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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.
1

Spectral Analysis of Atmospheric Pollutants in the Upper Great Lakes Region

Hassan, Ishmael 04 1900 (has links)
<p> Chemical data from atmospheric precipitation in the Upper Great Lakes region were collected on a monthly basis by various organizations from late 1972 to late 1975. The data for pairs of chemical parameters are regarded as simultaneously recorded time series and are analyzed by spectral analysis to bring out periodic components present in both time series and also to reflect the correlation and phase difference between the pairs of time series.</p> <p> The precipitation data have four major bands of periodicities: (1) a yearly cycle representing high and low atmospheric loadings in the summer and winter respectively with regards to Fe, PART, SO4 and P; (2) a 6 monthly period reflecting the four seasons of the year and affecting Fe, PART, P and pH; (3) a 9 monthly period for the heavy metals (Cu, Ni, Cd, Pb and Zn); and (4) 2 to 5 cycles/month periodicities caused by atmospheric turbulence and affecting all the parameters.</p> <p> The mining-smelting industry at Sudbury has been identified as a major point source of atmospheric emissions of acid, sulfate and the heavy metals, with the exception of iron, This is evident in view of the facts that the spectral intensities at the major periodicities decrease away from the mining-smelting centre; the strikingly high correlation and practically inphase relationship between Cu and Ni, and the 9 monthly period for the heavy metals which is associated with the industry.</p> / Thesis / Bachelor of Science (BSc)
2

Aspectos da biogeoquímica do mercúrio em lagos na planície costeira do Rio Grande do Sul

Kütter, Vinicius Tavares January 2006 (has links)
Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2006. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-03-12T14:43:01Z No. of bitstreams: 1 Kutter.pdf: 589899 bytes, checksum: 1ddba4cf713f5288dab0784d9fa6dd21 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-04-25T13:03:10Z (GMT) No. of bitstreams: 1 Kutter.pdf: 589899 bytes, checksum: 1ddba4cf713f5288dab0784d9fa6dd21 (MD5) / Made available in DSpace on 2013-04-25T13:03:10Z (GMT). No. of bitstreams: 1 Kutter.pdf: 589899 bytes, checksum: 1ddba4cf713f5288dab0784d9fa6dd21 (MD5) Previous issue date: 2006 / No ambiente aquático um dos mais perigosos contaminantes é o mercúrio.A contaminação por mercúrio na cadeia trófica em ambientes aquáticos pode ser severa e persistente, uma das principais fontes de contaminação por mercúrio em humanos através da cadeia alimentar são os peixes. Nesse estudo:- Foram mensurados os níveis de mercúrio em três lagos no extremo sul do Brasil e avaliou-se a relação entre mercúrio na precipitação atmosférica total, material particulado no ar, material particulado na água dos lagos, sedimentos, solo e água subterrânea as margens dos lagos, plantas aquáticas, molusco aquático e peixes de áreas próximas às fontes de emissão de mercúrio (áreas: industrial e suburbana) e distante das fontes de mercúrio (área de reserva natural).- Foram mensurados os níveis de mercúrio em vinte e sete espécies de peixes de quatro ambientes (lago fechado, lago aberto, estuário, marinho). Simulou-se o aporte de mercúrio atmosférico para os lagos, através de um experimento. No qual adicionou-se poeira contaminada por mercúrio em tanques contendo: peixe, sedimento e plantas aquáticas. As concentrações de mercúrio no sedimento e nas plantas aquáticas não demonstraram variação entre os lagos. Em molusco, água subterrânea, e material particulado na água dos lagos apresentam diferença muito pequena entre as três áreas estudadas. No entanto, o nível de mercúrio na precipitação atmosférico nesses lagos estudado apresentou aumento com a proximidade da fonte industrial. Mercúrio no tecido de peixe geralmente aumenta ao longo do mesmo gradiente, mas varia com o nível trofico. A concentração de mercúrio em peixe pode estar diretamente relacionada com a concentração de mercúrio na deposição atmosférica nesses lagos fechados. Foram encontradas altas concentrações de mercúrio em peixes do lago fechado na área suburbana, em relação ao lago aberto, estuário e oceano. Em todos os ambientes, as espécies piscívoras apresentaram maior valor de mercúrio no tecido do que as espécies não piscívoras. A simulação do processo de contaminação por mercúrio através do depósito das precipitações atmosféricas na superfície da água em laboratório demonstrou acumulação progressiva de mercúrio nas plantas aquáticas e no sedimento. / Mercury is one of the most hazardous contaminant in aquatic environment. Mercury contamination in aquatic environment food webs can be severe and persistent, and fish are a major source of mercury contamination in humans across food web. In this study: - Was measured mercury levels at three lakes in southern Brazil and assessed relationships between mercury in atmospheric precipitation, particulate matter in lake water, sediment, soil near the lake, groundwater, aquatic plants, aquatic mollusc and fish tissues at sites close to (industrial and suburban areas) and distant from (protected conservation area) sources of mercury emissions. - Mercury levels are measured in twenty-seven fish species from four sites (close lake, open lake, estuary, marine). Was simulated the input of mercury at atmosphere from lake, through the experiment. In this experiment to add the dust contamination with mercury in pools contained: fish, sediments and aquatic plants. Also assessed relationship between mercury in fish species and their trophic habits. Mercury concentrations in sediment and aquatic plants did not significant variation among lakes. In aquatic mollusc, groundwater and particulate matter in lake water has small difference between the three sites. In contrast, mercury in precipitation at the study lakes increased with proximity to industrial sources. Mercury in fish tissue generally increased along the same gradient, but also varied with trophic level. Atmospheric mercury deposition to these closed lakes may be directly linked to concentrations in fish. Was finding the highest mercury concentration in fish from close lake in relation than open lake, estuary and ocean. In every site the piscivorous species present more mercury in tissue than species non-piscivorous. The simulation of process of mercury contamination through the deposition of atmospheric precipitation in the water surface in laboratory demonstrates progressive mercury accumulation in aquatic plants and sediment.
3

[en] ATMOSPHERIC INPUTS OF NUTRIENTS AND POLLUTANTS INTO URBAN FOREST ECOSYSTEM, MACIÇO DA PEDRA BRANCA RJ / [pt] ENTRADAS ATMOSFÉRICAS DE NUTRIENTES E POLUENTES EM UM ECOSSISTEMA FLORESTAL URBANO, MACIÇO DA PEDRA BRANCA RJ

ANDREA TEIXEIRA DE FIGUEIREDO CINTRA 30 December 2004 (has links)
[pt] A ciclagem de nutrientes em ecossistemas florestais constitui um processo de troca dinâmica entre os componentes bióticos e abióticos. A precipitação pluviométrica é uma vertente do processo de ciclagem, representando uma importante fonte de entrada de nutrientes e de eventuais poluentes em ecossistemas localizados próximo a fontes poluidoras. O perfil de ciclagem e alocação de nutrientes de uma região influenciam a fisiologia, biologia de plantas e animais em florestas, além de auxiliar no entendimento de processos sucessionais. O presente estudo foi feito em área de Mata Atlântica na zona oeste do Rio de Janeiro. Os aportes atmosféricos de nutrientes e poluentes foram determinados pela análise da composição química da água da chuva incidente sobre a floresta e da que atravessou o dossel, coletadas por meio de pluviômetros espalhados aleatoriamente. Para as determinações químicas as técnicas empregadas foram espectrometria de emissão ótica com plasma indutivamente acoplado (ICPOES) e espectrometria de massas com plasma indutivamente acoplado (ICPMS). Para as análises de ânions empregou-se a técnica de cromatografia de íons com detecção condutimétrica após supressão química. A precipitação pluviométrica no período de estudo (de 21/11/02 a 7/11/03) foi de 1708 mm, sendo o valor médio de interceptação pelas copas das árvores de 28 por cento. Quanto ao aporte de nutrientes, as maiores massas foram de K e Ca, com respectivamente 10,3 e 4,8 Kg/há/ano. Quanto ao aporte de metais, as maiores entradas foram de Zn (375 g/ha/ano) e Mn (46,2 g/ha/ano). Fatores de enriquecimento de até 18 foram encontrados. Atribui-se a presença de metais traço na precipitação total e na interna à proximidade da área de estudos em relação à metrópole do Rio de Janeiro. / [en] The cycling of nutrients in forest ecosystems is a dynamics exchange process between biotic and abiotic components. Pluviometric precipitation is one of the processes which affect cycling, representing one important source for the input of nutrients and potential pollutants in ecosystems situated close to polluting sources. The cycling profile and the availability of nutrients in a forest region influence the physiology, the biology of plants and help to understand seasonal processos. The present study was performed in a region of the Atlantic Forrest (Mata Atlântica) in the west zone of Rio de Janeiro. The atmospheric inputs of nutrients and pollutants were measured by the analysis of rainwater, incident to the forest and that fraction penetrating the dossel. Water samples were collected by means of randomly distributed pluviometers. Elemental determinations were performed by optical emission spectrometry (OES) and by mass spectrometry (MS), both using inductively coupled plasma (ICP) as excitation/ionization source. Determination of anions was made by ion chromatography with conductimetric detection after chemical suppression. Pluviometric precipitation, during the time period studied from 11/21/02 to 11/07/03, was in an average 1708 mm, being the mean value intercepted by the canopy about 14 percent. Considering the input of nutrients, the largest contributions are from K and Ca with 10.3 and 4.8 Kg/ha/year, respectively. As regard to minor nutrients, Zn (375 g/ha/ano) and Mn (46.2 g/ha/ano) gave the major inputs. Calculated enrichment factors (EF) varied strongly from one element to the other. High values (EF > 100) were observed for some heavy metals (p.ex. Cd, Sb, Hg), indicating the proximity of polluting sources, as could be expected from the close vicinity of the studied area to the main city of do Rio de Janeiro.
4

O impacto do desmatamento no ciclo hidrológico: um estudo de caso para a rodovia Cuiabá-Santarém / The impact of the ongoing deforestation on the hydrological cycle: a case study of the Cuiabá-Santarém highway

Rosolem, Rafael 31 October 2005 (has links)
Este trabalho buscou quantificar alguns impactos no ciclo hidrológico, especialmente o padrão de precipitação, decorrentes do desmatamento regional nas proximidades da rodovia Cuiabá-Santarém (BR-163), por meio de um experimento numérico de simulação da atmosfera com o modelo RAMS (Regional Atmospheric Modeling System), na versão brasileira (Brazilian RAMS – BRAMS), com alta resolução (célula de 16x16 km). Foi utilizado um cenário de desmatamento, provido por modelos empíricos de desmatamento, para o ano de 2026, numa situação sem governância, com um tempo de simulação de 40 dias entre 20 de Outubro a 30 de Novembro. Os dados de forçamento na fronteira utilizaram a reanálise do NCEP para o ano de 2002. Houve uma redução média de 7% do padrão de chuva na região após o desmatamento, na área perturbada, e não houve efeitos substanciais nas regiões além da fronteira de desmatamento como um todo. Porém, a distribuição heterogênea do uso da terra induziu à formação de uma célula térmica, sobre a região desmatada, que resultou em uma certa variabilidade espacial da chuva próxima ao setor de desmatamento. Uma célula térmica induziu o levantamento de massa (por convergência) aproximadamente acima da região desmatada, carregando vapor d’água proveniente das regiões de floresta nas adjacências, e promovendo a formação de chuva convectiva. A extensão da célula, entre os dois ramos descendentes, foi aproximadamente o dobro da extensão da faixa de desmatamento. Neste caso da BR-163, a célula foi levemente deslocada para oeste, onde ocorreu aumento da precipitação. A leste, e sobre o setor central do desmatamento, houve redução da precipitação. Notou-se uma pequena mudança na distribuição da chuva ao longo do dia no caso do desmatamento, que não mostrou um horário de máxima precipitação bem definido, e também sugeriu um pequeno aumento da chuva no período noturno. As respostas ao desmatamento ocorreram de forma diferenciada conforme a faixa de topografia analisada. Nas áreas além das fronteiras do desmatamento, houve um pequeno sinal de redução da chuva, nos setores de cota superior à 500 m. / This study aim was to evaluate some impacts on the hydrological cycle, specially the precipitation pattern, due to the regional deforestation along the corridor of the Cuiaba-Santarem highway (BR-163), using a high resolution (16x16 km grid) atmospheric model, the Regional Atmospheric Modeling System (RAMS), in its Brazilian version, the Brazilian RAMS or BRAMS. A deforestation scenario for 2026 has been provided by empirical models of deforestation, under no governance conditions (also known as the business-as-usual scenario) and it has been used in this study. The time length of simulation was 40 days, from October 10th to November 30th. The forcing data of 2002 were provided by the NCEP/NCAR Reanalysis Project. Mean rainfall decreased 7% in the region in which the forest was replaced by pasture. There were no substantial changes where the forest land cover was kept undisturbed. However, the rainfall showed spatial variability due to the local circulation (thermal) induced by land cover heterogeneity. Over the pasture area (deforestation), hot air rises by convergence carrying water vapor from the undisturbed forest located close to the pasture increasing the convective precipitation. This local cell is approximately twice as big as the deforestation length. In the BR-163 study case, the cell was located nearest to the west side of the land cover transition area (forest-pasture) where the rainfall rate increased. On the east side and over the deforestation area, the precipitation rate was reduced. The diurnal cycle of the precipitation has been slightly changed in the deforestation case. During the day, it was not possible to identify the rainfall maximum while at night it suggested a slightly increase of precipitation. The response of the fluxes and surface variables may be different depending on its topography level. A small rainfall reduction has been observed where the forest was kept undisturbed over 500 meters.
5

Analýza významných srážkových událostí na povodí Kopaninského toku. / Analysis of selected precipitation events in the catchment of the Kopaninský stream.

ZAVŘEL, Bohuslav January 2014 (has links)
It is proven that the ongoing refinement of the quality of rainfall data hand in hand with time and space variability of the rainfall has immense effect on the management of watercourses, flood control and hydrologic modelling. The aim of this thesis is to do an analysis of selected precipitation events in the Kopaninský stream research basin for more accurate information on rainfall-runoff processes. The aim of the analysis of individual precipitation events is to evaluate differences in total precipitation and volume measurements recorded in the basin and radar estimated precipitation. The output is detailed data series of spatial and temporal distribution of major precipitation events in the GIS used as input to hydrologic models. The issues of atmospheric precipitatio and meteorological radars are discussed in the literature review, which explains selected basic concepts and principles of these topics.
6

O impacto do desmatamento no ciclo hidrológico: um estudo de caso para a rodovia Cuiabá-Santarém / The impact of the ongoing deforestation on the hydrological cycle: a case study of the Cuiabá-Santarém highway

Rafael Rosolem 31 October 2005 (has links)
Este trabalho buscou quantificar alguns impactos no ciclo hidrológico, especialmente o padrão de precipitação, decorrentes do desmatamento regional nas proximidades da rodovia Cuiabá-Santarém (BR-163), por meio de um experimento numérico de simulação da atmosfera com o modelo RAMS (Regional Atmospheric Modeling System), na versão brasileira (Brazilian RAMS – BRAMS), com alta resolução (célula de 16x16 km). Foi utilizado um cenário de desmatamento, provido por modelos empíricos de desmatamento, para o ano de 2026, numa situação sem governância, com um tempo de simulação de 40 dias entre 20 de Outubro a 30 de Novembro. Os dados de forçamento na fronteira utilizaram a reanálise do NCEP para o ano de 2002. Houve uma redução média de 7% do padrão de chuva na região após o desmatamento, na área perturbada, e não houve efeitos substanciais nas regiões além da fronteira de desmatamento como um todo. Porém, a distribuição heterogênea do uso da terra induziu à formação de uma célula térmica, sobre a região desmatada, que resultou em uma certa variabilidade espacial da chuva próxima ao setor de desmatamento. Uma célula térmica induziu o levantamento de massa (por convergência) aproximadamente acima da região desmatada, carregando vapor d’água proveniente das regiões de floresta nas adjacências, e promovendo a formação de chuva convectiva. A extensão da célula, entre os dois ramos descendentes, foi aproximadamente o dobro da extensão da faixa de desmatamento. Neste caso da BR-163, a célula foi levemente deslocada para oeste, onde ocorreu aumento da precipitação. A leste, e sobre o setor central do desmatamento, houve redução da precipitação. Notou-se uma pequena mudança na distribuição da chuva ao longo do dia no caso do desmatamento, que não mostrou um horário de máxima precipitação bem definido, e também sugeriu um pequeno aumento da chuva no período noturno. As respostas ao desmatamento ocorreram de forma diferenciada conforme a faixa de topografia analisada. Nas áreas além das fronteiras do desmatamento, houve um pequeno sinal de redução da chuva, nos setores de cota superior à 500 m. / This study aim was to evaluate some impacts on the hydrological cycle, specially the precipitation pattern, due to the regional deforestation along the corridor of the Cuiaba-Santarem highway (BR-163), using a high resolution (16x16 km grid) atmospheric model, the Regional Atmospheric Modeling System (RAMS), in its Brazilian version, the Brazilian RAMS or BRAMS. A deforestation scenario for 2026 has been provided by empirical models of deforestation, under no governance conditions (also known as the business-as-usual scenario) and it has been used in this study. The time length of simulation was 40 days, from October 10th to November 30th. The forcing data of 2002 were provided by the NCEP/NCAR Reanalysis Project. Mean rainfall decreased 7% in the region in which the forest was replaced by pasture. There were no substantial changes where the forest land cover was kept undisturbed. However, the rainfall showed spatial variability due to the local circulation (thermal) induced by land cover heterogeneity. Over the pasture area (deforestation), hot air rises by convergence carrying water vapor from the undisturbed forest located close to the pasture increasing the convective precipitation. This local cell is approximately twice as big as the deforestation length. In the BR-163 study case, the cell was located nearest to the west side of the land cover transition area (forest-pasture) where the rainfall rate increased. On the east side and over the deforestation area, the precipitation rate was reduced. The diurnal cycle of the precipitation has been slightly changed in the deforestation case. During the day, it was not possible to identify the rainfall maximum while at night it suggested a slightly increase of precipitation. The response of the fluxes and surface variables may be different depending on its topography level. A small rainfall reduction has been observed where the forest was kept undisturbed over 500 meters.
7

Late Quaternary Plant Zonation and Climate in Southeastern Utah

Betancourt, Julio L. January 1983 (has links)
Plant macrofossils from packrat middens in two southeastern Utah caves outline development of modern plant zonation from the late Wisconsin. Allen Canyon Cave (2195 m) and Fishmouth Cave (1585 m) are located along a continuous gradient of outcropping Navajo Sandstone that extends from the Abajo Mountains south to the San Juan River. By holding the site constant, changes in the floral composition for a plot of less than one hectare can be observed, even if sporadically, over tens of millennia. At Allen Canyon Cave, engelmann spruce-alpine fir forest was replaced by the present vegetation consisting of pinyon-juniper woodland on exposed ridgetops and cliffside stands of Douglas fir, ponderosa pine, and aspen. Xerophytic woodland plants such as pinyon, Plains prickly pear, and narrowleaf yucca arrived sometime in the middle Holocene between 7200 and 3400 B.P. At Fishmouth Cave, Utah juniper in Holocene middens replaced blue spruce, limber pine, Douglas fir, and dwarf and Rocky Mountain junipers in late Wisconsin samples. Disharmonious associations for the late Wisconsin occur only at the lower site with the xerophytes Mormon tea, Plains prickly pear, and narrowleaf yucca growing alongside subalpine conifers. One possible explanation involves the late Wisconsin absence of ponderosa and pinyon pines from the Colorado Plateaus. Released from competition at their lower limits, subalpine conifers were able to expand into lower elevations and mix with xerophytic plants found today in understories of pinyon-juniper and ponderosa pine woodlands. Quantitative climatic estimates are derived for the late Wisconsin by applying vertical lapse rates for temperature and precipitation to the amount of vegetation depression. The Fishmouth Cave sequence indicates a minimum lowering of 850 m for blue spruce, limber pine, and dwarf juniper. A depression of at least 700 m for engelmann spruce and alpine fir is suggested for the Allen Canyon locality. Use of conservatively low lapse rates for stations below 2080 m yields a 3-4°C cooling from present mean annual temperature and 35 to 60 percent more rainfall than today. Steeper lapse rates associated with more mountainous terrain suggest a 5°C lowering in temperature and up to 120 percent increase over modern precipitation.

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