Previous correlations have been established between the El Nino Southern Oscillation (ENSO) and both the tropical north Atlantic sea-surface temperatures (SSTs) and precipitation anomalies in the southeastern and mid-Atlantic states. Both bivariate and partial correlations are used over a five and six-month lag to assess the relevance the tropical Atlantic SSTs have in eastern United States precipitation patterns. Significant correlations between Pacific SSTs and precipitation were found during winter months which agree with previous literature. The relationship with the Atlantic SSTs was less robust, as some significant values were established over three seasons, excluding winter. Only the spring season showed a partial explanation of the Atlantic SST's role in the precipitation's response to Pacific SSTs. These relationships did not occur during the times when significant correlations were made between Pacific SSTs and precipitation. / Department of Geography

Three studies of precipitable water using the Global Positioning System are presented. The first study finds that precipitable water in Hawaiʻi is best described by a lognormal distribution. The long-term average value of precipitable water declines exponentially with height, but the dispersion of precipitable water declines more linearly. The change in skewness of the distributions is also linear, although in this case it increases with elevation. The second and third studies use GPS meteorology to investigate a climatological and a meteorological event respectively. First, the effect of the 1997-1998 El Nino on precipitable water in the western tropical Pacific is studied and found to be consistent with a model relating the formation of an anomalous high-pressure ridge to the El Nino episode. Finally, the details of the precipitable water field for the Kaʻu Storm, November 2000 are examined. The results highlight the role of topography in controlling the location of convection, The observed correlation between the precipitable water and rainfall is used to generate estimates of rainfall based on GPS data, Comparing the GPS precipitable water estimates with those from a weather model indicates that the underestimates of rainfall produced by the weather model are probably due to correlated underestimates of precipitable water. / Thesis (Ph. D.)--University of Hawaii at Manoa, 2002. / Mode of access: World Wide Web. / Includes bibliographical references (leaves 62-66). / Electronic reproduction. / Also available by subscription via World Wide Web / ix, 66 leaves, bound ill. 29 cm

Typescript. / Bibliography: leaves 64-69. / ix, 75 leaves ill., maps

Precipitation is one of the atmospheric variables that characterize the climate of a region. The South Island of New Zealand (SI of NZ) has an unusually large number of distinct regional climates and its climatic diversity includes the coldest, wettest, driest and windiest places in New Zealand. This thesis focuses on identifying precipitation trends and rainfall fluctuations for the SI of NZ. First, homogeneity of 184 precipitation series is assessed with the combination of three homogeneity tests (Standard Normal Homogeneity Test, Easterling & Peterson test, Vincent�s Multiple Linear Regression). More than 60% of tested time series are found to contain at least one inhomogeneity. About 50% of the inhomogeneities can be traced to information in the station history files with nearly 25% of all inhomogeneities caused by the relocation of the precipitation gauge. Five coherent precipitation regions are defined by the Principal Component Analysis. The objective of identifying the periods of water deficit and surplus in spatial and temporal domains is achieved by using Standardized Precipitation Index (SPI). The SPI series (for 3, 6, 12, 24 and 48 months time scales) are calculated for each region and used for analysis of dry and wet periods. Clear differences in the frequency, length and intensity of droughts and wet periods were found between individual regions. There is a positive (i.e. increase in wet periods) trend in SPI time series for the North, Westland and Southland regions during the 1921-2003 period at all times scales, and a negative trend for Canterbury during the same period. The results show longer wet periods than dry periods at all time scales. Extreme heavy precipitation, which causes floods, is the most common type of natural disaster accounting for about 40% of all natural disasters worldwide. A set of ten extreme indices is calculated for 51 stations throughout the South Island for the period 1951-2003. The west-east division is found to be the dominant feature of extreme precipitation trends for all extreme indices with more frequent and more intense extreme precipitation in the west/southwest and with a declining trend in the east. The significant decrease in extreme precipitation frequency was detected in Canterbury with 3 days less of precipitation above the long-term 95th percentile by 2003 as compared to 1951. The variability of precipitation, expressed by the SPI, is correlated with local New Zealand atmospheric circulation indices and large-scale teleconnections. The precipitation variability in the South Island is governed largely by the local circulation characteristics, mainly the strength and position of the westerly flow. The increase in precipitation in the West and SouthEast is associated with enhanced westerlies. The correlations between New Zealand�s circulation indices and regional SPI are seasonally robust. The SouthEast region exhibits a strong relationship with the Southern Oscillation Index on seasonal and annual time scales,and with Interdecadal Pacific Oscillation at the decadal scale. The predictability of seasonal precipitation one season ahead is very limited.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 11, 2008) Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (M. S.)--Florida State University, 2006. / Advisor: James J. O'Brien, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed Sept. 21, 2006). Document formatted into pages; contains ix, 40 pages. Includes bibliographical references.

Thesis (Ph.D.)--York University, 2005. Graduate Programme in Earth and Space Science. / Typescript. Includes bibliographical references (leaves 181-196). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11647

Orientadora: Profa. Dra. María Cleofé Valverde Brambila / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, 2016. / O objetivo deste estudo foi analisar a influência da precipitação sobre a quantidade produzida dos cultivos de milho, feijão e arroz no estado do Ceará, por agricultores familiares, em seis municípios: Aurora, Alto do Santo, Canindé, Limoeiro do Norte, Acopiara e Tauá. Para isso foram utilizados os dados do Censo Agropecuário (2006 ¿ IBGE): dados de quantidade produzida, área plantada, colhida para o período de 1990 a 2014, e séries históricas de precipitação para o período de 1974 a 2014. No tratamento dos dados da chuva elaborou-se a climatologia mensal, trimestral e anual, e se calculou um índice de seca (Standard Precipitation Index - SPI). Estas informações foram relacionadas com a quantidade produzida, área plantada e colhida dos cultivos. Finalmente se construíram calendários agrícolas para cada cultivo e município em estudo, que incluíram as informações mensais e decendiais. Os resultados mostraram que os municípios com 90% a 100 % de estabelecimentos familiares principalmente na área do Sertão Cearense detêm 40 % a 60 % de área agrícola total por município. Na análise da climatologia mensal dos municípios estudados, encontrou-se que os meses de maior total pluviométrico concentram-se entre fevereiro a abril devido à influência da Zona de Convergência Intertropical. Os municípios com máxima intensidade de chuva são Limoeiro do Norte, Aurora e Alto do Santo. A análise das tendências mostrou decréscimo das chuvas em todos os municípios para o período de 1974-2014. O índice de SPI destacou que os anos de seca associaram-se principalmente com eventos do El Niño, sendo estes mais intensos nos anos de 1990-1993 e 1997-1998, e houve uma relação direta com a diminuição da quantidade produzida de arroz no município de Aurora e Limoeiro do Norte, e do cultivo de milho em Acopiara. Os resultados dos calendários agrícolas de arroz, feijão e milho evidenciaram cada fase do cultivo para a melhor época do plantio em função do padrão mensal da chuva. Verificou-se que para cada localidade deve ser elaborado um calendário agrícola específico segundo o cultivo e o padrão mensal da chuva. Por esse motivo, foi sugerido que os municípios de Acopiara, Limoeiro do Norte e Tauá para os cultivos de feijão, arroz e milho respectivamente adiassem um mês a sua época de plantio. Este estudo pode auxiliar no aprimoramento das pesquisas sobre a chuva e sua influência na agricultura familiar no Ceará, servindo de base para uma melhor gestão de politicas públicas, de forma a otimizar a produtividade agrícola onde os ganhos sejam sentidos principalmente pelos agricultores familiares. / The objective of this study was to analyze the precipitation influence over the agricultural cultivation of corn, beans, and rice in the following six cities from the state of Ceará: Aurora, Alto do Santo, Canindé, Limoeiro do Norte, Acopiara, and Tauá. The information used was provided by the Farming Sense (IBGE-2006) and included: seeded and harvested area, and produced quantity from 1990 to 2014; historical precipitation series from 1974 to 2014. From the rain data manipulation it was elaborated the monthly, trimesterly, and annually climatology, where the SPI (Standard Precipitation Index) was calculated. This information was correlated with the seeded and harvested area, and produced quantity. Finally, agricultural calendars were created for each crop and city analyzed where rain information was available. The results showed that municipalities with 90% to 100% of domestic harvesting in the Sertão Cearense region detain 40% to 60% of the agricultural area. In the analysis of the monthly climatology of the scoped cities, the results also showed that from February to April the pluviometric indices were higher due to the influence of the Intertropical Convergency Zone. The cities with maximum rain density are: Limoeiro do Norte, Aurora, and Alto do Santo. The analysis of the rain density in the period of 1974 to 2014 exposed a decrease trend. The SPI showed that the drought periods were related with the El Niño, where it was more intense in the periods of 1990-1993 and 1997-1998, where a direct correlation was traced with the rice production in Aurora and Limoeiro do Norte, and corn production in Acopiara. The results of the agricultural calendars for rice, beans, and corn exposed the best match between the period of the year and each phase of the crops, based on the monthly rain standard. It was also verified that a specific agricultural calendar should be created for each locality, based on the crops phase and the local rain monthly standard. Due to this reason, it was suggested that the cities of Acopiara, Limoeiro do Norte e Tauá delay one month their seeding activity for beans, rice, and corn. This study can help in the improvement of the researches about the rain and its influence in the domestic harvesting in Ceará, serving as a base for a better management of the public politics aiming to optimize the agricultural production where gains can be granted especially to the domestic farmers.

Made available in DSpace on 2015-03-26T13:23:57Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1113635 bytes, checksum: b8aef25a6a094f3a901ad781dc51e11f (MD5) Previous issue date: 2013-10-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study analyzed the productivity and wood properties of two urograndis hybrid clones for energy production. Two genetic materials were compared and are represented by (P+), higher production, and (P-), lower production. Trials took place in two climatically contrasting areas of of southern Bahia, Brazil. Samples were collected at ages 24, 48, and 72 months. Six replicates were analyzed. In each sampled plant, disks were removed at 0, 25, 50, 75 and 100% of the commercial height of the trunk for analysis of Specific Mass (ME) and Power Calorific Value (PCS). ME was determined by removing the two sampled wedges diametrically opposite of each disks, and the PCS was determined with sawdust taken from the unused part of the disk. The Dry Mass (MS) per hectare was calculated with the values of Mean Annual Increment (IMA) and ME. The potential energy per hectare was calculated using PCS and MS values. Ecophysiological modeling was used to simulate the variation of the energy production of genetic materials for different rainfall conditions, alternating wet and dry periods during the development cycle of crops. Area East (AL) received an annual rainfall of 1,500 mm while area West (AO) only received 1,000 mm. Results showed an inverse relationship between IMA and ME. The results show clone P+ having the highest potential for biomass production and energy per hectare, but the clone P- show larger values of gross calorific value and density. This verifies that the clone with better yield is not always the one that gives the best woody characteristics to be used as energy. Despite Area East (AL) having higher water availability throughout the year, the highest biomass productivity and energy per hectare was collected in Area West (AO). Moreover, higher density values were observed in Area West (AO). This study shows selection of genetic material was more important than location to achieve higher productivity and wood quality. The study still accounts for the influence of environmental conditions , regardless of the genetic potential of each material. The 3-PG model satisfactorily simulated the IMA and the ME, making it possible to identify the range of variation of the energy potential due to climatic variations between the sites. We conclude that rainfall is the main factor that limits the mean annual growth and therefore, the energy potential. When the last three years happens less than in the first three years rainfall, a limiting occurs in the accumulation of biomass. / Este trabalho teve como objetivo principal analisar a influência das condições climáticas sobre a produtividade e as propriedades da madeira de dois clones híbridos do urograndis para produção de energia em duas áreas do extremo Sul da Bahia. Utilizou-se também a modelagem ecofisiológica para simular a variação da produção de energia dos materiais genéticos estudados para distintas condições de precipitação pluvial, alternando períodos secos e úmidos durante o ciclo de desenvolvimento dos plantios. O experimento foi desenvolvido em duas áreas climaticamente contrastantes do extremo Sul da Bahia, área Leste (AL) e Oeste (AO), sendo a primeira com maior índice de sítio com total anual de chuva de 1.500 mm e a segunda com reduzida chuva total de 1.000 mm. Em cada área foram coletadas árvores de dois clones híbridos de urograndis, com diferentes potenciais produtivos, para três distintas idades (24, 48 e 72 meses) e, seis repetições. Em cada planta amostrada foram retirados discos a 0, 25, 50, 75 e 100 % da altura comercial do tronco para as análises da ME e PCS. A MS por hectare foi calculada com os resultados de IMA e ME, e o potencial energético por hectare foi calculada com base nos resultados de PCS e MS. Utilizou-se o modelo 3-PG após realizada sua parametrização, calibração e validação com dados biométricos obtidos em inventário florestal realizados para as áreas e clones de estudo. Os resultados mostraram a mesma tendência verificada em outros estudos, em que é observada uma relação inversa entre IMA e ME. O clone menos produtivo (P-) obteve melhores propriedades da madeira para fins energéticos que o clone mais produtivo (P+), enquanto que o clone P+ mostrou maior potencial produtivo. Por outro lado, a área leste, apesar de apresentar a maior disponibilidade hídrica ao longo do ano, a maior produtividade de biomassa e energia por hectare foi mostrada na área com maior restrição hídrica. De igual forma, os maiores valores de Massa Específica foram verificados na mesma área. Assim, para obter uma maior produtividade e qualidade da madeira é mais importante à seleção do material genético que a localização da área, mas sem desmerecer a influencia das condições edafoclimáticas sobre o potencial genético de cada material. O modelo 3-PG simulou satisfatoriamente o IMA e a ME, sendo possível identificar a amplitude de variação do potencial energético em função das variações climáticas entre diferentes cenários simulados. A precipitação pluvial é o fator que mais limita o incremento médio anual e, por conseguinte o potencial energético. Quando nos três últimos anos de idade acontece uma precipitação pluvial menor que nos três primeiros anos, ocorre um limitante no acumulo de biomassa.