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Understanding Recent Mass Balance Changes Of The Greenland Ice Sheet
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Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721568406 Total Pages :24 pages Book Rating :4.5/5 (684 download)
Book Synopsis Understanding Recent Mass Balance Changes of the Greenland Ice Sheet by : National Aeronautics and Space Administration (NASA)
Download or read book Understanding Recent Mass Balance Changes of the Greenland Ice Sheet written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate goal of this project is to better understand the current transfer of mass between the Greenland Ice Sheet, the world's oceans and the atmosphere, and to identify processes controlling the rate of this transfer, to be able to predict with greater confidence future contributions to global sea level rise. During the first year of this project, we focused on establishing longer-term records of change of selected outlet glaciers, reevaluation of mass input to the ice sheet and analysis of climate records derived from ice cores, and modeling meltwater production and runoff from the margins of the ice sheet. vanderVeen, Cornelius Goddard Space Flight Center
Book Synopsis Mass Balance of the Cryosphere by : Jonathan L. Bamber
Download or read book Mass Balance of the Cryosphere written by Jonathan L. Bamber and published by Cambridge University Press. This book was released on 2004-02-12 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed and comprehensive overview of observational and modelling techniques for all climate change, environmental science and glaciology researchers.
Book Synopsis Greenland Ice-sheet Mass Balance and Sea-level Change by : N. Reeh
Download or read book Greenland Ice-sheet Mass Balance and Sea-level Change written by N. Reeh and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Mass Balance of the Greenland Ice Sheet by : J. Oerlemans
Download or read book The Mass Balance of the Greenland Ice Sheet written by J. Oerlemans and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Assessment of Glacier Mass Balances from Small Tropical Glaciers to the Ice Sheet of Greenland by : Todd Albert
Download or read book Assessment of Glacier Mass Balances from Small Tropical Glaciers to the Ice Sheet of Greenland written by Todd Albert and published by VDM Publishing. This book was released on 2008 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of climate change are most clearly reflected in the dynamic changes in Earth's ice cover. While the distribution of ice on Earth has fluctuated on all time scales, the recent, unprecedented warming of the last century is leading to an apparent collapse of much of the remaining glaciers and ice caps on the planet. What is the best way to study this ice cover? How can we best determine what changes are occurring and their causes? This book is addressed to researchers in the field of glaciers and climate that are interested in methods to study the ever-changing cryosphere. From the world's largest tropical ice cap to the Greenland Ice Sheet, this book takes you on a journey across the world and through several different methods of gleaming information from the ice. In the tropics, remote sensing classification techniques are applied to the Quelccaya Ice Cap to present a 40-year history of the retreat of glaciers there and some analysis of the linkages to climate. On the Greenland Ice Sheet, field measurements are employed to create an elevation profile of the mass balance components of the glacier. Finally, three mass balance models are investigated in their applicability to that profile with some surprising results.
Book Synopsis Glaciers and Ice Sheets in the Climate System by : Andrew Fowler
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.
Book Synopsis The Evolution of the Greenland Ice Sheet from the Last Glacial Maximum to Present-day: An Assessment Using Glaciological and Glacial Isostatic Adjustment Modelling by :
Download or read book The Evolution of the Greenland Ice Sheet from the Last Glacial Maximum to Present-day: An Assessment Using Glaciological and Glacial Isostatic Adjustment Modelling written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we constrain a three-dimensional thermomechanical model of Greenland ice sheet (GrIS) evolution from the Last Glacial Maximum (LGM, 21 ka BP) to the present-day using, primarily, observations of relative sea level (RSL) as well as field data on past ice extent. The new model (Huy2) fits a majority of the observations and is characterised by a number of key features: (i) the ice sheet had an excess volume (relative to present) of 4.1 m ice-equivalent sea level at the LGM, which increased to reach a maximum value of 4.6 m at 16.5 ka BP; (ii) retreat from the continental shelf was not continuous around the entire margin, as there was a Younger Dryas readvance in some areas. The final episode of marine retreat was rapid and relatively late (c. 12 ka BP), leaving the ice sheet land based by 10 ka BP; (iii) in response to the Holocene Thermal Maximum (HTM) the ice margin retreated behind its present-day position by up to 80 km in the southwest, 20 km in the south and 80 km in a small area of the northeast. As a result of this retreat the modelled ice sheet reaches a minimum extent between 5 and 4 ka BP, which corresponds to a deficit volume (relative to present) of 0.17 m ice-equivalent sea level. The results suggest that remaining discrepancies between the model and the observations are likely associated with non-Greenland ice load, differences between modelled and observed present-day ice elevation around the margin, lateral variations in Earth structure and/or the pattern of ice margin retreat. Predictions of present-day vertical land motion generated using the new Huy2 model are highly sensitive to variations of upper mantle viscosity. Depending on the Earth model adopted, different periods of post-LGM ice loading change dominate the present-day response in particular regions of Greenland. These results will be a useful resource when interpreting existing and future observations of vertical land motion in Greenland. In comparison to the sparse number of.
Book Synopsis Ice Sheets and Climate by : Johannes Oerlemans
Download or read book Ice Sheets and Climate written by Johannes Oerlemans and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate modelling is a field in rapid development, and the fltudy of cryospheric processes has become an important part of it. On smaller time scales, the effect of snow cover and sea ice on the atmospheric circulation is of concern for long-range weather forecasting. Thinking in decades or centuries, the effect of a C02 climatic warming on the present-day ice sheets, and the resulting changes in global sea level, has drawn a lot of attention. In particular, the dynamics of marine ice sheets (ice sheets on a bed that would be below sea level after removal of ice and full isostatic rebound) is a subject of continuous research. This interest stems from the fact that the West Antarctic Ice Sheet is a marine ice sheet which, according to some workers, may be close to a complete collapse. The Pleistocene ice ages, or glacial cycles, are best characterized by total ice volume on earth, indicating that on 4 5 large time scales (10 to 10 yr) ice sheets are a dominant component of the climate system. The enormous amount of paleoclimatic information obtained from deep-sea sediments in the last few decades has led to a complete revival of iriterest in the physical aspects of the Pleistocene climatic evolution.
Book Synopsis Glaciers and Environmental Change by : Atle Nesje
Download or read book Glaciers and Environmental Change written by Atle Nesje and published by Routledge. This book was released on 2016-04-29 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: This authoritative new text provides a thorough, updated account of glaciers and ice sheets as monitors and indicators of environmental change. It examines the record of environmental change within glaciers and ice sheets, and that of past environments left by retreating glaciers. These themes are examined within the context of environmental change in general and global climate change in particular. Methods of using palaeoenvironmental records are assessed and the implications for future environmental change are discussed. Evidence from glacier ice left in the landscape or within the geological record, provides one of the most important sources of information on environmental change. 'Glaciers and Environmental Change' is a comprehensive account of glaciers andice sheets as monitors and indictaors of environmental change. Based on the latest research, this book consolidates a diverse range of data and explains their applications. it also assesses methods of using palaeoenvironmental records. This authoritative new text examines not only the records of environmental change within glaciers but also that of past environments left by retreating glaciers. These themes are examined within the context of contemporary debates in environmental change and the volume also seeks to draw conclusions concernign past, present and future climatic change in relation to glaciers.
Book Synopsis Determining Greenland Ice Sheet Sensitivity to Regional Climate Change by : Nicole-Jeanne Schlegel
Download or read book Determining Greenland Ice Sheet Sensitivity to Regional Climate Change written by Nicole-Jeanne Schlegel and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Greenland Ice Sheet, which extends south of the Arctic Circle, is vulnerable to melt in a warming climate. Complete melt of the ice sheet would raise global sea level by about 7 meters. Prediction of how the ice sheet will react to climate change requires inputs with a high degree of spatial resolution and improved simulation of the ice-dynamical responses to evolving surface mass balance. No Greenland Ice Sheet model has yet met these requirements. A three-dimensional thermo-mechanical ice sheet model of Greenland was enhanced to address these challenges. First, it was modified to accept high-resolution surface mass balance forcings. Second, a parameterization for basal drainage (of the sort responsible for sustaining the Northeast Greenland Ice Stream) was incorporated into the model. The enhanced model was used to investigate the century to millennial-scale evolution of the Greenland Ice Sheet in response to persistent climate trends. During initial experiments, the mechanism of flow in the outlet glaciers was assumed to be independent of climate change, and the outlet glaciers' dominant behavior was to counteract changes in surface mass balance. Around much of the ice sheet, warming resulted in calving front retreat and reduction of total ice sheet discharge. Observations show, however, that the character of outlet glacier flow changes with the climate. The ice sheet model was further developed to simulate observed dynamical responses of Greenland's outlet glaciers. A phenomenological description of the relation between outlet glacier discharge and surface mass balance was calibrated against recent observations. This model was used to investigate the ice sheet's response to a hypothesized 21st century warming trend. Enhanced discharge accounted for a 60% increase in Greenland mass loss, resulting in a net sea level increment of 7.3 cm by year 2100. By this time, the average surface mass balance had become negative, and widespread marginal thinning had caused 30% of historically active calving fronts to retreat. Mass losses persisted throughout the century due to flow of dynamically responsive outlets capable of sustaining high calving rates. Thinning in these areas propagated upstream into higher elevation catchments. Large drainage basins with low-lying outlets, especially those along Greenland's west coast and those fed by the Northeast Greenland Ice Stream, were most susceptible to dynamic mass loss in the 21st century.
Book Synopsis Using Sea-Level Data to Constrain the Contribution of the Greenland Ice Sheet to Contemporary and Recent Sea-Level Change by : Leanne Mary Wake
Download or read book Using Sea-Level Data to Constrain the Contribution of the Greenland Ice Sheet to Contemporary and Recent Sea-Level Change written by Leanne Mary Wake and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the potentially wide-reaching impacts on climate and sea-level change of a declining Greenland Ice Sheet (GrIS), the mass balance of the past decade has caused concern that the ice sheet is reacting to increased temperatures of the industrial era and that the ice sheet is in the initial stages of deglaciation. Global mean sea-level has been rising at a rate of 1.8 +/- 0.5 mm/yr over the past 50 years (Bindoff et al. 2007), and this has accelerated to 3.1 +/-0.1mm/yr (Cazenave et al., 2008) over the past decade. This study shows that although the surface mass balance of the GrIS can react quickly to changes in temperature, overall the ice sheet is in near balance over the period 1866-2005. During 1866-2005, the contribution from the GrIS to eustatic sea-level change is not larger than the error attached to current estimates of global mean sea-level rise. A novel type of relative sea-level data gathered from salt marshes in the south west of Greenland cover the period from ~1200 to 1800AD and show that a major slowdown in local sea-level rise from ~3mm/yr to ~0mm/yr occurred around 1500-1600 AD, with no significant departure from a 0mm/yr trend thereafter. Large contributions to sea-level change from steric changes and cryospheric sources outside of Greenland are ruled out as major drivers of this deceleration in sea-level fall. Modelling results indicate that the slowdown in relative sea-level is most likely due to the combined contribution of dynamic-related ice loss from Jakobshavn Isbrae and a delayed earth response to mass loss during a period of elevated temperatures from ~1000-1500AD. When considering the saltmarsh sea-level data for the 20th century within the context of the complete time series, the magnitude of ice loss in west Greenland for the past decade does not appear to be anomalous. This analysis suggests that similar mass loss has been sustained for several centuries prior to 1500AD.
Book Synopsis Improving a Priori Regional Climate Model Estimates of Greenland Ice Sheet Surface Mass Loss Through Assimilation of Measured Ice Surface Temperatures by : Mahdi Navari
Download or read book Improving a Priori Regional Climate Model Estimates of Greenland Ice Sheet Surface Mass Loss Through Assimilation of Measured Ice Surface Temperatures written by Mahdi Navari and published by . This book was released on 2015 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Greenland ice sheet has been the focus of climate studies due to its considerable impact on sea level rise. Accurate estimates of surface mass balance components - including precipitation, runoff, and evaporation - over the Greenland ice sheet would contribute to understanding the cause of the ice sheet's recent changes (i.e., increase in melt amount and duration, thickening of ice sheet interior, thinning at the ice sheet margins) and help to forecast future changes. Deterministic approaches provide a general trend of the surface mass fluxes, but they cannot characterize the uncertainty of estimates. The data assimilation method developed in this dissertation aimed to optimally merge the satellite-derived ice surface temperature into a snow/ice model while taking into account the uncertainty of input variables. Satellite-derived ice surface temperatures were used to improve the estimates of the Greenland ice sheet surface mass fluxes. Three studies were conducted on the Greenland ice sheet. The goal of the first study was to provide a proof of concept of the proposed methodology. A set of observing system simulation experiments was performed to retrieve the true surface mass fluxes of the Greenland ice sheet. The data assimilation framework was able to reduce the RMSE of the prior estimates of runoff, sublimation/evaporation, surface condensation, and surface mass loss fluxes by 61%, 64%, 76%, and 62%, respectively, over the nominal prior estimates from the regional climate model. In the second study, satellite-derived ice surface temperatures were assimilated into a snow/ice model. The results show that the data assimilation framework was capable of retrieving ice surface temperatures with a mean spatial RMSE of 0.3 K which was 69% less than that of the prior estimate without conditioning on satellite-derived ice surface measurements. Evaluation of surface mass fluxes is a critical part of the study; however, it is limited by the spare amount of independent data sets. Several data sets were used to investigate the feasibility of verification of results. It was found that predicted melt duration is in agreement with melt duration from passive microwave measurements; however, more efforts are needed to further verify the results. In the third study, the feasibility of microwave radiance assimilation was investigated by characterizing the error and uncertainty in predicted passive microwave brightness temperature from the radiative transfer model. We found significant uncertainty between the predicted measurement and satellite-derived passive microwave brightness temperature due to error in snow states, coarse resolution of the passive microwave and also an imperfect coupled snow/ice and radiative transfer model. Based on our findings, radiance assimilation requires more accurate snow grain size parameterization to take into account temporal and spatial variability of snow grain size. Furthermore, coarse resolution of both passive microwave brightness temperature and snow/ice model and attribute uncertainties of both predicted and measured brightness temperature make the radiance assimilation unattractive. This research demonstrates that ice surface temperature measurements have valuable information that can be extracted by a data assimilation technique to improve the estimates of the Greenland ice sheet surface mass fluxes.
Book Synopsis Remote Sensing Observations of Modern-Day Regional Ice Sheet Change by : Tyler Clark Sutterley
Download or read book Remote Sensing Observations of Modern-Day Regional Ice Sheet Change written by Tyler Clark Sutterley and published by . This book was released on 2016 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Earth's great ice sheets are losing mass at accelerating levels, rising global sea levels and posing a significant problem to society. The ice sheets contain enough water to raise sea level by 65 meters, and are the largest reservoirs of freshwater on the planet. Measurements of current ice sheet mass change are important in order to assess their current contribution to sea level rise, and to constrain future projections. There are three general approaches for measuring the current mass balance of ice sheets: the gravimetric method using time-variable gravity measurements, the altimetric method combining surface elevation change measurements with estimates of the density change, and the mass budget method combining rates of mass input from snow and rain with rates of mass output from meltwater runoff, ice discharge and other processes. In this dissertation, we use multiple independent measurements to assess the current uncertainties in mass balance efforts, and to create new estimates of current ice sheet mass change. We investigate key regions of Antarctica, where changes in the ice sheet velocity structure have led to accelerating mass losses. We compile new assessments of the mass change of the Greenland ice sheet, where increased rates of surface runoff and losses from ice sheet dynamics have dramatically shifted the mass balance regime. The work helps constrain estimation errors from GRACE, provides new constraints to ice sheet and glacial isostatic adjustment models, and helps improve our general understanding of the mechanisms driving current ice sheet mass change.
Book Synopsis Science Under Attack by : Ralph B. Alexander
Download or read book Science Under Attack written by Ralph B. Alexander and published by Algora Publishing. This book was released on 2018-12-01 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evidence and logic are lacking in many areas of public debate today on hot-button issues ranging from dietary fat to vaccination. In Science Under Attack, Dr. Alexander shows how science is being abused, sidelined or ignored, making it difficult or impossible for the public to form a reasoned opinion about important issues. Readers will learn why science is becoming more corrupt, and also how it is being abused for political and economic gain, support of activism, or the propping up of religious beliefs. To illustrate how science is being ignored and abused, the author examines six different issues and the way they are currently discussed: evolution, dietary fat, climate change, vaccination, GMO crops and continental drift. In his research, he has gone back to the original source wherever possible rather than quoting second-hand sources, adding a degree of accuracy and nuance often missing. The controversial assertion that science does not support the conventional wisdom on climate change should be of particular interest. Alexander shows that the scientific evidence for a substantial human contribution to climate change is actually flimsy, and he demonstrates the fallacy of comparing the strong link between smoking and lung cancer to the much weaker connection between human activity and global warming.
Book Synopsis Greenland Ice Sheet Change: Surface Climate Variability and Glacier Dynamics by : Lei Yang
Download or read book Greenland Ice Sheet Change: Surface Climate Variability and Glacier Dynamics written by Lei Yang and published by . This book was released on 2007 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The co-variability of glacier ice discharges and climate variability is also examined by using Polar MM5 V1 modeled summer temperature and April-September Positive Degree Day (PDD) anomalies. Ice discharges from south Greenland glaciers are found to be sensitive to temperature change. Based on sensitivities of ice discharge to melt index anomalies, time series of total ice discharge from 28 major glaciers since 1958 are modeled. The global sea level rise contribution from Greenland ice sheet during past 50 years is estimated be ∼0.6 mm yr-1 in average.
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.
