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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
401

Using a Geospatial Approach to Evaluate the Impacts of Shipping Activity on Marine Mammals and Fish in Arctic Canada

Joyce, Jenna 14 June 2018 (has links)
A loss in sea ice cover, primarily attributed to climate change, is increasing the accessibility and navigability of the Arctic Ocean. This increased accessibility of the Canadian Arctic, and in particular the Northwest Passage, presents important global and national shipping and development opportunities. However, increased shipping in the region also present challenges related to the environmental sustainability, sovereignty and safety, and cultural sustainability. The Low Impact Shipping Corridors (the Corridors) is currently the foundational framework for governing ship traffic within the Canadian Arctic. However, the Corridors were largely established based on historic traffic patterns and thus they do not fully consider important areas for marine mammals and fish in the region. This research addresses this important research gap by spatially identifying important areas for marine mammals and fish in the Kitikmeot region of Nunavut using both Traditional Knowledge and western science, evaluating ship tracks from 1990-2015, and geospatially identifying and evaluating areas of potential disturbance for marine mammals and fish related to vessel noise from different ship types transiting the Corridors within the study region. The results of this study indicate that all vessel types have the potential to cause behavioural disturbance to marine mammals and fish when navigating through these important wildlife areas, and that louder vessels (i.e. Tanker ships) travelling outside of these important wildlife areas have a greater potential to cause behavioural disturbance to marine mammals and fish than quieter vessels (i.e. Pleasure Crafts). The results also indicate that vessels navigating through certain regions of the Kitikmeot have a higher potential to cause behavioural disturbances in these species, including through the Gulf of Boothia, Franklin Strait, Rae Strait, Rasmussen Basin, and Bathurst Inlet.
402

Business and Financial Analysis of Arctic Paper Munkedals AB

Aigbefo, Glory, Aseghehey, Mekonen Araia January 2011 (has links)
The thesis evaluates both the business and financial performance of Arctic Paper Munkedals AB. The company was founded in 1817 and is located in Munkedal, Sweden. The evaluation was achieved through ratio analysis of the annual reports of Arctic Paper Munkedals AB over a five-year period and business performance analysis using the balanced scorecard model. The data collections are from the annual financial reports for five years before the 2008 recession. Different financial ratios were evaluated such as short-term liquidity ratios, leverage ratios, profitability ratios, asset utilization and capital market ratios. The mathematical calculations were established for ratio analysis from 2003-2007 along with graphical analysis and comparisons. According to Altman (The Journal of Finance, 1968), observed evidence for five years prior to failure was cited as conclusive that ratio analysis can be useful in the prediction of failure. The research paper also analyzes the business performance of Arctic Paper Munkedals AB using the balanced scorecard model. This model is a customer-based planning and process improvement system, with its primary focus on driving an organization's change process by identifying and evaluating pertinent performance measures. It complements the traditional financial perspective with other non­financial perspectives such as customer satisfaction, internal business process as well as learning and growth. The balanced set of performance measures tells a concise yet complete story about the achievement and performance of the organization toward its mission and goals. It provides a holistic view of what is happening in the organization.
403

Terrestrial respiration across tundra vegetation types

Borgelt, Jan January 2017 (has links)
Large amounts of carbon (C) are stored in tundra soils. Global warming may turn tundra ecosystems from C sinks into sources or vice versa, depending on the balance between gross primary production (GPP), ecosystem respiration (ER) and the resulting net ecosystem exchange (NEE). We aimed to quantify the summer season C balance of a 27 km2 tundra landscape in subarctic Sweden. We measured CO2 fluxes in 37 widely distributed plots across five tundra vegetation types and in 7 additional bare soil plots, to assess effects of abiotic and biotic components on C exchange. C fluxes in bare soils were low and differed to all vegetation types. Thus, accounting for differences between bare soils and vegetated parts is crucial for upscaling a C balance using a landcover classification map. In addition, we found that both NEE and ER, varied within and across different tundra vegetation types. The C balance model for the growing season 2016 revealed a net C loss to the atmosphere. Most vegetation types acted as CO2 sources, with highest source strength in dense shrub vegetation at low elevations. The only considerable C sinks were graminoid-dominated upland meadows. In addition, we found a shift in C balance between different heath vegetation types, ranging from C source in dense deciduous shrub vegetation (Mesic Heath and Dry Heath) to C sink in low growing shrub vegetation (Extremely Dry Heath). These results highlight the importance to account for differences between vegetation types when modelling C fluxes from plot to landscape level.
404

Environmental Controls on Snow Cover Thickness and Water Equivalent in Two Sub-Arctic Mountain Catchments / Miljöns påverkan på snötäckets tjocklek och vattenvärde i två subarktiska höglänta avrinningsområden

Cosgrove, Christopher January 2015 (has links)
The spatial variability of snow cover characteristics (depth, density, and snow water equivalent [SWE]) has paramount importance for the management of water resources in mountain environments. Passive microwave (PM) inference of SWE from space-borne instrumentation is increasingly used but the reliability of this technique remains limited in mountainous areas. Complex topography and the transition between forest and alpine tundra vegetation zones create large spatial heterogeneities in the snowpack in such environments. A better understanding of the factors that control these heterogeneities is therefore needed to improve and extend the use of PM-derived SWE estimation to mountain settings. In this study, two seasonally snow-covered sub-Arctic mountain catchments at comparable latitudes, one in Hemavan, northern Sweden and the other in Wolf Creek, Yukon, Canada, were investigated to evaluate the relative influence of climate vs. landscape factors on the variability of snow cover characteristics. Field measurements of snowpack stratigraphy and SWE were performed at the approximate time of late winter snow depth maximum using various in situ methodologies. Regression analysis was then employed to identify possible relationships between snow depth, density and SWE, and landscape properties (altitude, slope angle and aspect) at both sites, both within and between different vegetation zones. Snow depth, density and SWE were found to be greatest in the alpine tundra zone of both catchments, and were largest in Hemavan, probably on account of the relatively warmer and wetter winter climate of northern Sweden compared to that of the Yukon. Elevation was the only quantifiable landscape property found to show a positive and significant relationship with SWE in both catchments. Notable differences in the spatial variability of snowpack properties were also found between the two study sites. The local variability of snow depth was greatest in the forest-alpine transition zone at Hemavan, but greatest in the alpine zone at Wolf Creek. Differences in the vegetation cover type between the two catchments (coniferous vs. deciduous in the forest zone) is suspected to exert an important influence on spatial patterns of snow depth, density and SWE, likely because of differences in the efficiency of snow interception. Further investigations of how different vegetation characteristics (e.g. leaf area index) influence snowpack properties over the course of the winter are recommended in order to improve and extend the use of PM-based SWE retrievals in high-latitude mountain environments.
405

Modélisation régionale des polluants à courte durée de vie (aérosols, ozone) en Arctique / Regional modeling of aerosols and ozone in the arctic : air quality and radiative impacts from local and remote pollution sources

Marelle, Louis 20 June 2016 (has links)
La région arctique s’ouvre peu à peu aux activités humaines, en raison du réchauffement climatique et de la fonte des glaces, dûs en partie aux effets radiatifs des aérosols et de l'ozone. En conséquence, les émissions locales de pollution en Arctique pourraient augmenter, et devenir prépondérantes comparées à la source historique liée au transport de pollution depuis les moyennes latitudes. Dans cette thèse, j’effectue des simulations régionales de la troposphère arctique avec le modèle WRF-Chem, combiné à de nouveaux inventaires des émissions de pollution locales en Arctique (navigation et torches pétrolières). Deux cas d’étude issus de campagnes de mesure par avion sont analysés. Premièrement, j’étudie un évènement de transport d’aérosols depuis l’Europe au printemps 2008, afin d’améliorer les connaissances sur cette source majeure de pollution. Deuxièmement, je détermine l’impact des émissions de la navigation en Norvège en été 2012, où la navigation Arctique est actuellement la plus intense. J’utilise ces cas d’étude pour valider la pollution modélisée et améliorer WRF-Chem en Arctique. J’effectue avec ce modèle amélioré des simulations des impacts actuels (2012) et futurs (2050) de la navigation et des torches pétrolières en Arctique. Les résultats indiquent que les torches sont et devraient rester une source majeure d’aérosols de carbone suie réchauffant en Arctique. La navigation en Arctique est une source de pollution importante en été et, en 2050, pourrait devenir une source majeure de pollution locale. / The Arctic is increasingly open to human activity due to rapid warming, associated with decreased sea ice extent. This warming is due, in part, to the effect of short-lived atmospheric pollutants (aerosols, ozone). As a result, Arctic pollutant emissions should increase in the future, and their impacts might become significant compared to the now predominant source due to pollution transport from the mid-latitudes. In this thesis, regional simulations of the Arctic troposphere are performed with the WRF-Chem model, combined with new emission estimates for oil and gas extraction and shipping in the Arctic. The model is used to analyze two case studies from recent airborne measurement datasets: POLARCAT-France in 2008, ACCESS in 2012. First, I investigate an aerosol transport event from Europe to the Arctic in spring 2008, in order to improve our understanding of this major source of Arctic pollution. Second, I determine the air quality and radiative impacts of shipping emissions in Northern Norway in summer 2012, where most current Arctic shipping occurs. I use these results to validate modeled pollution, and to improve WRF-Chem for Arctic studies. The updated model is used to investigate the current (2012) and future (2050) impacts of Arctic shipping and Arctic gas flaring in terms of air quality and radiative effects. Results show that Arctic flaring emissions are and should remain a strong source of local black carbon aerosols, causing warming, and that Arctic shipping is already a strong source of aerosols and ozone during summer. In 2050, diversion shipping through the Arctic Ocean could become a major source of local surface aerosol and ozone pollution.
406

Environmental information from the Svalbard ice core for the past 800 years

Kekonen, T. (Teija) 29 August 2006 (has links)
Abstract Major water soluble ions (Cl-, NO3-, SO42-, CH3SO3-, Na+, K+, NH4+, Mg2+, Ca2+) were determined and the results interpreted from a 121 m long ice core drilled at the summit of the Lomonosovfonna dome, Svalbard. The core covers about the past 800 years. The reliability of anion chemistry for paleoenvironmental studies, and various insoluble particles were also investigated. The ice core studied in this Thesis is the first relatively deep ice core from the central Svalbard that has been analyzed and the results interpreted and published at high resolution for all major ions. One of the clearest features of the ion profiles is anthropogenic impact. SO42- and NO3- concentrations show significant increases by the mid-20th century with slight increases already at the end of the 19th century. In addition excess Cl- and NH4+ from anthropogenic sources are detected arriving after the mid-20th century. Anthropogenically derived SO42- and NO3- have different sources on Lomonosovfonna. NO3- is correlated with NH4+ and requires interpretation in terms of both natural and anthropogenic NH4NO3 sources. The ice core ionic load consists mostly of sea salt ions (Na+, Cl-, K+ and Mg2+). Water soluble Ca2+ are mostly terrestrial in origin. Ion balance together with the Na+/Cl- ratio shows considerable change about 1730 that is most probably due to Na2CO3 input to the ice cap before 1730. Marine biogenic CH3SO3- concentrations are high and stable during the Little Ice Age. CH3SO3- concentrations show a clear change in concentrations in 1920, that is the end of the Little Ice Age in Svalbard. Regardless of anthropogenic impact, marine biogenic SO42- is appreciable in total SO42- budget even in the 20th century. The Laki volcanic eruption in Iceland in 1783 is identified in the ice core as a volcanic tephra layer and high SO42- concentration and acidity peaks. These show that SO42- arrived to the Lomonosovfonna ice cap 6–12 months later than insoluble tephra and the SO42- aerosol caused a drop in temperature. The reliability of ice core ion chemistry analyses was estimated – for the first time in an ice core using two different analytical procedures on 500 adjacent samples from the same depth. Small-scale inhomogeneity in ion concentrations shows that information from ice core layers is representative of the regional environmental and suitable for paleoclimate studies.
407

Seasonal adaptations in the energetics and biomechanics of locomotion in the Svalbard rock ptarmigan (Lagopus muta hyperborea)

Lees, John January 2013 (has links)
One of the most striking things about many animals is that they can be defined by the ways in which they move. Moving costs metabolic energy and is a significant contributor to the daily energy balance of organisms and therefore fitness. Balancing energy needs is critically important to species inhabiting areas of limited resources. The metabolic cost of locomotion is influenced by physiological, morphological and behavioural factors that vary across species. The influence of these factors within species is less well understood. The objective of my PhD is to elucidate the potential for variation in locomotor performance, in particular the energy consumed and the biomechanics of locomotion within a species, in response to differences in season, sex, age and the nature of the terrain. The Svalbard ptarmigan (Lagopus muta hyperborea) is the only year-round avian resident of the Arctic archipelago of Svalbard. Svalbard is characterized by extreme photoperiodic and climatic conditions, with 24 hours of daylight in summer and continuous darkness in winter, when ice makes food unpredictable. As a result, ptarmigan annually gain significant fat stores, as much as doubling their body mass in winter. The consequences of such large gains in mass upon the metabolic cost and biomechanics of terrestrial locomotion are yet to be quantified. The Svalbard ptarmigan represents a unique opportunity to gain insight into avian adaptations.Using respirometry, I present evidence that winter birds are able to carry their fat stores at no metabolic cost. Using kinematic and force plate data, I show that acquiring fat results in reduced locomotor performance in terms of speed and take-off ability. As well as exhibiting phenotypic variation, male and female Svalbard ptarmigan are behaviourally very different. I present evidence that these behavioural differences are reflected in the metabolic cost of locomotion. In particular, males are both more efficient and faster than female birds during both summer and winter. I suggest that this results from sexual selection upon male locomotor performance. Furthermore, I present data demonstrating that sub-adult males experiencing their first winter possess the same metabolic and speed capabilities of adults. These data may indicate that selection for improved male locomotor performance may act upon sub-adult birds. Regardless of season, age or sex, Svalbard ptarmigan must locomote on a predominantly sloping terrain. The influence of inclines upon the metabolic cost of locomotion in birds is poorly understood. I provide evidence that at the same degree of incline, the cost of lifting 1 kg by 1 vertical metre is similar regardless of season and is therefore dictated by increased positive work. However, this cost varies according to the degree of incline and may be influenced by gait.The principal findings of the 5 first author papers presented are that behavioural, physiological and morphological variation within a species can have significant impacts upon the metabolic cost of locomotion and other aspects of locomotor performance. The potential for intraspecific differences should therefore be taken into account in future research regarding the patterns of energy expenditure in animals.
408

Estimating Pre-Rift Bedrock Geology Under Shelf Sediments of the Circumpolar Arctic

Breker, Kaitlyn January 2016 (has links)
In the Arctic Ocean, almost 50% of the seafloor is underlain by continental shelf. However, the geology of the pre-rift continental crust that makes up the basement of the shelf is poorly constrained because it is overlain by thick Cenozoic sedimentary cover. This study explores the available data and methods for mapping the continental bedrock geology beneath the sediments. In a GIS framework, extrapolation of geological map units to the shelf edge was guided by onshore structure and offshore bathymetry. The compilation involved identification of data sources, development of a common legend for pre-rift basement geology, building attributes tables for analysis, and extrapolating geological contacts. As a first-order assessment of mineral resource potential of the continental shelf, permissive tracts for certain mineral deposit types were also identified. The analysis includes a case study of permissive geology for magmatic Ni-Cu deposits in the Taimyr Peninsula in northern Russia.
409

Connections Between the Mass Balance, Ice Dynamics, and Hypsometry of White Glacier, Axel Heiberg Island, Nunavut

Thomson, Laura Irene January 2016 (has links)
This thesis investigates how changing climate conditions have impacted the mass balance, dynamics and associated hypsometry (area-elevation distribution) of White Glacier, an alpine glacier on Axel Heiberg Island, Nunavut. The first article describes the production of a new map of White Glacier from which changes in ice thickness and glacier hypsometry could be determined. A new digital elevation model (DEM) was created using >400 oblique air photos and Structure from Motion, a method built upon photogrammetry but with the advantage of automated image correlation analysis. The result of this work demonstrates that the method is able to overcome the challenges of optical remote sensing in snow-covered areas. The resulting DEM and orthoimage facilitated the production of a map with 5 m vertical accuracy in the style of earlier cartographic works. The new map supported the calculation of the glacier’s geodetic mass balance and provides an updated glacier hypsometry, which improves the accuracy of mass balance calculations. A modeled glacier hypsometry time-series was created to support a reanalysis of the mass balance record over the period 1960-2014, which through comparison of the geodetic and glaciological methods enables the detection of potential sources of error in the glaciological method. Comparison of the two approaches reveals that within the error margin no significant difference exists between the average annual glaciological mass balance (-213 ± 28 mm w.e. a 1) and geodetic mass balance ( 178 ± 16 mm w.e. a-1). To determine how ice dynamics have responded to ice thinning and negative mass balances, dual-frequency GPS observations of ice motion were compared to historic velocity measurements collected at three cross-sectional profiles along the glacier. Comparisons of annual and seasonal velocities indicate velocity decreases of 10–45% since the 1960s. However, increased summer velocities at the highest station suggests that increased delivery of surface meltwater to the glacier bed has initiated basal sliding at elevations that did not experience high levels of melt in earlier decades. Modeled balance fluxes demonstrate that observed fluxes, both historically and currently, are unsustainable under current climate conditions.
410

Using Detrital-Zircon Geochronology and (U-Th)/He Thermochronology to Re-evaluate the Triassic-Jurassic Tectonic Setting of Northern Laurentia, Canadian Arctic

Midwinter, Derrick January 2016 (has links)
New geochronological and field data were examined from Triassic-Jurassic strata in the Sverdrup Basin, Arctic Canada. Detailed analysis of detrital-zircon data identified a pronounced near-syndepositional age-fraction in Triassic strata, which significantly is absent in Jurassic strata of the Sverdrup Basin suggesting a protracted history of magmatism and sediment dispersal from areas north of the basin during the Triassic. However, as a result of rifting, during the Early Jurassic, the northern source region became disconnected from the Sverdrup Basin, and opened the precursor basin (Amerasia Basin) to the Arctic Ocean. Jurassic rifting of the Amerasia Basin would have had associated rift-flank uplift. Time-temperature models produced from zircon (U-Th)/He thermochronological data elucidate the unknown thermal history between the regional Devonian-Cretaceous unconformity in the southwestern Canadian Arctic suggesting ~4 km of addition deposition on Banks Island and ≤1 km of deposition towards the craton interior.

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