• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 641
  • 59
  • 50
  • 50
  • 50
  • 50
  • 50
  • 47
  • 46
  • 31
  • 30
  • 13
  • 10
  • 9
  • 8
  • Tagged with
  • 1070
  • 174
  • 148
  • 134
  • 118
  • 113
  • 103
  • 85
  • 71
  • 70
  • 67
  • 66
  • 59
  • 58
  • 58
  • 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.
421

Ice conditions and ice forecasting in the Beaufort sea

Swenson, Paul B. January 1958 (has links)
Thesis (M.A.)--Boston University / Introduction The purpose of the thesis is; to develop and explain the location and extent of sea ice in the Beaufort Sea, and to describe methods in use and proposed by the science of ice forecasting to aid ship movements in the area. Much of the data in the thesis camas from unpublished or widely scattered papers, and the thesis is an attempt to assimilate such data into cohesive form. Chapter I. The Newly Acquired Importance of the Beaufort Sea Region and the Status of Ice Forecasting. Prior to World War II the area of the Beaufort Sea was little known or exploited. A few explorers occasionally had joined the native eskimos as inhabitants of the area. After the war, a program of oil exploration was undertaken on the southern shores of the Sea by the U.S. Navy. Discovery of oil and the newly feasible means of making trans-polar flights across the Arctic waters suddenly catipulated the area into a position of strategic importance to our national defense. Research programs devoted to gathering data on how to live in such a hostile climate bacame a natural outgrowth of this new importance. With the construction and resupply of the DEW line a vital necessity, methods of coping with sea ice had to be developed. In this respect, the Russians were far advanced over the Western Allies, having devoted much time and effort on the problem since the 1920's. Nonetheless, U.S. and Canadian scientists, under an accelerating research program, are well on the way to equality in the fields surrounding sea ice research. [TRUNCATED]
422

Arktis - det nya slagfältet : En kvalitativ studie över Sveriges och USA:s säkerhetsstrategi för den arktiska regionen

Röjerås, Ida, Trogen, Sara January 2022 (has links)
As temperatures in the Arctic continue to rise, so do the tensions between the Arctic states as Russia and China belligerently stake their claims in the Arctic region. Before the crippling effects of climate change, the Arctic was a region that was hard to gain access to due to the colossal glaciers that provided a natural barrier that kept countries at bay. The Arctic harbors massive amounts of natural resources that many countries have exhibited an interest in. The premise of this research paper is to compare the United States and Sweden’s security strategies regarding the Arctic region. What goals, assets, methods and environmental factors does each country have. The United States has a long standing status as a great power, this paper seeks to find out whether being a great power or not plays a significant role in the outcome of a security strategy. Using Westberg’s security strategy theory, Realism and small state theory this paper will compare and delve into the differences between the United States and Sweden’s strategies in the Arctic. The overall conclusion was that being a great power or small power impacted the security strategy to a great extent. Sweden’s strategy emphasized preventive measures and highlighted the importance of cooperation; meanwhile the American strategy took on a greater responsibility as the only great power able to balance out Russia’s military operation and placed more emphasis on their military strategy.
423

Quantifying the Vulnerability of Arctic Water Supply Lakes to Environmental Change Through Paleolimnological Assessment

Cincio, Paige 20 November 2020 (has links)
Anthropogenic stressors to freshwater environments have perpetuated water quality and quantity challenges for northern communities across Arctic Canada, making drinking water resources a primary concern for Arctic populations. To understand the ecological trajectory of freshwater supply sources, we conducted a paleolimnological assessment on two supplemental sources of freshwater in Igloolik, Nunavut, Canada. A stratigraphic examination of bioindicators (Insecta: Diptera: Chironomidae) allowed for paleotemperature reconstructions with decadal and centennial resolution over the past 2000 years. Between 200 and 1900 CE, the sub-fossil chironomid community was comprised of cold-water taxa, such as Abiskomyia, Micropsectra radialis-type, and Paracladius. Reconstructed temperatures were consistent with known climate anomalies during this period. A rapid shift in the composition of the chironomid community to warm-water adapted taxa (Chironomus anthracinus-type, Dicrotendipes, and Tanytarsus lugens-type) in the late 20th century was observed in both systems. Our results demonstrate that these lake ecosystems are undergoing marked transformations to warmer, more nutrient-rich environments, and suggest water sustainability pressures on freshwater and human systems will likely continue in tandem with ongoing climate change. To contextualize the influence of recent warming and elucidate the status of water resource vulnerability over the longer term, paleolimnological methods can be usefully applied as components of vulnerability assessments.
424

Etude des aérosols transportés en Arctique à partir des mesures aéroportées (ATR-42) du LaMP durant le projet POLARCART / Analysis of aerosol transported to the Arctic based on LaMP's airborne measurements (ATR-42) during the POLARCAT project

Quennehen, Boris 14 December 2011 (has links)
Ces travaux, effectués dans le cadre de la 4e année polaire internationale et à partir des mesures in-situ obtenues durant le projet POLARCAT-France, ont pour objectifs de fournir, dans un premier temps, une climatologie des panaches de pollution transportés depuis les continents sources (Amérique du Nord, Europe et Asie) vers l’Arctique. La climatologie contient des informations sur les propriétés physique, chimique et optique des particules d’aérosols, l’origine des panaches ayant été déterminée à l’aide du modèle lagrangien de rétro-trajectoire FLEXPART. Dans un second temps, les processus qui influent sur les propriétés des particules de pollution durant leur transport vers l’Arctique ont été étudiés. Si au cours de la campagne d’été au Groenland, il a été montré que la totalité des panaches rencontrés ont subit un processus de dépôt humide durant leur transport vers l’Arctique, la campagne de printemps au nord de la Suède a permis de mettre en avant l’évolution d’un même panache échantillonné lors de 3 vols consécutifs ainsi que des propriétés de mélange entre les contributions anthropiques et naturelles de deux panaches asiatiques. / The aims of this thesis were, in a first step, to build a climatology of pollution plumes transported from source continents to the Arctic as measured during the POLARCAT-France campaigns performed in spring and summer 2008, in the frame of the 4th International Polar Year. The climatology is including informations on aerosol particle physical, chemical and optical properties and is organized as a function of pollution plume origins (determined with the Lagrangian transport model FLEXPART). In a second step, aerosol processes which influenced aerosol properties during transport to the Arctic were studied. During the summer campaign, the whole plumes encounter experienced wet scavenging processes on their pathway to Groenland. In spring, a plume was sampled during three consecutive days and thus, its ageing was characterised. Finally, two Asian plumes allowed us to highlight the external mixing between anthropogenic and biomass burning contributions transported to northern scandinavia.
425

Impacts des événements météorologiques extrêmes et du changement climatique sur les régions arctiques et subarctiques : Perspectives croisées en climatologie et en sciences humaines et sociales / Impacts of extreme weather events and climate change in arctic and subarctic regions : A crossed approach in climatology, social sciences and humanities

Rojo, Maxence 23 September 2016 (has links)
La hausse des températures et les modifications du régime des précipitations affectent les écosystèmes particulièrement fragiles des régions arctiques et subarctiques et ont des conséquences socio-économiques pour les populations locales. La perception et l'évaluation des opportunités et des risques qui y sont associés, dépendent des moyens de subsistance, des normes, des valeurs et des représentations du monde des individus qui y sont confrontés.La perception du climat est culturellement et socialement construite. Cette perception varie dans le temps et dans l'espace et, parfois même, diffère parmi différents groupes sociaux en fonction des valeurs et des modes de représentation du monde. Pour toutes ces raisons, nous avons non seulement étudié certains phénomènes météorologiques mais aussi intégré le cadre culturel, politique et historique dans lesquels ils s'inscrivent. Nous avons analysé l'environnement et le climat – et par extension, les événements météorologiques à forts impacts – comme des objets socio-culturels afin de mieux comprendre à la fois leurs impacts mais aussi leurs perceptions par les habitants. Ce travail se situe à la croisée de ces chemins, en confrontant l'observation, et donc les changements, et la perception qu'en ont différents acteurs, en considérant deux régions distinctes, les mers nordiques et la République de Touva.Dans une première partie, nous avons analysés l'impact des Polar Lows, d'intenses cyclones de méso-échelle qui se développent sur les mers libres de glace de l'Arctique pendant l'hiver, sur les régions côtières du nord de la Norvège. Ces systèmes sont associés à des vents de surface forts avec bien souvent des rafales qui peuvent être très violentes (Heinemann et Claud, 1997). Les conditions en mer lors du passage d'un PL peuvent s'avérer dangereuses avec des fortes vagues, des précipitations neigeuses brutales et du blizzard. Ces événements météorologiques extrêmes représentent un véritable risque pour les activités maritimes et côtières de la région, notamment pour le transport maritime, la pêche et les plateformes pétrolières et gazières offshore. En effet, les nouvelles zones libres de glace offrent de multiples opportunités économiques dans ces régions, en particulier en mer de Barents. Or dans le même temps, le recul de la banquise élargit mécaniquement les régions de formation des PLs.Dans une seconde partie, nous avons regardé les impacts du changement climatique et des événements météorologiques sévères en République de Touva. La République de Touva se localise entre 49°5 et 53°5 N en latitude, 88°5 et le 99°E en longitude, c'est par conséquent une région subarctique très méridionale. Le climat y est extrêmement continental et les précipitations ont tendance à être faibles en raison de la faible teneur en humidité dans l'air froid. La plupart du territoire est caractérisé par une végétation forestière de taïga ou de steppe semi-aride. Au cours du XXème siècle, la région a connu des changements socio-économiques majeurs, parfois brutaux, avec notamment le passage d'une société communiste à l'économie planifiée à une économie de marché au début des années 1990. Malgré ces récents bouleversements, les pasteurs nomades (chevaux, vaches, yaks, moutons, chameaux) en Touva occidentale et les chasseurs-cueilleurs éleveurs de rennes en Touva orientale, vivent toujours en étroite relation avec l’environnement naturel. Les populations autochtones de Touva, confrontées à un changement rapide de la société et à des changements globaux causés par certaines politiques régionales et nationales contemporaines, avec notamment l’expansion de l'industrie minière et par le développement de mégaprojets (complexe hydroéléctrique, construction d'une voie chemin de fer), offrent des points de vue variés, en fonction de leurs modes de vie, sur les changements environnementaux qu'ils observent et leurs impacts sur leurs activités quotidiennes. / The perception of the climate is culturally and socially constructed. For this reason, we have studied some weather events integrating the cultural, political and historical contexts in which they occur.In a first part, we analyzed the impact of Polar Lows, intense mesocyclones that develop over ice-free Arctic seas during winter time, on coastal regions of Norway. The passage of PL can provoke dangerous sea conditions with strong waves, sudden snowfall and blizzard. This phenomenon may represent a risk to maritime and coastal activities in the region, particularly for shipping, fishing and oil and gas offshore platforms.In a second part we studied the impacts of climate change and severe weather events in the Republic of Tuva. Tuva is a very southern subarctic region. Its climate is extremely continental and precipitation tend to be low due to the low moisture content in the cold air. During the twentieth century, the region has experienced major socio-economic changes, sometimes brutal, including the transition from a communist and planned economy to a market economy in the early 1990. Despite these recent changes, pastoralists in western Tuva (horses, cows, yaks, sheep, camels) and reindeer herders in eastern Tuva, still live in close contact with the natural environment. Indigenous peoples of Tuva are facing global changes caused by certain contemporary regional and national policies, including the expansion of the mining industry and the development of mega projects. They offer different points of view, describing environmental changes and their impact on their daily activities.
426

Use It or Lose It: Canadian Identity and the Construction of Arctic Security Policy

McCormack, Michael P 07 December 2016 (has links)
This dissertation investigates the specific factors that drive state action in Canadian Arctic security policy, particularly in relation to securitization of the Arctic region and historical factors that influence decision-making. The purpose of this research is to develop stronger linkages between securitization processes and actual policymaking. When studying the Arctic as a defined geographical space, we see considerable differences between Arctic states when it comes to how cultural and historical attachment to the Arctic region may serve as a selling point for the ability of national governments to justify allocation of defense resources to their respective publics. Using the Canadian case, this research illustrates the strength of identity factors when compared to day-to-day bureaucratic politics and the influence of public opinion. This dissertation does not follow the ideas of one particular theoretical paradigm, but instead utilizes eclecticism to better illustrate the depth of the various factors that may contribute to policymaking. Additionally, the effects of policymaking and securitization processes are measured through public opinion. The ultimate findings of this research support a hypothesis of linear identity factors as a major influence on Canadian Arctic security policy, but also suggest that research on securitization theory needs to better connect rhetorical v securitization processes to actual policymaking. Through this, the research not only provides value in using this case as a test for the strengths and limits of securitization theory, but also emboldens understandings of security policy as being driven by a combination of domestic policy, foreign policy, endemic historical factors, and government strategic communication practices.
427

An Arctic Adaptation

Stein, Dylan 30 July 2019 (has links)
No description available.
428

Fire, Forest, Ice, and Fungi: Exploring The Mesh Of Relationships Driving Seedling Regeneration In The Siberian Arctic

Frankenberg, Sarah J. 24 August 2020 (has links)
No description available.
429

Unstable Ground : Arctic Regeneration and Rewilding

Dovberg, Ludvig January 2023 (has links)
This thesis investigates the characteristics of the Arctic region in terms of climate change, biodiversity, culture and exploiting human action. Is the 21st centurythe era where we reconcile between nature and societal development demands? Here it is questioning if we as humans have a responsibility to design for us, yet also for animals with equal value. Nonetheless, the animals that have been pushed towards ecological displacement have a significant important role on our earth and especially in the Arctic - to sustain balance in ecosystems and to protect the terrestrial carbon sinks. The thesis investigates if rewilding as a strategy can be used to reconcile that very conflict through four theoretical lenses: Tsing’s theory on friction, Bratton’s theory on automation, Ghosh theory on narrative and Latour’s theory on hybrids. In short, the project landed in a dual functional fauna bridge with a research centre intended for rewilding. This means that a bridge over a railway and a highway will be designed as a natural transition for animals to cross over, but also it will be inhabited by researchers and NGOs in which creates a node for knowledge exchanges between the users of the bridge and reindeer husbandry practitioners.
430

Species distribution and biomass characteristics of the terrestrial vascular flora, Resolute N.W.T.

Arkay, Katherine E. January 1972 (has links)
No description available.

Page generated in 0.0718 seconds