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Airborne Radar And Ice Core Observations Of Snow Accumulation In West Antarctica
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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 Airborne Radar Studies by : Rory Retzlaff
Download or read book Airborne Radar Studies written by Rory Retzlaff and published by . This book was released on 1991 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigating the Interior of West Antarctica with Light, Radar, and Electrical Conductance by : Tyler Jeffrey Fudge
Download or read book Investigating the Interior of West Antarctica with Light, Radar, and Electrical Conductance written by Tyler Jeffrey Fudge and published by . This book was released on 2013 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ice sheets play an important role in both the modern climate and in past variations of Earth's history. Our understanding of ice sheets has been limited by few observations until recent advances in technology, notably airplanes and satellites, which have allowed increasingly more detailed investigations. Here I focus on using the internal structure of ice sheets to place modern observations in context. This is done with a variety of tools. First, I investigated the ability of borehole camera measurements to recover information about the physical properties of firn. I found that a measurement with a single wavelength of light was not capable of differentiating between brightness variations due to changes in grain size and changes in density. An additional measurement in the near infrared, which is sensitive to grain size variations, was identified as a way to differentiate density variations from grain size variations. I also use the internal structure of the ice sheet imaged using ice penetrating radar to examine the past flow structure of a major outlet glacier of West Antarctica. The flow directions were found to have not changed significantly in the past few hundred years and the analysis also revealed that the satellite-derived velocities had uncertainties larger than reported. The internal structure of an ice sheet can also be investigated by drilling an ice core. By obtaining samples of ancient ice, many detailed measurements are possible to look at past variations in climate and ice sheet behavior. I measured the electrical properties of the WAIS Divide ice core and was able to identify an annual signal to a depth of 2800. I then developed the first annually resolved timescale from the Southern Hemisphere that spanned into the last glacial period, 30 ka. The annual timescale allowed identification of accumulation-rate changes not resolvable in other Antarctic ice cores. The timescale and accumulation-rate history were combined with the water stable isotopes, sea-salt sodium, and climate modeling to show that the onset of deglacial warming in West Antarctica occurred before a trigger from the Northern Hemisphere with a likely cause increasing local insolation. The annual timescale was also used to assess the timescales from other coastal Antarctic ice cores. The timescales of these 3 cores were based on linear interpolation, which causes significant problems: large age uncertainty between tie points, large changes in the duration of climate events at the tie points, and a consistent bias to older ages. Two inverse techniques were developed to improve timescale interpolation.
Book Synopsis Remote Sensing of Precipitation by : Silas Michaelides
Download or read book Remote Sensing of Precipitation written by Silas Michaelides and published by MDPI. This book was released on 2019-07-23 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precipitation is a well-recognized pillar in global water and energy balances. An accurate and timely understanding of its characteristics at the global, regional, and local scales is indispensable for a clearer understanding of the mechanisms underlying the Earth’s atmosphere–ocean complex system. Precipitation is one of the elements that is documented to be greatly affected by climate change. In its various forms, precipitation comprises a primary source of freshwater, which is vital for the sustainability of almost all human activities. Its socio-economic significance is fundamental in managing this natural resource effectively, in applications ranging from irrigation to industrial and household usage. Remote sensing of precipitation is pursued through a broad spectrum of continuously enriched and upgraded instrumentation, embracing sensors which can be ground-based (e.g., weather radars), satellite-borne (e.g., passive or active space-borne sensors), underwater (e.g., hydrophones), aerial, or ship-borne.
Author :Intergovernmental Panel on Climate Change (IPCC) Publisher :Cambridge University Press ISBN 13 :1009175351 Total Pages :2410 pages Book Rating :4.0/5 (91 download)
Book Synopsis Climate Change 2021 – The Physical Science Basis by : Intergovernmental Panel on Climate Change (IPCC)
Download or read book Climate Change 2021 – The Physical Science Basis written by Intergovernmental Panel on Climate Change (IPCC) and published by Cambridge University Press. This book was released on 2023-07-26 with total page 2410 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Working Group I contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) provides a comprehensive assessment of the physical science basis of climate change. It considers in situ and remote observations; paleoclimate information; understanding of climate drivers and physical, chemical, and biological processes and feedbacks; global and regional climate modelling; advances in methods of analyses; and insights from climate services. It assesses the current state of the climate; human influence on climate in all regions; future climate change including sea level rise; global warming effects including extremes; climate information for risk assessment and regional adaptation; limiting climate change by reaching net zero carbon dioxide emissions and reducing other greenhouse gas emissions; and benefits for air quality. The report serves policymakers, decision makers, stakeholders, and all interested parties with the latest policy-relevant information on climate change. Available as Open Access on Cambridge Core.
Book Synopsis Polar Environments and Global Change by : Roger G. Barry
Download or read book Polar Environments and Global Change written by Roger G. Barry and published by Cambridge University Press. This book was released on 2018-08-09 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surveys atmospheric, oceanic and cryospheric processes, present and past conditions, and changes in polar environments.
Book Synopsis Sea Ice Analysis and Forecasting by : Tom Carrieres
Download or read book Sea Ice Analysis and Forecasting written by Tom Carrieres and published by Cambridge University Press. This book was released on 2017-10-05 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the science involved in automated prediction of sea ice, for sea ice analysts, researchers, and professionals.
Book Synopsis First Annual West Antarctic Ice Sheet (WAIS) Science Workshop by : Robert A. Bindschadler
Download or read book First Annual West Antarctic Ice Sheet (WAIS) Science Workshop written by Robert A. Bindschadler and published by . This book was released on 1993 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: History, current behavior, internal dynamics, and environmental interactions concerning future behavior and potential for rapid collapse of the West Antarctic Ice Sheet (WAIS).
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:
Book Synopsis Radar Studies on Ice Stream C, West Antarctica by : Benjamin E. Smith
Download or read book Radar Studies on Ice Stream C, West Antarctica written by Benjamin E. Smith and published by . This book was released on 1999 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Exploration of Subsurface Antarctica by : M.J. Siegert
Download or read book Exploration of Subsurface Antarctica written by M.J. Siegert and published by Geological Society of London. This book was released on 2018-01-08 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our appreciation of glaciological processes in Antarctica suffers from a lack of observations in regions where numerical models indicate the ice sheet to be susceptible to ocean and/or atmospheric warming. The solution lies in the use and development of glacier geophysics. In this volume we present a series of papers that demonstrate how geophysics can be deployed in Antarctica to comprehend: (1) boundary conditions that influence ice flow such as subglacial topography, the distribution of basal water and ice-sheet rheology; (2) phenomena that might affect ice-flow processes, such as complex internal ice-sheet structures and the proposition of large stores of hitherto unappreciated groundwater; and (3) how glacigenic sediments and formerly glaciated terrain on, and surrounding, the continent can inform us about past ice-sheet dynamics. The volume also takes a historical view on developments leading to current knowledge, examines active ice-sheet processes, and points the way forward on how geophysics can advance quantitative understanding of Antarctic ice-sheet behaviour.
Author :National Academies of Sciences, Engineering, and Medicine Publisher :National Academies Press ISBN 13 :0309456002 Total Pages :83 pages Book Rating :4.3/5 (94 download)
Book Synopsis Antarctic Sea Ice Variability in the Southern Ocean-Climate System by : National Academies of Sciences, Engineering, and Medicine
Download or read book Antarctic Sea Ice Variability in the Southern Ocean-Climate System written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2017-04-24 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sea ice surrounding Antarctica has increased in extent and concentration from the late 1970s, when satellite-based measurements began, until 2015. Although this increasing trend is modest, it is surprising given the overall warming of the global climate and the region. Indeed, climate models, which incorporate our best understanding of the processes affecting the region, generally simulate a decrease in sea ice. Moreover, sea ice in the Arctic has exhibited pronounced declines over the same period, consistent with global climate model simulations. For these reasons, the behavior of Antarctic sea ice has presented a conundrum for global climate change science. The National Academies of Sciences, Engineering, and Medicine held a workshop in January 2016, to bring together scientists with different sets of expertise and perspectives to further explore potential mechanisms driving the evolution of recent Antarctic sea ice variability and to discuss ways to advance understanding of Antarctic sea ice and its relationship to the broader ocean-climate system. This publication summarizes the presentations and discussions from the workshop.
Book Synopsis Deep Core Studies of the Accumulation and Densification of Snow at Byrd Station and Little America V, Antarctica by : Anthony J. Gow
Download or read book Deep Core Studies of the Accumulation and Densification of Snow at Byrd Station and Little America V, Antarctica written by Anthony J. Gow and published by . This book was released on 1968 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Snow and ice cores from two deep drill holes in Antarctica were studied to determine past records of snow accumulation and density variations with depth in the Antarctic ice sheet. Data on the variation of porosity and ice load with depth were also obtained. Byrd Station, located on the inland ice of West Antarctica, was the site of the first drill hole, which reached a depth of 309 m in ice estimated to be about 2500 m thick. Detailed analysis of the core stratigraphy to 88.6 m depth showed that the snow has been accumulating at an average rate of 15.6 g cm sq cm. annually since 1549 AD. (Author).
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 Antarctic Journal of the United States by :
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:
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 Melt Water Retention Processes in Snow and Firn on Ice Sheets and Glaciers: Observations and Modeling by : W. Tad Pfeffer
Download or read book Melt Water Retention Processes in Snow and Firn on Ice Sheets and Glaciers: Observations and Modeling written by W. Tad Pfeffer and published by Frontiers Media SA. This book was released on 2018-11-08 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Melt takes place where the surface of glaciers or ice sheets interacts with the atmosphere. While the processes governing surface melt are fairly well understood, the pathways of the meltwater, from its origin to the moment it leaves a glacier system, remain enigmatic. It is not even guaranteed that meltwater leaves a glacier or ice sheet. On Greenland, for example, only slightly more than 50% of the meltwater runs off. The remainder mostly refreezes within the so-called firn cover of the ice sheet. This eBook contains 11 studies which tackle the challenge of understanding meltwater retention in snow and firn from various angles. The studies focus both on mountain glaciers and on the Greenland ice sheet and address challenges such as measuring firn properties, quantifying their influence on meltwater retention, modelling firn processes and meltwater refreezing as well as unravelling the mechanisms within the recently discovered Greenland firn aquifers.
