Greenland Ice Sheet Modeling Update

Greenland Ice Sheet Modeling Update PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Greenland Ice Sheet Modeling Update

Greenland Ice Sheet Modeling Update PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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An Update on Land-ice Modeling in the CESM.

An Update on Land-ice Modeling in the CESM. PDF Author:
Publisher:
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Category :
Languages : en
Pages :

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Mass loss from land ice, including the Greenland and Antarctic ice sheets as well as smaller glacier and ice caps, is making a large and growing contribution to global sea-level rise. Land ice is only beginning to be incorporated in climate models. The goal of the Land Ice Working Group (LIWG) is to develop improved land-ice models and incorporate them in CESM, in order to provide useful, physically-based sea-level predictions. LJWG efforts to date have led to the inclusion of a dynamic ice-sheet model (the Glimmer Community Ice Sheet Model, or Glimmer-CISM) in the Community Earth System Model (CESM), which was released in June 2010. CESM also includes a new surface-mass-balance scheme for ice sheets in the Community Land Model. Initial modeling efforts are focused on the Greenland ice sheet. Preliminary results are promising. In particular, the simulated surface mass balance for Greenland is in good agreement with observations and regional model results. The current model, however, has significant limitations: The land-ice coupling is one-way; we are using a serial version of Glimmer-CISM with the shallow-ice approximation; and there is no ice-ocean coupling. During the next year we plan to implement two-way coupling (including ice-ocean coupling with a dynamic Antarctic ice sheet) with a parallel, higher-order version of Glimmer-CISM. We will also add parameterizations of small glaciers and ice caps. With these model improvements, CESM will be able to simulate all the major contributors to 21st century global sea-level rise. Results of the first round of simulations should be available in time to be included in the Fifth Assessment Report (ARS) of the Intergovernmental Panel on Climate Change.

Modeling the Greenland Ice Sheet Response to Climate Change in the Past and Future

Modeling the Greenland Ice Sheet Response to Climate Change in the Past and Future PDF Author: Alexander Robinson
Publisher:
ISBN:
Category :
Languages : en
Pages : 100

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ICESat

ICESat PDF Author: H. Jay Zwally
Publisher:
ISBN:
Category : Artificial satellites in earth sciences
Languages : en
Pages : 22

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Regional Modeling of Greenland's Outlet Glaciers with the Parallel Ice Sheet Model

Regional Modeling of Greenland's Outlet Glaciers with the Parallel Ice Sheet Model PDF Author: Daniella N. Della-Giustina
Publisher:
ISBN:
Category : Glaciers
Languages : en
Pages : 78

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The most recent report from the Intergovernmental Panel on Climate Change cites ice sheet dynamics as the greatest source of uncertainty for predicting current and future rates of sea level rise. This has prompted the development and use of ice sheet models that are capable of simulating the flow and evolution of ice sheets and their corresponding sea level contribution. In the Arctic, the Greenland ice sheet appears to be responding to a warming climate more quickly than expected. In order to determine sea level contribution from Greenland, it is necessary to capture the regional dynamics of the fast flowing outlet glaciers that drain the ice sheet. This work has developed a novel regional model capable of simulating an outlet glacier, and its associated drainage basin, as a mode of using the Parallel Ice Sheet Model. Specifically, it focuses on modeling the Jakobshavn Isbrae as a demonstration. The Jakobshavn Isbrae is one of the world's fastest flowing outlet glaciers, and accounts for nearly 5% of ice loss from the Greenland Ice Sheet. Additionally, the Jakobshavn Isbrae has been widely studied for several decades, and a wealth of remotely sensed and in situ data is available in this region. These data are used as model input and for model validation. We have completed a parameter study in this work to examine the behavior of the regional model. The purpose of this study was not to tune the model to match observations, but rather to look at the influence of parameter choices on the ice dynamics. Model results indicate that we have identified the subset of the model parameter space that is appropriate for modeling this outlet glacier. Additionally, we are able to produce some of this more interesting features that have been observed at Jakobshavn, such as the development and disintegration of a floating ice tongue and the distribution of observed surface velocities. We validate these model results by comparison with recent spatially rich measurements of ice surface speeds, as well as ice geometry.

Polar Environments and Global Change

Polar Environments and Global Change PDF Author: Roger G. Barry
Publisher: Cambridge University Press
ISBN: 1108423167
Category : History
Languages : en
Pages : 445

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Surveys atmospheric, oceanic and cryospheric processes, present and past conditions, and changes in polar environments.

Melt Water Retention Processes in Snow and Firn on Ice Sheets and Glaciers: Observations and Modeling

Melt Water Retention Processes in Snow and Firn on Ice Sheets and Glaciers: Observations and Modeling PDF Author: W. Tad Pfeffer
Publisher: Frontiers Media SA
ISBN: 2889456196
Category :
Languages : en
Pages : 160

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Book Description
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.

Glacier Fluctuations and Climatic Change

Glacier Fluctuations and Climatic Change PDF Author: Johannes Oerlemans
Publisher: Springer Science & Business Media
ISBN: 9401578230
Category : Science
Languages : en
Pages : 414

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Proceedings of the Symposium on Glacier Fluctuations and Climatic Change, held in Amsterdam, June 1-5, 1987

Ice Sheets and Climate

Ice Sheets and Climate PDF Author: Johannes Oerlemans
Publisher: Springer Science & Business Media
ISBN: 9400963254
Category : Science
Languages : en
Pages : 220

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Book Description
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.

Physical Characteristics and Modeling of the Greenland Ice Sheet. Progress Report to the National Science Foundation, Division of Polar Programs

Physical Characteristics and Modeling of the Greenland Ice Sheet. Progress Report to the National Science Foundation, Division of Polar Programs PDF Author: R. G. BARRY
Publisher:
ISBN:
Category :
Languages : en
Pages : 65

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