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Theory and Application of Geophysical Geodesy for Studying Earth Surface DeformationKaregar, Makan A. 29 August 2018 (has links)
<p> An interdisciplinary approach at the interface between geodesy and geophysics has recently resolved several Earth science problems at regional and global scales. I use the term “geophysical geodesy” to distinguish the technical and theoretical aspect of geodesy from geophysical applications of geodetic techniques. Using a wide range of Earth observation data, I study the spatio-temporal characteristics of Earth surface deformation in the United States associated with several geophysical processes, including natural and anthropogenic subsidence and uplift, regional relative sea-level rise, and continental hydrological loading. The theoretical portion of this dissertation applies loading theory and develops a new hybrid method to improve the estimate of hydrologically-induced vertical deformation at time scales from sub-annual to multi-annual. The application part of this dissertation benefits from GPS and other geodetic and geologic data sets to study and model Earth’s surface uplift due to CO2 injection at an oil reservoir in coastal Texas, and coastal subsidence and nuisance flooding along the Mississippi River Delta and eastern seaboard of the United States.</p><p>
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The Fermenting Assemblage| Finding Latent Potential for Change in Emergent ProcessSancho-Rosi, Nicholas 25 August 2018 (has links)
<p>Chapter One of this thesis focuses on critiques of modernity and capitalism, both of which are deeply implicated in the advent of the Anthropocene. Drawing from Bruno Latour, Anna L. Tsing, Caroline Levine, and Adam Seligman, I examine the sincere drive to ?purify? the world of its entangled networks. I then consider Francois Jullien?s critique of the Western ?cult of action,? discussing it alongside Latour?s critique of modern temporality and Tsing?s critique of progress. Finally, I read David Mitchell?s novel, Ghostwritten, in the context of this discussion. In the second chapter I discuss how Latour, Tsing, and Jullien ask us to turn our attention to the entangled world, rather than striving to purify it. I present a metaphor of fermentation in order to consider how we rely on natural processes to bring about change rather than individual will. This alternate form of action relies on the propensity for transformation already latent in an assemblage. I end with a discussion of Ursula Le Guin?s Earthsea Cycle, arguing that the Immanent Grove and the Master Patterner illustrate this amodern form of action.
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Numerical Simulations of the Impact of Large Wind Farms on Local ClimateJanuary 2015 (has links)
abstract: Due to decrease in fossil fuel levels, the world is shifting focus towards renewable sources of energy. With an annual average growth rate of 25%, wind is one of the foremost source of harnessing cleaner energy for production of electricity. Wind turbines have been developed to tap power from wind. As a single wind turbine is insufficient, multiple turbines are installed forming a wind farm. Generally, wind farms can have hundreds to thousands of turbines concentrated in a small region. There have been multiple studies centering the influence of weather on such wind farms, but no substantial research focused on how wind farms effect local climate. Technological advances have allowed development of commercial wind turbines with a power output greater than 7.58 MW. This has led to a reduction in required number of turbines and has optimized land usage. Hence, current research considers higher power density compared to previous works that relied on wind farm density of 2 to 4 W/m 2 . Simulations were performed using Weather Research and Forecasting software provided by NCAR. The region of simulation is Southern Oregon, with domains including both onshore and offshore wind farms. Unlike most previous works, where wind farms were considered to be on a flat ground, effects of topography have also been considered here. Study of seasonal effects over wind farms has provided better insight into changes in local wind direction. Analysis of mean velocity difference across wind farms at a height of 10m and 150m gives an understanding of wind velocity profiles. Results presented in this research tends to contradict earlier belief that velocity reduces throughout the farm. Large scale simulations have shown that sometimes, more than 50% of the farm can have an increased wind velocity of up to 1m/s
at an altitude of 10m. / Dissertation/Thesis / Masters Thesis Engineering 2015
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Ecological Consequences of Constitutive versus Inducible Thermal Defense Strategies in Rocky Shore LimpetsKroupa, Thomas F. 02 February 2018 (has links)
<p> My study was designed to determine how different thermal defense strategies and the intensity of high temperature challenges might affect demographic and physiological performance of limpets on rocky shores. Found together in the high intertidal zone, <i>Lottia scabra</i> employs a constitutive thermal defense strategy, whereas <i>L. austrodigitalis</i> has an inducible one. I measured loss and growth rates of both species as a function of average daily maximum temperature exposure in the field, and respiration rates for field-collected and lab-acclimated individuals under benign conditions in the lab before and after exposure to one of five peak temperatures (14, 24, 28, 32, or 36 °C) during a 4.5-hour simulated low tide. <i>L. scabra</i> was relatively unaffected by exposure to high temperatures, whereas <i>L. austrodigitalis</i> exhibited significant increases in loss rates from experimental plates, decreases in growth rates, and increases in oxygen consumption, consistent with activation of the heat shock response.</p><p>
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Assessing Terrestrial Biosphere Model Simulation of Ecosystem Drought Response and RecoveryKolus, Hannah 20 April 2018 (has links)
<p> Severe drought plays a critical role in altering the magnitude and interannual variability of the net terrestrial carbon sink. Drought events immediately decrease net primary production (NPP), and drought length and magnitude tend to enhance this negative impact. However, satellite and in-situ measurements have also indicated that ecosystem recovery from extreme drought can extend several years beyond the return to normal climate conditions. If an ecosystem’s drought recovery time exceeds the time interval between successive droughts, these legacy effects may reinforce the impact of future drought. Since the frequency and severity of extreme climate events are expected to increase with climate change, both the immediate and prolonged impact of drought may contribute to amplified climate warming by decreasing the strength of the land carbon sink. However, it is unknown whether terrestrial biosphere models capture the impact of drought legacy effects on carbon stocks and cycling. Using a suite of twelve land surface models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we assessed model ability to simulate drought legacy effects by analyzing the modeled NPP response to drought events across forested regions of the US and Europe. We found that modeled drought legacy effects last about one year (2% reduction in NPP), with complete NPP recovery in the second post-drought year. Since observations suggest that legacy effects extend up to four years post-drought, with a 9% growth reduction in the first post-drought year, models appear to underestimate both the timescales and magnitude of drought legacy effects. We further explored vegetation sensitivity to climate anomalies through global, time-lagged correlation analysis of NPP and climatic water deficit. Regional differences in the lag time between climate anomaly and NPP response are prevalent, but low sensitivities (correlations) characterize the entire region. Significant correlations coincided with characteristic lag times of 0 to 6 months, indicating relatively immediate NPP response to moisture anomalies. Model ability to accurately simulate vegetation’s response to drought and sensitivity to climate anomalies is necessary in order to produce reliable forecasts of land carbon sink strength and, consequently, to predict the rate at which climate change will progress in the future. Thus, the discrepancies between observed and simulated vegetation recovery from drought points to a potential critical model deficiency.</p><p>
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Reconstructing the past climate at Gale crater, Mars, from hydrological modeling of late-stage lakesHorvath, David G., Andrews-Hanna, Jeffrey C. 28 August 2017 (has links)
The sedimentary deposits in Gale crater may preserve one of the best records of the early Martian climate during the Late Noachian and Early Hesperian. Surface and orbital observations support the presence of two periods of lake stability in Gale craterprior to the formation of the sedimentary mound during the Late Noachian and after the formation and erosion of the mound to its present state in the Early Hesperian. Here we use hydrological models and late-stage lake levels at Gale, to reconstruct the climate of Mars after mound formation and erosion to its present state. Using Earth analog climates, we show that the late-stage lakes require wetter interludes characterized by semiarid climates after the transition to arid conditions in the Hesperian. These climates are much wetter than is thought to characterize much of the Hesperian and are more similar to estimates of the Late Noachian climate.
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Buildings in a hot climate with variable ventilation at nightHafezi, Mohammad-Reza January 1989 (has links)
During the summer, buildings in hot dry climates have the inevitable problem of cooling. These climates are characterized by hot summer days with cold nights, a high degree of solar radiation, low humidity and with a nearly fixed seasonal and daily pattern of wind. These natural phenomena could be exploited by nocturnal ventilation to cool the building fabric, thus saving energy during the day and providing comfort at night. The procedures to evaluate thermal performance of buildings with special reference to nocturnal ventilation are studied. Various approaches to building thermal response are first reviewed. Dynamic thermal simulation computer models are developed to predict hourly 'internal temperatures'. These are used to study the various constituents of models. They are based on: -the Admittance Method (as suggested by the CIBSE Guide); -a similar procedure but with higher harmonics; -the Response Factor Method (suggested by ASHRAE); -and the Finite Difference Method. A room surrounded by similar rooms in a multi-storey building, having only one external wall, was simulated in the laboratory. It was subjected to typical variations of a hot climate. Predictions of the computer simulations are compared with laboratory results and it is shown that -the closest agreement was obtained with the Response Factor and Finite Difference methods which are equally good; -for higher rates of ventilation, representation of a room by a simple three nodes model thermal network will give sufficiently accurate results; while for lower rates of ventilation a more detailed model gives more accurate results; -the standard Admittance Method gives adequate results, especially with higher rates of ventilation. It could also be used for hourly temperature-, calculations and variable ventilation without loosing significant accuracy; -a fuller treatment in the Admittance Method of time-lag and time-lead, associated with the dynamic thermal factors, will not greatly improve the results. An increase in the number of harmonics in the procedure did not also result in significant improvements, especially with a high rate of ventilation. Natural ventilation into rooms through open windows in these climates is theoretically investigated. It is shown that the rate of natural air flow obtained may be sufficient to meet the requirements of passive cooling by nocturnal ventilation. A computer program is developed to calculate the rate of air flow in multi-zone buildings, and a new relationship is suggested, which will reduce the complexity of natural air flow calculations in multi-zone buildings subjected to cross ventilation.
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Better Coverage of Arizona's Weather and Climate: Gridded Datasets of Daily Surface Meteorological VariablesWeiss, Jeremy, Crimmins, Michael 08 1900 (has links)
7 pp. / Many areas that use agricultural and environmental science for management and planning – ecosystem conservation, crop and livestock systems, water resources, forestry and wildland fire management, urban horticulture – often need historical records of daily weather for activities that range from modeling forage production to determining the frequency of freezing temperatures or heavy rainfall. In the past, such applications primarily have used station-based observations of meteorological variables like temperature and precipitation. However, weather stations are sparsely and irregularly located throughout Arizona, and due to the highly variable terrain across the state (Figure 1), information recorded at these sites may not represent meteorological conditions at distant, non-instrumented locations or over broad areas. This issue, along with others related to quality, length, and completeness of station records, can hinder the use of weather and climate data for agricultural and natural resources applications. In response to an increasing demand for spatially and temporally complete meteorological data as well as the potential constraints of station-based records, the number of gridded daily surface weather datasets is expanding. This bulletin reviews a current suite of these datasets, particularly those that integrate both atmospheric and topographic information in order to better model temperature and precipitation on relatively fine spatial scales, and is intended for readers with knowledge of weather, climate, and geospatial data. In addition to addressing how these datasets are developed and what their spatial domain and resolution, record length, and variables are, this bulletin also summarizes where and how to access these datasets, as well as the general suitability of these datasets for different uses.
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Climate change and buildings : the impact on human healthShorthouse, Edward January 2015 (has links)
The health risks posed by hot weather are growing as increasingly frequent extreme weather is brought about by climate change. People spend upwards of 80% of time indoors and so human health is largely dependent on the internal environment of buildings. In the building industry engineers currently design buildings for high-energy performance by maximising heat retention, and whilst this may be effective in cold winters, it can lead to unbearable indoor conditions in hot summers. Thermal comfort inside buildings is a well-discussed topic both in industry and academia, but absolute peak thresholds, especially for heat stress still require development. In this thesis the outcomes of research into the effects of current and future hot weather on the heat stress of occupants inside buildings are presented. Hot weather data from the current climate and mortality rates are compared and several temperature metrics are analysed with respect to health risk forecasting performance, so that peak threshold limits for human health indoors are established for the building design industry. Reference weather data used in building simulations for health assessment is currently chosen based on air temperature alone. In this thesis new reference weather data is created for near-extreme and extreme weather and for current and future climates, based on the peak threshold metric research and future weather analysis. By 2050 hot weather reference years currently occurring once every seven years could become an annual occurrence, and by 2080 extreme hot weather reference years currently occurring once in twenty-one years could become an annual occurrence. Computational fluid dynamics is then used to simulate the internal heat stress inside a building model, and a surrogate model is created to emulate heat stress levels for full calendar years of future climates for several UK locations. It is envisaged that the results presented in this thesis will help inform the industry development of new reference data and aid better building design.
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Global Change and Trophic Interaction Diversity| Complex Local and Regional ProcessesPardikes, Nicholas A. 05 August 2017 (has links)
<p> The structure and functioning of ecosystems across the globe are rapidly changing due to several components of global environmental change (GEC). My dissertation aims to illustrate how regional and local aspects of GEC impact diverse assemblages of species and species interactions. All organisms are embedded in complex networks of species interactions, and future efforts to predict and mitigate the impacts of GEC on ecological communities will be facilitated by such studies that incorporate a suite of species and species interactions. This study advances our understanding of how GEC will impact ecological communities by investigating two questions about GEC: 1) How will shifts in global climate cycles (e.g., El Nino Southern Oscillation), as a consequence of global warming, impact a diverse assemblage of butterflies that exist across a heterogeneous landscape? 2) What are the consequences of woody plant encroachment on complex, specialized interactions between plants, insect herbivores, and natural enemies (e.g., insect parasitoids)? Furthermore, I helped develop a tool to identify characteristics of ecological communities that are essential for promoting the diversity of trophic interactions. While the loss of species diversity is well recognized, interactions among species are vanishing at an astonishing rate, yet we know little about factors that determine the diversity of interactions within a community. Using data from a long-term butterfly monitoring dataset, I was able to demonstrate the utility of large-scale climate indices (e.g., ENSO) for modeling biotic/abiotic relationships for migratory butterfly species. Next, I used encroaching juniper woodlands in the Intermountain West to uncover that population age structure of dominant tress, such as juniper, can affect plant-insect dynamics and have implications for future control efforts in the expanding woodlands. Additionally, reductions of understory plant diversity, as a consequence of juniper expansion, resulted in significantly lower parasitism rates and parasitoid species diversity. Finally, simulated food webs revealed that species diversity and, to a lesser degree, consumer diet breadth, promote the diversity of trophic interactions. As ecosystems across the globe experience changes and the loss of species diversity continues, these findings offer insight into how GEC will impact species and species interactions.</p><p>
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