Climate change, climate models, ice sheets Earth's ice sheets Physics of slow, cold, shallow ice of Mathematics and Statistics, Univ. of Alaska, Fairbanks 19 June, 2007 (ARSC) #12;Climate change, climate models for help making it all work on the big ...
E-print Network
The ice sheet model The polythermal ice sheet model SICOPOLIS (SImula- tion COde for POLythermal Ice Sheets) was developed by Ralf Greve at the Technical University in Darmstadt, Ger- many. The model ...
A High Resolution Parallel Ice Sheet Model Including Fast, Sliding Flow: Advanced ... but difficult to observe, conditions at the base of the ice. ...
NASA Website
A test program has been carried out to study ridging and rafting of model ice sheets. During each test, a sheet of floating model ice was pushed against another similar ice sheet. Two types of ice ...
National Technical Information Service (NTIS)
NOTES AND CORRESPONDENCE Surface Melting over Ice Shelves and Ice Sheets as Assessed from Modeled of ice shelves and their progenitor ice sheets. To explore the magnitude of surface melt occurring over) and most of the Greenland Ice ...
Digital elevation models (DEMs) of ice sheets and ice caps are usually constructed ... spatial resolution DEM of Austfonna, an ice cap in Svalbard. ...
State-ot-the-art thermomechanical models of the modern Greenland ice and the ancient Laurenticle ice
NASA Technical Reports Server (NTRS)
Ice elevation near the West Antarctic Ice Sheet divide during the Last Glaciation Robert P. Ackert October 2007; accepted 9 October 2007; published 10 November 2007. [1] Interior ice elevations of the West Antarctic Ice Sheet (WAIS) during the last glaciation, which can ...
... MODELS OF ICE SHEETS, USEFUL IN RADAR-SOUNDING PROBLEMS- ATMOSPHERIC AND OCEANIC PHYSICS, V8, NO4, P225-229. ...
DTIC Science & Technology
ISSM was awarded the 2011 NASA Honors Group Achievement Award for " outstanding accomplishment in the development of the Ice Sheet System Model that ...
... Accession Number : ADA148434. Title : Crystalline Structure of Urea Ice Sheets Used in Modeling Experiments in the CRREL Test Basin,. ...
This is technical comment and response to the subject of paleotophography of glacial age ice sheets. The model presented by Peltier reconstructing the paleotopography of glacial age ice sheets has implications for atmospheric general circulation models of ...
Energy Citations Database
Jun 18, 2009 ... The model is based on the shallow ice approximation, .... Presentation, Workshop on Ice Flow Modelling, Niels Bohr Institute for Astronomy, ...
The ability to predict rates of global climatic change, melting ice, ... on an accurate understanding (and modeling) of glacier and ice sheet behavior. ...
-stream dynamics dis- cussed above to test whether a model can generate the types of ice streams thought to haveThermomechanical modelling of the Scandinavian ice sheet: implications for ice-stream formation A images of the area covered by the former Scandinavian ...
. In the ice stream re- gion, basal sedimentshave very small shear strength and basal water pressure is near water at the baseof the ice shelf. Internal boundaries between bedrock and grounded ice must also warmingmigratesup from the ice/bedinterface into the ice sheet, ...
Peteet, D., D. Rind, and G. Kukla, 1992: Wisconsinan ice-sheet initiation: Milankovitch forcing, paleoclimatic data, and global climate modelling. In The Last ...
Unusual radar echoes from the percolation zone of the Greenland ice sheet. EOS Suppl., p. 247. Rignot, E. 1995. Backscatter model for the unusual radar ...
... a floating ice sheet under loads which act over a long period of time. ... the Voigt models has a negative spring constant which produces tertiary creep. ...
Work comparing the new computed balance fluxes to the observed flows in the East Antarctic Ice Sheet to explore patterns of ice sheet mass imbalance at a ...
Model simulations of the West Antarctic ice sheet suggest that sporadic, perhaps chaotic, collapse (complete mobilization) of the ice sheet occurred throughout the past one million years. The irregular behavior is due to the slow equilibration time of the...
A set of simple scaling formulas related to ice sheet evolution is derived from the dynamic and thermodynamic equations for ice and is used to consider two common situations: (1) when we wish to estimate potential ice sheet characteristics given the prescribed net snow accumulation over an ...
-rheology and ice-sheet numerical modelling over the last 20 or so years have predicted several types of Late inverse-type procedure 3.1. Modelling procedure Siegert et al. (1999) used a numerical ice-sheet model, this volume). An informal inverse-type procedure was employed in which the ...
This report describes the growth characteristics and crystalline textures of urea ice sheets which are now used extensively in the Cold Regions Research and Engineering Lab. (CRREL) test basin for modeling sea ice. The aims of the report are to describe t...
We suggested a relatively simple model describing changes in the total balance of the ice sheet mass due to global climate change. Taking into account the basic mechanisms behind change in the ice sheet mass and their relations with temperature, we obtained a nonlinear analytical dependence of ...
NASA Astrophysics Data System (ADS)
We evaluate the influence of uncertain ice sheet model input parameters on projections of Greenland ice sheet behavior in a warming world, using a low-order ice sheet model. Recent work by EJS and colleagues (Stone et al., accepted ...
Abstract: Computer models have been developed to investigate the present and future balance of ice accumulation and loss for the Antarctic ice sheet. ...
Using a digital computer calculations were made of the deformations and bending moments in a floating ice sheet. The ice behavior was described by a linear viscoelastic model consisting of a Maxwell and a Voigt element in series. Loading with circular sym...
Ice thickness and bedrock topography are essential boundary conditions for numerical modelling of the evolution of the Greenland ice-sheet (GrIS). The datasets currently in use by the majority of Greenland ice-sheet modelling studies are over two decades old and based on data collected from the ...
Solutions of the nonlinear water wave equations under an ice sheet are computed using a boundary integral equation method. The ice sheet is modelled as a thin elastic plate and the fluid equations are nonlinear. Depending on the velocity of the moving disturbance generating the flow, different ...
PubMed
The Center for Remote Sensing of Ice Sheets (CReSIS) provides links to educational materials that focus on topics related to global climate change and remote sensing, particularly changes in continental ice sheets and glaciers in Greenland and Antarctica. K-12 education resources include links to materials ...
NSDL National Science Digital Library
The great continental ice sheets of the Pleistocene represented a significant topographic obstacle to the westerly winds in northern midlatitudes. This work explores how consequent changes in the atmospheric stationary wave pattern might have affected the shape and growth of the ice sheets themselves. A one ...
The 2D climate model of Gallee et al. (1991) for the Northern Hemisphere is asynchronously coupled to an ice-sheet model, and the coupled model (named the paleoclimate model, PCM) is used to assess the effects of certain processes on producing plausible ice age simulations ...
The importance of ice shelves for the evolution of ice sheets has recently been discussed, and methods are currently being developed in order to couple ice shelf dynamics with ice sheet dynamics. SICOPOLIS (http://sicopolis.greveweb.net/) is an ice ...
A numerical model was designed to study the stability of a marine ice sheet, and used to do some basic experiments. The ice-shelf/ice-sheet interaction enters through the flow law in which the longitudinal stress is also taken into account. Instead of applying the model to some (measured) ...
Recent years has seen a dramatic increase in the mass loss from the Greenland ice sheet, as documented from satellite remote sensing, airborne surveys and in situ measurements. In recognition of these changes, the Danish Ministry of the Environment has now launched the new Programme for Monitoring of the Greenland Ice ...
The need to resolve large-scale climate-ice sheet feedbacks is motivating efforts to couple full ice sheet models to Earth System models that are capable of ensembles of multi-millennial simulations of climate change. To this end we have coupled the University of Victoria ...
Documentation. Ice sheet modeling � Users' manual � Validation manual; � Tutorials. Square ice shelf � Pine Island Glacier � FAQ � Publications � Developers site ...
Jun 18, 2009 ... Presentation, Workshop on Ice Flow Modelling, Niels Bohr Institute for Astronomy , Physics and Geophysics, University of Copenhagen, Denmark, ...
Sep 12, 2011 ... But the limit behaviour for friction should be an ice shelf sliding (no basal drag). Therefore, for any effective pressure Neff < 0, ...
Ice-ocean interactions are an important/dominant control of glacier changes. We need improved fjord bathymetry near glacier fronts to better constrain ...
The ice motion is a Stokes flow (acceleration negligible); The only body force is due to gravity (Coriolis effect negligible) ...
Dataset Title: Singular Value Decomposition Analysis of Ice Sheet Model Output. Dataset Release Date: 2009-05-30. Dataset Release Place: Boulder, Colorado, ...
Human Dimensions ... Singular Value Decomposition Analysis of Ice Sheet Model Output Fields ... a MATLAB script for performing singular value decomposition and analysis of the model fields, and a summary of experimental results in ...
Public Member Functions | Data Fields. planet Class Reference. Inheritance diagram for planet: ... Property planet::phi ... Generated on Mon Sep 12 2011 13 :57:48 for Ice Sheet System Model by doxygen 1.7.4.
Sep 12, 2011 ... Ice Sheet System Model 3.3. C/C++ code documentation ... Navigate the tabs above and browse through ISSM's C++ source code, ...
The great continental ice sheets of the Pleistocene represented significant obstacles to the Northern Hemisphere midlatitude westerlies. They must therefore have forced large changes in the atmospheric circulation, and consequently also in the patterns of accumulation and melting over the ice sheets themselves. A ...
Ice sheets are expected to shrink in size as the world warms, which in turn will raise sea level. The West Antarctic ice sheet is of particular concern, because it was probably much smaller at times during the past million years when temperatures were comparable to levels that might be reached or exceeded within ...
The need to better understand long-term climate/ice sheet feedback loops is motivating efforts to couple ice sheet models into Earth System models which are capable of long-timescale simulations. In this paper we describe a coupled model that consists ...
The need to better understand long-term climate/ice sheet feedback loops is motivating efforts to couple ice sheet models into Earth System models which are capable of long-timescale simulations. In this paper we describe a coupled model, that consists ...
The dynamic behavior of the West Antarctic ice sheet is of interest because of the possibility that it may change and cause rapid sea-level rise. Attention is focused on the fast-moving and rapidly responding ice streams that drain the ice sheet. One of these, ice stream C, ...
... to monitor and model local geologic hazards such as landslides and rock falls and to assess the impact of ice sheet and glacier system dynamics. ...
This activity from ANDRILL is a hands-on guided inquiry activity designed to highlight the role of an ice shelf on slowing the movement of continental ice sheets in Antarctica. Students build a model of Antarctica and both continental glaciers and ice shelves using paper ...
The Greenland Ice Sheet (GIS), like many elements in the climate system, is expected to exhibit hysteresis behaviour. This implies that for certain conditions, the GIS may have more than one stable state (for example ice-free and fully glaciated states). Several recent studies have confirmed that multistability exists for the GIS and ...
Despite the importance of rapidly-flowing ice streams to ice sheet mass balance, their incorporation into numerical ice sheet models is a major scientific challenge. This introduces large uncertainties in model output and inhibits a more complete ...
The wild card for reliable sea level rise prediction is the contribution of the Greenland Ice Sheet. There is an urgent need to determine the predictability of models that simulate the response of Greenland Ice Sheet to rising temperatures and the amount of freshwater flux that can be expected ...
Public awareness of changing atmospheric conditions, melting of the Greenland Ice Sheet, and sea level rise have become powerful instruments for intriguing and teaching middle and secondary science students the complex concepts of atmosphere-cryosphere interactions. Visualization of the changing atmosphere and cryosphere through simple mass balance and ...
. The Ronne Ice Shelf is over 1000 m thick in places (Doake, 1987), whereas George VI Ice Shelf is commonly upland centers. In the case of the Ronne Ice Shelf, a large proportion of the ice is derived from ice)summarizedresults from 26 sitesin Palmer Land, Alexander Island, and George VI ...
-HEINO (Calov et al poster; yesterday!) � Ross ice shelf model (i.e. reproduction of EISMINT I result) � Ongoing (force, to a mathematician) on base of ice from sliding: Fb = 0 ice shelf (Morland 1987) -u ice stream Results Conclusion Ice shelf flow: validation Recall ...
An International Polar Year aerogeophysical investigation of the high interior of East Antarctica reveals widespread freeze-on that drives substantial mass redistribution at the bottom of the ice sheet. Although the surface accumulation of snow remains the primary mechanism for ice sheet growth, beneath Dome A, 24% ...
... wish to understand the influence of the Antarctic Ice Sheet ice sheet on the Southern Ocean during the past, present, ... ...
NBII National Biological Information Infrastructure
The main force components on inclined offshore structures in the Arctic include the flexural and crushing behavior of the ice sheet, rotation and translation of broken ice, gravity and buoyancy in lifting and moving ice, and friction between ice and structure. Tests were carried out to isolate ...
of the quasi-periodic ice ages of the last 26106 years remain unknown, and it is thought likely-scales is not well understood, and studies of the ice ages typically employ simpli- fied parameterizations age leads to very different accumulation patterns. For example, the great ice sheets of the ...
of the lower ice sheet and freezing at the base of the upper ice sheet. We put the term "melting" in quotation and engineering point of view. From a geophysical perspective, rafted sea ice accounts for a significant fraction of layers of sea ice of equal thickness, ...
Sediment cores in the North Atlantic show evidence of periodic large-scale ice discharge events between 60 ka and 10 ka BP. These events occurred with a typical period between 5 kyr and 10 kyr. During each event, a significant amount of ice was discharged from the Hudson Bay region through the Hudson Strait and into the North Atlantic. This input of ...
In the context of global warming, the role of the Greenland Ice Sheet (GIS) is a key issue. Numerical modeling is a major tool to assess the future behavior of this ice sheet and its contribution to sea level change. In this kind of study one must associate an ice ...
Since the late 1970s, numerical modelling has become established as an important technique for the understanding of ice sheet and glacier dynamics, and several models have been developed over the years. Ice sheet models are particularly relevant for ...
The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast ...
DOE Information Bridge
A two-dimensional hydrodynamic ice-slope interaction problem is formulated in this paper. The solution of this elastohydrodynamic problem will give the desired ice force. The main objective is to determine the influence that ice sheet velocity, slope angle, and ice-structure friction have on ...
Model investigations of the drawing in of slush and ice under the edge of an ice sheet are a component part of the study of ice-dam and ice-jam formation processes in rivers, as well as a stage in the experimental development of methods for the hydraulic ...
The Antarctic ice cap is the largest ice sheet of modern times. It is of considerable importance to predict the sea level variability due to the associated changes in ice volume. We present the results of a simple grounded ice sheet model, developed ...
New calculations were performed to investigate the combined response of the Greenland and Antarctic ice sheets to a range of climatic warming scenarios over the next millennium. Use was made of fully dynamic 3D thermomechanic ice sheet models, which were coupled to a two-dimensional climate ...
The primary goals of this research were to identify and begin to comprehend the spatial and temporal variations in surface characteristics of the Greenland ice sheet using passive microwave observations, physically-based models of the snowpack and field o...
how climate change will affect the Greenland ice sheet, scientists modeled the melting Laurentide ice sheet of 9000 years ago. (Oct '08) + Read Science Brief * Cyclones at...
Science.gov Websites
... forcing for modeling the response of glaciers and ice sheets to climate change (e.g., Huybrechts and Oerlemans, ... driven by a glacial cyclone over the Laurentide Ice Sheet, created drier conditions over...
We present a new and original approach to understanding the sensitivity of the Greenland ice sheet to key model parameters and environmental conditions. At the heart of this approach is the use of an adjoint ice sheet model. Since its introduction by MacAyeal (1992), the ...
The current knowledge of the physical fate and behaviour of crude oil and petroleum products spilled in Arctic situations is reviewed. The fate and final deposition of oil in marine conditions is presented as based on the extant literature. Spreading models were evaluated for oil on ice, under ice, in snow, in brash ...
A lateral moraine band on Mount Waesche, a volcanic nunatak in Marie Byrd Land, provides estimates of past ice sheet surface elevations in West Antarctica. Helium-3 and chlorine-36 surface exposure ages indicate that the proximal part of the moraine, up to 45 meters above the present ice surface, was deposited about 10,000 years ago, ...
The melting of the West Antarctic Ice Sheet (WAIS), the world's largest marine ice sheet, would mean a ~5 meter sea level rise worldwide. About a third of the WAIS lies in the Amundsen Sea Embayment, where small ice shelves provide buttressing for outlet glaciers. Warming oceans may melt the ...
We use the Earth system model of intermediate complexity LOVECLIM to show the effect of coupling interactive ice sheets on the climate sensitivity of the model on a millennial time scale. We compare the response to a 2�CO2 warming scenario between fully coupled model versions including ...
In this paper the authors develop an algorithm based upon a combined surface and volume scattering model that is used to retrack individual altimeter waveforms from the ice sheets. Because the combined model is nonlinear, an iterative least-squares procedure is used to fit the combined model to ...
This bulletin contains articles on acoustic radar, resistance laws, similarity parameters in the planetary boundary layer model, energy exchange over young sea ice, velocity shear instability, gravitational stresses in floating ice sheets, oscillations an...
We present a dynamic equilibrium simulation of the ice sheet-shelf system on Antarctica with the Potsdam Parallel Ice Sheet Model (PISM-PIK). The simulation is initialized with present-day conditions for bed topography and ice thickness and then run to steady state with ...
Simulations of the Greenland Ice Sheet are carried out with a high-resolution version of the ice-sheet model SICOPOLIS for several global-warming scenarios for the period 1990-2350. In particular, the impact of surface-meltwater-induced acceleration of basal sliding on the stability of the ice ...
sheet by15 its ice shelf, the transverse direction must also be resolved. We introduce a16 model are23 carried out to determine how both ice shelf buttressing and ice rises affect24 the marine also find that the27 effect of an ice rise is similar to that of narrowing the ...
A review of snow and ice research in 1987-1990 is presented, focusing on the effects of layers in seasonal snow covers, ice mechanics on fresh water and sea ice, and remote sensig of polar ice sheets. These topics provide useful examples of general needs in snow and ice ...
Observations and models indicate that the Greenland ice sheet is and will continue to increase in both melt area and intensity. The impact of the increased inland surface melt on ice sheet dynamics remains an outstanding question that relates both to ablation losses at the ...
It is now widely accepted that Heinrich events are associated with internal oscillations of the Northern Hemisphere ice sheets leading to periodical large surges of ice in the ocean. It has been proposed that these large-scale surges likely occur when basal ice reaches the melting point in regions where ...
We present a new and original approach to understanding the sensitivity of the Greenland ice sheet to key model parameters and environmental conditions. At the heart of this approach is the use of an adjoint ice sheet model. MacAyeal (1992) introduced adjoints in the ...
Sea-level rise is one of the major concerns associated with the recent climate change. Thermal expansion of the oceans and melting of glaciers and ice-sheets are all believed to contribute to sea-level change in the next century. The Antarctic and Greenland ice-sheet could potentially rise sea-surface with 60 and 7 meter, respectively, but whereas the ...
When looking at glacial / interglacial climate evolution, one of the most standing issue is ice-sheets evolution and its relation to climate. While we have a good knowledge of the ice-sheet retreat during the last deglaciation (from different ice-sheet reconstructions, see https://pmip3.lsce.ipsl.fr/wiki/doku.php/pmip3), ...
A major problem for ice-sheet models is that no physically based law for the calving process has been established. Comparison across a diverse set of ice shelves demonstrates that iceberg calving increases with the along-flow spreading rate of a shelf. This relation suggests that frictional buttressing loss, which increases spreading, ...
Most studies that analyze the stability of 'slushball' Earth have been done with a climate model that did not include an active ice sheet module. These models can thus only generate ice on the low latitude continents spontaneously, neglecting the fact that ice can also be ...
Basal melting of Antarctic ice shelves is an important element in the overall balance of Antarctic ice. A heat-transfer model for the basal melting of the Drygalski Ice Tongue is presented. The model does not contain any adjustable parameter. The calculated basal melting rate agrees very well ...
Recent findings have suggested that the global Last Glacial Maximum occurred 26.5-20 ka. During this time, ice sheets were at their maximum extent and eustatic sea level was nearly 130 m lower than present. Such stability of Northern Hemisphere ice sheets suggests a nearly neutral net mass balance. Here we test the ...
We present a map of balance velocities for the Greenland ice sheet. The resolution of the underlying
Recent satellite observations of the Antarctic and Greenland ice sheets show accelerated ice flow and associated ice sheet thinning along coastal outlet glaciers in contact with the ocean. Both processes are the result of grounding line retreat due to melting at the grounding line (the ...
Sep 12, 2011 ... return type of analyses, number of analyses and core solution function. ... change boundary conditions of a model, using a solution vector ...
The Hadley Centre Global Environmental Model version 1 was developed from the Met Office Unified Model New Dynamics in the period 2000-2004. ...
The 3D ice sheet model of Marshall and Clarke, which includes both dynamics and thermodynamics, is used to successfully simulate millennial-scale oscillations within an ice sheet under steady external forcing. Such internal oscillations are theorized to be the main cause of quasi-periodic ...
Climatic warming is shown to be capable of inducing shear heating instability and basal melting in a model ice sheet that is creeping slowly downslope. Growth times of the instability are calculated from a nonlinear analysis of temperature and flow in the model ice sheet ...
Ice thickness and bedrock topography are essential boundary conditions for numerical modelling of the evolution of the Greenland ice-sheet (GrIS). The datasets currently in use by the majority of GrIS modelling studies are over two decades old and based on data collected from the 1970s and 80s. We use a newer, ...
There is some debate on the origin of subglacial Lake Vostok and whether the water within the present subglacial lake system contains biota that survived the buildup of the Antarctic ice sheet. One theory suggests that Lake Vostok existed as a preglacial lake before glaciation of the continent at around 15 Ma ago, survived the subsequent period of ...
Scaling analysis shows that the mean thickness of an ice sheet depends on the product of two poorly known quantities, the ice viscosity and the net snow accumulation rate. We adjust the viscosity of an ice sheet in order to get a consistent value of this product for the present-day ...
We synthesise recent work on the palaeoglaciology of the British-Irish Ice Sheet, focusing on the glacial geomorphology preserved on the seabed around the northern UK [Bradwell et al., 2008]; and a suite of numerical modelling experiments spanning the last ~40 ka [Hubbard et al., 2009]. In addition, we present a new temporal dataset to ...
When studying glacial / interglacial climate evolution, one of the most standing issue is ice-sheets evolution and its relation to climate. While we have a good knowledge of the ice-sheet retreat during the last deglaciation (from different ice-sheet reconstructions, see https://pmip3.lsce.ipsl.fr/wiki/doku.php/pmip3), ...
In this interactive activity adapted from Texas A&M University, a block of melting ice simulates ice shelves and ice sheets and their differing effects on global sea level.
The effects of runner material and surface conditions on the friction between runners and ice were studied. A model sled was pushed over a 6-m-longice sheet and the reduction of speed of the sliding sled was measured. The friction calculated by the reduct...
This activity was developed during the Teaching Climate Change Using Ice Core Data workshop, held in June 2008.Contributed by: B. Parizek, M. Kelly, M. Ver, and C. Wilbur Topic: Modeling, ice-sheet physics, ...
The specter of a west antarctic collapse has been with us for 25 years. Recently, certain official assessments concerned primarily with the future response to projected global warming have concluded that Antarctica will not cause much sea-level rise within the planning horizon of a century or so. At the same time startling new results on ice sheet ...
West Antarctic ice comes and goes, rapidly Wednesday, March 18, 2009 University Park, Pa. -- Researchers today worry about the collapse of West Antarctic ice shelves and loss of the West Antarctic ice and the University of Massachusetts have modeled the past 5 million years of the West Antarctic ...
The ability to track the origin of particles in ice has allowed advances in ice sheet modeling. Chemical (e.g., oxygen isotope concentration) and physical properties can be inferred from their values at the time of deposition. Our particle tracing technique provides the possibility to predict the stratification of ...
We simulate the volume and extent of the Greenland Ice Sheet during the Eemian using a 3D �shallow� ice sheet model forced with Eemian surface mass balance (SMB) and temperature fields. These Eemian forcing fields are obtained from a time slice experiment of the regional climate ...
A numerical flow-band model of a polar ice stream that includes dynamic interaction with a floating ice shelf has been developed. The model includes a basal sliding relationship that is calibrated by assuming that the future sliding behavior of the ice stream will be analogous to its present ...
It has been suggested that rapid thinning of the West-Antarctic ice sheet is due to increased melting under ice shelves caused by a gradual ocean warming. Payne et al. (2004, GRL) showed that such melting could lead to an acceleration of grounded ice flow. However, the model used in their ...
We present preliminary simulations of both static and dynamic ice shelves within a dynamical ocean model (the Parallel Ocean Program, POP) using an immersed boundary method (IBM) to represent the geometry of the ice-ocean interface. In this work, the ice shelf dynamics are prescribed, though our near-term goal is ...
During the last glacial-interglacial cycle, northern hemispheric (NH) ice-sheets experienced dramatic changes in radiative forcing, due to orbitally-driven insolation changes and varying greenhouse gas concentrations. This direct forcing caused temperature changes and eventually ablation anomalies. Orbital-scale variations in the atmospheric circulation caused anomalies in ...
Climate history from several hundreds of thousand years has been recorded in the terrestrial ice sheets. Drilling deep ice cores though the ice sheets and analyzing the ice and the impurities has assessed this climate history. The visible stratification that is seen the ...
The North-East Greenland Ice Stream (NEGIS) was discovered as a large fast-flow feature in north-east Greenland by synthetic aperture radar (SAR) imaginary of the ERS-1 satellite. In this study, the NEGIS is implemented in the ice-sheet model SICOPOLIS (Simulation Code for POLythermal Ice ...
The onset of major glaciations in the Northern Hemisphere about 2.7 million years ago was most probably induced by climate cooling during the late Pliocene epoch. These glaciations, during which the Northern Hemisphere ice sheets successively expanded and retreated, are superimposed on this long-term climate trend, and have been linked to variations in the ...
The spatial and temporal histories of accumulation and ice-sheet flow are necessary to recreate ice-volume and sea-level histories, and are important to correctly interpret ice-core chemistry. Internal layers preserve information about how the ice sheet responded to past spatial and temporal ...
Comparison of declassified satellite photography taken in 1963 with more recent satellite imagery reveals that large changes have occurred in the region where an active ice stream enters the Ross Ice Shelf. Ice stream B has widened by 4 kilometers, at a rate much faster than suggested by models, and has decreased ...
A common explanation for Heinrich events consists in an internal thermomechanical feedback of the Northern Hemisphere ice sheets allowing the occurrence of periodical large ice surges into the ocean. It has been proposed that these large-scale surges likely occur when basal ice reaches the melting point in regions ...
The West Antarctic ice sheet is confined by a large area of ice shelves, fed by inland ice through fast flowing ice streams. The dynamics of the grounding line, i.e. the line-boundary between grounded ice and the downstream ice shelf, has a major ...
The glacial geology of North America provides a rich resource from which reconstructions of paleo ice sheets can be made. An alternate avenue for cryospheric reconstruction is the numerical modeling of ice sheets based on ice physics; these models have ...
A parameterization for the motion of ice-shelf fronts on a Cartesian grid in finite-difference land-ice models is presented. The scheme prevents artificial thinning of the ice shelf at its edge, which occurs due to the finite resolution of the model. The intuitive numerical implementation ...
Peteet, D., D. Rind, and G. Kukla, 1992: Wisconsinan ice-sheet initiation: Milankovitch forcing, paleoclimatic data, and global climate modelling. In The Last...
Mar 25, 2010 ... Earth's Real Movers and Shakers Star in New Tectonic Model ... A JPL-designed camera submerged 600 feet beneath the Antarctic ice sheet to ...
Earth's Real Movers and Shakers Star in New Tectonic Model ... A JPL-designed camera submerged 600 feet beneath the Antarctic ice sheet to image its ...
Sep 12, 2011 ... For every * object that is not a clone, tell them to show their dofs, so that later ... Let the clones recover those true dofs: */ for (i=0 ...
Sep 12, 2011 ... For every * object that is not a clone, tell them to show their .... { /*Careful ! only use once all clones have been setup for all nodes! ...
Inverse methods. ISSM allows control method on the basal drag (k) and the depth average viscosity parameter (B) when an observed velocity field is available. ...
To mesh the domain, one needs a file containing all the coordinates of the domain outline in an Argus format. These files have a exp extension. ...
A summary is given of the glacial and marine chronology of Mars. Hydrological models of oceans and ice sheets, the cratering record, hydrological cycling, and episodic glaciation are discussed. Evidence for a Noachian ocean is evaluated.
A numerical flow-band model of a polar ice stream that includes dynamic interaction with a floating ice shelf has been developed. The model includes a basal sliding relationship that is calibrated by assuming that the future sliding behavior of the ice st...
This report describes a model for calculating the response of the marginal sector of the Inland Ice to mass-balance changes. In order to illustrate how the various parts of the ice margin of the west Greenland ice sheet between 69.2 deg N and 69.8 deg N w...
that rafting is most common between thin ice sheets (types of rafting haveClick Here for Full Article A model for the consolidation of rafted sea ice E. Bailey,1 D. L ice. This process is widespread in the north Caspian Sea, where multiple rafting produces thick sea
The mass balance of marine ice-sheets, such as the West Antarctic Ice Sheet, is mostly controlled by their grounding line dynamics. Most numerical models simulating marine ice-sheets involve simplifications and do not include all the stress gradients. First results obtained with a 3D ...
This educational brief describes the nature and properties of the Greenland and Antarctica ice sheets. Topics include the thickness and aereal extent of the ice sheets, volume of water contained in them, mass balance, and the mechanisms by which ice is lost from or accumulated by the ...
The current generation of prognostic ice-sheet models fails to adequately capture rapid and non-linear responses of the polar ice masses to environmental forcings, such as dramatic increase in ice discharge following weakening and disintegration of buttressing ice shelves and ...
Predicting future hydrological regimes with regard to climate change is an increasingly important task for hydrologists. In polar regions the task is more difficult due to the lack of datasets and long term monitoring as well as logistical difficulties in remote and inaccessible basins. Here, we demonstrate a case study predicting the future run-off in a difficult to model ...
The sudden growth of a continental-scale East Antarctic Ice Sheet (EAIS) in the earliest Oligocene (~34 Ma) has long been thought to represent the first major glaciation of the Cenozoic. The timing of the first significant ice on Greenland remains equivocal, however, the Northern Hemisphere is usually assumed to have remained mostly ...
Multiple observed evidence show that the continental based ice is losing mass since the 1990s. Significant accelerated mass loss from the major ice sheets has been indicated since year 2000. Here we use the National Center for Atmospheric Research Community Climate System model version 3 to study the potential ...
Timothy J. Tautges, Argonne National Laboratory Iulian Grindeanu, Argonne National Laboratory Simulations of land-based ice sheets require definitions of the basal and ice sheet top surface geometries; these models are used to generate discretizations/meshes on which the equations are solved, ...
Reduction in the polar ice caps and associated climate feedbacks are implicated in the warming of pre- Quaternary palaeoclimates. General Circulation Model (GCM) simulations of the last such warm period, the mid- Pliocene (3.29-2.97 Ma), suggests global surface temperatures were between 1.4�C and 3.6�C warmer than today. However, the changes are ...
The mid-Pliocene (~3Myr B.P.) is important for palaeoclimate reconstruction, as it was the last time in Earth history when global temperatures were significantly warmer than modern, over a period longer than any Quaternary interglacial. It is unique in that continental configurations were relatively unchanged from the modern, and geological proxies are superior to preceding warm periods, due to ...
Milankovitch cycles in insolation). It is interesting to ask whether the ice sheet � stationary wave feedback sheets and atmospheric stationary waves Received: 1 October 1999 / Accepted: 17 July 2000 Abstract stationary wave pattern might have aected the shape and growth of the ice sheets ...
Ice sheet thickness is determined mainly by the strength of ice-bed coupling that controls holistic transitions from slow sheet flow to fast streamflow to buttressing shelf flow. Byrd Glacier has the largest ice drainage system in Antarctica and is the fastest ice stream ...
Here, we present high-resolution stable isotope records from ODP Site 1264 in the South-Eastern Atlantic Ocean, which resolve the latest Oligocene to early Miocene (23.7�18.9 Ma) climate changes. Using an inverse modelling technique, we decomposed the oxygen isotope record into temperature and ice volume and found that the Antarctic ...
An Earth System Model of Intermediate Complexity is used to investigate the role of insolation and of the size of ice sheets on the regional and global climate of marine isotope stage (MIS) 13. The astronomical forcing is selected at two dates with opposite precession, one when northern hemisphere (NH) summer occurs at perihelion (at ...
The significance of the main components of the cryosphere, ice sheets, seasonal snow cover and glaciers, is discussed. Interpretation of climatic data from the past as a means of improving climate modeling techniques is called for. The physical basis for ...
Geologic time series indicate significant 100 ka and 400 ka pre-Pleistocene climate fluctuations, prior to the time of such fluctuations in Pleistocene ice sheets. The origin of these fluctuations must therefore depend on phenomena other than the ice shee...
The derivation and implementation of a three-dimensional model used to investigate the Last Glacial Maximum ice sheet across Iceland by Hubbard et al. [2006. A modelling insight into the Icelandic Last Glacial Maximum ice sheet. Quaternary Science Reviews] is described. It ...
A coupled finite difference ice sheet/ice shelf model is used to investigate the flow regime of Riiser-Larsen ice shelf, Eastern Weddell Sea, Antarctica, and its drainage area. The model takes into account higher order terms that are neglected in the popular shallow ice ...
Mar 1, 2011 ... The melt extent of the snow on the Greenland ice sheet is of considerable importance to the ice sheet's mass and energy balance, as well as ...
Jan 21, 2011 ... Science: Ice Sheet Mass Balance. Learn more about Ice Sheet Mass Balance ( Scientific Committee on Antarctic Research): ...
scientific literature and have been attributed to various responses of the ice sheet due to regional (and global) warming. Because melting of the ice sheet ...
The Podcast: RAGEing WISSARDs Study Ice Sheets in a Warming World is a production of the entire Web Seminar: RAGEing WISSARDs Study Ice Sheets in a Warming World
Ice sheet mass balance is a critical - the critical - parameter for ... The problem of glacier and ice sheet response to changing climate and ocean ...
... Title : MOVING LOADS ON A FLOATING ICE SHEET. ... Abstract : The paper considers a load moving with a constant velocity across an ice sheet that ...
Jul 28, 2011 ... CRYOSPHERE > GLACIERS/ICE SHEETS > GLACIERS � Parameter Definition � CRYOSPHERE > GLACIERS/ICE SHEETS > ICE SHEETS ...
The objectives and promises of the project are recalled and compared with the results achieved and products delivered. Products include a new physical description of the Antarctic ice sheet, extensive simulations of ice stream behavior with the only existing model of self-surging glaciers, and a description and ...
Proper knowledge of bedrock elevation is a crucial input parameter for ice sheet modeling. For obvious reasons of inaccessibility, the knowledge of bedrock elevation is fragmented, and the question of where future radar measurement campaigns should focus on is critical, especially in the context of global warming and related current ...
The problem of forecasting the future behaviour of the Antarctic ice sheet is considered. We describe a method for optimizing this forecast by combining a model of ice sheet flow with observations. Under certain assumptions, a linearized model of glacial flow can be ...
The problem addressed in the continuous indentation of a ship or offshore structure into an ice sheet. The impacting ship or offshore structure is represented by a mass-spring-dashpot system having a constant velocity relative to the ice sheet. The dynamic response of this simple analogue model ...
Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that maybe the ice ...
of glacial inception as a slow growth of ice caps from small nucleation centres [16, 61]. Such a growthGAMM-Mitt. 29, No. 1, 9 � 28 (2006) Modelling of terrestrial ice sheets in palaeo-climate re, Ger- many Received 12 March 2005, revised 2 May 2005, accepted 17 May 2005 Key words shallow ice
The objective of this project is to investigate the complex fracture of ice and understand its role within larger ice sheet simulations and global climate change. At the present time, ice fracture is not explicitly considered within ice sheet models due ...
Calculations were performed with the Earth system model of intermediate complexity LOVECLIM to study the response of the Greenland and Antarctic ice sheets to sustained multi-millennial greenhouse warming. Use was made of fully dynamic 3D thermomechanical ice-sheet models bidirectionally ...
Modeling continental ice sheets was inaugurated by meteorologists William Budd and Uwe Radok, with mathematician Richard Jenssen, in 1971. Their model calculated the thermal and mechanical regime using measured surface accumulation rates, temperatures, and elevations, and bed topography. This top-down approach ...
Current predictions of ice sheet mass balance and discharge variability including sea-level rise, are severely limited because subglacial processes are not reliably implemented in large scale ice sheet models. One of the most limiting factors is the challenging nature of simulating the fast and ...
An instability mechanism is widely predicted for marine ice sheets resting upon reversed bed slopes. In this case, ice-sheet thinning or rising sea level is thought to lead to irreversible retreat of the grounding line (e.g., Weertman, J. Glaciol., 1974; Schoof, JGR, 2007). Previous analyses of marine ice-sheet ...
Understanding the dynamics of marine ice sheets is integral to studying the evolution of the Antarctic Ice Sheet in both the short and long terms. An important component of the dynamics, grounding line migration, has proved difficult to represent in numerical models, with undesirable behavior ...
Using characteristics of the Antarctic surface elevation to infer information on ice flow dynamics. G. Navas, C. Ritz, F. R�my Sea level rise is one of the expected impacts of global warming. Among the processes responsible of this sea level rise, ice sheet dynamics is not only an important one, it is also a domain where our ability ...
These ice shelves lose mass continuously by melting into the sea, and periodically by ... CRYOSPHERE > GLACIERS/ICE SHEETS > GLACIER MOTION/ICE SHEET MOTION ...
Jun 6, 2002 ... The faster ice flow, ice thinning and consequent lowering of the surface elevation of the ice sheet can open a feedback to more melting that ...
A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes .... collected over the catchment and main trunk of Thwaites Glacier, ...
Model calculations of depth-age relations for deep ice cores in central Greenland are sensitive to stability of the ice-divide position. In addition, the folding of layers observed in the deep ice could be instigated by divide migration changing the velocity and particle paths of ice flow. We ...
Reduction or loss of a restraining ice shelf will cause speed-up of flow from contiguous ice streams, contributing to sea-level rise, with greater changes from ice streams that are wider, have stickier beds, or have higher driving stress. Loss of buttressing offsetting half of the tendency for ice-stream/ice-shelf ...
Covered by up to 4 km of ice, the basal zone of the West-Antarctic Ice Sheet is one of the most inaccessible and unknown environments on Earth. Yet basal conditions play a key role in facilitating fast ice streaming and influence the mass balance of the ice sheet by ...
We implemented a fully-three-dimensional, thermo-mechanical, finite element model of the Antarctic Ice Sheet with a spatial resolution varying from 10 km inland to 2 km along the coast on a massively-parallelized architecture named CIELO and developed at JPL. The model is based on a "Pattyn" type formulation for ...
Recent research has suggested that warmer conditions, that may result from increased levels of CO{sub 2} in the atmosphere, may induce the growth of the Northern Hemisphere ice sheets through the impact of warmer temperature on the water carrying capacity of the atmosphere and thus on precipitation. In this study we examine this possibility using a coupled ...
sea ice concentration, ice extent, ice depth/thickness, ice types, pack ice... GLACIERS/ICE SHEETS (820) Parameter Definition glaciers, ice sheets, glacier mass ...
... river and lake ice, sea ice, glaciers and ice caps, ice shelves and ice sheets, ... The ice sheet melt extent is a daily (or every-other-day, ... has been focused in recent years on the melting of ice ...
As a contribution to the Paleoclimate Modeling Intercomparison Project (PMIP), ice-sheet surface mass budgets are computed using the meteorologic forcing from 17 GCMs for three time periods: present, 6000 and 21,000 calendar years before present. The ice-budget calculations are performed on a common and relatively fine grid (0.5 ...
Recent interest in mapping the topography of basal surfaces of polar ice sheets motivated the development and deployment of a low-frequency imaging radar. The data available from this system can also be used to provide surface roughness properties at the upper surface of the ice sheet. The reflectivity of the basal ...
The Parallel Ice Sheet Model (PISM, www.pism-docs.org) is an open-source fully-parallel high-resolution ice sheet model. It provides, among other features, a hierarchy of available stress balances, verification and validation tools, and a polythermal conservation of energy ...
Ice sheets evolve over a wide range of time scales. They grow by snowfall, spread gravitationally, and diminish through melting or iceberg calving at the ice-sheet margin. The evolution of ice-sheets can be substantially affected by the rate of ice transport from their interior to their ...
This report presents results of small beam testing conducted in a test tank on ice corresponding in structure to the two major ice types, S1 and S2, encountered in lake ice sheets. Tests of 730 beams in the temperature range -1 to -19 C showed that macroc...
Thirty years after oxygen isotope records from microfossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth's orbital geometry control the ice ages, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles. Furthermore, an understanding of the behaviour of the ...
It has been demonstrated that many modern ice streams are fed by complex systems of tributaries extending far into the interior of ice sheets, thus raising questions about their potential implications in past and modern ice sheet response to climate forcing. However, little is known about the ...
We constrain a three-dimensional thermomechnical model of Greenland Ice Sheet evolution from the Last Glacial Maximum (LGM, 21 ka BP) to the present-day using primarily observations of relative sea level as well as data on past ice extent. Our new model (Huy2) fits the majority of the ...
An ice sheet that spreads into an ocean is forced to bend due to its buoyancy, and delaminate from the ground to form an ice shelf. The location of the transition between the grounded sheet and the ungrounded shelf is defined as the grounding-line. The dynamics of grounding lines may have a critical effect on the ...
An ice sheet that spreads into an ocean is forced to bend owing to its buoyancy and detaches from the bedrock to form a floating ice shelf. The location of the transition between the grounded sheet and the floating shelf, defined as the grounding line, behaves as a free boundary. We develop a ...
