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Characterizing The Subglacial Hydrology Of Thwaites Glacier West Antarctica Using Airborne Radar Sounding
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Book Synopsis Characterizing the Subglacial Hydrology of Thwaites Glacier, West Antarctica Using Airborne Radar Sounding by : Dustin Matthew Schroeder
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.
Book Synopsis Evolving Subglacial Water Systems in East Antarctica from Airborne Radar Sounding by : Sasha Peter Carter
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 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Airborne-radar and Ice-core Observations of Snow Accumulation in West Antarctica by : Brooke Medley
Download or read book Airborne-radar and Ice-core Observations of Snow Accumulation in West Antarctica written by Brooke Medley and published by . This book was released on 2013 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world's ice sheets store enough water to raise global eustatic sea level by several tens of meters, and therefore, any fluctuations in their size will cause sea level to rise or fall. The net mass exchanged with the ocean - defined as the mass balance - determines the glacial contribution to sea level and is the difference in snow accumulated in the interior and ice discharged into the ocean at the ice sheet periphery. While new techniques in remotely acquired surface velocities lead to improved discharge measurements, snow accumulation remains unmeasured over much of the of the ice sheet. This work aims to improve our understanding of snow accumulation over two of the most rapidly evolving glaciers in Antarctica: Pine Island and Thwaites. Specifically, we use two airborne radar systems to image and track the near-surface internal stratigraphy to measure snow accumulation rates over both glaciers. This method allows for investigation of the spatial and temporal variations in accumulation at the catchment-scale, which is essential for determining glacier mass balance. Examination of the radar-derived accumulation rates over Pine Island and Thwaites glaciers revealed several results including: (1) accumulation exhibited no significant trend between 1980 and 2009, (2) the sea-level contribution from Pine Island and Thwaites tripled from +0.09 mm yr[superscript-1] in the mid-1990s to +0.27 mm yr[superscript -1] by 2010, (3) a shift towards higher accumulation occurred between 1944-1984 and 1985-2009, observed in both ice core and radar records, and (4) atmospheric models are an adequate replacement for accumulation measurements in areas with few observations. These findings indicate that accumulation is not concurrently compensating the enhanced ice discharge from the region, and as a result, the sea-level contribution from these glaciers is increasing. Furthermore, a recent shift towards higher mean accumulation suggests these glaciers might have been out of balance earlier than originally thought.
Book Synopsis Handbook of Mathematical Geosciences by : B.S. Daya Sagar
Download or read book Handbook of Mathematical Geosciences written by B.S. Daya Sagar and published by Springer. This book was released on 2018-06-25 with total page 911 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Open Access handbook published at the IAMG's 50th anniversary, presents a compilation of invited path-breaking research contributions by award-winning geoscientists who have been instrumental in shaping the IAMG. It contains 45 chapters that are categorized broadly into five parts (i) theory, (ii) general applications, (iii) exploration and resource estimation, (iv) reviews, and (v) reminiscences covering related topics like mathematical geosciences, mathematical morphology, geostatistics, fractals and multifractals, spatial statistics, multipoint geostatistics, compositional data analysis, informatics, geocomputation, numerical methods, and chaos theory in the geosciences.
Book Synopsis The internal layering of Pine Island Glacier, West Antarctica, from airborne radar-sounding data by : N.B. KARLSSON
Download or read book The internal layering of Pine Island Glacier, West Antarctica, from airborne radar-sounding data written by N.B. KARLSSON and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling the Subglacial Environment with Geostatistics by : Emma Johanne MacKie
Download or read book Modeling the Subglacial Environment with Geostatistics written by Emma Johanne MacKie and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The conditions beneath glaciers and ice-sheets including the topography, hydrology, and geology are essential for understanding ice dynamics, interpreting ice-sheet history, and predicting ice-sheet retreat and sea-level-rise in response to a changing climate. Located in remote regions and overlain by several kilometers of ice, subglacial conditions are difficult to characterize at ice-sheet scales. In this thesis, I explore the use geostatistical simulation and machine learning methods to characterize subglacial hydrologic and geologic conditions and produce the first ensemble realizations of stochastically simulated subglacial topography.In Chapter 2 of this thesis, I consider the physical and geological controls on the sizes and locations of Antarctic subglacial lakes. Subglacial lakes play an important role in ice-sheet dynamics, biology, and geology. Hundreds of these lakes have been observed with ice-penetrating radar or inferred through changes in ice-surface elevation detected by satellite altimetry. However, the difference between radar and altimetry detected lakes is not fully understood, and the sizes, quantity, and locations of subglacial lakes across the continent remains unknown. In this study, I investigate statistical relationships between known subglacial lake locations and physical parameters such as heat flux and ice velocity in order to predict lake locations across the continent. I performed geostatistical simulations of Antarctic topography so that the predicted lakes would have realistic surface areas. My results provide estimates of the number and sizes of Antarctic subglacial lakes and expose major physical differences between radar and altimetry detected lakes.In Chapter 3 of this thesis, I investigate uncertainty in subglacial water routing at Jakobshavn Glacier in Greenland. Water routing is important for understanding ice-sheet dynamics. However, water routing models rely on uncertain and unrealistically smooth bed topography. I conduct geostatistical simulations of subglacial topography and apply a water routing model to each of these realizations. The results demonstrate that subglacial water pathways are highly sensitive to uncertainties in subglacial topography. This shows that geostatistical simulation is a powerful tool for quantifying uncertainty in subglacial drainage and could be used to add context to geophysical observations or investigate hydrologic controls on ice-sheet movement.In Chapter 4 of this thesis, I provide subglacial geological estimates for the Amundsen Sea Embayment in West Antarctica. The Amundsen Sea Embayment, and Thwaites Glacier in particular, are undergoing rapid ice loss that threatens the stability of the West Antarctic Ice Sheet. One of the primary sources of uncertainty in ice-sheet models for this region is the subglacial geology. However, observations of subglacial geology are extremely sparse due to the severely limited spatial extent of seismic surveys. In this chapter, I use a training image-based geostatistical simulation technique to stochastically simulate subglacial topography such that the simulated morphology is allowed to vary locally based on nearby data. I use the simulated topography to predict the geology by training on seafloor topography data. These results provide the first catchment-scale estimates of sediment and bedrock locations and offer vital information for ice-sheet models.
Book Synopsis Volcanism in Antarctica: 200 Million Years of Subduction, Rifting and Continental Break-up by : J.L. Smellie
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).
Book Synopsis Radar Investigations of the Ross Ice Shelf, Antarctica by : Kenneth Charles Jezek
Download or read book Radar Investigations of the Ross Ice Shelf, Antarctica written by Kenneth Charles Jezek and published by . This book was released on 1980 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Principles of Glacier Mechanics by : Roger LeB. Hooke
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.
Book Synopsis Spatial and Temporal Distributions of Accumulation Rates on the Catchment of Thwaites Glacier, West Antarctica by : Erick Leuro
Download or read book Spatial and Temporal Distributions of Accumulation Rates on the Catchment of Thwaites Glacier, West Antarctica written by Erick Leuro and published by . This book was released on 2014 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: We make a first-order calculation of accumulation rates in the catchment of Thwaites Glacier (TG), West Antarctica using the Nye and Daansgard-Johnson methodologies. Both formulations compute accumulations as a function of the age-depth relationship, including a thinning correction due to ice flow. For this purpose, I track and firn-correct two continuous, shallow ice layers obtained from radio echo soundings surveyed during the 2004-05 AGASEA expedition. The layers range from 60 to 700 meters depth between the ice divide and the coast. Dating of layers come from the ice core WDC06A, located on the West Antarctic Ice Sheet (WAIS) ice divide, which have ages 548 and 725 years, respectively. We compare our accumulation results with four independent datasets: 1)IceBridge snow radar (2009-2010), optimized for tracking near-surface layers; 2) a contemporary model of snowfall precipitation, 3) an interpolation of ice core data using satellite passive microwave; 4) ice cores data. We test the hypothesis that accumulation rates have increased since the beginning of the industrial era, a change that has not been observed. Indeed, I find that observations indicate that accumulation rates in the TG catchment have not changed during the past ~700 years. From here I assess the mass balance of the system and analyze what it tells about the history of the glacier.
Download or read book Impact Cratering written by G. R. Osinski and published by John Wiley & Sons. This book was released on 2012-12-26 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Impact cratering is arguably the most ubiquitous geological process in the Solar System. It has played an important role in Earth’s history, shaping the geological landscape, affecting the evolution of life, and generating economic resources. However, it was only in the latter half of the 20th century that the importance of impact cratering as a geological process was recognized and only during the past couple of decades that the study of meteorite impact structures has moved into the mainstream. This book seeks to fill a critical gap in the literature by providing an overview text covering broad aspects of the impact cratering process and aimed at graduate students, professionals and researchers alike. It introduces readers to the threat and nature of impactors, the impact cratering process, the products, and the effects – both destructive and beneficial. A series of chapters on the various techniques used to study impact craters provide a foundation for anyone studying impact craters for the first time.
Book Synopsis Polar Remote Sensing by : Robert Massom
Download or read book Polar Remote Sensing written by Robert Massom and published by Springer Science & Business Media. This book was released on 2006-08-31 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polar Remote Sensing is a two-volume work providing a comprehensive, multidisciplinary discussion of the applications of satellite sensing. Volume 2 focuses on the ice sheets, icebergs, and interactions between ice sheets and the atmosphere and ocean. It contains information about the applications of satellite remote sensing in all relevant polar related disciplines, including glaciology, meteorology, climate and radiation balance and oceanogaraphy. It also provides a brief review of the state-of-the-art of each discipline, including current issues and questions. Various passive and active remote sensor types are discussed, and the book then concentrates on specific geophysical applications. Its interdisciplinary approach means that major advances and publications are highlighted. Polar Remote Sensing: Ice Sheets summarizes fundamental principles of detectors, imaging and geophysical product retrieval includes a chapter on the important new field of satellite synthetic-aperture radar interferometry is a "one stop shop" for polar remote sensing information contains significant new information on the Earth's polar regions describes sophisticated groundbased remote sensing applications with specific reference to their use in polar regions.
Author :National Academies of Sciences, Engineering, and Medicine Publisher :National Academies Press ISBN 13 :0309492432 Total Pages :29 pages Book Rating :4.3/5 (94 download)
Book Synopsis Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space by : National Academies of Sciences, Engineering, and Medicine
Download or read book Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-06-18 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: We live on a dynamic Earth shaped by both natural processes and the impacts of humans on their environment. It is in our collective interest to observe and understand our planet, and to predict future behavior to the extent possible, in order to effectively manage resources, successfully respond to threats from natural and human-induced environmental change, and capitalize on the opportunities â€" social, economic, security, and more â€" that such knowledge can bring. By continuously monitoring and exploring Earth, developing a deep understanding of its evolving behavior, and characterizing the processes that shape and reshape the environment in which we live, we not only advance knowledge and basic discovery about our planet, but we further develop the foundation upon which benefits to society are built. Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space (National Academies Press, 2018) provides detailed guidance on how relevant federal agencies can ensure that the United States receives the maximum benefit from its investments in Earth observations from space, while operating within realistic cost constraints. This short booklet, designed to be accessible to the general public, provides a summary of the key ideas and recommendations from the full decadal survey report.
Book Synopsis Investigating Antarctic Ice Sheet Subglacial Processes Beneath the Whillans Ice Plain, West Antarctica, Using Satellite Altimetry and GPS by : Matthew Ross Siegfried
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.
Book Synopsis Antarctic Subglacial Aquatic Environments by : Martin J. Siegert
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.
Book Synopsis Psychrophiles: From Biodiversity to Biotechnology by : Rosa Margesin
Download or read book Psychrophiles: From Biodiversity to Biotechnology written by Rosa Margesin and published by Springer. This book was released on 2017-06-22 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cold adaptation includes a complex range of structural and functional adaptations at the level of all cellular constituents, and these adaptations render cold-adapted organisms particularly useful for biotechnological applications. This book presents the most recent knowledge of (i) boundary conditions for microbial life in the cold, (ii) microbial diversity in various cold ecosystems, (iii) molecular cold adaptation mechanisms and (iv) the resulting biotechnological perspectives.
Book Synopsis Quantifying Uncertainty in Subsurface Systems by : Céline Scheidt
Download or read book Quantifying Uncertainty in Subsurface Systems written by Céline Scheidt and published by John Wiley & Sons. This book was released on 2018-06-19 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under the Earth's surface is a rich array of geological resources, many with potential use to humankind. However, extracting and harnessing them comes with enormous uncertainties, high costs, and considerable risks. The valuation of subsurface resources involves assessing discordant factors to produce a decision model that is functional and sustainable. This volume provides real-world examples relating to oilfields, geothermal systems, contaminated sites, and aquifer recharge. Volume highlights include: A multi-disciplinary treatment of uncertainty quantification Case studies with actual data that will appeal to methodology developers A Bayesian evidential learning framework that reduces computation and modeling time Quantifying Uncertainty in Subsurface Systems is a multidisciplinary volume that brings together five major fields: information science, decision science, geosciences, data science and computer science. It will appeal to both students and practitioners, and be a valuable resource for geoscientists, engineers and applied mathematicians. Read the Editors' Vox: eos.org/editors-vox/quantifying-uncertainty-about-earths-resources
