Thesis (M.S.)--Ohio University, August, 2004. / Title from PDF t.p. Includes bibliographical references (p. 95-98)

Thesis (M.S)--Ohio University, November, 2004. / Title from PDF t.p. Includes bibliographical references (p. 66-71)

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 121-129).

Thesis (Ph.D.)--McMaster University, 2004. / Advisors: J.S. Chang and R.D. Findlay. Includes bibliographical references (leaves 193-212). Also available via World Wide Web.

Thesis (Ph. D.)(Metallurgical Engineering)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007. / Dr. Paul Steffes, Committee Member ; Dr. Irina Sokolik, Committee Member ; Dr. Robert Black, Committee Member ; Dr. Robert G. Roper, Committee Chair ; Dr. Derek Cunnold, Committee Member.

Thesis (M.S.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references (leaves 104-108). Online version available on the World Wide Web.

Made available in DSpace on 2014-10-09T12:23:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:31Z (GMT). No. of bitstreams: 1 00939.pdf: 1759518 bytes, checksum: 13e7c7b34c66d55c7d42e8522a1cc678 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

Este estudo teve por finalidade investigar a frequência e intensidade dos Sistemas Frontais (SF) avaliando-os com os episódios ENOS (El Niño Oscilação Sul) para o período da Primavera (SON) de 2000 a 2010 sobre o Estado do Rio Grande do Sul (RS). As análises mostraram que os anos em que se tem a menor ocorrência de SF estão associados principalmente a eventos de La Niña Fraco e Neutralidade. Em contrapartida, um número maior de Sistemas Frontais foi verificado com relação aos episódios de El Niño Moderado e Neutralidade. Especificamente, no que se refere à questão mensal, percebeu-se que no mês de Outubro há uma maior influência dos Sistemas Frontais do que em Setembro e Novembro. Outro fator pertinente e evidenciado deu-se pelas comparações entre o período escolhido (no qual não ocorreram eventos fortes) e os episódios de ENOS Fortes. Notou-se, neste caso, que não ocorreram variações impactantes no número de Sistemas Frontais, embora se tenha o conhecimento dos efeitos e alterações existentes nos padrões de circulação atmosférica devido à atuação dos fenômenos de escala interanual. Ainda, tendo a necessidade de ampliar a gama de entendimento, foi realizada uma abordagem com relação ao comportamento da precipitação em seis sub-regiões do Estado, onde se observou de forma geral, um aumento da precipitação em praticamente todas as áreas do RS, quando comparado com a média Histórica. Com isso, ressaltou-se que os volumes mensais abaixo da média Histórica estão ligados a episódios de Neutralidade. Já a normalidade do regime de precipitação, mostrou-se interligado em média para todas as regiões ao evento de El Niño e por último, as precipitações acima da normal climatológica estão mais presentes em condições de El Niño, mais especificamente de intensidade Moderada. Dentre as sub-regiões analisadas, destacou-se a parte Oeste do Estado por ter apresentado uma maior intensidade nos volumes de precipitação. Outro fator importante analisado foram os valores percentuais das precipitações derivadas dos sistemas frontais. Levando-se em conta a média das avaliações, verificou-se que as sub-regiões Sul e Sudoeste do Rio Grande do Sul são as mais influenciadas pelas passagens dos Sistemas Frontais, enquanto os menores impactos na precipitação podem ser notados nas regiões Central e Norte do Rio Grande do Sul. Além disso, realizou-se um estudo de caso para avaliar o comportamento dos Sistemas Frontais em episódios de ENOS diferentes, nos campos de pressão atmosférica e temperatura do ar. Logo, averigou-se que em um ano de Neutralidade, as passagens de SF sobre o Estado costumam ser mais prolongadas em sua duração de tempo, permanecendo mais dias, com algumas variações significativas nos campos meteorológicos observados. Enquanto para um ano referente à condição de El Niño Moderado, os Sistemas Frontais possuem, na maioria dos casos, uma duração de tempo menor, consequentemente com menores variações na temperatura e pressão. / This study aimed to investigate the frequency and intensity of the frontal systems (FS) evaluating them with respect to the episodes of El Niño – South Oscillation (ENSO) for the spring season (SON) from 2000 to 2010, over the state of Rio Grande do Sul (RS - Brazil). The analysis showed that the years having a smaller incidence of SF are mainly associated to events of weak La Nina and neutrality. In contrast, a larger number of frontal systems were observed with respect to episodes of moderate El Nino and neutrality. Specifically with relation to the monthly aspect, it was noticed that there is a major influence of the frontal systems in October than in September and November. Another inherent and evidenced factor was given by the comparisons between the selected period (with no occurrence of strong events) and the Strong ENSO episodes. In this case it was noticed that there has not occurred impacting variations in the number of frontal systems although the effects and changes of the atmospheric circulation patterns due to the action of the interannual scale phenomena are known. Further, to enlarge the range of understanding, it was made one approach relating to the precipitation behavior in six sub regions of the state where in general it was observed an increase in the precipitation almost in all areas of the RS when compared to the historic average. Thus, the monthly volumes below the historic average are linked to neutral episodes. Otherwise, the normal precipitation regime, on average, was proved to be interconnected for all regions to the event El Niño, and finally the rainfall above the climatology are more common in El Niño conditions, specifically with Moderate intensity. In this manner, considering the analyzed sub regions, the west part of the state has presented a higher intensity of precipitation volumes. Another important factor analyzed were the percentage values of rainfall derived from frontal systems. Taking into account the average of the evaluations, it was found that the South and southwest sub-region of Rio Grande do Sul is the most influenced by passages from the SF, while smaller impacts on precipitation can be noticed in the Central and North regions. In addition, it was realized a case study to evaluate the behavior of frontal systems in different episodes of ENSO, with respect to the fields of atmospheric pressure and air temperature. Thus, it was found that in a year of neutrality, the frontal systems crossings on the state tend to be more prolonged, remaining more days, with some significant variations in the observed meteorological fields. While for a year related to the condition of Moderate El Nino the frontal systems have, in mosta cases, a shorter duration, thus with minor variations in temperature and pressure.

The purpose of this paper is present the results of a developed, and implemented a Fuzzy rule based model to determine the probability of precipitation in the Marion Illinois area during the summer months. The model employs fuzzy logic and the results are compared to actual data to measure how reliable and viable this method is as an option in the precipitation prediction. Researchers, over the years, have been developing models for simulating, predicting and analyzing atmospheric phenomena, in order to accurately determine their immediate and long term effects on the environment and the quality of human life, such as in agriculture, ecosystem evolution, biodiversity, and disaster preparedness (decision support systems: drought/ warning or flash floods). To simulate global climate changes, researchers use General Circulation Models (GCMs). These have been developed using numerical weather predictions. These models are very useful for global impact studies such as global warming, but they are limited if applied to regional scenarios. This is because they are not able to neither simulate the local effects nor accurately present spatial and temporal resolutions. Continued work to improve the efficiency of these systems has led to the development of various models. Improvements have come in the form of Regional Climate Models; they have higher resolution and take into account orographic effects. These models use downscaling techniques, which bridge the gap between the global climate simulations and regional climate impact assessment. This paper presents the implementation of a fuzzy rule-based downscaling technique with specific application to the Marion, Illinois area. It shows that this method has the distinct advantage of being both computation and resource inexpensive while producing accurate information in a timely manner.