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Author: Tarun Luthra Publisher: ISBN: Category : Languages : en Pages :
Book Description
An accurate knowledge of the subglacial system is key in elucidating the mechanisms of ice stream motion and overall mass balance of the Antarctic Ice Sheet. Ice streams, owing to their geometry and low surface slopes, generate really low driving stress, thus typically require an extensive deformable subglacial sediment layer to allow fast flow conditions. This thin layer of sediment is highly sensitive to subglacial water pressure, which, if reduced, can dramatically alter the flow dynamics of ice streams. The flow regime of Whillans Ice Stream and Kamb Ice Stream highlight these basal conditions. Kamb Ice Stream stagnated about 150 years ago while current observations of the Whillans Ice Stream show that the ice stream is decelerating in the past few decades. Both attribute their current flow conditions to the presence of areas of high basal drag or the so-called sticky spots, which inhibit fast ice stream flow. This subglacial interface is highly influenced by the sediment porosity, fluid pressure, and water content which ultimately defines its overall strength in restricting the ice-stream flow. In this thesis, I employ the seismic amplitude analysis technique to study the subglacial interface of these two ice streams. The seismic amplitude analysis provides an insight into the subglacial regimes of ice stream flow in Antarctica. The knowledge about this subglacial interface and ground truthing of bed conditions is essential for the ice sheet models and discerning ice dynamics to understand the future evolution of these ice streams.
Author: Tarun Luthra Publisher: ISBN: Category : Languages : en Pages :
Book Description
An accurate knowledge of the subglacial system is key in elucidating the mechanisms of ice stream motion and overall mass balance of the Antarctic Ice Sheet. Ice streams, owing to their geometry and low surface slopes, generate really low driving stress, thus typically require an extensive deformable subglacial sediment layer to allow fast flow conditions. This thin layer of sediment is highly sensitive to subglacial water pressure, which, if reduced, can dramatically alter the flow dynamics of ice streams. The flow regime of Whillans Ice Stream and Kamb Ice Stream highlight these basal conditions. Kamb Ice Stream stagnated about 150 years ago while current observations of the Whillans Ice Stream show that the ice stream is decelerating in the past few decades. Both attribute their current flow conditions to the presence of areas of high basal drag or the so-called sticky spots, which inhibit fast ice stream flow. This subglacial interface is highly influenced by the sediment porosity, fluid pressure, and water content which ultimately defines its overall strength in restricting the ice-stream flow. In this thesis, I employ the seismic amplitude analysis technique to study the subglacial interface of these two ice streams. The seismic amplitude analysis provides an insight into the subglacial regimes of ice stream flow in Antarctica. The knowledge about this subglacial interface and ground truthing of bed conditions is essential for the ice sheet models and discerning ice dynamics to understand the future evolution of these ice streams.
Author: Martin J. Siegert Publisher: John Wiley & Sons ISBN: 1118671481 Category : Science Languages : en Pages : 642
Book Description
Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 192. Antarctic Subglacial Aquatic Environments is the first volume on this important and fascinating subject. With its underlying theme of bridging existing knowledge to future research, it is a benchmark in the history of subglacial lake exploration and study, containing up-to-date discussions about the history and background of subglacial aquatic environments and future exploration. The main topics addressed are identification, location, physiography, and hydrology of 387 subglacial lakes; protocols for environmental stewardship and protection of subglacial lake environments; details of three programs aiming to explore Vostok Subglacial Lake, Ellsworth Subglacial Lake, and Whillans Subglacial Lake over the next 3–5 years; assessment of technological requirements for exploration programs based on best practices for environmental stewardship and scientific success; and knowledge of subglacial lakes as habitats for microbial life and as recorders of past climate and ice sheet change. Its uniqueness, breadth, and inclusiveness will appeal to microbiologists and those interested in life in extreme environments, paleoclimatologists and those interested in sedimentary records of past changes, glaciologists striving to understand how water beneath glaciers affects their flow, and those engaged in developing technology to undertake direct measurement and sampling of extreme environments on Earth and in the solar system.
Author: Roger LeB. Hooke Publisher: Cambridge University Press ISBN: 1108427340 Category : Business & Economics Languages : en Pages : 537
Book Description
The principles of glacier physics are developed from basic laws in this up-to-date third edition for advanced students and researchers.
Author: Alan K. Cooper Publisher: American Geophysical Union ISBN: 9780875908847 Category : Science Languages : en Pages : 220
Book Description
Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 71. The Antarctic Ice Sheet has greatly affected global climate, sea level, ocean circulation, and southern hemisphere biota during Cenozoic times. Much of our understanding of the evolution of the ice sheet has been inferred from isotopic studies on distant deep-ocean sediments, because few Cenozoic rocks are exposed on the Antarctic continent. Yet, large differences occur between past ice volumes inferred from isotopic studies and those inferred from low-latitude sea-level variation. The massive quantities of glacially transported terrigenous sediments that lie beneath the Antarctic continental margin provide an additional, more direct record of the inferred ice sheet fluctuations. Volume 68 addresses the history of ice sheet fluctuations as recorded by geological and geophysical investigations of selected areas of the Antarctic continental margin. As described below, the volume gives data and results from on-going research by a major multinational project directed toward better understanding the impact of Antarctic Ice Sheet fluctuations on global sea levels and climates.
Author: Alan K. Cooper Publisher: American Geophysical Union ISBN: 9780875908847 Category : Science Languages : en Pages : 330
Book Description
Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 71. The Antarctic Ice Sheet has greatly affected global climate, sea level, ocean circulation, and southern hemisphere biota during Cenozoic times. Much of our understanding of the evolution of the ice sheet has been inferred from isotopic studies on distant deep-ocean sediments, because few Cenozoic rocks are exposed on the Antarctic continent. Yet, large differences occur between past ice volumes inferred from isotopic studies and those inferred from low-latitude sea-level variation. The massive quantities of glacially transported terrigenous sediments that lie beneath the Antarctic continental margin provide an additional, more direct record of the inferred ice sheet fluctuations. Volume 68 addresses the history of ice sheet fluctuations as recorded by geological and geophysical investigations of selected areas of the Antarctic continental margin. As described below, the volume gives data and results from on-going research by a major multinational project directed toward better understanding the impact of Antarctic Ice Sheet fluctuations on global sea levels and climates.
Author: Fabio Florindo Publisher: Elsevier ISBN: 0080931618 Category : Science Languages : en Pages : 606
Book Description
Antarctic Climate Evolution is the first book dedicated to furthering knowledge on the evolution of the world's largest ice sheet over its ~34 million year history. This volume provides the latest information on subjects ranging from terrestrial and marine geology to sedimentology and glacier geophysics. - An overview of Antarctic climate change, analyzing historical, present-day and future developments - Contributions from leading experts and scholars from around the world - Informs and updates climate change scientists and experts in related areas of study
Author: J. A. Dowdeswell Publisher: Geological Society of London ISBN: 9781862391208 Category : Nature Languages : en Pages : 398
Book Description
This book examines the process and patterns of glacier-influenced sedimentation on high-latitude continental margins and the geophysical and geological signatures of the resulting sediments and landforms. It contains a range of papers concerning modern and glacially-influenced sedimentation in high-latitude areas from both hemispheres, many of which discuss the relationship between glacier dynamics and the sediments and landforms preserved in the glacimarine environment.
Author: Tarun Luthra
Author: Tarun Luthra
Author: Martin J. Siegert
Author: Roger LeB. Hooke
Author: Alan K. Cooper
Author: Michael Robert Alexander Thomson
Author: Alan K. Cooper
Author: 
Author: Fabio Florindo
Author: J. A. Dowdeswell
Author: Stephen Bannister