Download or read book A Preliminary Study of the Drainage Systems of the Grounded Ice Sheet in Antarctica with Particular Reference to the Ice Regimen written by Mario Bartolomé Giovinetto and published by . This book was released on 1966 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Bibliography of Master s Theses in Geography American and Canadian Universities written by Merrill M. Stuart and published by Tualatin, Or. : Geographic and Area Study Publications. This book was released on 1973 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Study of Grounded Ice Accumulations written by J. Wong and published by . This book was released on 1985 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of the West Antarctic Ice Sheet written by C.J. van der Veen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Few scientists doubt the prediction that the antropogenic release of carbon dioxide in the atmosphere will lead to some warming of the earth's climate. So there is good reason to investigate the possible effects of such a warming, in dependence of geographical and social economic setting. Many bodies, governmental or not, have organized meetings and issued reports in which the carbon dioxide problem is defined, reviewed, and possible threats assessed. The rate at which such reports are produced still increases. However, while more and more people are getting involved in the 'carbon dioxide business', the number of investigators working on the basic problems grows, in our view, too slowly. Many fundamental questions are still not answered in a satisfactory way, and the carbon dioxide building rests on a few thin pillars. One such fundamental question concerns the change in sea level associated with a climatic warming of a few degrees. A number of processes can be listed that could all lead to changes of the order of tens of centimeters (e. g. thermal expansion, change in mass balance of glaciers and ice sheets). But the picture of the carbon dioxide problem has frequently be made more dramatic by suggesting that the West Antarctic Ice Sheet is unstable, implying a certain probability of a 5 m higher sea-level stand within a few centuries.
Download or read book CRREL Technical Publications 1950 1975 written by Cold Regions Research and Engineering Laboratory (U.S.) and published by . This book was released on 1992 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Journal of Glaciology written by and published by . This book was released on 1957 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glacial and Paleoclimatic History of the Ross Ice Drainage System of Antarctica written by and published by . This book was released on 2000 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evidence bearing on the former existence of grounded ice sheets in the Ross Sea Antarctica written by T.B. KELLOGG and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glacial and Paleoclimatic History of the Ross Ice Drainage System of Antarctica written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glacial and Paleoclimatic History of the Ross Ice Drainage System of Antarctica written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding Antarctic Ice stream Flow Using Ice flow Models and Geophysical Observations written by David A. Lilien and published by . This book was released on 2019 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ice streams are the primary pathway by which Antarctic ice is evacuated to the ocean. Because the Antarctic ice sheets lose mass primarily through oceanic melt and calving, ice-stream dynamics exert a primary control on the mass balance of the ice sheets. Thus, changes in melt rates at the ice-sheet margins, or in accumulation in the ice-sheet interiors, affect ice-sheet mass balance on timescales modulated by the response time of the ice streams. Even abrupt changes in melt at the margins can cause ice-stream speedup and resultant thinning lasting millennia, so understanding the upstream propagation of marginally forced changes across timescales is key for understanding the ice sheets’ ongoing contribution to sea-level rise. This dissertation is comprised of three studies that use observations and models to understand changes to Antarctic ice-stream dynamics on timescales from decades to millennia. The first chapter synthesizes remotely sensed observations of Smith, Pope, and Kohler glaciers in West Antarctica to investigate the causes and extent of their retreat. These glaciers have displayed some of the largest measured grounding-line retreat, most rapid thinning, and largest speedup amongst Antarctic ice streams. This retreat has drawn interest in their stability both in its own right and as a harbinger of future changes to larger neighboring ice streams. In this study, recent melt rates were determined using flux divergence estimates derived from observations of ice thickness and surface velocity. Out-of-balance melt at the beginning of the study period indicates that the imbalance of this system predates the beginning of satellite velocity observations in 1996. Throughout much of 1996-2010, there was both greater melt over the ice shelves than flux across the grounding line, implying loss of floating ice and elevated melt forcing, and greater grounding-line flux than accumulation, implying adjustment of the grounded ice in response to the ongoing imbalance. The grounding line position of Kohler glacier, and a large melt channel that is unlikely to be a steady-state feature, suggest that the perturbation to this system began on Kohler glacier sometime around the 1970s. Viscosity of the ice shelves, inferred using a numerical model, indicates that weakening of the Crosson ice shelf was necessary to allow the observed speedup, though it is unable to determine whether the weakening was a cause or effect of the ongoing retreat. The second chapter uses a suite of numerical model simulations to determine the dominant drivers of the recent retreat of Smith, Pope, and Kohler glaciers, and extends those simulations that best match observations to evaluate likely future retreat. Similar to the findings of previous studies, the distribution of sub-shelf melt is found to be the primary control on the rate of grounding-line retreat, while the shelf-averaged melt rate exerts a secondary control. The model simulations indicate that, despite ongoing imbalance, the grounding-line position in 1996 was not inherently unstable, but rather elevated melt at the grounding line was required to cause the observed retreat. A weakening of the ice-shelf margins was found to hasten the onset of grounding-line retreat and led to greater speedup. However, without increases in melt beyond 1996 levels, marginal weakening was insufficient to initiate grounding-line retreat. All simulations that capture the observed retreat continue to lose mass until at least 2100, suggesting that ice in this basin may contribute over 8 mm to global mean sea level by 2100. The magnitude of thinning deep in the catchment suggests that the retreat of Kohler and Smith glacier may hasten the destabilization of the neighboring Thwaites glacier catchment. The third chapter uses the timescale of the recently drilled South Pole Ice Core (SPICEcore) and nearby geophysical observations to infer the history of ice flow near the South Pole during the last 10,000 years. The South Pole is located 180 km from the nearest ice divide and drains from the East Antarctic plateau through Academy glacier/Foundation ice stream. As a result, ice flow near the South Pole is potentially affected by the dynamics of these ice streams, and so the history of ice flow in this region has the potential to inform understanding of how marginally forced changes affect the ice-sheet interior. Because the South Pole is far from an ice divide, the accumulation record in SPICEcore incorporates both spatial variations in accumulation upstream and temporal variations in regional accumulation. Comparison between the SPICEcore accumulation record, derived by correcting measured layer thicknesses for thinning, with an accumulation record derived from new GPS and radar measurements upstream, yields insight into past ice flow and accumulation. When ice speeds are modeled as increasing by 15% since 10 ka, the upstream accumulation explains 77% of the variance in the SPICEcore-derived accumulation (vs. 22% without speedup). This correlation is only expected if the ice-flow direction and spatial pattern of accumulation were stable throughout the Holocene. The 15% speedup in turn suggests a slight (3-4%) steepening or thickening of the ice-sheet interior and provides a new constraint on the evolution of the East Antarctic Ice Sheet following the glacial termination.
Download or read book Post LGM Grounding Line and Calving Front Translations of the West Antarctic Ice Sheet in the Whales Deep Paleo ice stream Trough Eastern Ross Sea Antarctica written by Austin James McGlannan and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glacial and Paleoclimatic History of the Ross Ice Drainage System of Antarctica written by and published by . This book was released on with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Stability of the Drygalski Ice Tongue written by Christine Indrigo and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Antarctica has the potential to contribute to sea-level rise by up to 58 m if it were to entirely melt. The Antarctic Ice Sheet is fringed by floating ice in the form of ice shelves and ice tongues, which help to buttress and slow the flow of grounded ice into the ocean. Monitoring the stability of these ice shelves and ice tongues is increasingly important in a warming world, as several areas of floating ice across Antarctica are already experiencing considerable mass loss and thinning due to warming air and ocean conditions. The primary goal of this thesis is to examine several factors contributing to the stability of the Drygalski Ice Tongue in East Antarctica using a combination of remote sensing imagery analysis and subglacial hydrology modelling. The Drygalski Ice Tongue is ~140 km long with an unconfined length of 90 km extending into the Ross Sea. This unconfined length influences local ocean conditions and has a significant control on the size of the nearby Terra Nova Bay polynya, keeping the area free of sea ice. The ice tongue has experienced three large scale calving events in its recorded history since the early 1900s. In this study, Landsat imagery from 1988 to 2018 is used to track the advance of the ice tongue, marginal fracture propagation, and to derive velocity using manual feature tracking. The Glacier Drainage Systems (GlaDS) model is applied to the David Glacier catchment, which feeds into the ice tongue, to reveal the locations and discharge from subglacial channels along the grounding line. These channels are compared with basal channels beneath the floating ice tongue that are identified using airborne radar-derived ice thickness and hydrostatically-derived ice thickness, which can reveal channels in basal draft beneath the ice tongue. The results of this study propose a cyclical relationship between the occurrence of large calving events and large marginal fracture formation, in which large calving events result in the formation of new large fractures where the ice tongue emerges from the coast. When these fractures advance to the ice front, they create an area of weakness where future large calving events can occur. The model output produces three subglacial channels at the grounding line, which align with three channels identified through ice thickness. The propagation of the marginal fractures into the width of the ice tongue is controlled by the presence of these basal channels, as fractures can propagate through the areas of thinner ice in the centre of the northmost channel and stops once they reach the channel keel where ice is thicker. These findings provide insight on the roles that subglacial hydrology, ice draft, and marginal rifting have on ice tongue stability for the Drygalski Ice Tongue and for other floating ice bodies.
Download or read book Glacial Sedimentary Processes and Products written by Michael J. Hambrey and published by Wiley-Blackwell. This book was released on 2007 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: ""The wide range of time periods, methods and concepts discussed should be of interest across many subject areas ... A wide mix of research published in this volume."" (Holocene, December 2008).
Download or read book Special Issue written by and published by . This book was released on 2000 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Antarctica s Geologic and Ice Sheet History from Isotopic Sedimentary Provenance Studies written by Elizabeth Lane Pierce and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the constraints of uncertainty in the nature of erosion and transport in the sub-glacial environment, the study of glacialy-derived material from marine sediments located off the margin of East Antarctica provides a means for characterizing the sub-glacial geology obscured by the more than 98% ice cover of the continent. These insights into the geology of East Antarctica in turn provide characterization of sedimentary source areas, the knowledge of which can be applied to sediment provenance studies of ice rafted detritus (IRD) and thus about East Antarctic ice sheet history. Much of what has been learned of East Antarctica's Cenozoic ice sheet evolution has been achieved through the study of marine sediments, as ice sheets tend to erode their own history and much of what is preserved is, like the geology, obscured the ice sheet. Determining the provenance of ice-rafted detritus allows for spatial and temporal reconstructions of ice sheet behavior. Accordingly sedimentary provenance studies are key to documenting how Antarctica's ice sheet evolved through the Cenozoic.
