Now showing items 1-20 of 6794

    • Alaska Earthquake Center Quarterly Technical Report July-September 2022

      Ruppert, Natalia (2022-11-10)
      This series of technical quarterly reports from the Alaska Earthquake Center (AEC) includes detailed summaries and updates on Alaska seismicity, the AEC seismic network and stations, field work, our social media presence, and lists publications and presentations by AEC staff. Multiple AEC staff members contribute to this report. It is issued in the following month after the completion of each quarter Q1: January-March, Q2: April-June, Q3: July-September, and Q4: October-December. The first report was published for January-March, 2021.
    • Some trends in non-native adaptation in villages along the Kobuk and Koyukuk Rivers in northwest Alaska

      Keim, Frank J. (1973-05)
      Non-Natives living in isolated village settings in Alaska have traditionally been Ignored in anthropological investigations. These non-Natives are the subject of this thesis. It is a preliminary treatment of the adjustments they must make as newcomers to a cultural environment that is at first unfamiliar to them. As a result of these adjustments ,• the newcomers develop a different approach to life, one which includes a blend of elements from both their own culture and that in which they find themselves as strangers. The thesis also briefly discusses these non-Natives as change agents in the modification of the life patterns of the Native people among whom they live. Finally, the thesis suggests tentative guidelines for the recruitment of bush personnel in Alaska.

      Zhang, Guohui; Yang, Hanyi; Yu, Hao; Li, Zhenning; Zou, Rong; Yuan, Runze; Ma, Tianwei (2022-09)
      This report documents the research activities to investigate the traffic crashes in Rural, Isolated, Tribal, or Indigenous (RITI) communities involving considerable incapacitating injuries and fatalities. The traffic crashes occurring in RITI communities, are different from urban traffic crashes, and are related more to the features like speeding, low application of safety devices (for instance, seatbelt), adverse weather conditions and lacking maintenance and repairs for road conditions, and inferior lighting conditions. Thus, it is necessary to study the properties and attributes of traffic crashes at the RITI area using data analysis methods, such as statistical methods, and data-driven methods. This project is trying to analyze the rural crash injury and fatality patterns caused by changing climates in RITI communities based on enhanced data analysis using latest mathematical method. The mixed logit model to examine the risk factors in determining driver injury severity in four crash configurations in two-vehicle rear-end crashes on state roads based on seven-years of data from the Washington State Department of Transportation. The differences between the MLM and the LCM are investigated for exploring the relationships between driver injury severity in the rain-related rural single-vehicle crash and its corresponding risk factors. Moreover, this project develops a latent class mixed logit model with temporal indicators to investigate highway single-vehicle crashes and the effects of significant contributing factors to driver injury severity. The results of this research will be beneficial to transportation agencies to propose effective methods to improve rural crash severities under special climate and weather conditions and minimize the rural crash risks and severities.
    • Western Ahtna Geographic Appendices during 2012-2014

      Kari, James; Smith, Gerad M. (2014-05)
    • The STEM trail: Alaska Native undergraduates find the right path in higher education

      Skinner, Olga J.; Leonard, Beth; Williams, Maria; Gilmore, Perry; Mercier, Ocean (2022-05)
      The goals of this research are twofold. (1) This research explores decision making and college experiences of Alaska Native undergraduates pursuing degrees in the science, technology, engineering, and mathematics (STEM) fields, and (2) this research, using participant observation explores the Indigenous metaphor of "the trail" to frame student persistence towards their degrees. Twelve participants, representing various STEM fields, Alaska Native cultures, and K12 schooling experiences, shared their motivations and aspirations through interviews and photographs. Key findings indicate the significant role that Indigenous Knowledge plays in influencing student decisions around majoring in STEM degrees. Findings also illuminate the variety of K12 STEM experiences and the influence on decisions to major in STEM. Awareness (ellangeq) and self-authorship as student development theory, also impact decision making. The use of "the trail" as a metaphor for persistence illustrates a strength-based model for persistence, that notes the importance of the individual and the role of the individual as a community member. This metaphor also displays aspects of preparation, finding the right path, obstacles, supports, and destinations. This metaphor also calls into question the role of the institution as students work to navigate the terrain towards their degrees.
    • Optimization and forecasting algorithms for converter dominated distribution networks using blockchain and AI

      Shah, Chinmay; Wies, Richard W.; Al-Badri, Maher; Huang, Daisy; Cicilio, Phylicia (2022-05)
      Integration of power electronic converter-based distributed energy resources (DERs) in electric power distribution networks is growing exponentially with the recent interest in reducing carbon emissions from fossil fuel-based generation. As the contribution of renewable energy sources in the DER mix continues to increase, so does the incorporation of battery energy storage systems and other controllable loads to compensate for the high variability and uncertainty in the generation from renewable DERs and grid demand. Strategies for increasing the contribution of renewable energy sources and using reserves to accommodate for variations and uncertainty in generation and load include distributed optimal power flow (OPF) methods and improved forecasting. This work proposes a co-optimization of power flow and flexibility reserves, executed on a private blockchain for security, solved using a parameterized deterministic method based on semi-distributed architecture and alternating direction method of multipliers (ADMM) based distributed architecture that addresses uncertainty and enhances the flexibility of the distribution network. However, ADMM guarantees convergence only for strictly convex problems and hence a relax-and-fix heuristic algorithm is proposed in co-ordination with ADMM to solve the OPF problem, which is non-convex in nature. Also, an accurate short-term load forecasting algorithm is essential to reduce the uncertainty in the dispatch results using the OPF algorithm. In this work, a short-term residential load forecasting algorithm is proposed using a two-stage stacked long short-term memory network-based recurrent neural network and Hampel filter to address this issue. All the proposed algorithms are tested using different case studies. Results demonstrate that the proposed algorithms reduce the impact of uncertainty in the distribution network, automate scheduling flexibility reserve and minimize its cost, reduce the OPF execution time using a distributed architecture, and produce residential load forecast with a significantly lower prediction error.
    • Marine debris in the Bering Sea: combining historical records, toxicology, and local knowledge to assess impacts and identify solutions

      Padula, Veronica M.; Beaudreau, Anne; Causey, Douglas; McDonnell, Andrew; Konar, Brenda; Hollmen, Tuula (2022-05)
      Marine debris, particularly plastic marine debris, has numerous impacts on the environment, wildlife, and human communities. This research examines dimensions of marine debris in the Bering Sea and Aleutian Islands, Alaska, including impacts of marine debris pollution on wildlife and the environment; the history of marine debris research, monitoring, and cleanup activities; and community perspectives on local to global solutions. The first chapter of this dissertation is an integrative literature review to better understand the current status of marine debris knowledge in the Bering Sea region and identify critical knowledge gaps. We synthesized the depth and breadth of research, monitoring, and cleanup activities to better understand the sources, prevalence, and impacts of marine debris on wildlife and coastal communities. Our review revealed several knowledge gaps, including two that were a focus of the final chapters of the dissertation: measuring the extent of plastic-associated contaminants in the Bering Sea and capturing community perspectives and concerns about marine debris in the Bering Sea. The second chapter examined variation in phthalates, a class of plastic-associated chemicals, in Aleutian Islands seabirds, to refine hypotheses regarding ecological and environmental factors that affect phthalate exposure in marine wildlife. We quantified phthalates in seabirds collected across >1700 km of the Aleutian Islands, Alaska, and measured six phthalate congeners in seabirds representing ten species and four feeding guilds. Phthalates were detected in 100% of specimens (n = 115) but varied among individuals (range 3.64 - 539.64 ng/g). Total phthalates did not vary geographically, but differed among feeding guilds, with significantly higher concentrations in diving plankton-feeders compared to others. Our findings suggest feeding behavior could influence exposure risk for seabirds and lend further evidence to the ubiquity of plastic pollutants in marine ecosystems. The final chapter of the dissertation explored perspectives and concerns of St. Paul Island community members regarding marine debris and plastic pollution. This component of the research aimed to catalyze the inclusion of local knowledge in marine debris solutions for St. Paul Island, Alaska, by documenting community members' perceptions of marine debris, including its origin, impacts, and proposed solutions. We interviewed thirty-six St. Paul Island community members from 2017 to 2020 about the types, amount, distribution, and impacts of marine debris they have observed on the island and its surrounding waters over recent decades. Research participants reported increases in plastic debris since the 1980s, particularly plastic bottles. Nearly 80% expressed concern about impacts to subsistence resources, including entanglement and ingestion of plastic particles by marine mammals and fishes. St. Paul Island community members' experiences highlight that solving the problem of marine debris cannot rely on local efforts alone but requires broader policies and mitigation strategies to address the sources of debris and advance environmental justice for coastal communities. Overall, this dissertation contributes an improved understanding of the social and ecological impacts of plastic pollution in the Bering Sea region and the potential science and policy solutions that can stem the tide of marine debris.
    • Seeing the forest through the trees: how site conditions mediate white and black spruce responses to climate in Interior Alaska

      Nicklen, E. Fleur; Ruess, Roger W.; Roland, Carl A.; McGuire, A. David; Lloyd, Andrea H. (2022-05)
      The boreal forest provides essential ecosystem services and helps regulate global climate. With climate change occurring at a faster rate at high latitudes, including in the boreal forest biome, it is critical to understand how boreal forests are responding to these unprecedented changes. Despite much effort, uncertainty remains as to how boreal forest productivity has and will change with ongoing climate changes. Some of the uncertainty reflects the complex mosaic of regional climatic patterns, direct and indirect species-specific responses to regional climate, and heterogenous local site conditions that affect boreal forest productivity. I focused on the latter uncertainty: the potential role of topographic, edaphic, and biotic conditions in mediating the climate-growth responses of boreal tree species. My overarching goal was to quantify the radial growth response of black spruce (Picea mariana) and white spruce (Picea glauca), the two most common tree species in interior Alaska, to climate variability across a suite of site conditions to better understand the observed and predicted variation in climate driven productivity across a variable landscape. I employed a systematic sampling design to quantify the landscape-scale patterns in both environmental conditions and incremental annual growth of trees distributed across a 1.28 million-ha study area in Denali National Park and Preserve (and beyond in Chapter 4). I also used targeted sampling of carbon isotopes in tree rings to investigate potential drought stress. I found that near-surface permafrost, slope angle, and elevation strongly modified the magnitude, shape, and, in some cases, the direction of radial growth response of both species. For white spruce, the negative growth response to warm and dry summer conditions intensified in high competition stands and in areas receiving high potential solar radiation. During years with high cone and seed production, white spruce shifted its current year's carbon resources from radial growth to reproduction and showed signs of drought stress. I also observed differences between black and white spruce climate-growth responses, with near-surface permafrost driving their contrasting responses to June-July temperatures and with black spruce growth showing an overall more positive response to summer precipitation. These results demonstrate that local site and stand variables can force contrasting growth responses to similar climate conditions and help predict how future black and white spruce growth may play out with climate changes across a heterogeneous landscape. My results underscore the pivotal role of near surface permafrost in both the climate-growth responses and competitive dynamics of black and white spruce. Consequently, my results emphasize the importance of ongoing and predicted changes in the distribution and prevalence of permafrost for the future of the boreal forest.
    • The linguistic dreamstate: Freud, Lacan, and intertextuality in Samuel Beckett's The Unnamable

      Kay, Michael R.; Coffman, Chris; Holt, Joseph; Carr, Richard; Brightwell, Gerri (2022-05)
      This thesis focuses on the process of symbolization and signification in Samuel Beckett's novel, The Unnamable. The introduction presents readers with important and relevant critical interpretations of the novel, primarily those that are focused on the self, the use of language, and psychoanalytic theory. Then, the thesis introduces readers to key concepts in semiotic and psychoanalytic criticism, such as that of the signifier, sign, big-O Other, and the Lacanian Imaginary, Symbolic, and Real, by applying these concepts to a reading of The Unnamable. The next section, "The Linguistic Dreamstate," argues that the novel's narrator occupies a state tangential to consciousness, subconsciousness, and unconsciousness. In occupying this state, one that is outside of physical reality, the narrator is confronted with a language he does not understand and, while speaking, seeks to understand what he has previously said, mirroring the process of psychoanalysis as it concerns the meaning of dreams. Finally, it is shown that the narrator attempts to use language to as a means to stop using language. In so doing, the narrator illustrates the inability of language (and the Symbolic) to reconstruct the Real, and the innate desire for the Real (or objet a) even in those who do not have a reality within which they see the lack of the Real.
    • Snow as structural habitat for wolverines in a changing Arctic

      Glass, Thomas Rutherford Winder; Kielland, Knut; Breed, Greg; Williams, Cory; Robards, Martin (2022-05)
      Arctic snowpack provides critical wintertime habitat for animals to facilitate thermoregulation and avoid predators. Wolverines (Gulo gulo) are iconic among such animals, relying on snow burrows for resting sites and reproductive dens. Most of the knowledge regarding this mesocarnivore's association with snow, however, has so far originated in more southerly latitudes. In this dissertation, I investigated Arctic wolverines' behaviors associated with snow, focusing on how specific snow properties influence resting, habitat selection, and avoiding predators. Motivated by the paucity of published descriptions of wolverine resting burrows and reproductive dens on tundra, I first described terrain features and architecture of such sites. I found that resting burrows typically consist of a single tunnel leading to a resting chamber, sometimes associated with non-snow structure such as stream cutbanks and river shelf ice. By contrast, reproductive dens typically consist of longer tunnels associated with snowdrift-forming terrain. Second, I used GPS collar data from 21 adult wolverines, coupled with snowpack information at 10 meter pixel resolution, to evaluate wolverine habitat selection and movement response to snow depth, density, and melt status. I found that wolverines select deeper, denser snow, except when snow is melting, likely reflecting resting site use. Third, I developed a machine learning model to classify wolverine behaviors using tri-axial accelerometers based on direct observations of three captive wolverines, and applied this model to free-living wolverines in Arctic Alaska. I found that the model performs better when allowed to predict behaviors as "unknown," and that it accurately predicts resting, food handling, running, and scanning surroundings. Finally, based in part on this classification model, I evaluated the extent to which wolverines' use of snow burrows and surface beds for resting sites is influenced by thermoregulatory needs versus predation avoidance. I found evidence in support of both demands driving resting behavior; wolverines trade thermoregulation off against predation avoidance by resting on the snow surface on warm, sunny days, but use snow burrows on cold, dark days to meet both demands simultaneously. Collectively, this dissertation demonstrates the importance of Arctic snowpack to wolverines, a topic of increasing importance as the snow season shortens with climate change, and serves as a model for investigating behavioral processes associated with snow among other species.
    • Experimental investigation of nonthermal enhanced oil recovery techniques for improving oil recovery on Alaska North Slope

      Cheng, Yaoze; Zhang, Yin; Dandekar, Abhijit; Ahmadi, Mohabbat; Li, Xiaoli (2022-05)
      Exploitation of viscous and heavy oils on Alaska North Slope (ANS) requires nonthermal enhanced oil recovery (EOR) techniques. Currently, three nonthermal EOR methods, including solvent injection, low salinity water (LSW) flooding, and low salinity polymer (LSP) injection, have been proved to be useful on ANS. ANS viscous and heavy oils can be developed effectively by combining those three nonthermal EOR techniques. In this dissertation, lab experiments have been conducted to investigate the potential of the proposed hybrid nonthermal EOR techniques, including HSW (high salinity water)-LSW-softened LSW flooding, HSW-LSW-LSP flooding, CO₂-enriched LHS (light hydrocarbon solvent)-alternating-LSW flooding, LHS-alternating-LSW flooding, CO₂-enriched LHS (light hydrocarbon solvent)-alternating-LSP flooding, and LHS-alternating-LSP flooding, to improve ANS viscous oil recovery. Besides, the effect of essential clay minerals, including sodium-based montmorillonite (Na-Mt), calcium-based montmorillonite (Ca-Mt), illite, and kaolinite, on LSW flooding has been examined. In addition, the CO₂ influence on solvent-alternating-LSP flooding in enhancing ANS viscous oil recovery has been investigated. Furthermore, the blockage issue during CO₂-enriched LHS-alternating-LSP flooding has been investigated, and its solution has been proposed and analyzed. The EOR potential of the proposed hybrid EOR techniques has been evaluated by conducting coreflooding experiments. Additionally, relative permeability, swelling property, zeta potential, interfacial tension (IFT), and pressure-volume-temperature (PVT) tests have been conducted to reveal the EOR mechanisms of the proposed hybrid EOR techniques. Moreover, water ion analysis of DI-water/natural-sand and DI-water/natural-sand/CO₂ systems has been carried out to reveal the complex reaction between CO₂, sand, and LSP solution. It was found that, compared to conventional waterflooding, all the proposed hybrid EOR techniques could result in better oil recovery potential. It was noticed that the presence of CO₂ in LHS could be more beneficial to the solvent-alternating-LSW/LSP flooding processes during the 1st cycle due to the greater effectiveness of oil viscosity reduction. In particular, severe blockage issue occurred when conducting CO₂-enriched LHS-alternating-LSP flooding using sand pack due to the polymer precipitation. Additionally, the calculated water relative permeabilities are much lower than the typical values, implying more complex interactions between the reservoir rock, heavy oil, and injected water. Moreover, comparing to HSW, LSW could further swell Na-Mt significantly, which may benefit LSW flooding by improving sweep efficiency since in-situ swelling of Na-Mt has the potential to block the higher permeable water-flooded zone and divert the injected brine to lower permeable and unswept area. Comparing to Na-Mt, LSW couldn't swell Ca-Mt and illite further, whereas kaolinite was incapable of swelling in both HSW and LSW. Furthermore, about 60 mole% of solvent could be dissolved into the ANS viscous oil at target reservoir condition, resulting in oil swelling and viscosity reduction effects, which provided better microscopic displacement efficiency. Although the presence of CO₂ in LHS had a negative impact on the oil swelling effect, the influence on the oil viscosity reduction was positive. In addition, reducing the salinity of water could generate more negative zeta potential values on the surface of clay minerals and sand, making it more water wet. Besides, IFT of oil/LSW system is higher than that of oil/HSW system, indicating that IFT reduction is not an EOR mechanism of LSW flooding in our proposed hybrid EOR techniques. Additionally, after introducing CO₂ to the DIwater/natural-sand system, the concentration of multivalent cations was increased, which may be responsible for the polymer precipitation. The blockage issue could be solved by injecting LSW as a spacer between CO₂-enriched LHS injection and LSP injection.
    • Benthic carbon demand and community structure across the Pacific Arctic continental shelves

      Charrier, Brittany Robinson; Mincks, Sarah; Danielson, Seth; Ingels, Jeroen; Kelly, Amanda; Thurber, Andrew (2022-04)
      High latitude continental shelves are experiencing rapid environmental change. The Pacific Arctic, which includes the northern Bering and southern Chukchi Sea continental shelves, is undergoing warming temperatures, reductions in sea ice, and changes to the marine ecosystem. Fieldwork was conducted across the northern Bering and southern Chukchi Sea continental shelves in June 2017 and June 2018 on the R/V Sikuliaq. The overall objective of this dissertation was to characterize benthic community structure, function, and carbon demand in the Pacific Arctic to serve as baselines for assessing impacts of environmental change. Spatial patterns of macrofauna and meiofauna were characterized, including abundances, biomass, composition, and vertical distribution within the sediment. Polychaete structure and function were assessed in detail by identifying polychaetes to family level and assigning each a functional guild based on feeding mode, motility, and feeding structures. Nematodes were identified to genus level and characterized by feeding type and life-history strategy. Clusters of polychaete functional guilds and nematode genera assemblages were similar and occupied different general regions within the Pacific Arctic: northern Bering Sea, Bering Strait, offshore Chukchi Sea, and coastal Chukchi Sea. These polychaete and nematode assemblages were associated with different depositional and food environments, characterized by grain size and the amount and quality of sediment organic matter. In addition, metabolic and carbon demand of dominant macrofaunal were estimated based on oxygen consumption rates. Species-specific rates suggest that shifts in macrofaunal community composition in the region will impact benthic carbon demand. Overall, the research presented here provides critical baseline data for benthic community structure, function, and carbon demand in the Pacific Arctic and can be used to evaluate change and constrain region-specific ecosystem models, especially in the context of a rapidly changing environment.
    • Study on emulsification/demulsification behavior and mechanism of produced liquid from polymer flooding on Alaska North Slope

      Chang, Hongli; Zhang, Yin; Dandekar, Abhijit; Trainor, Tom; Guerard, Jennifer (2022-05)
      Heavy oil reservoirs on Alaska North Slope (ANS) are unconsolidated and contain abundant clay minerals, where the first-ever field pilot is currently implemented to validate the use of polymer floods for heavy oil enhanced oil recovery (EOR). The polymer molecules and/or fine clay particles carried with the produced liquid could potentially affect the oil/water separation, which is one of the major concerns for field operators. This dissertation aims to investigate the emulsification behavior of produced liquid, understand the emulsifying mechanism, and seek an adaptive and cost-effective method to treat the produced liquid from polymer flooding. Emulsions were prepared by mechanically mixing the actual heavy oil and the produced water from the pilot site, of which the stability was investigated by bottle test method or multiple light scattering method. Drop size distribution and interfacial properties were measured via microscope and pendant drop technique to probe the stability mechanism further. Results showed that oil-continuous or water-continuous emulsion could be generated depending on the water cut, clay types, clay concentration, and polymer concentration. In the crude oil/water system, the increasing water cut triggered the phase inversion of oil-continuous emulsion to water-continuous emulsion, resulting in faster separation and lower emulsion stability. Whereas, clay particles, no matter added to the oil or water phase, resulted in an unfavorable phase inversion from the loose watercontinuous emulsion to the tight oil-continuous emulsion as clay concentration increased. For all four types of clay except Ca-montmorillonite, clay particles added to water led to an earlier phase inversion and higher emulsion stability than that added to the oil. The dual function of polymer on emulsion stability was observed. On the one hand, both sheared and unsheared polymer tended to convert the oil-continuous emulsion formed in either crude oil/water system or complex crude oil/water/clay particle system to the water-continuous emulsion, acting as a weak demulsifier to accelerate the oil/water separation. On the other hand, the addition of polymer to the watercontinuous emulsion could result in enhanced emulsion stability, which is primarily attributed to the increased viscosity of the continuous phase and the decreased drop size of the dispersed oil phase. Particularly, the sheared polymer had a weaker ability to stabilize the o/w emulsion than the unsheared polymer due to the lower viscosity of the sheared polymer solution resulting from the breakdown of the polymer macromolecules. As for the chemical demulsification tests, the performance of demulsifiers showed a complex dependency upon the water cut, the shearing intensity, demulsifier type and dosage, and the polymer concentration. A compound emulsion breaker, E12+E18, exhibited the most satisfactory demulsification performance despite the varied test conditions. For severe water-continuous emulsions that might require a multi-fold dosage of demulsifier, a less expensive electrolyte, KCl, was proposed to be used in combination with demulsifier E12+E18 to improve the demulsification performance. In the proposed demulsifier formula, the effectiveness of the commercial demulsifier relied on its destructive effect on the interfacial film, while the efficacy of KCl was mainly dependent on its viscosity reduction effect on the continuous phase. This dissertation illustrates that intermediate layer elimination and water clarification are the major challenges for produced liquid treatment from polymer flooding. It also provides practical and theoretical guidance in advance for the demulsification strategy of the produced liquid from the ongoing first-ever polymer flooding pilot on ANS.
    • Drivers and mechanisms of migration in an Arctic caribou herd

      Cameron, Matthew D.; Kielland, Knut; Breed, Greg; Joly, Kyle; Mulder, Christa (2022-05)
      Migration is one of the world's great natural wonders and the scale of some migratory journeys is astounding. Yet migration is globally imperiled and effective conservation of the remaining migrations will require a thorough understanding of the drivers and mechanisms underlying how migrants complete such journeys. In this dissertation, I present three chapters that sought to better understand spring and autumn migration for the Western Arctic Herd, a population of barren-ground caribou (Rangifer tarandus) that complete some of the longest terrestrial migrations on the planet. In the first chapter, I applied and validated an analytical method to infer parturition events from GPS data with robust statistical confidence. In the second chapter, I examined the parturition events detected with these methods to better understand the drivers and mechanisms of spring migration because the calving grounds are the destination for pregnant females in spring. I quantified annual spatial patterns of calving and assessed what environmental factors influenced calving site selection by caribou through time. I found evidence of both memory and perception influencing spring migration, such that caribou use memory to return to an area of generally high-quality forage at the time of calving, and consequently adjust calving sites each year based on experienced conditions. In the third chapter, I sought to understand the environmental cues caribou respond to in deciding when to migrate in autumn. I found that decreasing temperatures and the timing of first snowfall events of the season had the greatest influence on migratory movements, but notably, caribou re-assessed decisions throughout the migration period as the conditions they experience changed. I also found that the cues caribou used are similar across individuals despite the herd being broadly dispersed in late summer, and the variability in migration timing observed each year is likely due to variability in environmental conditions experienced across the range. These findings pertaining to the drivers and mechanisms of migratory behavior, and broader aspects of movements by caribou, are highly relevant for conservation and management of the species across the circumpolar North. Moreover, the observation that caribou movement exhibits strong responses to particular climate phenomena, such as temperature and precipitation, have important implications for how caribou might respond as the climate of the Arctic continues to change.
    • Control problems for the wave and telegrapher's equations on metric graphs

      Alam, Gazi Mahmud; Avdonin, Sergei A.; Rhodes, John A.; Rybkin, Alexei; Avdonina, Nina (2022-05)
      The dissertation focuses on control problems for the wave and telegrapher's equations on metric graphs. In the first part, an algorithm is constructed to solve the exact control problems on finite intervals. The algorithm is implemented numerically to solve the exact control problems on finite intervals. Moreover, we developed numerical algorithms for the solution of control problems on metric graphs based on the recent boundary controllability results of wave equations on metric graphs. We presented numerical solutions to shape control problems on quantum graphs. Specifically, we presented the results of numerical experiments involving a three-star graph. Our second part deals with the forward and control problems for the telegrapher's equations on metric graphs. We consider the forward problem on general graphs and develop an algorithm that solves equations with variable resistance, conductance, constant inductance, and constant capacitance. An algorithm is developed to solve the voltage and current control problems on a finite interval for constant inductance and capacitance, and variable resistance and conductance. Numerical results are also presented for this case. Finally, we consider the control problems for the telegrapher's equations on metric graphs. The control problem is considered on tree graphs, i.e. graphs without cycles, with some restrictions on the coefficients. Specifically, we consider equations with constant coefficients that do not depend on the edge. We obtained the necessary and sufficient conditions of the exact controllability and indicate the minimal control time.
    • Understanding permafrost dynamics and geohazards with a terrain-cryofacies approach

      Stephani, Eva; Shur, Yuri; Doré, Guy; Darrow, Margaret; Kanevskiy, Mikhail (2021-12)
      The Arctic and its permafrost terrain are inherently dynamic, complex, and sensitive environments. Understanding the past and current changes occurring in these systems is key in predicting future variations, including the response of permafrost to climate change, and to terrain modifications resulting from natural processes or anthropogenic activities. This study contributes to advance our understanding of permafrost dynamics in varying permafrost environments of northern Alaska and northwestern Canada using a terrain-cryofacies approach. This unique approach helps to increase our understanding of permafrost dynamics from the site-specific scale to over extended areas by recognizing linkages between terrain and subsurface properties, and by identifying similar terrain units in remote sensing analysis. In the Colville River Delta (Alaska), our terrain-cryofacies study integrated data from 79 boreholes with a remote sensing analysis to evaluate the temporal changes in the Nigliq channel positions from 1948 to 2013 and the related permafrost dynamics. Most land cover changes occurred as land exposition (64%), whereas about 36% of the total changes were classified as eroded. The erosion of the older terrain units from the floodplain toposequence, such as the inactive-floodplain cover deposits, implied ground loss volumes of about one-fifth of soil solids and four-fifths of ground ice. Along this channel, we also identified the typical configuration and properties of taliks and cryopegs, as well as subsequent epigenetic permafrost growth. We found that the active channel was underlain by closed taliks, rather than through taliks and thus did not penetrate the entire layer of permafrost connecting supra- and sub-permafrost groundwater. A cryopeg connected to the active channel talik was identified from borehole data in the adjacent terrain units that developed following channel migration. We estimated the likelihood of encountering such taliks and cryopegs over extended areas. The terrain-cryofacies approach was also applied to understand permafrost dynamics of hillslope thermokarst located in multiple ecoregions of northern Alaska and northwestern Canada, including areas affected by interactions with infrastructure. Six features were studied through the combination of field-based and remote sensing methods, whereas 150 others were assessed solely by remote sensing. Studies along a pipeline indicated that embankment construction led to an increase in the active layer thickness, reaching the underlying ice-rich intermediate layer, and causing thaw settlement. This formed a thermokarst-ditch that facilitated channelization of cross-drainage water, and thermal erosion of the ice-rich permafrost that became affected by thermal denudation and caused a retrogressive thaw slump (RTS). The RTS later selfstabilized mainly due to the lateral discontinuity of massive ice (i.e., ice wedge) and the low-relief terrain. We suggested approaches to develop adaptation strategies for infrastructure at risk of RTS based on: these findings and conditions that favor or limit RTS growth by local feedbacks; considering the interaction patterns that we identified between RTS and infrastructure; and the main destabilization processes that we highlighted by terrain units. Further research is necessary, however, and must include testing potential mitigation techniques at multiple sites with monitoring programs to assess the variability in performance with respect to site-specific conditions.
    • Landslides in the Fairbanks North Star Borough, Alaska: inventory map and Tanana 440 landslide assessment

      Schwarber, Jaimy A.; Darrow, Margaret; Kidanu, Shishay; Daanen, Ronald (2021-12)
      Landslides are geologic hazards that threaten human life, property, and infrastructure. Effective threat mitigation requires knowledge of where past landslides occurred. Until now, no published landslide inventory maps existed for any part of Alaska. Here we present an overview of our landslide mapping within parts of the Fairbanks North Star Borough (FNSB), Alaska and a thorough investigation and assessment of the Tanana 440 (T440) landslide. We mapped 1,679 landslides, and field-verified 51 landslides within the FNSB. These landslides vary in age, movement type, and material. Most are prehistoric, but we did observe some historic and active landslides. Observed slope failures include flows in soil, translational and rotational slides in bedrock, and complex features that combine multiple types of movement. Potential landslide triggers may include thawing permafrost, increased pore water pressure conditions, seismic events, and river erosion. The landslide inventory map, the first of its kind for Alaska, directly benefits the Borough, the State, and the general public, as it can be used by public agencies to make informed land management decisions and to incorporate landslides within multiple-disaster scenarios. Additionally, the map serves as the foundation for future landslide analysis within the FNSB. We also present results of in-depth mapping, subsurface exploration, soil engineering properties, and slope stability analysis of the T440 landslide. Based on analysis of stratigraphy, soil testing, and geomorphology, we determined the T440 landslide is a flow slide in loess that occurred during the late Pleistocene to mid-Holocene. Our modeling results suggest that thawing permafrost and/or seismic loading were possible triggers for the T440 landslide. We also present the first comprehensive direct shear testing of non-plastic silt with variation in moisture content, as well as the first comparison of direct shear and field vane shear measurements of silt. These results can be used for engineering design purposes for Interior Alaska silt for any gravimetric water content over 5%.
    • Celebrating Alutiiq cultural revitalization: pathways to holistic individual health and community wellness

      Mete, Margaret Susan Draskovich; John, Theresa; Koskey, Michael; Counceller, April; Drabek, Alisha; Topkok, Sean Asiqłuq (2021-12)
      It is well understood that disease is a consequence of varied causation. Despite the fact that many health care providers acknowledge the importance of treating patients in a comprehensive manner in order to successfully cure sickness or alleviate symptoms, the contemporary medical system dispenses care in a fragmented and frequently incomplete manner. The essential differences between Indigenous epistemologies and the predominant Western worldview has had a more devastating impact on well-being and infirmity than is often recognized. The intention of this research is to explore the importance of promoting balanced holistic health care at a deeper and more essential level in order to address root causes, accessed through communication with the natural and spiritual realms, versus merely treating the physical expressions of illness.
    • Melt on Antarctic ice shelves: observing surface melt duration from microwave remote sensing and modeling the dynamical impacts of subshelf melting

      Johnson, Andrew Carl; Hock, Regine; Fahnestock, Mark; Aschwanden, Andy; Bueler, Ed (2021-12)
      Melt on the surface and underside of Antarctic ice shelves are important to the mass balance and stability of the ice sheet, and therefore pose significance to global sea levels. Satellite-based passive microwave observations provide daily or near-daily coarse resolution surface observations from 1978 on, and we use this record to identify days in which melt water is present on the ice sheet and ice shelf surfaces, called melt days. There are significant differences in the results of melt detection methods however, and we evaluate four different passive microwave melt detection algorithms. There is a lack of sufficient ground truth observations, so we use Google Earth Engine to build time series of Sentinel-1 Synthetic Aperture Radar images from which we can also detect melt to serve as a comparison dataset. A melt detection method using a Kmeans clustering algorithm developed here is shown to be the most effective on ice shelves, so we further apply this method to quantify melt days across all Antarctica ice shelves for every year from 1979/80 to 2019/20. The highest sums of melt days occur on the Antarctic Peninsula at 89 melt days per year, and we find few linear trends in the annual melt days on ice shelves around the continent. The primary mode of spatial variability in the melt day dataset is closely related to the Southern Annular Mode, a climate index for the southward migration of Southern Westerly Winds, which has been increasing in recent decades. Positive Southern Annular Mode index values are associated with decreased melt days in some regions of Antarctica. We also present a novel application of passive microwave analysis to detect changes in firn structure due to unusually large melt events in some regions and we show how this method detects ice lens formation and grain growth on specific ice shelves. To study the impacts of subshelf melt we focus on the Filchner-Ronne region of Antarctica, which contains the second largest ice shelf on the continent. We performed an ensemble of ice sheet model runs for a set of ocean warming scenarios. Each ensemble used a realistic range of physical parameters to control ice dynamics and sliding, generated by a Bayesian analysis of a surrogate model and observed velocities. Increased ocean temperatures were associated with increased mass loss, and by the year 2100 this region contributed 14 mm to sea level per degree of ocean warming at depth between +0°C and +4°C of ocean potential temperature. Beyond +4°C, the rate mass loss increased substantially. This mass loss corresponded to grounding line retreat across the region.
    • Rooted in environmental justice: phytogeography and ethnoecology of Serianthes

      Demeulenaere, Else; Ickert-Bond, Stefanie M.; Lovecraft, Amy Lauren; Yamin-Pasternak, Sveta; Jernigan, Kevin; Rubinstein, Donald H. (2021-12)
      Serianthes Benth. (Fabaceae) is one of the most endangered plant genera in the world, with 12 of the 18 species listed on the IUCN Red List of Threatened Species. Serianthes trees are culturally important to island communities of the Indo-Pacific region for canoes, boats, traditional houses, and medicine. Habitat loss and ecosystem degradation increased pressure on these trees, also threatening its Indigenous cosmology and traditional practices. This interdisciplinary study integrated genomic, biogeographic and ethnoecological approaches to develop appropriate policies that protect the Indigenous biocultural diversity of Serianthes. Phylogenomics of 401 nuclear exons and non-coding flanking regions using both a multi-species coalescent model and a partition gene tree analysis confirmed the monophyly of the genus and inferred the biogeography and phylogenetic relationships within Serianthes. The Guåhan (Guam) and Luta (Rota) endemic Serianthes nelsonii (known locally as Håyun lågu and Tronkon guåfi respectively) are closely related to South Pacific species. Serianthes kanehirae from Belau (Palau) and Wa'ab (Yap) are closely related to Malesian and Papuasian species. Phylogeographical patterns of Serianthes in Micronesia are discussed to inform conservation management. The ethnoecological study revealed interspecies relationships between people, animals, and plants remain strong. The traditional use of Ukall and Gumor (Serianthes kanehirae) on Belau and Wa'ab respectively remain part of Belau and Wa'ab's culture and are intertwined with rituals respecting the spiritual world. On Luta, Tronkon guåfi is an established flagship for endangered species conservation, while the last adult Håyun lågu tree on Guåhan became a rallying point for spiritual resistance when its habitat became threatened by military plans to construct a firing range. Despite its listing as critically endangered by the Endangered Species Act, its habitat is still at risk of being lost. The social movement guided by Prutehi Litekyan brought the community together to protect the Håyun lågu tree based on Indigenous belief systems. The social movement and policy research used a qualitative mixed-method approach to evaluate the dimensions of the Endangered Species Act in relation to environmental justice and biocultural rights. I concluded that a bottom-up co-management approach with polycentric networks best fits the social-cultural system of Guåhan. I propose Indigenous participation and the creation of an advisory council, comprising traditional and scientific knowledge holders, to advise on biocultural diversity preservation in the Mariana Islands.