• Multi-decadal variability of Atlantic water heat transports as seen in the community climate systems model version 3.0

      Sterling, Kara (2006-05)
      Changes in oceanic heat transports from the North Atlantic to the Arctic, via Atlantic Water (AW), can have widespread impacts upon Arctic climate. Using a multi-century control simulation from the National Center for Atmospheric Research (NCAR) Community Climate Systems Model version 3.0 (CCSM3), the natural multi-decadal variability (MDV) of AW is characterized. Calculations of AW volume fluxes and heat transports into the Arctic are analyzed for the Svinøy transect, Fram Strait, and Barents Sea Opening (BSO), and compared with observations. Warm and cold phases of AW are examined through composite analysis, and quantified with respect to their effects on Arctic climate. The model captures several key features of AW, such as the overall circulation and depth of the AW core, but over-estimates AW temperatures by about 1 ⁰C. AW heat anomalies can be tracked from the Svinøy transect to the Arctic interior with a timescale of 13 years, which is comparable to observations. Composites reveal a deepening (shoaling) of the AW core during warm (cold) periods. Warm (cold) periods are also characterized by greater AW transports through the BSO (Fram Strait), implying the existence of an internal ocean feedback mechanism that helps to regulate oscillations of AW between warm/cold periods.
    • Multi-Dimensional Frost Heave Modeling With Sp Porosity Growth Function

      Kim, Koui; Huang, Scott L. (2011)
      This dissertation presents a multi-dimensional frost-heave modeling with coupled heat transfer, moisture transfer, and mechanical analysis. A series of laboratory frost-heave tests was conducted to determine segregation potential (SP) values using the effect of cooling rate and overburden pressure in two different freezing modes. Regardless of the freezing mode, consistent SP values were obtained at the formation of the final ice lens. Continuous heave and water-intake measurements made it possible to determine the time at the formation of the final ice lens. The SP porosity growth function was developed using simulations of the growing ice lens and frozen fringe. The developed frost-heave model was verified by laboratory frost-heave tests in one dimension. The simulated temperature distribution and amount of heave were in good agreement with experimental values. The SP porosity growth function was then expanded to two dimensions to simulate the soil-pipeline interaction of an experimental buried chilled pipeline constructed in Fairbanks, Alaska in the early 2000s. A two-dimensional frost-heave simulation was conducted at the free-field area, where the influence of pipeline resistance in frozen ground was negligible. This model, which considers the effect of frozen soil creep on stress distribution due to temperature variation, analyzed the influence of stress fields on soil frost-heave susceptibility and deformation. Simulations of pipe displacement were conducted for two cases, with and without the use of the long-term creep characteristics of frozen soils. Using the long-term creep characteristics, the simulated result agreed well with the observed value, differing by only a few percentage points. However, without using long-term creep characteristics, the simulated pipe heave was approximately 75% of the observed heave because of an unrealistic stress buildup. Finally, the SP porosity growth function was expanded to predict soil-pipeline interaction around a frozen-unfrozen boundary. Temperature distribution was successfully predicted in both the pre-frozen soil and the unfrozen zones, as well as at the time when differential pipeline movement started. The developed three-dimensional frost-heave model could predict pipe movement and induced bending due to differential frost heave for a 20-year period.
    • A multi-proxy approach to determine paleoecological change of mangroves, during the holocene, in Belize, Central America

      Monacci, Natalie Marie (2007-12)
      This thesis presents multiple analyses of mangrove peat cores from Spanish Lookout Cay (BT - 79) and from along the banks of the Sibun River (SR-63), Belize to examine ecosystem responses to environmental change during the Holocene. Radiocarbon measurements showed these sites were colonized by mangroves ~8,000 cal. yrs BP and have decreased sedimentation rates from ~6,000 to ~1,000 cal. yrs BP, which is attributed to a decrease in sea-level inundation. Core SR-63 has a change in lithology from primarily mangrove peat to fluvial material at 2,500 cal. yrs BP, which is attributed to erosion inputs of the drainage basin. Changes in the pollen assemblage, such greater input from non-mangrove pollen, are coeval with changes in sedimentation rates at both sites. Subfossil mangrove leaves, from core BT-79, are used for stable isotope ([delta]¹⁵N, [delta]¹³C, and [delta]¹⁸O) analyses to illustrate past physiology and seawater inundation. The composition of organic material in core SR-63 changes from autochthonous to allochthonous sources, which is coeval with the change in lithology. A decrease in the rate of sea-level rise is assumed to be the cause of the significant changes seen in these mangroves, which counters existing sea-level curves.
    • Multi-Resolution Changes in the Spatial Extent of Perennial Arctic Alpine Snow and Ice Fields with Potential Archaeological Significance in the Central Brooks Range, Alaska

      Tedesche, Molly E.; Freeburg, Adam K.; Rasic, Jeffrey T.; Ciancibelli, Christopher; Fassnacht, Steven R. (2015-12)
      Perennial snow and ice fields could be important archaeological and paleoecological resources for Gates of the Arctic National Park and Preserve in the central Brooks Range of Alaska. These features may have cultural significance, as prehistoric artifacts may be frozen within the snow and ice. They also act as important hydrological indicators of climate change within the Park. Globally significant discoveries have been made recently as ancient artifacts and animal dung have been found in melting alpine snow and ice patches in the Southern Yukon (Hare et al. 2004) and Northwest Territories (Meulendyk et al. 2012) in Canada, as well as in the Wrangell mountains in Alaska. The loss of perennial snow and ice coverage in the Brooks Range may yield similar discoveries over time.
    • Multi-scale movement of demersal fishes in Alaska

      Nielsen, Julie K.; Seitz, Andrew C.; Loher, Timothy; McDermott, Susanne F.; Mueter, Franz J.; Adkison, Milo D. (2019-05)
      Information on the movement of migratory demersal fishes such as Pacific halibut, Pacific cod, and sablefish is needed for management of these valuable fisheries in Alaska, yet available methods such as conventional tagging are too coarse to provide detailed information on migration characteristics. In this dissertation, I present methods for characterizing seasonal and annual demersal fish movement at multiple scales in space and time using electronic archival and acoustic tags. In Chapter 1, acoustic telemetry and the Net Squared Displacement statistic were used to identify and characterize small-scale movement of adult female Pacific halibut during summer foraging in a Marine Protected Area (MPA). The dominant movement pattern was home range behavior at spatial scales of less than 1 km, but a more dispersive behavioral state was also observed. In Chapter 2, Pop-up Satellite Archival Tags (PSATs) and acoustic tags were deployed on adult female Pacific halibut to determine annual movement patterns relative to MPA boundaries. Based on observations of summer home range behavior, high rates of year-round MPA residency, migration timing that largely coincided with winter commercial fisheries closures, and the demonstrated ability of migratory fish to return to previously occupied summer foraging areas, the MPA is likely to be effective for protecting both resident and migrant Pacific halibut brood stock year-round. In Chapter 3, I adapted a Hidden Markov Model (HMM) originally developed for geolocation of Atlantic cod in the North Sea for use on demersal fishes in Alaska, where maximum daily depth is the most informative and reliable geolocation variable. Because depth is considerably more heterogeneous in many regions of Alaska compared to the North Sea, I used simulated trajectories to determine that the degree of bathymetry heterogeneity affected model performance for different combinations of likelihood specification methods and model grid sizes. In Chapter 4, I added a new geolocation variable, geomagnetic data, to the HMM in a small-scale case study. The results suggest that the addition of geomagnetic data could increase model performance over depth alone, but more research is needed to continue validation of the method over larger areas in Alaska. In general, the HMM is a flexible tool for characterizing movement at multiple spatial scales and its use is likely to enrich our knowledge about migratory demersal fish movement in Alaska. The methods developed in this dissertation can provide valuable insights into demersal fish spatial dynamics that will benefit fisheries management activities such as stock delineation, stock assessment, and design of space-time closures.
    • A multi-sensor approach to determining volcanic plume heights in the North Pacific

      Ekstrand, Angela L. (2012-05)
      During a volcanic eruption, accurate height information is necessary to forecast a volcanic plume's trajectory with volcanic ash transport and dispersion (VATD) models. Recent events in the North Pacific (NOPAC) displayed significant discrepancies between different methods of plume height determination. This thesis describes two studies that attempted to resolve this discrepancy, and identify the most accurate method for plume height determination. The first study considered the 2009 eruption of Redoubt Volcano. This study found that the basic satellite temperature method, in which satellite thermal infrared temperatures are compared to temperature-altitude profiles, vastly underestimates volcanic plume height due to decreased optical depth of plumes soon after eruption. This study also found that the Multi-angle Imaging SpectroRadiometer (MISR) produced very accurate plume heights, even for optically thin plumes. The second study investigated the application of MISR data to multiple eruptions in the NOPAC: Augustine Volcano in 2006, Okmok, Cleveland, and Kasatochi volcanoes in 2008, and Redoubt and Sarychev Peak volcanoes in 2009. This study found that MISR data analysis retrieves accurate plume heights regardless of grain size, altitude, or water content. Exceptions include plumes of low optical depth over bright backgrounds. MISR is also capable of identifying ash clouds by aerosol type.
    • Multi-sensor techniques for the measurement of post eruptive volcanic deformation and depositional features

      McAlpin, David B.; Meyer, Franz J.; Begét, James; Webley, Peter W.; Dehn, Jonathan (2019-08)
      Remote sensing of volcanic activity is an increasingly important tool for scientific investigation, hazard mitigation, and geophysical analysis. These studies were conducted to determine how combining remote sensing data in a multi-sensor analysis can improve our understanding of volcanic activity, depositional behavior, and the evolutionary history of past eruptive episodes. In a series of three studies, (1) optical photogrammetry and synthetic aperture radar are combined to determine volumes of lahars and lava dome growth at Redoubt Volcano, Alaska; (2) applied data from multiple synthetic aperture radar platforms are combined to model long-term deposition of pyroclastic flow deposits, including past deposits underlying current, observable pyroclastic flow deposits at Augustine Volcano, Alaska; and finally (3) combined, low-spatial-resolution thermal data from Advanced Very High Resolution Radiometer sensors are combined with high resolution digital elevation models derived from the microwave TanDEM-X mission, to increase the accuracy of eruption profiles and effusion rates at Tolbachik Volcano on the Kamchatka Peninsula, Russian Far East. As a result of this study, the very diverse capabilities of multiple remote sensing instruments were combined to improve the understanding of volcanic processes at three separate locations with recent eruptive activity, and to develop new methods of measurement and estimation by merging the capabilities of optical, thermal, and microwave observations. With the multi-sensor frameworks developed in this study now in place, future efforts should focus on increasing the diversity of sensor types in joint analyses, with the objective of obtaining better solutions to geophysical questions.
    • Multimodal meaning making with culturally responsive images: designing tasks for 6th - 8th grade special education students

      Surman, Audra Ruth Panigacungaq; Siekmann, Sabine; Martelle, Wendy; Patterson, Leslie; Moses, Catherine (2019-05)
      The following study describes the patterns that emerged from collaborative tasks among middle school students within a special education intervention class in rural Alaska. The study integrated the multiliteracies pedagogy, as well as multimodalities and task-based language teaching. The tasks utilized culturally appropriate illustrations to promote collaborative discussion throughout a structured set of five tasks. The research aims to answer the following question: How do sixth through eighth grade students co-construct meaning when doing tasks that incorporate culturally appropriate images? Three students native to the community participated in this study over a two-month period. The tasks were designed around culturally relevant illustrations allowing students to use their funds of knowledge as they collaborated to complete the tasks. The data collection included field notes, class artifacts, video and audio recordings, and student interviews. The data presented multimodal events where students utilized their semiotic resources and funds of knowledge to make meaning during each task. The analysis revealed telling incidents of multimodal meaning making moments where culturally relevant resources support the application of funds of knowledge. The analysis also uncovered critical insights for the task design variables which can impact the ending outcome and final product of a task. As a result, I encourage the use of open-ended tasks addressing multimodal teaching to encourage culturally relevant meaning making moments, particularly within special education settings.
    • Multiphysics Modeling Of Gaseous Contaminant Transport In Deep Open Pit Mines Under Arctic Air Inversions

      Choudhury, Abhishek; Bandopadhyay, Sukumar (2011)
      Entrapment of pollutants in a deep open pit operating in a cold climate could occur due to atmospheric inversion. The process of air inversion is complex and requires thorough understanding in order to design a mine ventilation plan to remove trapped pollutants in open-pit mines operating in the arctic/sub-arctic regions. The objective of this dissertation is to develop a model using Computational Fluid Dynamics (CFD) tools for analysis of gaseous pollutant transport in deep, open pit mines under air inversion in arctic or subarctic regions. An Eulerian 3-D model was used for the development and validation of the CFD model of pollutant transport in an idealized open pit mine. No prior assumptions, turbulent or laminar, were considered for the nature of the flow. The 2-D model results indicated that air velocity, air temperature, diffusivity coefficient and slope angle were important controlling parameters in the inversion process. The flow regime was laminar at the origin, but as the flow progressed toward the center of the pit it changed to quasi-laminar and generated local eddies towards the pit bottom. The total energy of the quasi-laminar flow as well as the small local eddies was not enough to lift the inversion cap. However, a combination of quasi-turbulent flow and the local eddy transport resulted in removal of some of the pollutant mass from the pit bottom, either due to turbulent mixing, or due to advection. Presence of backflow may appear to be a logical mode of flow in deep open-pit mines in arctic regions. Next, the 3D model was validated using data from a selected open-pit mine. Influent air velocity, diffusivity coefficient, larger pit geometry were found to influence the retention and transport of pollutant out of the pit. The most important conclusion that was drawn from this research is that natural ventilation alone cannot remove the pollutants from an open pit or lift the inversion cap.
    • Multiple imputation of missing multivariate atmospheric chemistry time series data from Denali National Park

      Charoonsophonsak, Chanachai; Goddard, Scott; Barry, Ronald; McIntyre, Julie; Short, Margaret (2020-05)
      This paper explores a technique where we impute missing values for an incomplete dataset via multiple imputation. Incomplete data is one of the most common issues in data analysis and often occurs when measuring chemical and environmental data. The dataset that we used in the model consists of 26 atmospheric particulates or elements that were measured semiweekly in Denali National Park from 1988 to 2015. The collection days were alternating between three and four days apart from 3/2/88 - 9/30/00 and being consistently collected every three days apart from 10/3/00 - 12/29/15. For this reason, the data were initially partitioned into two in case the separation between collection days would have an impact. With further analysis, we concluded that the misalignments between the two datasets had very little or no impact on our analysis and therefore combined the two. After running five Markov chains of 1000 iterations we concluded that the model stayed consistent between the five chains. We found out that in order to get a better understanding of how well the imputed values did, more exploratory analysis on the imputed datasets would be required.
    • Multiple stable isotopic analyses ([delta]¹³C, [delta]¹⁵N, [delta]¹⁸O, and [delta]D) of the Boulder Patch, a high arctic kelp community: trophic and temporal perspectives

      Debenham, Casey William Jones (2005-12)
      The Boulder Patch, a high Arctic kelp community, is a rarity in the Alaskan Beaufort Sea. Considered a biodiversity oasis, this area provides habitat for many organisms. Trophic relationships, spatial patterns, and isotopic changes over time were examined within the Boulder Patch using stable carbon and nitrogen isotopes. 394 samples, representing over 55 species were analyzed. Isotope values showed considerable variability in the food web base, particularly for the kelp Laminaria solidungula. Isotopic values for most animals fit their known feeding strategies. Little spatial variation was observed in isotope values, however temporal differences were found in L. solidungula isotope values between 2002 and 2004, and between archived samples collected during the 1980's. To better understand patterns in stable oxygen and hydrogen isotopes, values were assessed and applied in an ecological context. Sixty-four samples were analyzed, encompassing 29 species. Results indicated distinct differences between primary producers and animals, offering insights into a possible application of [delta]¹⁸O and [delta]D in ecological studies. By defining trophic structure and elucidating feeding strategies of organisms, this study enhanced the biological knowledge in the Boulder Patch, providing ecological information on a high arctic kelp community.
    • Multiresolution digital soil mapping of permafrost soils using a random forest classifier: an investigation along the Dalton Highway corridor, Alaska

      Paul, Joshua D.; Ping, Chien-Lu; Prakash, Anupma; Rossello, Jordi Cristobal; Libohova, Zamir (2018-12)
      In order to complete soil inventories in the remote permafrost zones of Alaska, there is a need to develop efficient digital soil mapping tools that can be applied over large areas using a minimum of ground truth data. This investigation first used a random forest classifier to test combinations of environmental input data at multiple resolutions (10m, 30m, and 100m). Five tiers of soil taxonomic units were predicted: Order, Suborder, Great Group, "Series Concept", and Particle Size Class. Model outputs are compared quantitatively via estimated out-of-bag accuracy, and qualitatively via visual inspection by soil scientists. Estimated out-of-bag accuracy ranged from ~45% to ~75%, with results improving when fewer classes were modeled. Model runs at 10m and 30m resolution performed comparably, with 100m resolution performing ~5-10% worse in most cases. Increasing the number of trees used, including categorical environmental input data (e.g. landforms), and replacement of environmental covariates with principal component analysis (PCA) bands did not significantly improve model performance. The random forest classifier was then used in a digital soil mapping pilot study along the Dalton Highway in northern Alaska. Parameters suggested in the initial study were used to predict multiple soil taxonomic classes from a basic collection of environmental covariates generated using high resolution (10m) satellite images and sparsely sampled pedon data. Covariates included maximum curvature, multiresolution valley bottom flatness, normalized height, potential incoming solar radiation, slope, terrain ruggedness index, and modified soil and vegetation index. Five tiers of soil taxonomic units were predicted: Order, Suborder, Great Group, "Series Concept", and Particle Size Class. Model outputs are compared quantitatively via estimated out-of-bag accuracy. Estimated out-of-bag accuracy ranged from ~45% to ~75%, with results improving when fewer classes were modeled. We suggest future research into optimized sampling to ensure an adequate distribution of samples across the feature space, and the incorporation of expert knowledge into accuracy assessments. Overall, digital soil mapping with random forest classifiers appears to be a promising method for completing the soil survey of Alaska.
    • Multispecies Age-Structured Assessment Modeling As A Tool Of Fisheries Management In The Gulf Of Alaska

      Van Kirk, Kray F.; Quinn, Terrance J. II; Collie, Jeremy; Criddle, Keith; Kruse, Gordon; Mueter, Franz (2012)
      A multispecies age-structured assessment model (MSASA) for the Gulf of Alaska (GOA) is developed to examine the effects of integrating predation mortality into stock assessment efforts. Age-specific predation mortality is modeled as a flexible function of predator and prey abundances, constructed from species-preference and size-preference parameters and fitted to stomach-content data. Modeled species include arrowtooth flounder ( Atheresthes stomias), Pacific cod (Gadus macrocephalus), walleye pollock (Theragra chalcogramma), Pacific halibut (Hippoglossus stenolepis) and Steller sea lion ( Eumatopias jubatus). Recruitment, residual natural mortality, full-recruitment fishing mortality, and fishery/survey selectivities are estimated for pollock, cod, and flounder; abundances for apex predators sea lions and halibut are input. Estimated trophic structures and predation links show significant changes as a result of the inclusion of higher trophic level predators, and model results are highly sensitive to assumptions regarding sea lion diet. Simulation exercises suggest that model performance degrades more due to model misspecification and data scarcity than assumptions regarding data weighting and variance. Estimates of predation mortality work in tandem with survey data, constraining predation estimates in the face of incomplete diet data and potentially improving estimates of cohort structure. Exploration of predator functional responses (PFR) shows the default GOA MSASA Holling Type II PFR to be more flexible than initially thought, and that explicitly modeling predator competition for the same prey can improve model fit to stomach-content data. Median parameter estimates and their respective variances from the fitted MSASA model are used to construct management strategy simulations. Reducing fishing pressure on pollock during periods of high predator biomass is less effective at preserving pollock stocks than raising fishing pressure on flounder, and multispecies harvest control rules and biological reference points are shown to be more conservative and more efficient at preserving stock abundance while maintaining catch levels than their single-species counterparts.
    • Multistate Ornstein-Uhlenbeck space use model reveals sex-specific partitioning of the energy landscape in a soaring bird

      Eisaguirre, Joseph M.; Goddard, Scott; Barry, Ron; McIntyre, Julie; Short, Margaret (2019-12)
      Understanding animals’ home range dynamics is a frequent motivating question in movement ecology. Descriptive techniques are often applied, but these methods lack predictive ability and cannot capture effects of dynamic environmental patterns, such as weather and features of the energy landscape. Here, we develop a practical approach for statistical inference into the behavioral mechanisms underlying how habitat and the energy landscape shape animal home ranges. We validated this approach by conducting a simulation study, and applied it to a sample of 12 golden eagles Aquila chrysaetos tracked with satellite telemetry. We demonstrate that readily available software can be used to fit a multistate Ornstein-Uhlenbeck space use model to make hierarchical inference of habitat selection parameters and home range dynamics. Additionally, the underlying mathematical properties of the model allow straightforward computation of predicted space use distributions, permitting estimation of home range size and visualization of space use patterns under varying conditions. The application to golden eagles revealed effects of habitat variables that align with eagle biology. Further, we found that males and females partition their home ranges dynamically based on uplift. Specifically, changes in wind and the angle of the sun seemed to be drivers of differential space use between sexes, in particular during late breeding season when both are foraging across large parts of their home range to support nestling growth.
    • The music of water

      Balvanz, Lisa Ellen; Farmer, Daryl; Burleson, Derick; Carr, Richard (2016-05)
    • Music: a portrait of woman

      Wellman, Amy R.; DeCaro, Peter; Richey, Jean; Anahita, Sine (2012-08)
      Music in today's society is ubiquitous. It is in the car, the cinema, on television, in the doctor's office, in the home, on the other end of the phone; it really is everywhere. Music arguably is a large part of culture and as such, has the ability to construct social realities. In hopes to understand how media constructs the image of the female, a contextual analysis was performed on the lyrics of the top twenty-five country and pop songs according to Billboard.com. This was done using Grounded Theory through the employment of coding. Results showed that although country and pop music depict women in a slightly different manner, they both for the most part depict women in traditional gender roles. Furthermore, the propitiation and adherence to traditional gender roles sustain and conciliate patriarchy. Therefore the depictions of women in the music lyrics were then analyzed as processes of patriarchy.
    • Muskox Bibliography

      Triplehorn, Julia H.; Johnson, Lee E. (Institute of Arctic Biology, University of Alaska Fairbanks, 1980)
      This bibliography is intended to be a comprehensive reference source on muskoxen that will serve the biological researcher, the historian, and the person interested in the economic potential and current status of the muskox. It includes books, periodicals, and newspapers, and ranges from technical to popular coverage. The only systematic exclusions were fiction and juvenile books. Those references which are available at the University of Alaska, Fairbanks, are marked with an asterisk (*) in front of the title.
    • The Muskox: a new northern farm animal

      Helfferich, Deirdre (Agricultural and Forestry Experiment Station, School of Agriculture and Land Resources Management, University of Alaska Fairbanks, 2008)