• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 66
  • 29
  • 6
  • 4
  • 4
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 139
  • 139
  • 69
  • 30
  • 30
  • 28
  • 28
  • 24
  • 20
  • 16
  • 13
  • 12
  • 12
  • 11
  • 11
  • 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

Regional groundwater monitoring in the Olifants-Doorn water management area.

Seward, Paul January 2006 (has links)
<p>The aim of this investigation was to provide a framework or strategy for prioritising and implementing regional groundwater monitoring in the Olifants-Doorn Water Management (WMA) area. The general approach was to attempt to reconcile monitoring requirements with existing resources, while investigating the hypothesis that regional monitoring should focus on resource status monitoring. Groundwater science needs to focus on clarifying the sustainability options available to the stakeholders, and monitoring the chosen option. This can best be done by adopting an adaptive management approach to both the management of the groundwater resources, and the management of the monitoring programme.</p>
32

Water as 'n bron van politiek konflik en samewerking: 'n vergelykende studie van die Midde-Ooste en Suider-Afrika

29 October 2008 (has links)
M.A. / The potential for conflict over water can one day become a reality. This so, especially when the world’s population is growing at a phenomenal rate. Regions that are vulnerable to this sort of conflict are semi-arid to arid in character. One can ask the question if conflict over water in these regions is possible. In examining the situation surrounding waterpolitics in two regions, and drawing comparisons, one can shed light on state’s interaction when it comes to the allocation of international water sources. The Middle East has vast experience in international water politics, while countries in Southern Africa seem to be still learning the game of international water politics. Using a framework for analysis, four case studies will be looked at. The Orange and Okavango Rivers are the subjects in Southern Africa where, it seems, cooperation on international water resources is the norm. The Tigris-Euphrates and the Jordan Rivers are considered in the case of the Middle East. Here a much higher level of conflict can be seen. The main reason for this difference in dealing with international water resources in the two regions seems to be the will (or lack thereof) among states to cooperate over water sources. In Southern Africa this will is evident, especially after 1994 when a new democratically elected government came to power in South Africa. In the Middle East, however, the region is still going about international politics in ways reminiscent of the Cold War. The theory of realism helps to explain the situation in this region, where mistrust plays a very big part in the interaction between states. Complex interdependence by contrast characterises the international political interaction between the states in the Southern African region. International and national water projects, in both regions, play a very big role in water politics. In both the regions there seem to be a number of these projects, that contributed to either conflict and/or cooperation between the states. In the Orange River it is the Lesotho Highlands Water Project, a cooperative endeavour between Lesotho and South Africa and in the Okavango Namibia’s Eastern National Water Carrier (ENWC). In the Tigris -Euphrates, Turkey’s Greater Anatolia Project, in the Tigris -Euphrates, is influencing the interaction between the three riparians, and the Jordan River had it’s share of projects in the past, and here Israel’s National Water Carrier had a role to play. / Prof. D.J. Geldenhuys Dr. M.M.E. Schoeman
33

The impact of price on residential water demand: (a comparative study)

04 October 2010 (has links)
M.Comm. / Southern Africa is considered by the rest of the world to be a water scarce region. Previously within the region water was not regarded as a high profile subject in the development process. A paradigm shift is required in the region to recognise the need to concentrate on demand management instead. The paper briefly examines the climatic conditions as a contributing factor to scarcity of the water resources. It further focuses on the human factor which is regarded as a factor that can be managed as opposed to the climatic conditions. In managing the human factor, the usage of water cannot remain the same as it was before the scarcity problem that the SADC region is faced with. It is also recognised that water resource is necessary for survival, therefore basic human requirements are examined. This scarcity makes water to be regarded as an economic good. The paper further explains the elements that make water to be regarded as an economic good. Water being an economic good, it commands a price. The study explains pricing the resource as the only method of making the population understand about the importance of the resource. Different pricing methods are explained in detail. To demonstrate this demand management of water the study interrogates three cities namely Soweto, Cape Town and Durban. In this interrogation the demand management techniques used and their efficiency are compared and contrasted to ascertain the efficiency of the chosen demand management techniques and the existence of gaps within these techniques.
34

Simultaneous minimisation of water and energy within a water and membrane network superstructure

Buabeng-Baidoo, Esther January 2016 (has links)
A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering, 2015 / The scarcity of water and strict environmental regulations have made sustainable engineering a prime concern in the process and manufacturing industries. Water minimisation involves the reduction of freshwater use and effluent discharge in chemical plants. This is achieved through water reuse, water recycle and water regeneration. Optimisation of the water network (WN) superstructure considers all possible interconnections between water sources, water sinks and regenerator units (membrane systems). In most published works, membrane systems have been represented using the “black-box” approach, which uses a simplified linear model to represent the membrane systems. This approach does not give an accurate representation of the energy consumption and associated costs of the membrane systems. The work presented in this dissertation therefore looks at the incorporation of a detailed reverse osmosis network (RON) superstructure within a water network superstructure in order to simultaneously minimise water, energy, operating and capital costs. The WN consists of water sources, water sinks and reverse osmosis (RO) units for the partial treatment of the contaminated water. An overall mixed-integer nonlinear programming (MINLP) framework is developed, that simultaneously evaluates both water recycle/reuse and regeneration reuse/recycle opportunities. The solution obtained from optimisation provides the optimal connections between various units in the network arrangement, size and number of RO units, booster pumps as well as energy recovery turbines. The work looks at four cases in order to highlight the importance of including a detailed regeneration network within the water network instead of the traditional “black-box’’ model. The importance of using a variable removal ratio in the model is also highlighted by applying the work to a literature case study, which leads to a 28% reduction in freshwater consumption and 80% reduction in wastewater generation. / GR2016
35

Towards an integrated and sustainable water resource monitoring framework in South Africa

Chabalala, Simphiwe January 2017 (has links)
A thesis submitted to the faculty of science, at the University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2017. / Water resource monitoring plays a pivotal role in a number of sectors such as determining sustainable abstraction and use of water, determining the feasibility of development projects in relation to water, and developing systematic strategies for efficient overall management of the water resources. It has been observed by a number of scholars and policy makers that through periodic monitoring of water resources, valuable data can be collected which can then provide information sufficient to determine trends and develop predictive models. It is only when sound and reliable data is available that informed decisions about sustainable and efficient use of water resources can be made. Despite the importance of water resource monitoring, many countries in Sub-Saharan Africa, particularly in South Africa, are not effectively and adequately monitoring the quantity and quality of water resources. Part of the reason for this state of affairs has been the absence of clearly defined roles, policies, strategies and responsibilities and a combination of these factors have resulted in significant fragmentations in the institutional structures mandated to manage water resources. Using expert sampling, interviews with key informants and other purposively chosen participants, revealed the challenges in the changing political landscape of South African water resource monitoring many of which were further reiterated in the focus group discussions. The identified challenges served as entry points that would improve water resources monitoring and enable decision makers to make sustainable management decisions. It is suggested that water resource monitoring programmes could be used as a tool for sustainable water resource monitoring in South Africa. However, climate change and urbanization bring about a certain level of complexity, uncertainty and conflict as the water landscape of water resources changes continuously. The impact of the above phenomena cannot be measured as current monitoring systems are not functioning optimally. Furthermore, monitoring programmes are not being used to their full potential due to governance challenges. This is due to conflicting roles that the Department of Water and Sanitation (DWS) plays in the water sector i.e. policy developer, supporter and regulator, which in turn confound the roles and responsibilities of its employees. Moreover, it was found that five major challenges impede the formation of a comprehensive water resources management system namely; lack of financial resources, lack of skilled human resources, poor governance structure, ineffective stakeholder engagement – ‘working in silos’ and inefficient data management. More importantly, it was found that sustainability of monitoring programmes relies on human and economic investment. The main recommendations made include institutional reform and enabling legislation which form the basis upon which any development efforts can be pursued to achieve sustainable water resource monitoring. In addition, capacity building and strengthening is recommended as another way to help build sustainable resource management institutions which include skills and institutional memory transfer from the experienced players to the younger and newer employees. The creation and/or optimization of water resource monitoring databases is one of the viable ways for sustainable water resource management to be realized. Furthermore, research can be conducted to assess the challenges in water resource monitoring and provide sustainable solutions; with the aim of quantifying the impact of policy reforms in the water sector. And finally, research can be done on how effective regulation and co-operative governance for water sector can be achieved in South Africa through participatory processes that are aimed at developing priority water research questions. Keywords: water resource monitoring, institutional framework, integrated water resource management, water governance. / GR2018
36

Antecedentes do relacionamento e da performance em empresas da cadeia de suprimentos: especificação e aplicação de modelos de equações estruturais / Antecedents of relationship and performance on the supply chain: specification and application of structurals equations models

Cunha, Valeriana 01 November 2006 (has links)
O tema central deste trabalho é a importância da Comunicação e da Tecnologia da Informação como forma de garantir que o fluxo de informações entre empresas da Cadeia de Suprimentos seja adequado e influencie de maneira positiva o Relacionamento entre as empresas e a Performance. O objetivo principal do trabalho é estruturar e testar modelos para investigar as relações existentes entre as seguintes variáveis: Comunicação, Tecnologia da Informação, Relacionamento Comprador-Fornecedor e Performance. A Comunicação e a Tecnologia da Informação foram consideradas antecedentes do Relacionamento e da Performance. A população alvo desta pesquisa compreende todos os fornecedores ativos da Empresa Alfa, uma distribuidora de medicamentos e produtos de higiene e beleza com sede na cidade de São Paulo. Dadas as várias relações causais que se pretende testar, a Modelagem de Equações Estruturais (Structural Equation Modeling - SEM) foi considerada a metodologia mais apropriada para esta pesquisa. Tal abordagem permite testar simultaneamente as várias relações para cada um dos modelos propostos. Após a preparação e validação das escalas, foram testadas as influências das variáveis exógenas no Relacionamento e na Performance, bem como a influência do Relacionamento na Performance. Nos modelos de Comunicação, as variáveis exógenas testadas foram Feedback, Compartilhamento de Informações, Periodicidade da Comunicação Convencional, Periodicidade da Comunicação por fax/carta e Periodicidade da Comunicação por Meio Eletrônico. Nos modelos de Tecnologia da Informação, foram testadas as seguintes variáveis exógenas: EDI, Sistemas de Gestão Transacionais e Sistemas de Gestão Colaborativos. Os indicadores de performance utilizados foram, em sua maioria, os mesmos tanto para a empresa compradora quanto para seus fornecedores (preço, prazo, rapidez na entrega, cumprimento dos prazos de entrega e entrega do pedido completo). O Relacionamento foi representado apenas pelo Comprometimento da Empresa Fornecedora. Apenas as variáveis exógenas EDI e Sistemas de Gestão Transacionais não se mostraram estatisticamente significantes em suas relações com o Relacionamento e com a Performance. Para todas as outras variáveis, observou-se algum tipo de influência no Relacionamento e/ou na Performance. Também foi verificada a influência positiva do Relacionamento na Performance. / The central theme of this work is the importance of Communications and of Information Technology as a way of ensuring that the flow information between companies in the Supply Chain is adequate, positively influencing the companies\' relationships and Performance. This study\'s main objective is to structure and test models to investigate the relations existing among the following variables: Communications, Information Technology, Buyer-Supplier Relationship, and Performance. In this work, Communications and Information Technology are considered antecedents of Relationship and Performance. The target population of this research comprises all the active suppliers of the Alpha Company, a distributor of pharmaceuticals and hygiene and beauty products headquartered in the city of São Paulo. Structural Equation Modeling (SEM) was considered the most suitable methodology for this research, given the various causal relations to be tested. This approach allows for the simultaneous testing of the various relations for each of the models proposed. After preparation and validation of the scales, the influence of the exogenous variables on Relationship and Performance was tested, as was the influence of Relationship on Performance. In the Communications models, the exogenous variables tested were Feedback, Information Sharing, Periodicity of Conventional Communications, Periodicity of Communications via fax/letter, and Periodicity of Electronic Communications. In the Information Technology models, the following exogenous variables were tested: Electronic Data Interchange (EDI), Transactional Management Systems, and Collaborative Management Systems. The performance indicators utilized were, for the most part, the same for the buyer and its suppliers (price, lead time, fast delivery, on time deliveries, and delivery of complete orders). Relationship was represented solely by the Supplier\'s Commitment. Only the exogenous variables of EDI and Transactional Management Systems proved statistically nonsignificant in their relations with Relationship and Performance. All the other variables showed some kind of influence on Relationship and/or Performance. Relationship was also found to positively influence Performance.
37

Proposta de um método para planejamento e gestão da cadeia de suprimentos de empresas compradoras de frutas no Brasil / Proposal of a supply chain planning and management method for a Brazilian fruits buyer company

Nakatani, Julio Kyosen 13 August 2013 (has links)
No cenário mundial, o Brasil ocupa a terceira posição de maior produtor de frutas no mundo. E para a economia nacional, a importância desse setor de frutas fica evidenciada, pois o mercado de frutas corresponde a aproximadamente 10% do PIB agropecuário, sendo que as frutas frescas movimentaram mais de 270 milhões de dólares em 2009 e o mercado de sucos e néctares mais de 1,8 bilhão de dólares. No entanto, as empresas compradoras de frutas estão sofrendo pelo efeito da flutuação da demanda na produção, ineficiência coletiva, falta de compreensão da dinâmica do processo de fornecimento e redução na rentabilidade de todos os membros da cadeia de frutas. O gerenciamento de suprimentos tem sido apontado como uma das formas de diminuir esta instabilidade e melhorar os resultados de todos os envolvidos na entrega do produto. No entanto, as evidências empíricas não estão relacionadas ao setor de frutas. Na tentativa de contribuir com a solução deste problema, o presente estudo tem o objetivo de caracterizar a cadeia de suprimentos de frutas, analisar o planejamento e gestão da cadeia de suprimento de uma empresa compradora de fruta e identificar contribuições e melhorias as teorias, métodos e modelos relacionados ao gerenciamento da cadeia de suprimentos para propor um método para o planejamento e gestão da cadeia de suprimentos de empresas compradoras de frutas. Foram utilizadas entrevistas em profundidade para caracterização da cadeia de manga e o estudo de caso único de uma empresa compradora de manga com especialistas do setor para avaliar a aplicabilidade, funcionalidade e utilidade do ponto de vista gerencial do método proposto. A análise dos dados se deu por meio da triangulação do referencial teórico com os métodos e modelos de gerenciamento da cadeia de suprimentos e com a descrição do caso. Os resultados do estudo indicaram que a cadeia de suprimentos de frutas pode ser caracterizada como receptiva à melhorias de planejamento e gestão da cadeia de suprimentos; que a análise do planejamento e gestão da cadeia de suprimentos de frutas no Brasil se mostrou eficiente para avaliar os seus fornecedores em quatro regiões produtoras distintas; que existe congruência e sinergias entre a teoria, métodos e modelos do gerenciamento da cadeia de suprimentos; e permitiram a elaboração de um método de planejamento e gestão da cadeia de suprimentos de empresas compradoras de frutas. Com a proposição desse método, espera-se contribuir com uma sequência de passos que auxilie nas atividades de planejamento e gestão da cadeia de suprimentos por gestores e especialistas de uma empresa compradora de fruta. / On the world stage, Brazil is the third largest world fruit producer. As for the Brazilian economy, the importance of the fruit sector is evidenced because the fruit market accounts for approximately 10% of agricultural GDP, while fresh fruits accounted for more than 270 million dollars in 2009 and the market for juices and nectars for more than 1.8 billion dollars. However, purchasing fruit companies are suffering from the effects of fluctuations in production and demand, collective inefficiency, lack of understanding of the dynamics of supply and reduction in profitability for all members of the fruit production chain. The supply chain management has been touted as one of the ways to reduce this volatility and improve outcomes for all involved with the fruit supply. However, empirical evidence does not relate to the fruit industry. To solve this problem, the present research aimed to characterize the supply chain of fruits, to analyze the planning and management of the supply chain of a company buying fruit and identify contributions and improvements to the theories, methods and models related to supply chain management supply to propose a method for planning and managing the supply chain of buying fruit companies. It was conducted a case study from a single purchasing fruit company and in-depth interviews with industry experts to assess the applicability, functionality and usefulness from the managerial point of view of the proposed method. In-depth interviews were used to characterize the chain sleeve and a single case study of a purchasing company sleeve with industry experts to evaluate the applicability, functionality and usefulness of the managerial point of view of the proposed method. Data analysis was done through the triangulation of the theoretical with the methods and models of supply chain management and the description of the case. The results of the study indicated that the supply chain of fruits can be characterized as receptive to improvements in planning and managing the supply chain, the analysis of the planning and management of the supply chain of fruit in Brazil is efficient to evaluate their suppliers into four distinct regions, that there is consistency and synergy between theory, models and methods of supply chain management, and allowed the elaboration of a method for planning and managing the supply chain of companies purchasing fruit. With the proposition of this method is expected to contribute with a sequence of steps to assist in planning and management of supply chain managers and specialists from a buyer fruit company.
38

Critérios de seleção de fornecedores para relacionamentos de parceria: um estudo em empresas de grande porte / Supplier selection criteria for partnering relationships: a study in big size companies

Furtado, Gustavo Adolfo Pudenci 06 December 2005 (has links)
Esta dissertação buscou identificar junto a empresas de grande porte quais os critérios de seleção de fornecedores que são considerados mais importantes quando se deseja construir relacionamentos de parceria dentro da cadeia de suprimentos. A revisão de literatura foi dividida em três grandes partes. Na primeira parte procurou-se abordar aspectos da gestão de suprimentos que são relevantes para o tema, como organização de compras, classificação de tipos de produtos e tipos de relacionamentos entre empresas, onde as características teóricas das parcerias com fornecedores foram exploradas. A segunda parte foca as características do processo de seleção de fornecedores. A terceira parte é dedicada ao estudo dos critérios encontrados na literatura para a escolha da mais adequada fonte de suprimentos. A consolidação desta parte do trabalho resultou na apresentação de uma lista com 45 critérios de seleção de fornecedores e suas respectivas definições para uniformização de abrangência e compreensão dos critérios. Com base nesta lista, a pesquisa foi conduzida na forma de estudo de casos junto às Gerências de Suprimentos de três empresas de grande porte com operações no mercado brasileiro de bens industriais e de consumo. Através de questionários e entrevistas foram identificados 17 critérios como sendo os mais importantes para o processo de seleção parceiros. A pesquisa também encontrou que os conceitos de parcerias com fornecedores são definidos pelas realidades de mercado de cada empresa e não convergem para os conceitos apresentados na literatura acadêmica. Parcerias vêm sendo definidas somente como relacionamentos de longo prazo com fornecedores em detrimento de qualquer outro atributo referenciado pela literatura acadêmica. Portanto, a utilização deste termo precisa vir precedida de uma conceituação precisa para evitar duplicidade de interpretações. / This dissertation aimed the identification of the most important supplier selection criteria used by large size companies when they want to build partnering relationships in their supply chains. The review of literature was separated in three parts. The first one concerns the supply management subjects that are relevant to the theme, such as purchase structure, product classification and sort of companies relationships, where the supplier partnerships characteristics were explored. The second part focuses the characteristics of supplier selection process. The third part is dedicated to the selection criteria found in the literature used to choose the most appropriated source of supply. The consolidation of this part resulted in the presentation of a list with 45 supplier selection criteria and their definitions to standardize the scope and comprehension. Based on this list, the research was conducted as case studies with Purchasing Managers of three large size companies that have operations in the Brazilian markets of industrial and consumer goods. Using questionnaires and interviews procedures, 17 criteria were considered the most important for the partner selection process. The research also found that the suppliers’ partnerships concepts are defined by the market realities of each company e do not converge to concepts shown in the academic literature. Partnerships has been defined only as long term relationships with suppliers rather than any other attribute mentioned in the academic literature. Therefore, before making use of the term Partnership it should be precisely defined in order to avoid misinterpretation.
39

Diretrizes para a implantação da gestão estratégica de suprimentos em empresas construtoras. / Guidelines for strategic sourcing implementation at construction companies.

Moratti, Tathyana 19 April 2010 (has links)
Todo e qualquer empreendimento começa a se materializar na área suprimentos de uma empresa, sendo a principal função de esta área adquirir os materiais e serviços que compõem os empreendimentos. A gestão de suprimentos estabelecida para um determinado empreendimento pode fazer com que este tenha, ou não, um bom desempenho, bem como possibilitar que a execução seja mais eficiente e eficaz. Esta gestão, além de ser a mais adequada para a execução do empreendimento, deve também refletir a estratégia da organização, para que seja garantida a vantagem competitiva escolhida. Dada a sua importância, esta pesquisa tem como objetivo identificar as principais diretrizes envolvidas para a implantação da gestão estratégica de suprimentos em empresas construtoras. Inicialmente, foi realizada uma revisão bibliográfica a respeito dos temas: gestão da cadeia de suprimentos, gestão de suprimentos e gestão estratégica de suprimentos. Em seguida, foi realizado um estudo das características do setor da construção e de suas respectivas gestão da cadeia de suprimentos e gestão de suprimentos. Para que fossem identificadas as diretrizes, foi realizada uma revisão bibliográfica a cerca dos processos envolvidos na gestão estratégica de suprimentos, em geral. As diretrizes foram então identificadas considerando as características do setor da construção, bem como os processos da gestão estratégica de suprimentos investigados. Ao final desta pesquisa são apresentadas as conclusões e sugestões para pesquisas futuras. Com a identificação destas diretrizes, espera-se contribuir para que a gestão de suprimentos em empresas construtoras seja tratada, cada vez mais, de forma estratégica, agregando valor ao processo construtivo e conseguindo tornar factíveis alguns conceitos da gestão da cadeia de suprimentos. / All and any project starts to turn real in the purchasing department, which has the main function of supplying the projects materials and services. The supply management established for a project can determine its performance as well as make the constructions more efficient and effective. This management must even be the most appropriated to the construction; either reflects the organization strategy to ensure the chosen competitive advantage. Due to its importance, this research objective is to identify the main guidelines involved at the strategic sourcing implementation in construction companies. At first, a bibliographical research was accomplished considering the themes: supply chain management, supply management and strategic sourcing. Afterwards, it was made a study about the characteristics of the construction industry and its supply chain management and supply management. In order to identify the guidelines, it was made a bibliographic research about the strategic sourcing processes. The guidelines were identified considering the construction industry characteristics and the strategic sourcing processes searched. At the end of this research, are presented the conclusions and the suggestions to orientate further researches. By the guidelines identification, it is expected to contribute to contractors supply management to be, more than ever, administered with a strategic view, adding value to the construction process and making feasible some supply chain management constructs.
40

From Diagnosis to Water Management: The role of Atmospheric Dynamics and Climate Variability on Hydrological Extremes

Lu, Mengqian January 2014 (has links)
The recent extreme hydrological extremes over the globe highlight the importance of understanding the role of atmospheric dynamics and climate variability on the occurrence of these extreme events and the associated temporal and spatial characteristics of sequences of the precipitation events. Most of the studies have been focusing on overall average impacts of long-term global climate change on extremes. Majority are driven largely by considering the changes of the moisture holding capacity as a function of temperature, as indicated by the Clausius-Clapeyron equation. Given the complex dynamical structure of the atmosphere, one needs to also consider the attendant atmospheric circulation and moisture transport mechanisms that lead to extreme precipitation and subsequent floods as evidenced in the recent major floods. This study first develops insights into the causative climatic factors associated with precipitation induced regional floods events and understand the roles of Atmospheric Rivers (AR) or Tropical Moisture Exports (TME) and atmospheric circulation patterns associated with the frequency and/or persistency of such events in the midlatitudes. The second part explores the spatiotemporal relationship between climate variability and global extreme precipitation occurrence using a graph based approach based upon the concept of reciprocity to investigated the linkages and influences of the slowly changing boundary conditions on the development or propagation of atmospheric circulations, to assess the predictability of global precipitation extremes given the leading modes of identified climate dipole networks. A multi-timescale statistical, climate informed, stochastic streamflow forecast model serves as the bridge linking the first two parts to the application in the third part: application on water resources management by developing a multi-timescale climate informed stochastic hybrid stimulation-optimization model for multi-purpose reservoir systems, which enables the utilization of the streamflow forecast. The novel reservoir operation model attempts to change the game of water resources management from its conservative, rigid rule-following scheme to a robust, market-based, reliable water allocation strategy. Part I. Tropical Moisture Exports, Extreme Precipitation and Major Flood Atmospheric Rivers are being increasingly identified as associated with some extreme floods. More generally, such floods may be associated with tropical moisture exports that exhibit relatively robust teleconnections between moisture source regions and flood regions. First, a large-scale flood event that persisted over Western Europe in January 1995 is studied. During the last ten days of the month, two rare flooding events, associated with heaviest rainfall in 150 years, occurred in two places, one over Brittany (West of France), and the second in the France-Germany border region and parts of neighboring countries. In this study, we explore the month-long evolution of tropical moisture exports (TME) and their connection to the precipitation events that led to the Brittany event. The persistent large-scale atmospheric circulation patterns that led to the birth, death and evolution of these TME as atmospheric rivers with landfalls in Western Europe are identified, and the relationship of daily extreme precipitation to these patterns is examined. Singular value decomposition (SVD) analysis and a generalized linear model (GLM) are used to assess whether knowledge of the atmospheric circulation patterns from the prior record is useful for explaining the occurrence of their rare events. The analysis establishes the importance of both global and regional atmospheric circulation modes for the occurrence of such persistent events and the hydrologic importance of diagnosing global atmospheric moisture pathways. Part II. Seasonal to Interannual Variability of Tropical Moisture Exports, Extremes and ENSO A statistically and physically based framework is put forward that investigates the relationship between Tropical Moisture Exports (TMEs), Extreme Precipitation and Floods. TMEs is the more general phenomena than Atmospheric Rivers (ARs) in terms of (1) facilitates the poleward transport of warm and moist air masses from low latitudes, primarily tropical oceanic areas, to higher latitudes; (2) contributes to the global climatology precipitation and its extremes; (3) closely relates to floods events, especially in the midlatitudes. The TMEs itself has seasonal and interannual variability that is regulated by slowly changing boundary conditions and climate variability, such El Niño Southern Oscillation (ENSO), while the trajectories and movements are presumably led by atmospheric circulations patterns driven by the balance of global energy and water budgets. In this study, we take Northwest US (NE US) to show how the TMEs is related to extreme precipitation and then floods, and the results of the variability of TMEs, coupled with atmospheric circulation patterns, on the extremes. Historical large floods events in NE US in different seasons are studied for their link to the TMEs. Major moisture sources of TMEs that contributes to precipitation, extremes and floods in NE US are identified, together with the sources' seasonally and interannually varying characterizes in terms of both birth and entrance to the NE US, with the consideration of large scale climate regulations and atmospheric circulation patterns. Part III. Correlation Networks for Identifying Predictors for Extended Range Forecasts for Extreme Precipitation Correlation networks identified from financial, genomic, ecological, epidemiological, social and climate data are being used to provide useful topological insights into the structure of high dimensional data. Strong convection over the oceans and the atmospheric moisture transport and flow convergence indicated by atmospheric pressure fields may determine where and when extreme precipitation occurs. Here, the spatiotemporal relationship between climate and extreme global precipitation is explored using a graph based approach that uses the concept of reciprocity to generate cluster pairs of locations with similar spatiotemporal patterns at any time lag. A global time-lagged relationship between pentad sea surface temperatures (SST) anomalies and pentad sea level pressure (SLP) anomalies is investigated to understand the linkages and influence of the slowly changing oceanic boundary conditions on the development of the global atmospheric circulation. We explore the use of this correlation network to predict extreme precipitation globally over the next 30 days, using a Principal Component logistic regression on the strong global dipoles found between SST and SLP. Unprecedented success of the predictive skill under cross validation for 30 days precipitation higher than the 90th percentile is indicated for selected global regions for each wet season considered. Part IV. Applications of Climate Informed Streamflow Forecasts for Water Management Streamflow forecasts at multiple time scales (e.g., season and year ahead) provide a new opportunity for reservoir management to address competing objectives. Market instruments such as forward contracts with specified reliability are considered as a tool that may help address the perceived risk associated with the use of such instruments in lieu of a traditional operation and allocation. A water allocation process that enables multiple contracts with different durations, to facilitate participatory management of the reservoir by users and system operators, is presented here. Since these contracts are based on a verifiable reliability they may in turn be insurable. A Multi-timescale climate informed Stochastic Hybrid Simulation - Optimization Model (McISH) is developed, featuring (1) dynamic flood control storage allocation at a specified risk level; (2) multiple duration energy/water contracts with user specified reliability and prices; and (3) contract sizing and updating to reflect changes in both demands and supplies. The model incorporates multi-timescale (annual and seasonal) streamflow forecasts, and addresses uncertainties across both timescales. The intended use is as part of an interaction between users and water operators to arrive at a set of short-term and long term contracts through disclosure of demand or needs and the value placed on reliability and contract duration. An application is considered using data for the Bhakra Dam, India. The issues of forecast skill and contract performance given a set of parameters are examined to illustrate the approach. Prospects for the application in a general setting are discussed.

Page generated in 0.4936 seconds