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Author : Sasha Peter Carter
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (276 download)
Download or read book Evolving Subglacial Water Systems in East Antarctica from Airborne Radar Sounding written by Sasha Peter Carter and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Dustin Matthew Schroeder
Publisher :
ISBN 13 :
Total Pages : 208 pages
Book Rating : 4.:/5 (888 download)
Download or read book Characterizing the Subglacial Hydrology of Thwaites Glacier, West Antarctica Using Airborne Radar Sounding written by Dustin Matthew Schroeder and published by . This book was released on 2014 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrologic, lithologic, and geothermal basal boundary conditions can exert strong, even dominating, control on the evolution, stability, and sea level contribution of ice sheets and glaciers. However, the scales at which the physical processes and observable signatures of this control occur are typically smaller than the spatial resolutions currently achievable using ice penetrating radar. Further, the strength of radar bed echo returns is affected by the material and geometric properties of the bed as well as englacial attenuation from unknown ice temperature and chemistry, making assessment of basal conditions from echo strengths difficult. To address these challenges in interpreting basal properties at glaciologically relevant scales, a new algorithmic approach is applied to measuring the radar scattering function of the bed in terms of the relative contribution of angularly narrow specular energy and isotropically scattered diffuse energy. This relative specularity content is insensitive to englacial attenuation and can be used to constrain the geometry of the bed down to the centimeter scale. This approach is applied to an airborne radar sounding survey of Thwaites Glacier, West Antarctica using the information in the along-track scattering function to assess the extent and geometry of water across the catchment and detect the transition of that water from distributed canals to concentrated channels. This information is also used to constrain the morphology of subglacial bedforms and infer that the distribution of deformable sediments and exposed bedrock is similar to deglaciated paleo ice streams that experienced meltwater intensive retreats. Finally, models of radar echo strength and subglacial water routing are compared to estimate a catchment-wide distribution of geothermal flux consistent with rift-associated magma migration and volcanism. These observations of basal conditions provide new context for the past, current, and future evolution of Thwaites Glacier, the West Antarctic Ice Sheet, and their contribution to global sea level.
Author : National Research Council
Publisher : National Academies Press
ISBN 13 : 0309179246
Total Pages : 162 pages
Book Rating : 4.3/5 (91 download)
Download or read book Exploration of Antarctic Subglacial Aquatic Environments written by National Research Council and published by National Academies Press. This book was released on 2007-07-09 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antarctica is renowned for its extreme cold; yet surprisingly, radar measurements have revealed a vast network of lakes, rivers, and streams several kilometers beneath the Antarctic ice sheet. Sealed from Earth's atmosphere for millions of years, they may provide vital information about microbial evolution, the past climate of the Antarctic, and the formation of ice sheets, among other things. The next stage of exploration requires direct sampling of these aquatic systems. However, if sampling is not done cautiously, the environmental integrity and scientific value of these environments could be compromised. At the request of the National Science Foundation, this National Research Council assesses what is needed to responsibly explore subglacial lakes. Exploration of Antarctic Subglacial Aquatic Environments concludes that it is time for research on subglacial lakes to begin, and this research should be guided by internationally agreed upon protocols. The book suggests an initial protocol, which includes full characterization of the lakes by remote sensing, and minimum standards for biological and other types of contamination.
Author : T. SHEPHERD
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (77 download)
Download or read book Subglacial geology in Coats Land, East Antarctica, revealed by airborne magnetics and radar sounding written by T. SHEPHERD and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Martin J. Siegert
Publisher : American Geophysical Union
ISBN 13 : 9780875904825
Total Pages : 0 pages
Book Rating : 4.9/5 (48 download)
Download or read book Antarctic Subglacial Aquatic Environments written by Martin J. Siegert and published by American Geophysical Union. This book was released on 2011-01-10 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 : Martin J. Siegert
Publisher : John Wiley & Sons
ISBN 13 : 1118671481
Total Pages : 642 pages
Book Rating : 4.1/5 (186 download)
Download or read book Antarctic Subglacial Aquatic Environments written by Martin J. Siegert and published by John Wiley & Sons. This book was released on 2013-05-02 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 13 : 1108427340
Total Pages : 537 pages
Book Rating : 4.1/5 (84 download)
Download or read book Principles of Glacier Mechanics written by Roger LeB. Hooke and published by Cambridge University Press. This book was released on 2019-12-05 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: The principles of glacier physics are developed from basic laws in this up-to-date third edition for advanced students and researchers.
Author : Jamin Stevens Greenbaum
Publisher :
ISBN 13 :
Total Pages : 236 pages
Book Rating : 4.:/5 (13 download)
Download or read book Geophysical Investigations of the Coastal Evolution of the Totten Glacier System, East Antarctica written by Jamin Stevens Greenbaum and published by . This book was released on 2015 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sabrina Coast is the primary outlet of ice from the Aurora Subglacial Basin, draining more than 3.5 meters of eustatic sea level potential into the Indo-Pacific sector of the Southern Ocean. Recent work has shown that the Aurora Subglacial Basin has drained and filled many times since large scale glaciation began including evidence that it collapsed during the Pliocene. Ice predominantly flows from the interior to the coast through two outlet glaciers, Totten Glacier and the unnamed glacier feeding the Moscow University Ice Shelf. Steady thinning rates near the grounding line of Totten Glacier are the largest in East Antarctica and the nature of the thinning suggests that it is driven by enhanced basal melting due to ocean processes while thinning rates are modest for the glacier feeding the Moscow University Ice Shelf. Warm modified Circumpolar Deep Water (mCDW), which has been linked to glacier retreat in West Antarctica, has been observed in summer and winter on the Sabrina Coast continental shelf in the 300-600 m depth range. Here we show that entrances to the cavity deeper than this range of thermocline depths indicate that the TGIS is vulnerable to intrusions of mCDW. We relate areas of elevated basal specularity and reflectivity (flatness and brightness of the ice-ocean interface, respectively), supported by independent model predictions and ice flow divergence estimates of basal melt, to ice draft and ice thinning rates, demonstrating that the current climatological regime is enhancing melting of ice deeper than 800 mbsl in the cavity, possibly resulting in a bifurcated coastal ice thinning signal. For the first time in East Antarctica, and the first time using ice sounding radar, we identify large basal channels and flat terraces several kilometers wide and several hundred meters deep produced by complex ice-ocean melt processes in the deep, warm cavity waters. Finally, by analyzing new physical oceanographic data recently acquired along the Sabrina Coast, we show that the depths of deep, warm mCDW observed on the continental shelf relative to the coastal bathymetry control the coastal thinning of ice between the Moscow University Ice Shelf and Totten Glacier; moderate shoaling the average depth of the thermocline would allow the observed mCDW to breach this topography and enhance coastal melting. The lack of dense, cool Shelf Water at depth on the continental shelf indicates that that variability in heat content along the Sabrina Coast is driven by far-field oceanic boundary conditions, not to polynya activity as has been proposed. Predicting future change in this important area of the coastline requires improved knowledge of the sub-ice shelf boundary conditions and processes, and controls on continental shelf circulation and heat transfer.
Author : Matthew Ross Siegfried
Publisher :
ISBN 13 :
Total Pages : 179 pages
Book Rating : 4.:/5 (926 download)
Download or read book Investigating Antarctic Ice Sheet Subglacial Processes Beneath the Whillans Ice Plain, West Antarctica, Using Satellite Altimetry and GPS written by Matthew Ross Siegfried and published by . This book was released on 2015 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Antarctic ice sheet has an extensive basal water system that lubricates the ice-bed interface and enables the fast flow of ice streams and outlet glaciers, which account for a majority of Antarctic ice discharge to the ocean. In the past decade, observational evidence has suggested that the subglacial hydrology of Antarctica can be non-steady, changing on sub-decadal timescales, but the effect of dynamic hydrology on ice flow remains uncertain. The Whillans Ice Plain (WIP), at the confluence of the Whillans and Mercer ice streams, West Antarctica, has been studied for over 50 years and has been identified as a region with extensive active subglacial hydrology. In this dissertation, we develop and implement methods using a combination of ground-based Global Positioning System (GPS) data and satellite-based radar and laser altimetry to observe the surface expression of water movement beneath WIP, quantify the dynamic ice-flow response to an evolving basal water system, and investigate processes driven by the interaction of WIP with ocean tides that may impact subglacial water flow near the grounding line. We find that the coupled subglacial-ice stream system can respond rapidly to basal perturbations on sub-annual timescales and in ways that are not captured by simple models. We demonstrate that the location where subglacial water enters the ocean is a complex interface that requires significant improvement to our measurement precision to better understand important time-varying processes. We also apply our method for observing dynamic ice-surface height changes to the inventory of known subglacial lakes in Antarctica to extend our observational record and assess variability of the subglacial hydrologic system in different physical settings. Through this continent-wide analysis of subglacial lakes, we suggest that our current knowledge of the characteristic spatial and temporal scales of hydrologic variability is still limited by our observational capacity. We conclude by proposing future studies that would address knowledge gaps currently preventing the inclusion of an evolving basal water system into large-scale predictive models of ice-sheet flow.
Author : V.V. Bogorodsky
Publisher : Springer Science & Business Media
ISBN 13 : 9400952759
Total Pages : 265 pages
Book Rating : 4.4/5 (9 download)
Download or read book Radioglaciology written by V.V. Bogorodsky and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antarctica, the sixth continent, was discovered more than 160 years ago. Since then this large, mysterious continent of ice and penguins has attracted world interest. Scientific expeditions from various countries have begun to study the geographical and natural conditions of the icy continent. Systematic and comprehensive inves tigations in the Antarctic started in the middle of our century. In 1956 the First Soviet Antarctic Expedition headed to the coast of Antarctica. Their program included studies of the atmosphere, hydrosphere and cryosphere. Thirty years have since passed. Scientists have unveiled many secrets of Antarctica: significant geophysical processes have been investigated, and a large body of new information on the Antarctic weather, Southern Ocean hydrology and Antarctic glaciers has been obtained. We can now claim that the horizons of polar geo physics, oceanology, and particularly glaciology, have expanded. Scientific inves tigators have obtained new information about all Antarctic regions and thus have created the opportunity to use the Antarctic in the interests of mankind.
Author :
Publisher : American Geophysical Union
ISBN 13 :
Total Pages : 297 pages
Book Rating : 4./5 ( download)
Download or read book The West Antarctic Ice Sheet written by and published by American Geophysical Union. This book was released on 1998 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : J.L. Smellie
Publisher : Geological Society of London
ISBN 13 : 178620536X
Total Pages : 802 pages
Book Rating : 4.7/5 (862 download)
Download or read book Volcanism in Antarctica: 200 Million Years of Subduction, Rifting and Continental Break-up written by J.L. Smellie and published by Geological Society of London. This book was released on 2021-06-09 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: This memoir is the first to review all of Antarctica’s volcanism between 200 million years ago and the Present. The region is still volcanically active. The volume is an amalgamation of in-depth syntheses, which are presented within distinctly different tectonic settings. Each is described in terms of (1) the volcanology and eruptive palaeoenvironments; (2) petrology and origin of magma; and (3) active volcanism, including tephrochronology. Important volcanic episodes include: astonishingly voluminous mafic and felsic volcanic deposits associated with the Jurassic break-up of Gondwana; the construction and progressive demise of a major Jurassic to Present continental arc, including back-arc alkaline basalts and volcanism in a young ensialic marginal basin; Miocene to Pleistocene mafic volcanism associated with post-subduction slab-window formation; numerous Neogene alkaline volcanoes, including the massive Erebus volcano and its persistent phonolitic lava lake, that are widely distributed within and adjacent to one of the world’s major zones of lithospheric extension (the West Antarctic Rift System); and very young ultrapotassic volcanism erupted subglacially and forming a world-wide type example (Gaussberg).
Author : Fabio Florindo
Publisher : Elsevier
ISBN 13 : 0080931618
Total Pages : 606 pages
Book Rating : 4.0/5 (89 download)
Download or read book Antarctic Climate Evolution written by Fabio Florindo and published by Elsevier. This book was released on 2008-10-10 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 :
Publisher :
ISBN 13 :
Total Pages : 422 pages
Book Rating : 4.:/5 (319 download)
Download or read book Antarctic Journal of the United States written by and published by . This book was released on 1991 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Emanuele Bozzo
Publisher : Terra Antartica Publication
ISBN 13 :
Total Pages : 126 pages
Book Rating : 4.0/5 ( download)
Download or read book The Italian-British Antarctic Geophysical and Geological Survey in Northern Victoria Land, 2005-06 written by Emanuele Bozzo and published by Terra Antartica Publication. This book was released on 2007 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Igor A. Zotikov
Publisher : Springer Science & Business Media
ISBN 13 : 3540377239
Total Pages : 150 pages
Book Rating : 4.5/5 (43 download)
Download or read book The Antarctic Subglacial Lake Vostok written by Igor A. Zotikov and published by Springer Science & Business Media. This book was released on 2006-08-31 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book on the subject, this monograph examines the phenomenon of a huge sealed, freshwater lake, isolated from the rest of the world by kilometers' thick ice. The existence of melting ice at the bottom of the huge Vostok Lake has served as a model and inspired the team planning the Galileo space craft to gather data on the ice sheet of the Jupiterian moon Europa. The book provides interpretation of, and calculations for, stimulating factors for possible melting and a huge lake's existence at the bottom of the Martian ice sheets.
Author : Guy Kouemou
Publisher : BoD – Books on Demand
ISBN 13 : 9533070293
Total Pages : 432 pages
Book Rating : 4.5/5 (33 download)
Download or read book Radar Technology written by Guy Kouemou and published by BoD – Books on Demand. This book was released on 2010-01-01 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book “Radar Technology”, the chapters are divided into four main topic areas: Topic area 1: “Radar Systems” consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: “Radar Applications” shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: “Radar Functional Chain and Signal Processing” describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: “Radar Subsystems and Components” consists of design technology of radar subsystem components like antenna design or waveform design.
