Now showing items 1-20 of 1166

    • Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System

      Vore, Margot E.; Bartholomaus, Timothy, C.; Winberry, J. Paul; Walter, Jacob I.; Amundson, Jason M. (American Geophysical Union, 2019-02-09)
      Subglacial water flow impacts glacier dynamics and shapes the subglacial environment. However, due to the challenges of observing glacier beds, the spatial organization of subglacial water systems and the time scales of conduit evolution and migration are largely unknown. To address these questions, we analyze 1.5‐ to 10‐Hz seismic tremor that we associate with subglacial water flow, that is, glaciohydraulic tremor, at Taku Glacier, Alaska, throughout the 2016 melt season. We use frequency‐dependent polarization analysis to estimate glaciohydraulic tremor propagation direction (related to the subglacial conduit location) and a degree day melt model to monitor variations in melt‐water input. We suggest that conduit formation requires sustained water input and that multiconduit flow paths can be distinguished from single‐conduit flow paths. Theoretical analysis supports our seismic interpretations that subglacial discharge likely flows through a single‐conduit in regions of steep hydraulic potential gradients but may be distributed among multiple conduits in regions with shallower potential gradients. Seismic tremor in regions with multiple conduits evolves through abrupt jumps between stable configurations that last 3–7 days, while tremor produced by single‐conduit flow remains more stationary. We also find that polarized glaciohydraulic tremor wave types are potentially linked to the distance from source to station and that multiple peak frequencies propagate from a similar direction. Tremor appears undetectable at distances beyond 2–6 km from the source. This new understanding of the spatial organization and temporal development of subglacial conduits informs our understanding of dynamism within the subglacial hydrologic system.
    • Meltwater Intrusions Reveal Mechanisms for Rapid Submarine Melt at a Tidewater Glacier

      Kienholtz, C.; Sutherland, D. A.; Jackson, R. H.; Nash, J. D.; Amundson, J. M.; Motyka, R. J.; Winters, D.; Skyllingstad, E.; Pettit, E. C. (American Geophysical Union, 2019-11-25)
      Submarine melting has been implicated as a driver of glacier retreat and sea level rise, but to date melting has been difficult to observe and quantify. As a result, melt rates have been estimated from parameterizations that are largely unconstrained by observations, particularly at the near-vertical termini of tidewater glaciers. With standard coefficients, these melt parameterizations predict that ambient melting (the melt away from subglacial discharge outlets) is negligible compared to discharge-driven melting for typical tidewater glaciers. Here, we present new data from LeConte Glacier, Alaska, that challenges this paradigm. Using autonomous kayaks, we observe ambient meltwater intrusions that are ubiquitous within 400 m of the terminus, and we provide the first characterization of their properties, structure, and distribution. Our results suggest that ambient melt rates are substantially higher (×100) than standard theory predicts and that ambient melting is a significant part of the total submarine melt flux. We explore modifications to the prevalent melt parameterization to provide a path forward for improved modeling of ocean-glacier interactions.
    • The Impact of Language Acquisition and Language Learning On Learning Process: A Meta-Synthesis

      Allman, Ashley (University of Alaska Southeast, 2018-07-20)
      This meta-synthesis explores the correlation between language acquisition and learning. Children who are bilingual have advantages and disadvantages to how they learn. When research first started on this idea, common opinion was that it was a disadvantage to be bilingual. However, as research has progressed more advantages than disadvantages of being bilingual have been found. Furthermore, new ways children can learn language have appeared. Options can include but are not limited to parents and guardians, an immersion program, and/or a dual/multi-language program. An important factor of language acquisition is for children to be fluent in one language before they learn a second language. Children that do not have a firm grasp of their first language combine two language patterns and create a different language. The combining of languages causes them to have challenges throughout their education.
    • Test

      Cox, David (2020-01-28)
      This is a test upload to check on the status of submissions. This is only a test.
    • Using traditional ecological knowledge to understand and adapt to climate and biodiversity change on the Pacific coast of North America

      de Echeverria, V. R. W.; Thornton, Thomas F. (Springer Netherlands, 2019-10-09)
      We investigate the perceptions and impacts of climate change on 11 Indigenous communities in Northern British Columbia and Southeast Alaska. This coastal region constitutes an extremely dynamic and resilient social-ecological system where Indigenous Peoples have been adjusting to changing climate and biodiversity for millennia. The region is a bellwether for biodiversity changes in coastal, forest, and montane environments that link the arctic to more southerly latitudes on the Pacific coast. Ninety-six Elders and resource users were interviewed to record Traditional Ecological Knowledge (TEK) and observations regarding weather, landscape, and resource changes, especially as concerns what we term Cultural Keystone Indicator Species (CKIS), which provide a unique lens into the effects of environmental change. Our findings show that Indigenous residents of these communities are aware of significant environmental changes over their lifetimes, and an acceleration in changes over the last 15–20 years, not only in weather patterns, but also in the behaviour, distributions, and availability of important plants and animals. Within a broader ecological and social context of dwelling, we suggest ways this knowledge can assist communities in responding to future environmental changes using a range of place-based adaptation modes.
    • Raven’s Work in Tlingit Ethno-geography

      Thornton, Thomas F.; Deur, Douglas; Adams, Bert (University of Hawaii Press, 2019-01-01)
    • Whalesong 2008-11-27 (v.27 no.1)

      University of Alaska Southeast, 2008-11-27
    • Whalesong 2008-05

      University of Alaska Southeast, 2008-05
    • Whalesong 2008-04

      University of Alaska Southeast, 2008-04
    • Whalesong 2008-02

      University of Alaska Southeast, 2008-02
    • Whalesong 2007-04-01

      University of Alaska Southeast, 2007-04-01
    • Whalesong 2007-02-12

      University of Alaska Southeast, 2007-02-12
    • Whalesong 2006-12-04 (v.27 no.4)

      University of Alaska Southeast, 2006-12-04
    • Whalesong 2006-11-20 (v.27 no.3)

      University of Alaska Southeast, 2006-11-20
    • Whalesong 2006-11-06 (v.27 no.2)

      University of Alaska Southeast, 2006-11-06
    • Chancellor's Comments 2019-06-24

      Caulfield, Richard (University of Alaska Southeast, 2019-06-24)
    • Whalesong 2012-12-12

      University of Alaska Southeast, 2012-12-12
    • Whalesong 2012-11-28

      University of Alaska Southeast, 2012-11-28
    • Whalesong 2012-11-14

      University of Alaska Southeast, 2012-11-14
    • Whalesong 2012-10-31

      University of Alaska Southeast, 2012-10-31