de mar?o e maio de 2009, utilizando-se uma embarca??o com 10 metros de comprimento e 0,70 metros de calado, equipada com sistema de posicionamento global e ecossonda (feixe duplo, 200KHz, 14?). A campanha resultou em 44 perfis batim?tricos com espa?amento de 1,5 km e extens?o m?dia de 30 km. O montante das campanhas foi de 111.200 pontos v?lidos de profundidade em 1.395,7 km navegados numa ?rea de 1.850 km2. Os dados batim?tricos foram corrigidos em rela??o ao n?vel de mar?, calado da embarca??o e posteriormente foram inseridos em um sistema de informa??es geogr?ficas para outros processamentos. Para o desenvolvimento das an?lises, a partir de produto de sensor remoto orbital, foi utilizada a banda 1 do Landsat 7/ETM+, de 19 de novembro de 1999. A imagem foi utilizada para visualiza??o e mapeamento de fei??es submersas. Os resultados obtidos evidenciaram, de forma muito expressiva, a presen?a de fei??es geomorfol?gicas caracter?sticas da regi?o em estudo. Foram observados, a partir da an?lise da batimetria local e imagem orbital sete tipos de fei??es geomorfol?gicas. Os canais, com a presen?a de canais longitudinais (e. g. canal de S?o Roque, Cioba de Dentro e Cioba de Fora) e outros perpendiculares a costa (e. g. Touros, Pititinga e Barretas). Os altos costeiros, caracterizados como forma??es recifais, sendo estes os altos de Maracaja?, Rio do Fogo e Cioba. As ondula??es longitudinais, descritas na literatura como sendo dunas longitudinais. Foi verificada a presen?a de um campo de dunas transversais. Outra fei??o observada foi o alto oce?nico, um alinhamento rochoso paralelo a costa. Foram identificadas quatro riscas, de norte para sul: risca do Liso, Gameleira, Zumbi, Pititinga (esta ?ltima sendo descrita pela primeira vez). Por fim, um terra?o oce?nico foi observado na regi?o mais profunda da ?rea de estudo. A interpreta??o das imagens corroboraram com os resultados in situ, sendo poss?vel vizualisar e descrever todas as fei??es existentes na regi?o. A integra??o dos resultados, das metodologias aplicadas neste trabalho, foi fundamental para que todas as fei??es existentes na ?rea fossem amplamente discutidas e possibilitou avaliar quais m?todos geraram melhores resultados para descrever certas fei??es. A partir dos resultados obtidos foi poss?vel comprovar a existencia de fei??es submersas na plataforma continental rasa do litoral oriental do Rio Grande do Norte. Desta forma, foi poss?vel destacar que (1) o presente trabalho contribuiu com a disponibiliza??o de novas informa??es a respeito da ?rea em quest?o, principalmente no que diz respeito a coleta de dados in situ de profundidades, (2) o m?todo de coleta e interpreta??o dos dados se mostrou eficiente visto que, por meio deste, foi poss?vel visualizar e interpretar as fei??es presentes na ?rea em estudo e (3) a interpreta??o e discuss?o dos resultados de forma integrada, entre diferentes metodologias, podem fornecer melhores resultados
33

Panorama da poluição costeira por pellets de plástico em praias de SP (Brasil): uma contribuição aos estudos de geografia do litoral / Panorama of the coastal pollution through plastic pellets in beaches of SP (Brazil): a contribution to Coastal Geography studies

Plínio Martins Falcão 17 September 2015 (has links)
O lixo marinho é um problema discutido desde a década de 1970, quando cientistas começaram a observar e quantificar materiais diversos nos mares e costas de alguns países, como por exemplo os plásticos. Nessa categoria se encontram os pellets de plástico, que constituem a matéria-prima de base para a produção da indústria mundial de insumos plásticos. Desde então o tema é tratado entre as formas de poluição marinha e costeira mais observadas. A pesquisa foi desenvolvida no litoral do Estado de São Paulo (Brasil), na qual se avaliou a presença de pellets e os mecanismos de sua distribuição, realizada em duas etapas: a primeira, em 55 praias de 15 municípios entre o Litoral Norte, a Baixada Santista e o Litoral Sul. A segunda, em 9 praias da Região Metropolitana da Baixada Santista. Pesquisa bibliográfica, documental, trabalhos de campo e de laboratório formaram as etapas da investigação, para a qual foram usados métodos de amostragem. Os resultados obtidos levaram à conclusão da maior concentração de pellets nas praias próximas às áreas consideradas pelo estudo como fontes emissoras do material no mar, como as zonas portuárias / industriais de São Sebastião, Santos e a de Paranaguá (Paraná). Ao longo das praias, foi constatado que os eventos extremos de ressacas / marés meteorológicas são os principais responsáveis pela distribuição dos pellets de plástico nas praias. A principal contribuição do trabalho foi a inclusão da temática da poluição costeira nos estudos de Geografia do Litoral, uma demanda desafiadora para a Geografia brasileira. / Marine debris is an issue discussed since the 1970s, when scientists began to observe and quantify different materials in the seas and coastlines of some countries, such as plastics. In this category are the plastic pellets, which are the basic raw material for the production of plastics industry worldwide inputs. Since then the issue is treated between forms of marine pollution and more coastal observed. The research was conducted in the São Paulo state coast (Brazil), in which it evaluated the presence of pellets and the mechanisms of its distribution, carried out in two stages: the first, on 55 beaches in 15 municipalities across the North Coast, the Baixada Santista and the South Coast. The second, on 9 beaches of Baixada Santista. Bibliographical research, documental, field work and laboratory formed the stages of the investigation, for which sampling methods were used. The results led to the conclusion of the higher concentration of pellets at the nearby beaches to areas considered by the study as sources emitting material at sea, such as port / industrial areas of São Sebastião, Santos and Paranaguá (Paraná). Along the beaches, it was found that extreme storm surge events are mainly responsible for the distribution of plastic pellets on beaches. The main contribution of this study was the inclusion of the issue of coastal pollution in the studies of Geography of the Coastline, a challenging demand for Brazilian Geography.
34

Dynamique des environnements fluvio-lagunaires du Narbonnais à l'Holocène (Golfe du Lion, France) / Holocene fluvio-lagoonal environments of Narbonne coast (Gulf of Lion, France)

Salel, Tiphaine 13 December 2018 (has links)
Le paysage littoral de la basse vallée de l’Aude est composé d’une mosaïque de milieux laguno-deltaïques mobiles à l’échelle des derniers millénaires. Du fait de cette mobilité et de l’ancienneté de l’occupation humaine, continue depuis le Néolithique, la compréhension des dynamiques environnementales passées constitue une problématique incontournable de la recherche archéologique narbonnaise. Le travail que nous présentons vise à identifier et expliquer les transformations de ce paysage fluvio-lagunaire à l’Holocène, à partir de l’analyse sédimentologique et micropaléontologique des enregistrements sédimentaires datés au radiocarbone. Dans un premier temps, une étude de la répartition spatiale actuelle des ostracodes des lagunes et embouchures fluviales modernes est proposée en vue d’utiliser cette microfaune comme bioindicateur privilégié des conditions environnementales passées dans la zone d’étude. Elle repose sur le prélèvement d’une soixantaine d’échantillons de sédiments de surface provenant de différents complexes paraliques de Méditerranée nord-occidentale. Les assemblages d’ostracodes actuels permettent de caractériser différents stades d’isolement des bassins, des lagunes complètement fermées jusqu’aux baies largement ouvertes sur la mer, ainsi que la variabilité intra-lagunaire des milieux en relation avec la proximité des embouchures et des graus. La base de données présentée peut être utilisée, à titre comparatif, pour reconstituer les dynamiques géomorphologiques littorales holocènes, telles que la mobilité deltaïque et l’évolution des systèmes barrières-lagunes, dans le golfe du Lion. Dans un second temps, l’étude des enregistrements sédimentaires a permis d’appréhender l’évolution du littoral narbonnais à l’Holocène. Elle repose sur neuf sondages carottés répartis sur les deux branches deltaïques, méridionale et orientale, de l’Aude. Les résultats obtenus permettent de proposer un scénario paléogéographique reconstituant la dynamique des environnements de la basse vallée depuis 9500 ans cal. BP, en même temps qu’ils renseignent le contexte local de la remontée du niveau marin holocène dans l’intervalle 9500-6000 ans cal. BP. Plusieurs problématiques sous-jacentes à l’évolution des paléoenvironnements littoraux narbonnais sont discutées. Elles concernent les modalités de la transgression holocène dans les lagunes du golfe du Lion, l’enregistrement d’un événement marin extrême en fond de ria vers 5200-5000 ans cal. BP, et le rythme de progradation accéléré du delta de l’Aude durant le dernier millénaire. L’identification de deux périodes d’enrichissement en plomb cohérentes avec les principaux pics d’exploitation minière connus en Languedoc à la charnière du changement d’ère et au début du Moyen-âge classique suggère un enregistrement de la fluctuation historique des activités métallurgiques. / The present day Aude valley’s coastal landscape is the result of unstable lagoonal and deltaic environments during the last millennia. The understanding of past environmental dynamics is a key issue of the local ar-chaeological research, because since the Neolithic period human beings have settled in this area. This work aims to identify and explain the fluvio-lagoonal landscape’s evolution in the Narbonne region during the Holocene by using sedimentology, micropalaeontology and radiocarbon sediment datations. First, we analysed the present ostracods spatial distribution in modern lagoons and river mouths in order to use this microfauna as a bioindicator of past environmental conditions in the study area. Various aquatic envi-ronments (60) from the NW Mediterranean coastline were studied. The present ostracod assemblages characterize different stages of isolation, from completely closed lagoons to widely open marine bays, as well as intra-lagoonal environmental variability in relation to the inlets and river mouth proximities. The proposed database can be used to reconstruct coastal geomorphologies and dynamics, such as the holocene evolution of delta and barrier-lagoon systems in the Gulf of Lion. Second, sedimentary recording studies have been used to analyse the Narbonne’s coastal evolution. This study is based on nine cores distributed over the southern and eastern deltaic branches of the Aude river. With theses results, it is possible to propose a palaeogeographic scenario associated with the environmental dynamics of the lower valley since 9500 years cal. BP. This same data informs us about the local context of the Holocene sea level rise during the 9500-6000 years cal. BP. Several issues are discussed such as : the Holocene’s transgressions of the Gulf of Lion’s lagoons, the extreme marine event near the bay head delta around 5200-5000 years cal. BP, and the Aude delta’s rapid progradation during the last millennium. Additionally, we identified two periods of lead enrichment; which are consistent with the major mining peaks known in Languedoc (beginning of the first century AD - beginning of the classical Middle ages) and suggest a record of fluctuating metallurgical activity.
35

Avaliação de impactos ambientais no município de Ubatuba: uma proposta a partir dos geoindicadores / Evaluation of environmental impacts in Ubatuba: a proposal based on geoindicators

Buzato, Esmeralda 23 November 2012 (has links)
As características ambientais do município de Ubatuba, localizado no litoral norte do Estado de São Paulo, foram modificadas nos últimos 100 anos por causa da dinâmica natural própria de áreas costeiras e das modificações decorrentes da intervenção antrópica. Estas mudanças foram acentuadas a partir da década de 1970 com a construção da rodovia BR 101 gerando impactos em diversos setores da área do município. A paisagem atual mostra o setor norte mais preservado e os setores centro e sul mais impactados. Levantamentos de campo e análises cartográficas - que incluíram sensoriamento remoto identificaram cinco compartimentos representativos dos setores sul, centro e norte da área de pesquisa para avaliação detalhada dos efeitos do uso e ocupação da terra e outras intervenções antrópicas nas mudanças ambientais. Esta avaliação foi baseada nos princípios dos geoindicadores propostos por Berger (1996) e da geomorfologia aplicada. Os procedimentos adotados mostraram que na faixa onde confluem processos continentais e marinhos é possível descrever e avaliar alterações naturais e induzidas pela intervenção antrópica mediante a aplicação dos geoindicadores. Na área da pesquisa foi possível estabelecer a cronologia e o caráter das mudanças de origem antrópica em um prazo aproximado de sessenta anos para mudanças mais recentes, e outro de aproximadamente cem anos, que abrange tantos registros históricos (documentos das prefeituras) como evidências da vegetação secundária em áreas de mata atlântica em fotografias aéreas. O conceito de geoindicador aponta a possibilidade de identificar essas mudanças ocorridas em períodos de cem anos ou menos se utilizando de técnicas simples e de baixo custo que permitam estabelecer, se possível, comparações entre áreas preservadas e áreas modificadas de forma natural ou induzida. Os resultados obtidos servem como subsídios para orientar políticas públicas voltadas à gestão ambiental territorial de regiões litorâneas. / The environmental characteristics of Ubatuba, located on the northern coast of São Paulo, were modified in the last 100 years because of the dynamic nature of coastal areas and changes resulting from human intervention. These changes increased since the 1970s with the construction of the BR 101 highway generating impacts in diverse sectors of the municipality. Nowadays the landscape shows a best preserved northern sector and two decaying ones in the central and southern areas. Field surveys and cartographic analysis - including remote sensing, identified five compartments representing the southern, central and northern research areas for detailed evaluation of effects of land use and occupation and other human interventions in environmental changes. This evaluation was based on the principles of geoindicators proposed by Berger (1996) and applied geomorphology. Later proceedings showed that where continental and marine processes converge it is possible to describe and evaluate natural and anthropogenic changes by applying geoindicators. In the research area it was also possible to identify the chronology and character of changes of anthropogenic origin for approximately the last sixty years for more recent changes, and another one around a hundred years covering many historical records (municipal documents) as well as evidences of secondary vegetation in Atlantic forest areas in aerial photographs. The geoindicator concept suggests the possibility to identify those changes for around one hundred years or less by using simple and low cost techniques to validate if possible comparisons among preserved areas and naturally or induced modified areas. Final data will serve as inputs to support public policies for regional environmental management in coastal regions.
36

Erosive water levels and beach-dune morphodynamics, Wickaninnish Bay, Pacific Rim National Park Reserve, British Columbia, Canada

Heathfield, Derek Kenneth 10 September 2013 (has links)
Increases in the frequency and magnitude of extreme water levels and storm surges are observed along some areas of the British Columbia coast to be correlated with known climatic variability (CV) phenomena, including the El Niño/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). Since a shift to a positive PDO regime in 1977, the effect of ENSO events have been more frequent, persistent, and intense. Teleconnected impacts include more frequent storms, higher surges, and greater coastal erosion. Geomorphic recovery of regional beach-dune systems from erosive events is usually rapid (i.e., within a year) by way of high onshore sand transport and aeolian delivery to the upper beach and dunes. At Wickaninnish Bay on the west coast of Vancouver Island, fast progradation rates (to +1.46 m a-1) have been observed in recent decades, in part due to rapid regional tectonic uplift and a resulting fall in relative sea level of ~ -0.9 mm a-1. The Wickaninnish foredune complex has rapidly extended alongshore in response to a net northward littoral drift and onshore sediment delivery. Bar deposition and welding processes supply sediment to the foredune complex via aeolian processes, and as a result, this is forcing Sandhill Creek northward toward the prograding (+0.71 m a-1) Combers Beach system, in part maintaining active erosion (-1.24 m a-1) of a bluff system landward of the channel. Bluff erosion generates substantial sediment volumes (-0.137 m3 m-2 a-1) that feed a large intertidal braided channel and delta system as the creek purges into the Pacific Ocean. As a first step in exploring the interactions between ocean-atmosphere forcing and beach-dune responses on the west coast of Vancouver Island, British Columbia, Canada, the proposed thesis: 1) Examines and assembles the historic erosive water level regime and attempts to draw links to observed high magnitude storm events that have occurred in the Tofino-Ucluelet region (Wickaninnish Bay); and 2) Explores the geomorphic response of local shorelines by examining the geomorphology and historical evolution of a foredune-riverine-backshore bluff complex. Despite rapid shoreline progradation, foredune erosion occurs locally with a recurrence interval of ~1.53 yrs. followed by rapid rebuilding, often in the presence of large woody debris and rapidly colonizing vegetation, which drives a longer-term trend of shoreline progradation. This process is complicated locally, however, by the influence of local geological control (bedrock headlands) and backshore rivers, such as Sandhill Creek, which alter spatial-temporal patterns of both intertidal and supratidal erosion and deposition. This work is necessary to understand mechanisms responsible for erosive water levels and the process interaction responsible for subsequent coastal rebuilding following erosive periods. / Graduate / 0368 / derek.heathfield@gmail.com
37

Investigating Time Series Shoreline Changes By Integration Of Remote Sensing And Geographical Information Systems

Fulat, Alper Ihsan 01 December 2005 (has links) (PDF)
Spatial analyses of shoreline recession and accretion, and future shoreline position predictions in coastal countries have considerable importance due to engineering, planning, management and environmental concerns. In spite of this importance, there are only a few studies in Turkey. The aim of this thesis are to determine the shoreline rate-of-change of B&uuml / y&uuml / k Menderes Delta, by geographical information systems for the last fifty-year period, in order to approximate future shoreline position of B&uuml / y&uuml / k Menderes Delta shoreline, and to evaluate appropriate models while predicting the future shoreline position. To achieve the purpose of the study time series shoreline position data is extracted from three sets of topographic maps belonging to 1954-1957, 1977-1978 and 1993 aerial photographs and two sets of high resolution satellite imageries (January 2002 Ikonos, August 2004 QuickBird). Then Coastal script of TNTMips, which uses some statistical shoreline analyses methods, that are End Point Rate (EPR), Average of Rates (AOR), Linear Regression (LR) and Jackknifing (JK) is edited so that it can locate the future shoreline positions on the map. Suitable baselines are created and appropriate transect intervals are decided to analyze the shoreline. Finally, some additional analyses that are Backward Analysis and Oscillation Analysis are done to obtain most suitable future shoreline position with rate-of-changes. The results showed that, shorelines having different geomorphologic characteristics needed to be analyzed separately and the linear methods to model the future shoreline position differ from one geomorphologic region to another.
38

Évolution morphologique actuelle d'une flèche littorale holocène : le Cap Ferret, à l'embouchure du Bassin d'Arcachon / Ongoing morphological evolution of a Holocene coastal barrier spit : the Cap Ferret, at the entrance of the Bay of Arcachon

Nahon, Alphonse 05 October 2018 (has links)
La flèche littorale du Cap Ferret s'est édifiée au cours des derniers 3 000 ans, à la faveur du ralentissement de l'élévation du niveau global des océans. Depuis 250 ans, les cartes marines révèlent une importante instabilité de l'extrémité libre de la flèche, à laquelle les travaux présentés dans ce mémoire tentent d'apporter une explication physique. Dans un premier temps le croisement des données cartographiques avec des données environnementales révèle la synchronisation des déplacements de la flèche avec d'une part l'Oscillation Nord Atlantique (NAO), et, d'autre part, les structuations décennales à multidécennales de la vitesse de l'élévation du niveau de l'Atlantique Nord-est. Les processus sous-jacents à cette synchronisation sont alors détaillés avec un modèle numérique de transport sédimentaire. Puis, l'érosion chronique de la flèche entre 1986 et 2016, ainsi que les mécanismes d'évolution de la plage océanique de la Pointe du Cap Ferret sont décrits et quantifiés à l'aide de données topographiques. A l'échelle locale, ces résultats apportent des preuves tangibles du rôle du climat dans l'érosion actuelle de la Pointe du Cap Ferret. D'un point de vue plus général, ces travaux contribuent à la meilleure description des processus contrôlant l'évolution des systèmes de barrières holocènes, dans le contexte actuel d'accélération de l'élévation du niveau de la mer. / Low rates of global sea level rise have allowed the Cap Ferret coastal barrier-spit to develop since about 3 000 years ago. Over the last 250 years, navigation charts attest of a significant instability of the distal end of the spit, to which the present study aims to provide a physical explanation. First, the crossing of cartographic data with meteoceanic data reveals a strong relationship of the spit-end behaviour with, on the one hand, the North Atlantic Oscillation (NAO), and, on the other hand, decadal to multidecadal variations in the rate of sea level rise in the Northeast Atlantic. Underlying processes were then investigated using a numerical model for sediment transport. Finally, the chronic erosion of the spit between 1986 and 2016, as well as the evolution mechanisms of the oceanic beach of the spit-end are described and quantified by means of topographic data. Locally, these results support the role of climate in the ongoing erosion of the spit-end. From a wider perspective, this study brings new insigths on the processes controling the evolution of Holocene barrier systems, in the present context of an accelerating sea level rise.
39

Avaliação de impactos ambientais no município de Ubatuba: uma proposta a partir dos geoindicadores / Evaluation of environmental impacts in Ubatuba: a proposal based on geoindicators

Esmeralda Buzato 23 November 2012 (has links)
As características ambientais do município de Ubatuba, localizado no litoral norte do Estado de São Paulo, foram modificadas nos últimos 100 anos por causa da dinâmica natural própria de áreas costeiras e das modificações decorrentes da intervenção antrópica. Estas mudanças foram acentuadas a partir da década de 1970 com a construção da rodovia BR 101 gerando impactos em diversos setores da área do município. A paisagem atual mostra o setor norte mais preservado e os setores centro e sul mais impactados. Levantamentos de campo e análises cartográficas - que incluíram sensoriamento remoto identificaram cinco compartimentos representativos dos setores sul, centro e norte da área de pesquisa para avaliação detalhada dos efeitos do uso e ocupação da terra e outras intervenções antrópicas nas mudanças ambientais. Esta avaliação foi baseada nos princípios dos geoindicadores propostos por Berger (1996) e da geomorfologia aplicada. Os procedimentos adotados mostraram que na faixa onde confluem processos continentais e marinhos é possível descrever e avaliar alterações naturais e induzidas pela intervenção antrópica mediante a aplicação dos geoindicadores. Na área da pesquisa foi possível estabelecer a cronologia e o caráter das mudanças de origem antrópica em um prazo aproximado de sessenta anos para mudanças mais recentes, e outro de aproximadamente cem anos, que abrange tantos registros históricos (documentos das prefeituras) como evidências da vegetação secundária em áreas de mata atlântica em fotografias aéreas. O conceito de geoindicador aponta a possibilidade de identificar essas mudanças ocorridas em períodos de cem anos ou menos se utilizando de técnicas simples e de baixo custo que permitam estabelecer, se possível, comparações entre áreas preservadas e áreas modificadas de forma natural ou induzida. Os resultados obtidos servem como subsídios para orientar políticas públicas voltadas à gestão ambiental territorial de regiões litorâneas. / The environmental characteristics of Ubatuba, located on the northern coast of São Paulo, were modified in the last 100 years because of the dynamic nature of coastal areas and changes resulting from human intervention. These changes increased since the 1970s with the construction of the BR 101 highway generating impacts in diverse sectors of the municipality. Nowadays the landscape shows a best preserved northern sector and two decaying ones in the central and southern areas. Field surveys and cartographic analysis - including remote sensing, identified five compartments representing the southern, central and northern research areas for detailed evaluation of effects of land use and occupation and other human interventions in environmental changes. This evaluation was based on the principles of geoindicators proposed by Berger (1996) and applied geomorphology. Later proceedings showed that where continental and marine processes converge it is possible to describe and evaluate natural and anthropogenic changes by applying geoindicators. In the research area it was also possible to identify the chronology and character of changes of anthropogenic origin for approximately the last sixty years for more recent changes, and another one around a hundred years covering many historical records (municipal documents) as well as evidences of secondary vegetation in Atlantic forest areas in aerial photographs. The geoindicator concept suggests the possibility to identify those changes for around one hundred years or less by using simple and low cost techniques to validate if possible comparisons among preserved areas and naturally or induced modified areas. Final data will serve as inputs to support public policies for regional environmental management in coastal regions.

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