Download or read book Seasonal and Interannual Variations of Ice Sheet Surface Elevation at the Summit of Greenland written by H. Jay Zwally and published by BiblioGov. This book was released on 2013-08 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observed seasonal and interannual variations in the surface elevation over the summit of the Greenland ice sheet are modeled using a new temperature-dependent formulation of firn-densification and observed accumulation variations. The observed elevation variations are derived from ERS (European Remote Sensing)-1 and ERS-2 radar altimeter data for the period between April 1992 and April 1999. A multivariate linear/sine function is fitted to an elevation time series constructed from elevation differences measured by radar altimetry at orbital crossovers. The amplitude of the seasonal elevation cycle is 0.25 m peak-to-peak, with a maximum in winter and a minimum in summer. Inter-annually, the elevation decreases to a minimum in 1995, followed by an increase to 1999, with an overall average increase of 4.2 cm a(exp -1) for 1992 to 1999. Our densification formulation uses an initial field-density profile, the AWS (automatic weather station) surface temperature record, and a temperature-dependent constitutive relation for the densification that is based on laboratory measurements of crystal growth rates. The rate constant and the activation energy commonly used in the Arrhenius-type constitutive relation for firn densification are also temperature dependent, giving a stronger temperature and seasonal amplitudes about 10 times greater than previous densification formulations. Summer temperatures are most important, because of the strong non-linear dependence on temperature. Much of firn densification and consequent surface lowering occurs within about three months of the summer season, followed by a surface build-up from snow accumulation until spring. Modeled interannual changes of the surface elevation, using the AWS measurements of surface temperature and accumulation and results of atmospheric modeling of precipitation variations, are in good agreement with the altimeter observations.

Download or read book Seasonal and Interannual Changes in Surface Elevation of the Greenland Ice Sheet from Satellite Radar Altimetry written by Diana M. Segura and published by . This book was released on 1998 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Glaciers and Ice Sheets in the Climate System written by Andrew Fowler and published by Springer Nature. This book was released on 2020-10-28 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our realisation of how profoundly glaciers and ice sheets respond to climate change and impact sea level and the environment has propelled their study to the forefront of Earth system science. Aspects of this multidisciplinary endeavour now constitute major areas of research. This book is named after the international summer school held annually in the beautiful alpine village of Karthaus, Northern Italy, and consists of twenty chapters based on lectures from the school. They cover theory, methods, and observations, and introduce readers to essential glaciological topics such as ice-flow dynamics, polar meteorology, mass balance, ice-core analysis, paleoclimatology, remote sensing and geophysical methods, glacial isostatic adjustment, modern and past glacial fluctuations, and ice sheet reconstruction. The chapters were written by thirty-four contributing authors who are leading international authorities in their fields. The book can be used as a graduate-level textbook for a university course, and as a valuable reference guide for practising glaciologists and climate scientists.

Download or read book Glaciers and Glaciation 2nd edition written by Douglas Benn and published by Routledge. This book was released on 2014-02-04 with total page 817 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glaciers and Glaciation is the classic textbook for all students of glaciation. Stimulating and accessible, it has established a reputation as a comprehensive and essential resource. In this new edition, the text, references and illustrations have been thoroughly updated to give today's reader an up-to-the minute overview of the nature, origin and behaviour of glaciers and the geological and geomorphological evidence for their past history on earth. The first part of the book investigates the processes involved in forming glacier ice, the nature of glacier-climate relationships, the mechanisms of glacier flow and the interactions of glaciers with other natural systems such as rivers, lakes and oceans. In the second part, the emphasis moves to landforms and sediment, the interpretation of the earth's glacial legacy and the reconstruction of glacial depositional environments and palaeoglaciology.

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.

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.

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.

Download or read book Global Land Ice Measurements from Space written by Jeffrey S. Kargel and published by Springer. This book was released on 2014-07-08 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Multi Year Elevation Changes Near the West Margin of the Greenland Ice Sheet from Satellite Radar Altimetry written by Craig S. Lingle and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mean changes in the surface elevation near the west margin of the Greenland ice sheet are measured using Seasat altimetry and altimetry from the Geosat Exact Repeat Mission (ERM). The Seasat data extend from early July through early October 1978. The ERM data extend from winter 1986-87 through fall 1988. Both seasonal and multi-year changes are measured using altimetry referenced to GEM T2 orbits. The possible effects of orbit error are minimized by adjusting the orbits into a common ocean surface. Seasonal mean changes in the surface height are recognizable during the Geosat ERM. The multi-year measurements indicate the surface was lower by 0.4 +/- 0.4 m on average in late summer 1987 than in late summer 1978. The surface was lower by 0.2 +/- 0.5 m on average in late summer 1988 than in late summer 1978. As a control case, the computations are also carried out using altimetry referenced to orbits not adjusted into a common ocean surface.

Download or read book Understanding Ice sheet Dynamics Using Geophysical Observations and Numerical Ice flow Models written by Laura Kehrl and published by . This book was released on 2018 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass loss from the world’s ice sheets is one of the largest sources of uncertainty in sea-level rise projections for the 21st century. One way to improve sea-level rise projections is to better understand the processes driving past ice-sheet mass loss. This dissertation investigates past changes in ice flow for two regions: (1) Helheim and Kangerlussuaq Glaciers, two fast-flowing tidewater glaciers in Southeast Greenland, and (2) the Allan Hills Blue Ice Area, a slow-flowing blue ice area in East Antarctica. For both regions, I constrain changes in ice-sheet dynamics using geophysical observations and interpret those changes using numerical ice-flow models. At Helheim and Kangerlussuaq, I examine seasonal and interannual variations in surface velocity, elevation, and terminus position from 2001 to 2016. I show that glacier dynamics depend on the extent of floating ice near the terminus. Helheim’s grounded terminus calved small, nontabular icebergs, while Kangerlussuaq’s floating ice tongue calved large, tabular icebergs. Furthermore, terminus-driven, seasonal speedups and dynamic thinning were generally larger at Helheim than at Kangerlussuaq, likely due to its grounded rather than floating ice tongue. To interpret the observed changes at Helheim and Kangerlussuaq, I use inverse methods to investigate changes in basal conditions under the two glaciers. The basal shear stress under Helheim and Kangerlussuaq decreased or remained relatively constant during terminus-driven speedup events, suggesting that changes in the stress balance were generally supported outside of the region of fast flow. Finally, I use the inferred basal shear stresses to help constrain the form of the basal sliding law. At the Allan Hills Blue Ice Area, I combine ice-penetrating radar data, an ice-flow model, and age constraints to determine a potential site to drill a million-year-old ice core. I also show that thickness anomalies in the englacial stratigraphy suggest that glacier velocity was 30% of present-day values during the last glaciation. While the dynamics of the Allan Hills Blue Ice Area are likely unimportant for sea-level rise projections, an ice core from the region could provide insight into the past stability of the Ross Sea Sector and West Antarctic Ice Sheet.

Download or read book Mountain Geography written by Martin F. Price and published by Univ of California Press. This book was released on 2013-08-24 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mountains cover a quarter of the Earth’s land surface and a quarter of the global population lives in or adjacent to these areas. The global importance of mountains is recognized particularly because they provide critical resources, such as water, food and wood; contain high levels of biological and cultural diversity; and are often places for tourism and recreation and/or of sacred significance. This major revision of Larry Price’s book Mountains and Man (1981) is both timely and highly appropriate. The past three decades have been a period of remarkable progress in our understanding of mountains from an academic point of view. Of even greater importance is that society at large now realizes that mountains and the people who reside in them are not isolated from the mainstream of world affairs, but are vital if we are to achieve an environmentally sustainable future. Mountain Geography is a comprehensive resource that gives readers an in-depth understanding of the geographical processes occurring in the world’s mountains and the overall impact of these regions on culture and society as a whole. The volume begins with an introduction to how mountains are defined, followed by a comprehensive treatment of their physical geography: origins, climatology, snow and ice, landforms and geomorphic processes, soils, vegetation, and wildlife. The concluding chapters provide an introduction to the human geography of mountains: attitudes toward mountains, people living in mountain regions and their livelihoods and interactions within dynamic environments, the diverse types of mountain agriculture, and the challenges of sustainable mountain development.

Download or read book Ice Sheets and Climate written by Johannes Oerlemans and published by Springer. This book was released on 1984-02-29 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discusses the specific role ice sheets play in the climate system, at a level suitable for post-graduate courses. Includes mathematical models.

Download or read book Greenland Outlet Glacier Behavior During the 21st Century written by Twila Moon and published by . This book was released on 2014 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Ice Sheet Response to Climate Changes written by Ayako Abe-Ouchi and published by . This book was released on 1993 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessing Climate Change written by Donald Rapp and published by Springer Science & Business Media. This book was released on 2008-02-12 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book Donald Rapp provides a balanced assessment of global warming, tending neither to the views of alarmists or nay-sayers. Rapp has the ability to move into a highly technical field, assimilate the content, organize the knowledge base and succinctly describe the field, its content, its unresolved issues and achievements. This is precisely what he does in this book in relation to global climate change. As such his approach is refreshingly different.

Download or read book Seasonal and Interannual Variability in the Hydrology and Geochemistry of an Outlet Glacier of the Greenland Ice Sheet written by Benjamin Shawn Linhoff and published by . This book was released on 2016 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Berichte zur Polar und Meeresforschung written by and published by . This book was released on 2007 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: