[PDF] Past To Future And Land To Sea Constraining Global Glacier Models By Observations And Exploring Ice Ocean Interactions eBook

Author : Jan-Hendrik Malles
Publisher :
Page : 0 pages
File Size : 35,7 MB
Release : 2023
Category :
ISBN :

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Glacier mass loss is an iconic process induced by anthropogenic climate change. It threatens human livelihood at coasts affected by the rising sea level and in glacierized hydrological basins where the glacial runoff is essential for water availability. Moreover, as glacier mass loss adds large amounts of freshwater to the oceans, it might alter ocean circulation in a way that affects marine ecosystems and the climate system. Only recently, satellite-data processing revealed mass changes on an individual glacier level (outside the large ice sheets), but only for the last two decades. Glacier mass change observations become increasingly sparse going back in time. Therefore, the glaciers' past contribution to global mean sea level rise can only be reconstructed using numerical models. Since glacier mass change will continue during this century, it is vital to understand how this will affect global mean sea level, ocean circulation, and regional hydrology. Again, this is only possible using numerical models. Hence, it is essential to improve these models by incorporating previously neglected processes of glacier mass change into them, mainly in the form of parametrizations, and by constraining them using observations. Moreover, it is crucial to understand the uncertainties of results produced by numerical models, as they can never fully represent the natural world, which also hinges on the amount and quality of observational data. This work will tackle aspects of three issues in numerically modeling glacier mass changes: past glacier mass change reconstructions' uncertainties, future mass change projections' uncertainties, specifically regarding marine-terminating glaciers, and ice-ocean interactions in the northern hemisphere outside the Greenland ice sheet. All three issues are relevant in addressing the question of how glaciers respond to changes in their mass balance due to climatic changes and what consequences such changes have for the Earth system and, ultimately, human livelihood. It is found that the further outside the glaciological and meteorological observations' spatial and temporal domain a numerical model is applied, the more uncertain reconstructed glacier mass changes become. Similarly, one primary source of uncertainty in future glacier mass change projections is the difference in climate models' outputs of near-surface temperatures and precipitation. More accurately describing marine-terminating glacier dynamics and considering volume changes below sea level reduces estimates of future glacier contribution to global mean sea level rise systematically. However, significant uncertainties due to uncertainty about appropriate values for parameters involved in modeling (marine-terminating) glaciers' dynamics are detected. Concerning ice-ocean interactions, it was found that including the freshwater input from glacier mass loss in the northern hemisphere (outside the Greenland ice sheet) in an ocean general circulation model significantly impacts the simulated high-latitude ocean circulation. Finally, a first estimate of the ice mass glaciers lose due to melting directly into the ocean was produced.

Author : Intergovernmental Panel on Climate Change (IPCC)
Publisher : Cambridge University Press
Page : 755 pages
File Size : 10,67 MB
Release : 2022-04-30
Category : Science
ISBN : 9781009157971

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The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.

Author : Jonathan L. Bamber
Publisher : Cambridge University Press
Page : 672 pages
File Size : 29,48 MB
Release : 2004-02-12
Category : Science
ISBN : 9780521808958

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A detailed and comprehensive overview of observational and modelling techniques for all climate change, environmental science and glaciology researchers.

Author : Robert M. Sanchez
Publisher :
Page : 0 pages
File Size : 22,70 MB
Release : 2023
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Mass loss of the Greenland Ice Sheet is expected to accelerate in the 21st century in response to both a warming atmosphere and ocean, with consequences for sea level rise, polar ecosystems and potentially the global overturning circulation. Glacial fjords connect Greenland's marine-terminating glaciers with the continental shelf, and fjord circulation plays a critical role in modulating the import of heat from the ocean and the export of freshwater from the ice sheet. Understanding fjord dynamics is crucial to predicting the cryosphere and ocean response to a changing climate. However, representing glacial fjord dynamics in climate models is an ongoing challenge because fjord circulation is complex and sensitive to glacial forcing that is poorly understood. Additionally, there are limited observations available for constraining models and theory. This dissertation aims to improve our understanding of fjord dynamics, focusing on key aspects (heat variability, freshwater residence time, and fjord exchange) which need to be included in glacial fjord parameterizations. We use three approaches combining novel observations, idealized, modeling and numerical simulations to investigate the dynamics of fjord circulation at different spatial scales. First, we investigate the heat content variability in the fjord using acoustic travel time (Chapter 2). We demonstrate that acoustic travel time can be used to model fjord stratification during winter months and monitor heat content variability at synoptic and seasonal timescales. Secondly, we use a combination of in situ observations and an idealized box model to evaluate freshwater residence time in a west Greenland Fjord (Chapter 3). We find that meltwater from the ice sheet is mixed downward across multiple layers near the glacier terminus resulting in freshwater storage and a delay in freshwater export from the fjord. Finally we analyze a multi-year realistically forced numerical simulation of Sermilik Fjord in southeast Greenland and identify the impact of shelf and glacial forcing on fjord exchange (Chapter 4). We show that the glacial-driven circulation is more efficient at renewing the fjord and that the sign of the exchange flow is related to the along-shelf wind stress. This dissertation strengthens our understanding of the fundamental connections between oceans and glaciers, and will lead to improved representation of ice-ocean interactions in climate models.

Author : Fabio Florindo
Publisher : Elsevier
Page : 606 pages
File Size : 22,92 MB
Release : 2008-10-10
Category : Science
ISBN : 0080931618

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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 : Richard I. Waller
Publisher : John Wiley & Sons
Page : 325 pages
File Size : 29,58 MB
Release : 2024-07-01
Category : Science
ISBN : 1118620984

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Glacier-Permafrost Interactions A systematic exploration of the interactions between glaciers and permafrost In Glacier-Permafrost Interactions, experienced glaciologist Richard I. Waller delivers a comprehensive discussion of the interactions between glaciers and permafrost. The book is highly relevant to contemporary debates regarding ongoing recession of glaciers and the degradation of permafrost in the face of global warming. By integrating modern-era observations with findings from Quaternary science, this book demonstrates how glaciers and permafrost can interact and behave as an integrated system. This summary of the current thinking and emerging research on glacier-permafrost interaction also provides: Comprehensive discussions of permafrost in modern and ancient glacial environments A focused review of the distinctive characteristics of glaciers found in permafrost environments An integrated overview of the nature and impacts of glacier-permafrost interactions on the hydrology and dynamic behaviour of glaciers and their landscape expression A survey of current research efforts and future directions in the field Lying at the boundary between a research monograph and an advanced textbook, Glacier-Permafrost Interactions contributes to the future development of this rapidly evolving field by incorporating new approaches and ideas while still offering a summary of the current state of knowledge. It is perfect for advanced undergraduate students, postgraduate students, researchers, and professionals with an interest in polar and alpine environments.

Author : Vivien Gornitz
Publisher : Columbia University Press
Page : 364 pages
File Size : 37,92 MB
Release : 2019-06-11
Category : Science
ISBN : 0231548893

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The Arctic is thawing. In summer, cruise ships sail through the once ice-clogged Northwest Passage, lakes form on top of the Greenland Ice Sheet, and polar bears swim farther and farther in search of waning ice floes. At the opposite end of the world, floating Antarctic ice shelves are shrinking. Mountain glaciers are in retreat worldwide, unleashing flash floods and avalanches. We are on thin ice—and with melting permafrost’s potential to let loose still more greenhouse gases, these changes may be just the beginning. Vanishing Ice is a powerful depiction of the dramatic transformation of the cryosphere—the world of ice and snow—and its consequences for the human world. Delving into the major components of the cryosphere, including ice sheets, valley glaciers, permafrost, and floating ice, Vivien Gornitz gives an up-to-date explanation of key current trends in the decline of ice mass. Drawing on a long-term perspective gained by examining changes in the cryosphere and corresponding variations in sea level over millions of years, she demonstrates the link between thawing ice and sea-level rise to point to the social and economic challenges on the horizon. Gornitz highlights the widespread repercussions of ice loss, which will affect countless people far removed from frozen regions, to explain why the big meltdown matters to us all. Written for all readers and students interested in the science of our changing climate, Vanishing Ice is an accessible and lucid warning of the coming thaw.

Author : Jeffrey S. Kargel
Publisher : Springer
Page : 936 pages
File Size : 35,58 MB
Release : 2014-07-08
Category : Technology & Engineering
ISBN : 3540798188

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An international team of over 150 experts provide up-to-date satellite imaging and quantitative analysis of the state and dynamics of the glaciers around the world, and they provide an in-depth review of analysis methodologies. Includes an e-published supplement. Global Land Ice Measurements from Space - Satellite Multispectral Imaging of Glaciers (GLIMS book for short) is the leading state-of-the-art technical and interpretive presentation of satellite image data and analysis of the changing state of the world's glaciers. The book is the most definitive, comprehensive product of a global glacier remote sensing consortium, Global Land Ice Measurements from Space (GLIMS, http://www.glims.org). With 33 chapters and a companion e-supplement, the world's foremost experts in satellite image analysis of glaciers analyze the current state and recent and possible future changes of glaciers across the globe and interpret these findings for policy planners. Climate change is with us for some time to come, and its impacts are being felt by the world's population. The GLIMS Book, to be released about the same time as the IPCC's 5th Assessment report on global climate warming, buttresses and adds rich details and authority to the global change community's understanding of climate change impacts on the cryosphere. This will be a definitive and technically complete reference for experts and students examining the responses of glaciers to climate change. World experts demonstrate that glaciers are changing in response to the ongoing climatic upheaval in addition to other factors that pertain to the circumstances of individual glaciers. The global mosaic of glacier changes is documented by quantitative analyses and are placed into a perspective of causative factors. Starting with a Foreword, Preface, and Introduction, the GLIMS book gives the rationale for and history of glacier monitoring and satellite data analysis. It includes a comprehensive set of six "how-to" methodology chapters, twenty-five chapters detailing regional glacier state and dynamical changes, and an in-depth summary and interpretation chapter placing the observed glacier changes into a global context of the coupled atmosphere-land-ocean system. An accompanying e-supplement will include oversize imagery and other other highly visual renderings of scientific data.

Author : Twila Moon
Publisher :
Page : 116 pages
File Size : 36,69 MB
Release : 2014
Category : Ice sheets
ISBN :

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Outlet glacier ice dynamics, including ice-flow speed, play a key role in determining Greenland Ice Sheet mass loss, which is a significant contributor to global sea-level rise. Mass loss from the Greenland Ice Sheet increased significantly over the last several decades and current mass losses of 260-380 Gt ice/yr contribute 0.7-1.1 mm/yr to global sea-level rise (~10%). Understanding the potentially complex interactions among glacier, ocean, and climate, however, remains a challenge and limits certainty in modeling and predicting future ice sheet behavior and associated risks to society. This thesis focuses on understanding the seasonal to interannual scale changes in outlet glacier velocity across the Greenland Ice Sheet and how velocity fluctuations are connected to other elements of the ice sheet-ocean-atmosphere system. 1) Interannual velocity patterns Earlier observations on several of Greenland's outlet glaciers, starting near the turn of the 21st century, indicated rapid (annual-scale) and large (>100%) increases in glacier velocity. Combining data from several satellites, we produce a decade-long (2000 to 2010) record documenting the ongoing velocity evolution of nearly all (200+) of Greenland's major outlet glaciers, revealing complex spatial and temporal patterns. Changes on fast-flow marine-terminating glaciers contrast with steady velocities on ice-shelf-terminating glaciers and slow speeds on land-terminating glaciers. Regionally, glaciers in the northwest accelerated steadily, with more variability in the southeast and relatively steady flow elsewhere. Intraregional variability shows a complex response to regional and local forcing. Observed acceleration indicates that sea level rise from Greenland may fall well below earlier proposed upper bounds. 2) Seasonal velocity patterns. Greenland mass loss includes runoff of surface melt and ice discharge via marine-terminating outlet glaciers, the latter now making up a third to a half of total ice loss. The magnitude of ice discharge depends in part on ice-flow speed, which has broadly increased since 2000 but varies locally, regionally, and from year-to-year. Research on a few Greenland glaciers also shows that speed varies seasonally. However, for many regions of the ice sheet, including wide swaths of the west, northwest, and southeast coasts where ice loss is increasing most rapidly, there are few or no records of seasonal velocity variation. We present 5-year records of seasonal velocity measurements for 55 glaciers distributed around the ice sheet margin. We find 3 distinct seasonal velocity patterns. The different patterns indicate varying glacier sensitivity to ice-front (terminus) position and likely regional differences in basal hydrology in which some subglacial systems do transition seasonally from inefficient, distributed hydrologic networks to efficient, channelized drainage, while others do not. Our findings highlight the need for modeling and observation of diverse glacier systems in order to understand the full spectrum of ice-sheet dynamics. 3) Seasonal to interannual glacier and sea ice behavior and interaction Focusing on 16 northwestern Greenland glaciers during 2009-2012, we examine terminus position, sea ice and ice m??lange conditions, seasonal velocity changes, topography, and climate, with extended 1999-2012 records for 4 glaciers. There is a strong correlation between near-terminus sea ice/mélange conditions and terminus position. In several cases, late-forming and inconsistent sea ice/mélange may induce sustained retreat. For all of the 13-year records and most of the 4-year records, sustained, multi-year retreat is accompanied by velocity increase. Seasonal speedup, which is observed across the region, may, however, be more heavily influenced by melt interacting with the subglacial hydrologic system than seasonal terminus variation. Projections of continued warming and longer ice-free periods around Greenland suggest that notable retreat over wide areas may continue. Sustained retreat is likely to be associated with multi-year speedup, though both processes are modulated by local topography. The timing of seasonal ice dynamics patterns may also shift.

Author : R. C. L. Wilson
Publisher : Psychology Press
Page : 290 pages
File Size : 47,9 MB
Release : 2000
Category : Nature
ISBN : 9780415198417

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The Great Ice Age documents and explains the natural climatic and palaeoecologic changes that have occurred during the past 2.6 million years, outlining the emergence and global impact of our species during this period. Exploring a wide range of records of climate change, the authors demonstrate the interconnectivity of the components of the Earths climate system, show how the evidence for such change is obtained, and explain some of the problems in collecting and dating proxy climate data. One of the most dramatic aspects of humanity's rise is that it coincided with the beginnings of major environmental changes and a mass extinction that has the pace, and maybe magnitude, of those in the far-off past that stemmed from climate, geological and occasionally extraterrestrial events. This book reveals that anthropogenic effects on the world are not merely modern matters but date back perhaps a million years or more.