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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

The Columbia River's region: Politics, place and environment in the Pacific Northwest, 1933--present

Vogel, Eve, 1964- 12 1900 (has links)
xiv, 296 p. : ill. A print copy of this title is available through the UO Libraries under the call numbers: KNIGHT F853 .V64 2007 / This dissertation argues that Columbia River management and politics have been shaped ever since the New Deal by a conception of the Columbia River as the defining feature of the Pacific Northwest region. The study examines how that conception was developed, how it became institutionalized within and by a government agency, the Bonneville Power Administration, and what its impacts have been. Drawing on a mix of archival materials, published and unpublished secondary accounts, interviews, and the author's experience working on Columbia River policy, the dissertation shows that the definition of a Columbia River-centered Pacific Northwest was laid out in 1935 by the four-state Pacific Northwest Regional Planning Commission, influenced in part by a "regionalist" ideal of shared social and environmental well-being. It was institutionalized but narrowed into the federal BPA in 1937. Soon, a three-and-a-half-state Pacific Northwest consisting of Washington, Oregon, Idaho and western Montana was being knit together by shared transmission lines and uniformly inexpensive power rates, and by a federal power agency that positioned itself as a regional Chamber of Commerce. Since the Second World War, the Columbia River-centered Pacific Northwest has shaped its collective economic fortunes around exclusive regional access to BPA-provided Columbia River hydropower. But geographically distributed wealth did not end political conflict; private power companies, state governors, Native American tribes, and fish and wildlife agencies have had to be accommodated with distributions of BPA power and money. BPA-centered Columbia River management has through political conflict gradually expanded to serve wider interests, moving closer to the New Deal regionalist ideal. Yet in controversial decisions since 2000, Columbia River managers have chosen to risk wild salmon rather than breach federal Columbia River hydropower dams or allow Pacific Northwest power costs to escalate. They have done this because they have prioritized the most fundamental, and the most regional, Columbia River benefit of all: broadly shared inexpensive power. Understanding the opportunities and constraints of BPA-centered regional Columbia River management is essential in order to meet upcoming Columbia River policy challenges. / Adviser: Alexander B. Murphy
92

Restoring oak habitats in the Southern Willamette Valley, Oregon: A multi-objective tradeoffs analysis for landowners and managers

Ulrich, Nathan D., 1977- 12 1900 (has links)
xvii, 160 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Restoring oak habitats is an emerging conservation priority in Oregon's Willamette Valley. Both private and public landowners face multiple challenges to conservation and restoration of oak habitats, including a lack of knowledge about the potential tradeoffs and constraints for achieving multiple priorities on a given site. This study simulated 25 alternative oak habitat restoration scenarios to develop estimates of outcomes related to six different restoration priorities: costs, income potential, habitat value, scenic quality, fire hazard reduction potential, and time requirements. Model results indicated that initial land conditions strongly influence a landowner's ability to optimize among these different priorities. To assist landowners with decision-making, model estimates were organized into a digital decision matrix that communicates advantages and tradeoffs associated with each alternative scenario. In doing so, it aims to help landowners choose restoration goals that better meet their broader needs and objectives. / Committee in Charge: Dr. Bart Johnson, Chair; Dr. Robert Ribe
93

Defining Biomass as a Source of Renewable Energy: The Life-Cycle Carbon Emissions of Biomass Energy and a Survey and Analysis of Biomass Definitions in States' Renewable Portfolio Standards, Federal Law, and Proposed Legislation / Life-Cycle Carbon Emissions of Biomass Energy and a Survey and Analysis of Biomass Definitions in States' Renewable Portfolio Standards, Federal Law, and Proposed Legislation

Zeller-Powell, Christine Elizabeth 06 1900 (has links)
xii, 97 p. / Electricity generated from woody biomass material is generally considered renewable energy and has been considered carbon neutral. However, recent criticism from scientists argues that the greenhouse gas (GHG) emission profile of bioenergy is nuanced and the carbon neutral label is inappropriate. An initial carbon debt is created when a forest is harvested and combusted for bioenergy. Because forests re-grow over a period of years, life cycle analyses show that bioenergy generated from whole trees from forests may not reduce GHG emissions in the short term, as required to combat climate change. State renewable portfolio standards and federal laws and proposed legislation designed to incentivize renewable energy typically define eligible forms of biomass that qualify for these incentives. Most of these definitions are very broad and do not account for GHG emissions from bioenergy. Federal and state laws should incorporate life cycle analyses into definitions of eligible biomass so that these laws incentivize biomass electricity that reduces GHG emissions in the next several decades. / Committee in charge: Roberta Mann, Chairperson; Scott Bridgham, Member
94

Intensification rapide des cyclones tropicaux du sud-ouest de l’océan Indien (SWIO) : dynamique interne et influences externes / Tropical Cyclone rapid intensification in the southwest Indian ocean : internal processes and external influences

Leroux, Marie-Dominique 13 December 2012 (has links)
Dans un contexte international, la prévision d'intensité des cyclones tropicaux connaît encore de graves déficiences tandis que la prévision de trajectoire de ces phénomènes météorologiques extrêmes s'est grandement améliorée ces dernières décennies. Une source d'erreur pour la prévision d'intensité est le manque de connaissance des processus physiques qui régissent l'évolution de la structure et de l'intensité des cyclones. Cette thèse, proposée dans le cadre des responsabilités du Centre Météorologique Régional Spécialisé (CMRS) de la Réunion et des axes de recherche du LACy et du CNRM, a pour but d'améliorer la prévision numérique et la compréhension des mécanismes de changement de structure et d'intensité des cyclones dans le sud-ouest de l'océan Indien. On observe statistiquement dans le bassin de fréquents déferlements d'ondes de Rossby qui correspondent à une intrusion des talwegs d'altitude depuis les moyennes latitudes vers les régions où évoluent les cyclones. Ces déferlements advectent dans la troposphère tropicale de l'air d'origine stratosphérique à fort tourbillon potentiel (PV). Le cœur d'un cyclone tropical étant caractérisé par un vortex cyclonique de fort PV, il est donc légitime de se demander si de tels talwegs sont capables de « nourrir » un cyclone en déferlant jusqu'à lui, et l'intensifier par superposition de PV. D'un autre côté, l'approche d'un talweg est associée à d'autres facteurs pouvant jouer en défaveur d'une intensification, comme un fort cisaillement vertical de vent. L'étude de processus est réalisée sur le cyclone Dora (2007) avec le modèle opérationnel du CMRS sur le bassin, Aladin-Réunion. Ce modèle hydrostatique à aire limitée bénéficie d'une résolution horizontale de 8 km et de son propre schéma d'assimilation 3Dvar avec bogus de vent. Un tel bogus permet d'affiner la structure du cyclone à l'instant initial en ajoutant des observations de vent déduites d'un profil analytique et des paramètres de structure du cyclone estimés par les images satellites. Des diagnostiques sur les variables thermodynamiques en sortie de modèle montrent que la phase d'intensification rapide de Dora est bien associée à l'advection de tourbillon potentiel (PV) en provenance du talweg. Bien que fortement cisaillé, le système parvient à s'intensifier grâce à la forte inclinaison du talweg qui advecte du PV au cœur du cyclone en 2 temps et à 2 niveaux (haute et moyenne troposphère). Lorsque le talweg est au plus proche du cyclone, il force un processus dynamique interne appelé « cycle de remplacement du mur de l'œil ». On observe une inclinaison et un renforcement des vitesses verticales à l'extérieur du mur de l'œil principal, associé à une accélération de la circulation cyclonique tangentielle par advection de moment angulaire sur toute l'épaisseur de la troposphère dans cette zone annulaire (mis en évidence par les flux d'Eliassen-Palm). Un second maximum de vent relatif apparaît alors et une deuxième phase d'intensification rapide s'ensuit avec la contraction du mur secondaire. Le forçage de processus internes par une influence externe (un talweg) semble donc être le moteur de l'intensification rapide de Dora dans un environnement cisaillé, et potentiellement celui d'autres cyclones dans le bassin qui sont approchés par des talwegs d'altitude. Les prévisionnistes du CMRS sont invités à surveiller les champs de PV de tels systèmes, en attendant que de plus amples diagnostiques soient réalisés avec l'outil d'inversion du tourbillon potentiel développé sur le modèle global Arpège. / Despite significant improvements in Tropical Cyclone (TC) track forecasts over the past few decades, anticipating the sudden intensity changes of TCs remains a major operational issue. The main purpose of this thesis is to analyze TC rapid intensification processes in relation with external forcing induced by upper-level troughs originating from the mid-latitudes. The impact of initial storm structure on storm evolution and prediction is also documented. An objective definition for rapid intensification in the southwest Indian Ocean is first proposed. The location and frequency of TC-trough interactions are identified, as well as TC-trough arrangements conducive to TC intensification. An interesting study case, TC Dora (2007), is chosen to run numerical simulations initialized with synthetic TC observations blended in a global analysis. The simulated TC-trough interaction is intricate with potential vorticity (PV) advection from the trough into the TC core at mid and upper levels. Vortex intensification first occurs inside the eyewall and results from PV superposition. Further intensification is associated with a subsequent secondary eyewall formation triggered by external forcing from the trough. The numerical model is able to reproduce the main features associated with outer eyewall spin-up, inner eyewall spin-down, and their effects on vortex intensity changes. Another numerical study examines typhoons in the northwest Pacific and demonstrates the critical role played by initial vortex structure in TC track and intensity prediction. Upgrading the initial specification of a TC inner-core structure in numerical models is recommended for future TC prediction improvements.

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