http://hdl.handle.net/11122/13043 Includes Humans and the Environment Tue, 10 Mar 2026 02:46:20 GMT 2026-03-10T02:46:20Z http://hdl.handle.net/11122/16222 Detection of overflow using Synthetic Aperture Radar Ornelas, Cristina Overflow is a common and dangerous ice condition that challenges travel, presents risks to people, and impacts the growth and structure of ice. Overflow occurs due to ice cracking and water seeping through. The resulting water and slush from flooded snow that overlies the ice cover can complicate all modes of travel (e.g., snow machines, dog sled teams, skiing, on foot) and introduce the hazards associated with getting wet and stuck amid the cold air temperatures of winter. Synthetic Aperture Radar (SAR) bounces microwave signals off the Earth’s surface to detect physical properties and is not affected by cloudy or dark conditions. Overflow detection with SAR is a novel application of this technology that would enhance historical and present ice monitoring and modeling to ultimately improve traveler safety. This study was conducted to test SAR capability to detect overflow based on our ground-based observation. This study initiates overflow exploration in arctic research and advances SAR as a tool for overflow detection. We determined seasonal changes and ice characteristics through field observations, in situ sensors, and ice models. We found a significant decrease in backscatter intensity during a December overflow event in both bands, with VH decreasing from -17.6 dB to -18.8 dB. Backscatter intensity gradually increased throughout winter until a March overflow event which exhibited only marginal declines in backscatter. Our results of a rapid decrease in backscatter in connection to ground data indicate successful overflow detection. SAR technology paired with ground investigation advances historical investigation and future remote sensing developments specific to overflow, ultimately improving winter travel safety and initiating more scientific information about overflow. Master's Project (M.N.R.E) University of Alaska Fairbanks, 2024 Sun, 01 Dec 2024 00:00:00 GMT http://hdl.handle.net/11122/16222 2024-12-01T00:00:00Z http://hdl.handle.net/11122/15989 Post-typhoon Merbok impact on geographically isolated western Alaska communities and sustainable recovery process for vulnerable populations Schaffer, Daryl A sustainable climate-resilient community depends on their location and what is considered to be resilient. In western Alaska, primarily sustainable Indigenous subsistence lifestyle communities have proven quite resilient to climate for over 5000 years. Indigenous communities have been experiencing exponentially greater challenges from changes of climate in recent years. One storm, which traversed the entire 1300-mile geographically isolated Alaska west coast in September 2022, was more significant than previous generations. Extratropical post-typhoon Merbok became part of a disaster cascade as many communities had already endured various disasters to their locations and livelihoods which made them more vulnerable to include prior climate-related land erosion, damage to infrastructure, food insecurity, and sustainable livelihood. Mitigation, response, and recovery planning policies are typically addressed from an urban and rural perspective but changes are needed to address the challenges found in remote and geographically isolated locations, which include the vulnerable populations. Federal, state, and local planning has not understood, nor taken into consideration, historical Indigenous knowledge of continual adaptation to climate. This dissertation will look at Merbok as a single storm, how Merbok cascaded and exacerbated existing problems of housing, food, geography, and infrastructure insecurity, and compare Merbok to similar storms impacting geographically isolated locations with similar underserved vulnerable populations. The findings and conclusions from this research will benefit local to federal emergency management professionals in addressing and adapting plans for communities in geographically isolated locations. Dissertation (Ph.D.) University of Alaska Fairbanks, 2025 Thu, 01 May 2025 00:00:00 GMT http://hdl.handle.net/11122/15989 2025-05-01T00:00:00Z http://hdl.handle.net/11122/15968 Control of invasive plants at high latitudes with persistent herbicides: understanding persistence, to manage pesticide residues and achieve effective control Graziano, Gino Invasive plants are considered a problem in management of natural resources and maintenance of ecosystem services in Alaska. Persistent herbicides are often used to control invasive plants because of increased duration and efficacy of control; however, applicators must understand that persistence impacts rotations to sensitive crops or restoration to sensitive desirable species. The purpose of this study was to define and document the impacts of aminopyralid and clopyralid degradation and movement in boreal ecosystems when used in agricultural settings or applied to Prunus padus, a problematic invasive tree in the boreal ecosystem. In laboratory microcosms clopyralid did not adsorb to soil particles under any conditions. Aminopyralid adsorbed to soil particles with increased adsorption at lower pH due to protonation of the amine group. Amnopyralid and clopyralid were compared in agricultural field treatments of fallow ground, followed by two years of small grain production before rotation to field peas, a sensitive species in the third year. Herbicide was detected one year after treatment with both herbicides, but by two years after treatment only aminopyralid was detectable in soil. Bioassays performed with these same soils had a similar pattern with smaller plants 1 and 2 years after treatment, but no indication of herbicide 3 years after treatment. Despite the lack of detection in soils, herbicide sensitive field peas were unable to grow in aminopyralid treated plots 3 years after treatment, indicating the presence of biologically significant concentrations of herbicide. Aminopyralid applied to stems of invasive Prunus padus saplings was exuded from the roots of treated trees, with herbicide detected in soils and resulting in damage to some susceptible species. Applications of triclopyr resulted in the detections of herbicide and observations of non-target damage without significant change in defoliation of the target trees. Reduced rates were equally effective for aminopyralid. Dissertation (Ph.D.) University of Alaska Fairbanks, 2025 Thu, 01 May 2025 00:00:00 GMT http://hdl.handle.net/11122/15968 2025-05-01T00:00:00Z http://hdl.handle.net/11122/15961 Power dynamics in Arctic community and citizen science: perspectives from youth, educators, and scientists Sarah, Clement Arctic research is shifting from a culture of scientist-driven inquiry and extractive relationships with Indigenous communities to a culture more conscious of local priorities and reciprocal research relationships. Today, Arctic research has dual goals of studying circumpolar issues through large-scale research and collaborating with local individuals and communities. The emergence of methods like community and citizen science (CCS), in which non-scientists participate in research, has risen in popularity to meet these priorities. The broad aims of CCS are to advance scientific understanding; aid decision-making; and support individual outcomes. I address the third aim by investigating three growing, yet understudied, groups in CCS research in the Arctic and sub-Arctic: youth, teachers, and scientists. In Chapter 2, I tested the effect of two CCS program models (contributory versus co-created) on youths’ science self-efficacy and science interest, finding that while the youths’ survey data did not detect post-program changes in either learning outcome, their interview data revealed substantial differences in youths’ science self-efficacy between program models. In Chapter 3, I examined how teachers supported their students’ development of critical environmental agency in a co-created CCS program. Teachers braided Indigenous knowledge and Western science, positioned their students as leaders in their projects, and helped them create projects to address community needs, which supported students’ critical environmental agency-linked identity development, relationship to place, and environmental action. Finally, in Chapter 4, I interviewed CCS practitioners about their engagement in CCS research. They identified benefits, challenges, and their motivations across six themes: actionable science, communication, cross-cultural engagement, data, multiple perspectives, and relationships. Across the three studies, the key theme emerged of how shifting power from scientists to youth, teachers, or communities changes the nature of the outcomes in CCS projects. Together, the chapters provide insights into how CCS is aiding the culture shift in Arctic research. Dissertation (Ph.D.) University of Alaska Fairbanks, 2025 Thu, 01 May 2025 00:00:00 GMT http://hdl.handle.net/11122/15961 2025-05-01T00:00:00Z