Icebergs calved from tidewater glaciers represent significant portions of freshwater flux from the Greenland Ice Sheet to the ocean. Using satellite data sets we quantify properties and distributions of icebergs in three fjords with varied properties: Sermilk, Rink Isbræ, and Kangerdlugssûp Sermerssua. Total iceberg volumes in summer in the three fjords average 6.43, 1.69, and 0.19 km^3, respectively, and we calculate cumulative submerged surface areas of iceberg faces to be 213, 55.2, and 7.57 km^2, respectively. We calculate a freshwater flux from iceberg melt of 0.009 – 0.083 m^3 d^-1 in Sermilik Fjord, suggesting a strong potential of iceberg melt water to influence water properties. Properties of icebergs and size distributions are influenced by calving style and grounding line depths of parent glaciers. Variations are represented in the coefficients of generalized Pareto distributions which best describe size distributions in the fjords.

Thesis (Ph. D.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Dept. of Earth and Atmospheric Sciences, University of Alberta. Includes bibliographical references. Also available via the Internet.

Thesis (M.Sc.). / Written for the Dept. of Atmospheric and Oceanic Sciences. Title from title page of PDF (viewed 2008/05/13). Includes bibliographical references.

Thesis (M.Eng.) -- Memorial University of Newfoundland, 1982. / Bibliography : leaves 116-119. Also available online.

Tidewater glaciers drain a significant proportion of the Greenland Ice Sheet and ice masses of the Canadian Arctic and provide the primary source of icebergs in Canadian waters. However, there remains uncertainty surrounding the processes controlling ice discharge from Canadian Arctic glaciers, the drift paths of icebergs in Canadian waters, and the proximity of icebergs to shipping in the region. This thesis quantifies the processes controlling glacier dynamics from four primary glacier basins on the Prince of Wales (POW) Icefield and using a multi-year dataset of iceberg drift tracks, identifies drift patterns and proximity to ships throughout the eastern Canadian Arctic. On the POW Icefield between 2009 and 2019, Cadogan and Ekblaw glaciers underwent multiyear acceleration and deceleration limited to their lower parts, consistent with characteristics of "pulse-type" glaciers. Trinity and Wykeham glaciers underwent repeating multiyear periods of velocity acceleration between 2009 and 2019 which coincided with significant thinning at their termini. As of 2017, Trinity and Wykeham were each within ~10 m of flotation over their lowermost 4 km. These findings suggest that Trinity and Wykeham glaciers have transitioned to a flow type dominated by dynamic thinning, which is strongly influenced by subglacial topography and may be susceptible to instability of the glacier front and large-scale collapse. Given that both glaciers are grounded below sea level for ~40 km up-glacier from their termini, this process could lead to significant increases in acceleration, retreat, and solid ice discharge. Using a multi-year dataset (2011-2019) of in-situ iceberg drift locations, it was found that icebergs consistently drifted southeast along the east coast of Baffin Island, controlled by a combination of local conditions including short-term wind events, ocean surface currents and semi-diurnal tidal oscillations. A test of the assumption that icebergs drift at 2% of the wind speed indicates that this rule does not apply for the majority of icebergs in this study, which typically exceeded 2% of the wind speed, particularly at low values. The highest median iceberg drift speeds occurred during the winter and spring, reaching up to 2.3 m s⁻¹ in Nares Strait. Icebergs in this study commonly became grounded near eastern Coburg Island and along the SE coast of Baffin Island, where mean residence time exceeded 180 days in all seasons. Through an analysis of a comprehensive database of ship tracks derived from AIS (automatic identification system) data in combination with a subset of iceberg drift locations derived from in-situ satellite trackers and the Canadian Ice Island Drift, Deterioration, and Detection Database (CI2D3), areas of iceberg-ship coexistence throughout Baffin Bay were identified between 2012 and 2019. The regions that saw the largest increases in iceberg-ship coexistence were along the east coast of Baffin Island and east of Bylot Island for dry bulk vessels, and northward into Smith Sound for passenger vessels. As passenger vessels commonly have little ice strengthening, this could pose an elevated hazard to vessels operating in these regions. The results of this study provide a comprehensive examination of the factors controlling glacier terminus dynamics and stability on SE Ellesmere Island, and the drift paths of icebergs once calved. This provides insights into the life cycle of icebergs in Canadian waters, how they may change in a warming climate, and the hazards that they may pose for shipping, particularly given the rapid recent increase in ship transits across the Canadian Arctic.

Les prochaines modèles climatiques comprendront un modèle de calotte polaire afin de tenir en compte la dynamique de la glace et les interactions glace-océans dans ses projections. D'une part, l'océan Austral (SO) pilote l'accélération des glaciers de l'Antarctique via une augmentation de la fonte basale des ice shelves. D'autre part, l'accélération de la décharge de glace de l'Antarctic Ice Sheet (AIS) contribue à la montée du niveau de la mer et est susceptible de devenir le plus grand contributeur de la cryosphère d'ici la fin du siècle. En outre, l'adoucissement relié, peut avoir des répercussions importantes sur la glace de mer et sur la formation des eaux profondes. Cependant, on ne sait pas encore comment les modèles d'océan et de calotte polaire des futurs systèmes couplés vont représenter les interactions glace-océan, causes et conséquences du déséquilibre de masse de AIS. Ici, dans ce travail, les différents aspects des modèles de océan et calotte polaire ont été étudiés. Une première étape de cette thèse a été concentrée à la représentation des flux d'eau douce glaciaires dans les modèles océaniques actuels. Basé dans estimations glaciologiques, la fonte basal des ice shelves a été répartie dans une grille de ORCA025, et les taux de production d'icebergs ont été appliqués dans une version améliorée du modèle d'iceberg NEMO-ICB. Cette étude préliminaire a été utilisé pour produire une climatologie d'eau de fonte provenant des icebergs, valable pour forcer les modèles de océan actuels. Ce travail montre l'importance de représenter les flux d'eau de fonte des icebergs lors de la modélisation de la glace de mer, qui peut être obtenu en utilisant notre climatologie. Ces améliorations ont été pris en compte dans l'étude de la réponse du modèle de océan a la perte de masse de AIS. Cette étude considère une perturbation réaliste de l'eau douce glaciaire aussi près que possible de sa représentation dans les futurs modèles couplés ice-sheet/océan. Selon nos résultats, jusqu'à 50% des changements récents de volume de la glace de mer pourrait être causée par le bilan masse de l'AIS. Le forçage en eau douce glaciaire semble être cruciale pour représenter correctement les interactions glace-océan et projeter la glace de mer dans les futurs systèmes couplés. Cependant, l'estimation de l'apport d'eau douce glaciaire dans les modèles climatiques futurs sera fortement affecté par la capacité des modèles de calotte polaire de reproduire les migrations de grounding line des glacières de "marine ice sheets". Les modèles de calotte polaire actuels présentent grandes incertitudes liées aux différents réglages. Dans le contexte des futurs modèles climatiques, nous avons étudié la sensibilité des retraites de la grounding line produites par l'océan à l'application de deux lois de frottement différentes et deux différentes approximations du stress glacier. Les modèle réagit de façon presque similaire aux approximations SSA ou SSA *. Par contre, les différences dans la contribution du glacier à l'élévation du niveau de la mer peuvent être jusqu'à 50% en fonction de la loi de frottement considéré. La loi de friction Schoof, la plus physique, est nettement plus réactif aux perturbations océaniques que la loi Weertman, et devrait être pris en compte dans les systèmes couplés futurs. Ce travail souligne que les incertitudes liées aux estimations des modèles de la calotte glaciaire de migrations de grounding line peuvent contribuer non seulement à des incertitudes du futur niveau de la mer, mais aussi de la glace de mer à travers des interactions glace-océan dans les futures models climatiques. Tel conclusion suggère la nécessité d'améliorer la représentation de la fonte basal des ice shelves et le frottement du glacier, afin d'améliorer les projections climatiques des modèles climatiques, dans lequel la distribution spatiale et saisonnière des eau douce glaciaires peut jouer un rôle important en établir la glace de mer. / The next generation of climate models will include an ice-sheet model in order to improve the ice sheet mass balance projections by accounting for the ice dynamics and ice-oceans interactions. On the one hand, the Southern Ocean (SO) is indeed driving the acceleration of the Antarctic outlet glaciers via an increase in the basal melting of the ice shelves. On the other hand, the increasing ice discharge from Antarctic Ice Sheet (AIS) contributes to the current sea level rise and is likely to become the largest cryospheric contributor to sea level rise by the end of the current century. In addition, the related freshening may have significant implications on future sea-ice cover and on bottom water formation. However, it is not clear yet how the ocean and ice-sheet components of future coupled systems will account for the ice-ocean interactions, which are both causes and consequences of the AIS mass imbalance. Here in this work, different aspects of the standalone ocean and ice-sheet components have been investigated. A first step of this thesis has been focused in the representation of the glacial freshwater fluxes in current ocean models. Based on recent glaciological estimates, the ice shelf basal melting fluxes have been spatially distributed in an ORCA025 grid, and the calving rates have been applied into an improved version of the NEMO-ICB iceberg model. This preliminary study has been used to produce a monthly iceberg meltwater climatology, to be used to force current ocean models. This work shows the importance of representing the iceberg meltwater fluxes when modeling sea ice, which can be inexpensively achieve by using our climatology. The improvements in the representation of the glacial freshwater fluxes have been considered in the study of the ocean model response to the Antarctic mass imbalance. This study considers a realistic perturbation in the glacial freshwater forcing as close as possible as it will be represented in future ice-sheet/ocean models. According to our results, up to 50% of the recent Antarctic sea ice volume changes might be caused by the observed decadal AIS mass imbalance rate. Glacial freshwater forcing appears to be crucial to correctly represent the ice-ocean interactions and projecting sea ice cover of future coupled systems. However, the estimation of the glacial freshwater input in future climate models will be strongly dependent upon the capacity of ice-sheet models to reproduce the grounding line migrations of marine ice sheet glaciers. Current ice-sheet models present large uncertainties related to different parametrizations. In the context of the future climate models, we have studied the sensitivity of ocean-driven grounding line retreats to the application of two different friction laws and two different englacial stress approximations. The model responses almost indistinctively to either the SSA or the SSA* englacial stress approximations. However, differences in the contribution of the glacier to the sea level rise can be up to 50% depending on the friction law considered. The more physically constrained Schoof friction law is significantly more reactive to the ocean perturbations than Weertman law and should be considered in future coupled systems. This work underlines that uncertainties related to the ice sheet model estimates of grounding line migrations may not only contribute to uncertainties in sea level projections, but also the sea ice cover through the ice-ocean interaction in future ocean models.This conclusion suggests the need for improving the representation of both the ice shelf basal melting and the glacier interaction with the bedrock, in order to improve the climate projections of future climate models, in which the spatial and seasonal distribution of the glacial freshwater fluxes may play an important role in setting the sea ice cover.

Iceberg calving is an efficient ablation process which introduces mechanical instability to glacier systems and can cause non-linear climatic response. This thesis uses glaciological and limnological data to examine the relative contributions of calving and melting to mass loss at glacier termini, and the interplay between glaciological and limnological processes. Calving dynamics are investigated at two lake-terminating glaciers; Glaciar Leon in Chile and Fjallsjokull in Iceland. Glaciar Leon, a temperate, grounded outlet of the North Patagonian Icefield, terminates at an active but stable calving margin in Lago Leones. The calving rate of 880 m a-1 in a mean water depth of 65 m is high for lake-calving glaciers. Detailed survey of the physical limnology of Lago Leones, important for considering heat transfer to the subaqueous ice face, revealed thermocline development towards the terminus between spring and summer. Melting at the waterline along the glacier terminus facilitates calving by undercutting the subaerial calving cliff, and accounts for around a quarter of mass loss at the terminus. Waterline melting is also an important rate-controlling process for calving at Fjallsjokull. Precise quantification of melt rates (subaerial, waterline and subaqueous) at the termini of calving glaciers is difficult and hazardous, but this study has demonstrated the value of two techniques: (1) detailed survey of melt notch growth, and (2) use of a radiocontrolled boat to record water temperatures at the ice-water interface. Continuous automated monitoring showed that lake-level fluctuations are integral to calving behaviour, influencing calving event timing and size over diurnal and hourly timescales. Fjallsjokull is sensitive to climatic forcing whereas Glaciar Leon, which exhibits larger seasonal than annual fluctuations, is less sensitive. Additional controls on calving at both sites are (1) buoyancy, (2) longitudinal stretching, and (3) the force balance at the ice-water interface. Calving operates along a continuum defined by the relative importance of interacting calving mechanisms, to which the climatic response of calving glaciers is sensitive.

Thesis (M.Eng.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 204-212.

Thesis (M.S.) -- Brigham Young University. Dept. of Electrical and Computer Engineering, 2002. / Includes bibliographical references (p. 99-103).

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2011. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-03-12T12:42:52Z No. of bitstreams: 1 2011_lorena_collares.pdf: 4980623 bytes, checksum: fe164915b150fc2e5673516c2d5626b7 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-07-15T17:50:41Z (GMT) No. of bitstreams: 1 2011_lorena_collares.pdf: 4980623 bytes, checksum: fe164915b150fc2e5673516c2d5626b7 (MD5) / Made available in DSpace on 2013-07-15T17:50:41Z (GMT). No. of bitstreams: 1 2011_lorena_collares.pdf: 4980623 bytes, checksum: fe164915b150fc2e5673516c2d5626b7 (MD5) Previous issue date: 2011 / Os icebergs representam uma distinta feição no Oceano Austral. As correntes oceânicas, o gelo marinho, a batimetria e os ventos são responsáveis por determinar a trajetória destes grandes blocos de gelo. Desta forma, informações sobre a distribuição e a concentração dos icebergs podem auxiliar no melhor entendimento da circulação oceânica e atmosférica nas regiões polares. Diferentes métodos de observação de icebergs têm sido utilizados ao longo do tempo para o entendimento desta componente da criosfera. Duas metodologias despontam para tal objetivo, plataformas de coleta de dados (PCDs) rastreadas via sistema satelital ARGOS e as imagens de radar. A fim de monitorar o deslocamento de icebergs, no noroeste do Mar de Weddell, foram utilizados dados de posição de PCDs fixadas em três icebergs (em 19 de fevereiro de 2009) nas proximidades da ilha James Ross. Imagens Advanced Synthetic Aperture Radar (ASAR) foram utilizadas como medida complementar no rastreamento de icebergs durante os anos de 2008 e 2009. A partir dos resultados foi possível associar a deriva dos icebergs monitorados aos principais sistemas de correntes e frentes desta região, como a Corrente Costeira Antártica, a Frente de Talude Antártico e a Frente de Weddell. Mais especificamente, pode-se observar aspectos da circulação regional, tal como a identificação de uma célula de circulação anticiclônica no entorno da ilha James Ross e a deriva de icebergs em direção ao Estreito de Bransfield. Um estudo de caso demonstrou a recirculação de um iceberg no interior do Estreito de Bransfield e sua desintegração associada. A estimativa média da taxa de desintegração dos icebergs monitorados foi de 19%, associadas com um fluxo de volume de água doce para o oceano de aproximadamente 0.57 m3 s-1 e 0.94 m3s-1, respectivamente durante o período de observações nos anos de 2008 e 2009. A velocidade média de deriva calculada através do monitoramento via PCDs e imagens ASAR foi de 3.04 ±1.9 cm s-1 e 5.97 ± 2.8cm s-1, respectivamente. / Icebergs represent a distinctive feature of the Southern Ocean. Ocean currents, sea ice, bathymetry and winds determine the icebergs trajectory and its drift. Thus, information about icebergs distribution and concentration help to better understand the ocean and atmospheric circulation in Polar Regions. Several methods to observe icebergs have been used to comprehend the behavior and the role of this component of the cryosphere. Two methodologies are emerging for this purpose recently, such as icebergs tagging (for satellite tracking) and orbital radar images. In order to monitor the displacement of icebergs in the northwestern Weddell Sea, we used data from three icebergs tagged with Data Collection Platforms - DCPs (19/02/2009) in the vicinity of the James Ross Island. Additionally, ASAR images were used as a complementary measure to track the icebergs during the years 2008 and 2009 in the same area. Observing the results, it was possible to associate the icebergs drift with the main currents and fronts systems found in this region, as the Antarctic Coastal Current, Antarctic Slope Front and Weddell Front. More specifically, one can observe the regional circulation, such as the identification of an anticyclonic circulation cell around the James Ross Island and icebergs drifting into the Bransfield Strait. A case study demonstrated the recirculation of iceberg within the Bransfield Strait and its corresponding loss of mass. The icebergs disintegration estimated was 19%, associated with a freshwater volume flow toward the ocean of approximately 0,57 m3 s-1 and 0,94 m3 s-1 , respectively during the observation period, for the years 2008 and 2009. The drift rates determined by monitoring icebergs via DCPs and ASAR images were, respectively, 3,04 ±1,9 cm s-1 and 5,97 ± 2,8cm s-1.