Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 128-156). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

Thesis (Ph. D.)--Wageningen University, 2008. / Includes bibliographical references.

Thesis (M. Sc. (Botany))--Rhodes University, 2000.

Este estudo visa à estimativa dos fluxos de calor à superfície a partir de imagens orbitais, com os modelos SEBAL/METRIC e aplicação na modelagem hidrológica, com o modelo SWAT. Para isso, foram utilizados os dados da torre micrometeorológica da Ilha do Bananal, coletados durante os Experimentos do LBA, e os dados pluviométricos e fluviométricos. Os dados utilizados compreendem o período de outubro de 2003 a dezembro de 2006 da sub-bacia do rio Lajeado, localizada na bacia do rio Tocantins- Araguaia no estado do Tocantins. O clima na área de estudo tem sazonalidade bem definida, com períodos chuvosos de outubro a março e secos de abril a setembro. As estimativas a partir dos modelos SEBAL/METRIC variaram em função do tipo de solo, com estimativas coerentes dos fluxos de calor à superfície. Em geral, as estimativas dos fluxos de calor representam uma subestimativa de 10% para todo o período estudado. No entanto, sazonalmente observou-se subestimativas de 17% no período chuvoso e de 35% no período seco. De maneira geral, os resultados da utilização da evapotranspiração estimada por sensores remotos no modelo SWAT foi satisfatória. A assimilação da evapotranspiração a partir de imagens orbitais resultou em valores de COE que variaram de 0,57 a 0,84 com os dados diários e de 0,69 a 0,77 com os dados mensais de vazão. Isto indica melhoria no ajuste do modelo, devido a uma melhoria de 0,27 de COE no dado diário e de 0,08 no mensal. Observou-se ainda, que em termos percentuais a vazão simulada pelo modelo SWAT na bacia do rio Lajeado, após a assimilação dos dados de evapotranspiração, apresentou uma redução no erro, de 13% (superestimativa) para 3% (subestimativa) na vazão diária e de 9% para 7% (subestimativa) na vazão mensal. / This study presents estimate of the heat flow to the surface from orbital images with the models SEBAL / METRIC for use in hydrological modeling with the SWAT model. For this, we used data from micrometeorological tower of Island Bananal, collected during the experiments the LBA, rainfall and hydrological data. The data used is defined for the period October 2003 to December 2006, in the State Tocantins of catchments river Tocantins- Araguaia of the basin river Lajeado. We observed that the climate in the study area is seasonally well-defined with the rainy season from October to March and the dry are from April to September. Estimates from the models SEBAL / METRIC, varied according to soil type, are consistent with estimates of heat fluxes to the surface. In general, estimates of heat fluxes indicated underestimate of 10% for the period studied. However, seasonally there was an underestimates of 17% in the rainy season and of 35% in the dry season. The results of the hydrologic model can be judged satisfactory by the COE values which vary from 0.57 to 0.84 when comparing the streamflow daily data and from 0.69 to 0.77 with streamflow monthly data, with assimilation of evapotranspiration. This indicates benefits to the model, because was observed an improvement of 0.27 in the COE as daily and of 0.08 as monthly. It was also observed that in percentage terms the streamflow simulated by the SWAT model in the basin river Lajeado after the assimilation of evapotranspiration data showed a reduction error of 13% (overestimation) to 3% (underestimate) to the daily flow and from 9% to 7% (underestimate) to the monthly flow.

The United States is the world's top virtual water exporting nation, but not much is known about the country's internal virtual water flow patterns and the volumes involved. Previous studies have suggested that the import of virtual water, defined as the volume of water required to produce a commodity or service, can relieve pressure on a region's water resources. This study seeks to quantify virtual water flows among U.S. states using the water footprint and input-output analytical methods, and to compare the quantitative results to actual water use volumes in agriculture. The results showed an overall pattern where virtual water is transferred from sparsely populated states mostly in the Midwest, where the country's most fertile agricultural land is located, to the relatively dry Western states, and to the densely populated, but relatively wet coastal regions in the East of the country. For the year 2008, states used 196 Gm3 of water to produce agricultural commodities (crops and livestock) that were exported for consumption in other states. This total virtual water export volume is equivalent to 35 percent of total water withdrawals for all sectors in the U.S., or 41 percent of total rainfall evapotranspiration volume. Gross annual virtual water import volumes were 191 Gm3, giving a net interstate virtual water flow volume of 5 Gm3 for all states. The total virtual water import volume represent 34 percent of total water withdrawals in the U.S., or 40 percent of total rainfall evapotranspiration volume. The estimates in this study cover virtual water flows as a result of trade in 9 primary crops which represent 95 percent of the cultivated area harvested, and trade in nine primary animals that represent nearly 90 percent of animal establishments, and 97 percent of the total national sales in the U.S. for the year 2008. The estimates do not include virtual water flows as a result of trade in processed crop and livestock products and industrial products, which would have resulted in even higher virtual water flow volumes. Commodities making the greatest call on the nation's water resources were corn for grain, with 20 percent of total water use, and milk cows with 17 percent. The total evapotranspiration volume for the nine primary crops analyzed was 332 Gm3/yr. This consists of 93 Gm3 irrigation water (excluding 25 percent irrigation losses), and 239 Gm3 from rainfall, showing that rainfall contributed 72 percent of the total water volumes required to produce primary crops. If irrigation return flows are considered, the proportion contributed by rainfall becomes 65 percent, compared to 35 percent (128 Gm3) for irrigation water. The nine live animals for all states used 636 Gm3 in 2008, with beef cattle taking up 340 Gm3, or 53 percent of the total volumes used for animal production. Net virtual water exports in absolute terms ranged from 91 Mm3/yr in the state of Washington, to 15 Gm3/yr in Iowa, while the minimum net virtual water import value was 47 Mm3/yr in Vermont, to 11 Gm3/yr in Florida. On a per capita basis, the people of North Dakota were responsible for the largest agricultural net virtual export volume (16,011 m3/yr/ca), although the state has only 0.2 percent of the national population. Washington was responsible for the lowest per capita net virtual water export (375 m3/yr/ca). The people of Delaware (0.3 percent the total population) were responsible for the largest net virtual water imports related to agricultural commodities on a per capita basis (1511 m3/yr/ca), with Nevada ranking lowest. In absolute terms, water footprint values in relation to the 18 primary crops and livestock groups ranged from 1157 Mm3/yr in Rhode Island, to 61,471 Mm3/yr in California. Water footprint per capita values ranged from 1,083 m3/yr/capita in New York, to 4,872 m3/yr/capita in Nebraska. Both water footprint and input-output methodologies showed that virtual water transfer constitutes a substantial portion of the water balance in water scarce states such as California, where imports and exports were found to be 13 and 15 percent of total actual water use. The ratios of net virtual water import to agricultural water use volumes were very high for relatively humid states such as Rhode Island (nearly 5,000 percent) and Connecticut (more than 3,500 percent), partly showing that factors related to economic structure dominate climatic factors (water endowments) in shaping virtual water flow patterns in most U.S. states. These results suggest that rather than being the main reason behind observed virtual water flow patterns, water availability is complimentary to other factors of production, mainly the availability of suitable agricultural land. Similar to Japan or some European countries, most highly states in the eastern part of the country rely heavily on virtual water imports to meet their local agricultural consumption requirements, while their economies focus on sectors that are less land and water intensive, such as the services industry. The study also revealed that the volumes of international virtual water imports and exports are dwarfed by internal (interstate) virtual water volumes in the U.S., showing an overall preference for home consumption to international trade. The productive value of water ($/m3 used) was found to be much higher for industry and domestic sectors, in comparison to more water intensive agricultural use. While input-output analysis appears less prone to estimation errors and is less laborious to implement, it is limited in assessing the virtual water content of individual commodities when compared to water footprint analysis. However, the two alternative methodologies both produced results that are to a large extent consistent with production and consumption patterns in the U.S. The study adds new insights and information to earlier global studies that did not elaborate much on the internal virtual water flow dynamics of the world's largest virtual water exporter. The knowledge is relevant for this large country, where there are wide variations in water and other natural resource endowments between regions.

Terrestrial evapotranspiration (ET) is a significant component of the energy and water balances at the land surface. However, direct, continuous measurements of ET are spatially limited and only available since the 1990s. Due to this lack of observations, detecting and attributing long-term regional trends in ET remains difficult. This dissertation aims to alleviate the data limitation and detect long-term trends by developing a method to infer ET from data collected at common weather stations, which are spatially and temporally abundant. The methodology used to infer ET from historical meteorological data is based on an emergent relation between the land surface and atmospheric boundary layer. We refer to this methodology as the Evapotranspiration from Relative Humidity at Equilibrium method, or the “ETRHEQ method”. In the first section of this dissertation, we develop the ETRHEQ method for use at common weather stations and demonstrate the utility of the method at twenty eddy covariance sites spanning a wide range of climate and plant functional types. Next, we apply the ETRHEQ method at historical weather stations across the continental U.S. and show that ET estimates obtained via the ETRHEQ method compare well with watershed scale ET, as well as ET estimates from land surface models. From 1961 to 1997, we find negligible or increasing trends in summertime ET over the central U.S. and the west coast and negative trends in the eastern and western U.S. From 1998 to 2014, we find a sharp decline in summertime ET across the entire U.S. We show that this decline is consistent with decreasing transpiration associated with declines in humidity. Lastly, we assess the sensitivity of ET to perturbations in soil moisture and humidity anticipated with climate change. We demonstrate that the response of ET to changing humidity and soil moisture is strongly dependent on the biological and hydrological state of the surface, particularly the degree of water stress and vegetation fraction. In total, this dissertation demonstrates the utility of the ETRHEQ method as a means to estimate ET from weather station data and highlights the critical role of vegetation in modulating ET variability.

abstract: The North American Monsoon System (NAMS) contributes ~55% of the annual rainfall in the Chihuahuan Desert during the summer months. Relatively frequent, intense storms during the NAMS increase soil moisture, reduce surface temperature and lead to runoff in ephemeral channels. Quantifying these processes, however, is difficult due to the sparse nature of coordinated observations. In this study, I present results from a field network of rain gauges (n = 5), soil probes (n = 48), channel flumes (n = 4), and meteorological equipment in a small desert shrubland watershed (~0.05 km2) in the Jornada Experimental. Using this high-resolution network, I characterize the temporal and spatial variability of rainfall, soil conditions and channel runoff within the watershed from June 2010 to September 2011, covering two NAMS periods. In addition, CO2, water and energy measurements at an eddy covariance tower quantify seasonal, monthly and event-scale changes in land-atmosphere states and fluxes. Results from this study indicate a strong seasonality in water and energy fluxes, with a reduction in Bowen ratio (B, the ratio of sensible to latent heat fluxes) from winter (B = 14) to summer (B = 3.3). This reduction is tied to shallow soil moisture availability during the summer (s = 0.040 m3/m3) as compared to the winter (s = 0.004 m3/m3). During the NAMS, I analyzed four consecutive rainfall-runoff events to quantify the soil moisture and channel flow responses and how water availability impacted the land-atmosphere fluxes. Spatial hydrologic variations during events occur over distances as short as ~15 m. The field network also allowed comparisons of several approaches to estimate evapotranspiration (ET). I found a more accurate ET estimate (a reduction of mean absolute error by 38%) when using distributed soil moisture data, as compared to a standard water balance approach based on the tower site. In addition, use of spatially-varied soil moisture data yielded a more reasonable relationship between ET and soil moisture, an important parameterization in many hydrologic models. The analyses illustrates the value of high-resolution sampling for quantifying seasonal fluxes in desert shrublands and their improvements in closing the water balance in small watersheds. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2011

Resumo: planejamento mais eficaz do aproveitamento da água na agricultura, e o desenvolvimento de tecnologias que permitam estimar volumes cada vez mais exatos para a melhor eficiência da irrigação, têm papel fundamental para se alcançar ótimas produções agrícolas, aliada a melhor qualidade. Nesse caso a exata determinação da evapotranspiração da cultura (ETc) é um ponto crucial para o uso eficiente da água, bem como pelo fato da atual escassez dos recursos hídricos, principalmente em regiões áridas e semi-áridas, fazendo com que se utilize da água salina para irrigação. Diante disso, o presente trabalho teve como objetivo determinar a evapotranspiração da melancia e melão, em diferentes níveis de salinidade da água de irrigação e verificar seus efeitos no crescimento e na produção destas culturas. Para tanto foram realizados dois experimentos em campo, na Fazenda Experimental da Alagoinha pertencente a Universidade Federal Rural do SemiÁrido situada em Mossoró-RN, com melancia e posteriormente com melão, na mesma área, medindo 0,24 ha. Os níveis de salinidade da água de irrigação foram de S1=0,55, S2=1,65, S3=2,35, S4=3,5 e S5=4,5 dS m-1 para a melancia e S1=0,57, S2=1,65, S3=2,65, S4=3,45 e S5=4,5 dS m-1 para o melão. Os experimentos constaram de quatro blocos ao acaso com quatro repetições, cada um dividido nos cinco níveis de salinidade e no caso do melão em mais três níveis de nitrogênio subdivididas em cada parcela de salinidade. Os níveis de nitrogênio aplicados no melão foram de 67,5%, 90% e ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The water agricultural used effective design and the developments of technologies to estimated irrigation water exact are important irrigation management. Once evapotranspiration culture determinations (ETc) is crucial for use efficient irrigation water and irrigation water salinity. The objectives this work were determined evapotranspiration of watermelon and melon, in different levels of irrigation water salinity and verify effects in growth and production of these cultures. Were conducted two experiments in field, watermelon and melon, in same area with 0,24 ha. The levels of irrigation water salinity were of S1=0.55, S2=1.65, S3=2.35, S4=3.5 and S5=4.5 dS m-1 for watermelon and S1=0.57, S2=1.65, S3=2.65, S4=3.45 and S5=4.5 dS m-1 for melon. The experiments was four randomized blocks with four replications, divided in five salinity levels and in the case of melon in more three levels of nitrogen subdivided. The levels of nitrogen applied were of 67.5%, 90% and 135% of the applied dose (92.5 kg ha-1). The determination of evapotranspiration reference (ETo) was realized by method Penmam-Monteith-FAO through from formulations by Allen et al. (2006), and the ETc readings from two weight lysimeters installed in S1 and S5. The results showed that ETc of watermelon decreases between S1 and S5 where the total evapotranspiration was 245 and 214 mm, respectively. In melon the ETc also decreased between the two salinities, but was observed reduction 0.56 for S1, and 0.22, 0.64, 0.98 and 0.40values for the S5 in the watermelon. In melon observed medium Kc of 0.14, 0.57, 1.13, 0.66 for S1, and 0.11, 0.34, 0.91 0.54 for the S5 respectively. These values of Kc are verified for S1 was larger than Kc recommended by FAO (Allen et al., 2006), excepting for stage initial and final of each culture, and smaller for the S5, so much for melon as watermelon. There wasn't significant ...(Complete abstract click electronic access below) / Orientador: João Luis Zocoler / Coorientador: José Francismar de Medeiros / Banca: Antônio de Pádua Souza / Banca: João Carlos Cury Saad / Banca: Fernando Braz Tangerino Hernandez / Banca: Roberto Terumi Atarassi / Doutor

Submitted by Vanessa Christiane (referencia@ufersa.edu.br) on 2016-11-14T15:01:32Z No. of bitstreams: 1 PamellaCCS_DISSERT.pdf: 1776323 bytes, checksum: 65a6beafdc49985e63cb06e80a5bd6ef (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2016-11-14T15:02:19Z (GMT) No. of bitstreams: 1 PamellaCCS_DISSERT.pdf: 1776323 bytes, checksum: 65a6beafdc49985e63cb06e80a5bd6ef (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-02-15T15:05:07Z (GMT) No. of bitstreams: 1 PamellaCCS_DISSERT.pdf: 1776323 bytes, checksum: 65a6beafdc49985e63cb06e80a5bd6ef (MD5) / Made available in DSpace on 2017-03-21T15:06:32Z (GMT). No. of bitstreams: 1 PamellaCCS_DISSERT.pdf: 1776323 bytes, checksum: 65a6beafdc49985e63cb06e80a5bd6ef (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil there is a great irregularity and no radiation data that has just committing several studies. Thus, the use of remote sensing techniques is presented as a promising field, with the advantage of determining the components of the radiation balance with high spatial coverage quickly and accurately, and together with surface data have been indispensable in the application models and algorithms to estimate the components of the energy balance at the surface and evapotranspiration at various scales of time and space, which is the main factor to be considered in estimating water needs of the crop. The aim of this research project was to determine the components of the radiation balance in sugarcane area from MODIS (MODIS) inserted in SEBAL model (Surface Energy Balance Algorithm for Land) and validate them with data to the surface in the production area of sugarcane irrigated belonging to the company Agribusiness of the São Francisco Valley SA - Agrovale in Juazeiro - BA. It was concluded that there was no unusual condition in the behavior of the terms of the radiation balance obtained on the surface, when considering the different growth stages although the absolute values of the terms were different. The terms of the Radiation Balance found through MODIS images by applying the model SEBAL had expected behavior for targets with consistent and similar values to those found on the surface except for the albedo that had errors 54.5%, 50%, 11.7% and 26% for phases I to IV, respectively. Finally, the evapotranspiration using Rn from the satellite imaging showed no significant difference we react to ETcBERB and ETcPM1. It follows, therefore, that remote sensing can be perfectly used in determining the water needs of the crop of sugarcane in the region under study / No Brasil há uma grande irregularidade ou inexistência de dados de radiação, que acaba comprometendo diversos estudos. Desta forma, o emprego de técnicas de sensoriamento remoto apresenta-se como um campo promissor, com a vantagem da determinação dos componentes do balanço de radiação com grande cobertura espacial de forma rápida e precisa e, juntamente com dados de superfície têm sido indispensáveis na aplicação de modelos e algoritmos destinados à estimativa dos componentes do balanço de energia à superfície e da evapotranspiração em várias escalas de tempo e espaço, sendo este o principal fator a ser considerado na estimativa das necessidades hídricas da cultura. O objetivo deste projeto de pesquisa foi determinar os componentes do balanço de radiação em área de cana-de-açúcar a partir de dados MODIS (Moderate Resolution Imaging Spectroradiometer) inseridos no modelo SEBAL (Surface Energy Balance Algorithm for Land) e validá-los com dados obtidos à superfície em área produtiva de cana-de-açúcar irrigada pertencente à empresa Agroindústrias do Vale do São Francisco S.A - Agrovale no município de Juazeiro - BA. Concluiu-se que não houve nenhuma condição atípica no comportamento dos termos do balanço de radiação obtidos à superfície, quando se consideraram os diferentes estádios de desenvolvimento da cultura embora os valores absolutos dos termos tenham sido diferentes. Os termos do Balanço de Radiação encontrados através de imagens MODIS aplicando o modelo SEBAL apresentaram comportamento esperado para os alvos, com valores consistentes e próximos aos encontrados à superfície, exceto para o albedo que apresentou erros de 54,5%, 50%, 11,7% e 26% para as fases de I a IV, respectivamente. Por fim, a evapotranspiração usando o Rn proveniente do processamento de imagens de satélite não apresentou diferença significativa em realação a ETcBERB e a ETcPM1. Conclui-se, portanto, que o sensoriamento remoto pode perfeitamente ser usado na determinação das necessidades hídricas da cultura da cana-de-açúcar na região em estudo / 2016-11-14

As respostas das plantas medicinais as diversas técnicas de manejo da irrigação são pouco conhecidas. Os efeitos da irrigação complementar e suplementar na produtividade das plantas medicinais é de interesse para a industria farmacéutica. A flora brasileira é uma das mais ricas da Terra e neste conjunto de plantas existem espécies medicinais de alto valor com aptidão farmacêutica e bioquímica. Dentre elas está a carqueja, uma planta brasileira conhecida popularmente pelo seu chá com efeito emagrecedor. O objetivo do trabalho foi verificar as respostas da carqueja frente ao manejo da irrigação via clima em ambiente protegido. Em casa de vegetação, foram realizados dois experimentos em vasos de 11 L. O primeiro ensaio foi realizado no período primavera/verão de 2015/2016 e o segundo ensaio no outono/inverno de 2016. Foi adotado o delineamento em blocos casualizados composto por seis níveis de reposição hídrica (25, 50, 75, 100, 125 e 150% da ETo) e 6 repetições, totalizando 36 parcelas. Foi adotado o sistema de irrigação localizada por gotejamento. O conteúdo de água no solo foi monitorado por meio da refletectometria no domínio do tempo. O monitoramento meteorológico foi realizado por meio de uma estação meteorológica automática com datalogger. Após o transplantio das mudas foram realizadas três colheitas, realizando a avaliação das plantas cultivadas, por meio da determinação da biomassa, biometria, produtividade da água e teor do óleo essencial extraído por hidrodestilação. A cultura da carqueja (Baccharis crispa Spreng.) apresentou uma resposta diferencial aos níveis de reposição hídrica, nas diferentes colheitas, no período primavera/verão. O maior aumento da biomassa se obervou no ciclo primavera/verão aos 95 dias após o transplantio (DAT). A deficiência hídrica afetou em menor proporção às plantas submetidas ao nível de reposição hídrica de 75% em ambos ciclos. A maior produção de biomassa seca foi obtda aos 95 DAT no ciclo primavera/verão e o teor de óleo essencial no tratamento 75% de reposição hídrica no ciclo primavera/verão aos 205 DAT. / The responses of medicinal plants to the various techniques of irrigation management are little known. The effects of supplementary and supplemental irrigation on the productivity of medicinal plants is of interest to the pharmaceutical industry. The Brazilian flora is one of the richest on Earth and in this set of plants has high value as medicinal species with pharmaceutical and biochemical aptitude. Among them is the carqueja, a Brazilian plant popularly known for its tea with a slimming effect. The objective of the study was to verify the responses of the carqueja to the management of irrigation through climate in a protected environment. In the greenhouse, two experiments were carried out in 11 L pots. The first test was performed in the spring / summer of 2015/2016 and the second in the fall / winter of 2016. A randomized block design was adopted, consisting of six water replacement level (25, 50, 75, 100, 125 and 150% of ETo) and 6 replicates, totaling 36 plots in the greenhouse. Drip irrigation system was adopted. The water content in the soil was monitored by time domain reflectectometry and the meteorological monitoring will be done by means of an automatic weather station with datalogger. After the transplanting of the seedlings, three harvests were carried out evaluating the cultivated plants, through determination of the biomass, biometry, water productivity and essential oil content extracted by hydrodistillation. The Baccharis crispa Spreng. presented a differential response to water replacement levels, in the different harvests, in the spring/summer period. The greatest development of the crop was observed in the summer spring cycle at 95 DAP. The water deficiency affected to a lesser extent the plants submitted to the water replacement level of 75% in both cycles. The highest dry biomass production at 95 DAP in the spring/summer cycle and the essential oil content in the treatment 75% of water replacement in the spring / summer cycle at 205 DAP.