The Global Last Glacial Maximum: the Eastern North Atlantic (marine sediments) and the Greenland Ice Sheet climatic signal

2022 ◽  
pp. 189-194
Author(s):  
Samuel Toucanne ◽  
Amaelle Landais ◽  
Filipa Naughton ◽  
Teresa Rodrigues ◽  
Natalia Vázquez Riveiros ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Marine Sediments ◽  
North Atlantic ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Climatic Signal ◽  
Eastern North Atlantic

scholarly journals Ice-age ice-sheet rheology: constraints from the Last Glacial Maximum form of the Laurentide ice sheet

2000 ◽  
Vol 30 ◽  
pp. 163-176 ◽  
Author(s):  
W. Richard Peltier ◽  
David L. Goldsby ◽  
David L. Kohlstedt ◽  
Lev Tarasov
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
Ice Age ◽  
Laurentide Ice Sheet ◽  
Last Glacial ◽  
Flow Law ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractState-of-the-art thermomechanical models of the modern Greenland ice sheet and the ancient Laurentide ice sheet that covered Canada at the Last Glacial Maximum (LGM) are not able to explain simultaneously the observed forms of these cryospheric structures when the same, anisotropy-enhanced, version of the conventional Glen flow law is employed to describe their rheology. The LGM Laurentide ice sheet, predicted to develop in response to orbital climate forcing, is such that the ratio of its thickness to its horizontal extent is extremely large compared to the aspect ratio inferred on the basis of surface-geomorphological and solid-earth-geophysical constraints. We show that if the Glen flow law representation of the rheology is replaced with a new rheology based upon very high quality laboratory measurements of the stress-strain-rate relation then the aspect ratios of both the modern Greenland ice sheet and the Laurentide ice sheet, that existed at the LGM, are simultaneously explained with little or no retuning of the flow law.

scholarly journals Geodetic measurements reveal similarities between post–Last Glacial Maximum and present-day mass loss from the Greenland ice sheet

2016 ◽  
Vol 2 (9) ◽  
pp. e1600931 ◽  
Author(s):  
Shfaqat A. Khan ◽  
Ingo Sasgen ◽  
Michael Bevis ◽  
Tonie van Dam ◽  
Jonathan L. Bamber ◽  
...  
Keyword(s):  
Mass Loss ◽  
Sea Level ◽  
Last Glacial Maximum ◽  
Hot Spot ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
Satellite Mission ◽  
Last Glacial ◽  
Modern Mass

Accurate quantification of the millennial-scale mass balance of the Greenland ice sheet (GrIS) and its contribution to global sea-level rise remain challenging because of sparse in situ observations in key regions. Glacial isostatic adjustment (GIA) is the ongoing response of the solid Earth to ice and ocean load changes occurring since the Last Glacial Maximum (LGM; ~21 thousand years ago) and may be used to constrain the GrIS deglaciation history. We use data from the Greenland Global Positioning System network to directly measure GIA and estimate basin-wide mass changes since the LGM. Unpredicted, large GIA uplift rates of +12 mm/year are found in southeast Greenland. These rates are due to low upper mantle viscosity in the region, from when Greenland passed over the Iceland hot spot about 40 million years ago. This region of concentrated soft rheology has a profound influence on reconstructing the deglaciation history of Greenland. We reevaluate the evolution of the GrIS since LGM and obtain a loss of 1.5-m sea-level equivalent from the northwest and southeast. These same sectors are dominating modern mass loss. We suggest that the present destabilization of these marine-based sectors may increase sea level for centuries to come. Our new deglaciation history and GIA uplift estimates suggest that studies that use the Gravity Recovery and Climate Experiment satellite mission to infer present-day changes in the GrIS may have erroneously corrected for GIA and underestimated the mass loss by about 20 gigatons/year.

scholarly journals Modelling of Last Glacial Maximum ice sheets using different accumulation parameterizations

1997 ◽  
Vol 24 ◽  
pp. 223-228 ◽  
Author(s):  
Adeline Fabre ◽  
Catherine Ritz ◽  
Gilles Ramstein
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Circulation Model ◽  
Climatic Conditions ◽  
Glacial Maximum ◽  
Elastic Model ◽  
Last Glacial ◽  
The Third

We use a three-dimensional thermomechanical ice-sheet model, previously tested on the Greenland ice sheet, to reconstruct Last Glacial Maximum (LGM) ice sheets. We compare the effects on the results of the ice-sheet model of three different accumulation parameterization schemes. In the first and second schemes, LGM precipitation is computed from the present precipitation, taking and not taking into account moisture transport. In the third scheme, LGM precipitation and surface temperatures are computed using outputs of an atmospheric global circulation model (AGCM), treated in anomaly mode.Results are compared to the last reconstruction of the Northern Hemisphere ice sheets (Peltier, 1994), computed using global rebound rates in a visco-elastic model of the Earth’s crust. The first two accumulation parameterizations do not give satisfactory reconstructions of the LGM ice sheets, since they are unable to compute realistic LGM climatic conditions. The third method gives very satisfactory results, which leads us to conclude that the best way to obtain realistic LGM climatic conditions is to use AGCM outputs.

Ice stream influence on West Greenland Ice Sheet dynamics during the Last Glacial Maximum

2009 ◽  
Vol 25 (6) ◽  
pp. 850-864 ◽  
Author(s):  
David H. Roberts ◽  
Antony J. Long ◽  
Bethan J. Davies ◽  
Matthew J. R. Simpson ◽  
Christoph Schnabel
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
West Greenland ◽  
Last Glacial ◽  
Ice Stream ◽  
Ice Sheet Dynamics ◽  
The Last Glacial Maximum ◽  
The Last Glacial

10Be ages from central east Greenland constrain the extent of the Greenland ice sheet during the Last Glacial Maximum

2007 ◽  
Vol 26 (19-21) ◽  
pp. 2316-2321 ◽  
Author(s):  
Lena Håkansson ◽  
Jason Briner ◽  
Helena Alexanderson ◽  
Ala Aldahan ◽  
Göran Possnert
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
East Greenland ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Modelling of Last Glacial Maximum ice sheets using different accumulation parameterizations

1997 ◽  
Vol 24 ◽  
pp. 223-228 ◽  
Author(s):  
Adeline Fabre ◽  
Catherine Ritz ◽  
Gilles Ramstein
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Circulation Model ◽  
Climatic Conditions ◽  
Glacial Maximum ◽  
Elastic Model ◽  
Last Glacial ◽  
The Third

We use a three-dimensional thermomechanical ice-sheet model, previously tested on the Greenland ice sheet, to reconstruct Last Glacial Maximum (LGM) ice sheets. We compare the effects on the results of the ice-sheet model of three different accumulation parameterization schemes. In the first and second schemes, LGM precipitation is computed from the present precipitation, taking and not taking into account moisture transport. In the third scheme, LGM precipitation and surface temperatures are computed using outputs of an atmospheric global circulation model (AGCM), treated in anomaly mode. Results are compared to the last reconstruction of the Northern Hemisphere ice sheets (Peltier, 1994), computed using global rebound rates in a visco-elastic model of the Earth’s crust. The first two accumulation parameterizations do not give satisfactory reconstructions of the LGM ice sheets, since they are unable to compute realistic LGM climatic conditions. The third method gives very satisfactory results, which leads us to conclude that the best way to obtain realistic LGM climatic conditions is to use AGCM outputs.

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