Freshwater routing by the Laurentide Ice Sheet during the last deglaciation

1999 ◽  
pp. 177-201 ◽  
Author(s):  
Joseph M. Licciardi ◽  
James T. Teller ◽  
Peter U. Clark
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Last Deglaciation ◽  
The Last Deglaciation

scholarly journals Supplemental Material: Near-constant retreat rate of a terrestrial margin of the Laurentide Ice Sheet during the last deglaciation

2021 ◽  
Author(s):  
Thomas V Lowell ◽  
et al.
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Last Deglaciation ◽  
The Last Deglaciation

Methods description, <sup>10</sup>Be sample metadata, and modeling results and error calculations.<br>

The last deglaciation simulated with a coupled atmosphere/ocean/ice sheet/solid earth model

2021 ◽  
Author(s):  
Uwe Mikolajewicz ◽  
Olga Erokhina ◽  
Marie-Luise Kapsch ◽  
Clemens Schannwell ◽  
Florian Ziemen
Keyword(s):  
Deep Water ◽  
Climate Changes ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Earth Model ◽  
Last Deglaciation ◽  
The Holocene ◽  
Simulated Climate ◽  
The Last Deglaciation

&lt;p&gt;It is challenging to model the last deglaciation, as it is characterized by abrupt millennial scale climate events, such as ice-sheet surges, that are superimposed on long-term climate changes, such as a global warming and the decay of a substantial part of the glacial ice sheets. Within PMIP, several groups have simulated the last deglaciation with CMIP-type models prescribing ice sheets from reconstructions. Whereas this type of simulations accounts for the effects of ice-sheet changes including meltwater release on climate, the prescribed ice sheet evolution is typically not consistent with the simulated climate evolution. Here we present a set of deglacial simulations that include fully interactive ice sheets that respond to changes in the climate. The setup also allows for feedbacks between ice sheets and climate and , hence, allows for a more realistic representation of the mechanisms of the last deglaciation, as the simulated climate and ice sheet changes are fully consistent..&lt;/p&gt;&lt;p&gt;The model consists of the coarse resolution set-up of MPI-ESM coupled to the ice sheet model mPISM (Northern Hemisphere and Antarctica) and the solid earth model VILMA. The model includes interactive icebergs and an automated calculation of the land-sea mask and river routing directions. A set of synchronously coupled simulations were started from an asynchronously coupled spin-up at 26ky and integrated throughout the deglaciation into the Holocene. The only prescribed external forcing are atmospheric concentrations of greenhouse gases and earth orbital parameters. One goal of this ensemble was to find the optimal combination of model parameters for the simulation of the deglaciation.&lt;/p&gt;&lt;p&gt;The model simulates the decay of the ice sheets, the rise of sea level, the flooding of shelf seas and the opening of passages. A large fraction of the ice sheet retreat is due to dynamical events (e.g. the final decay of the ice sheets on Barents Shelf or the Hudson Bay). Superimposed on the relatively slow glacial/interglacial transition are abrupt climate changes, triggered for example by recurrent ice sheet surges. These surges correspond to Heinrich Events tand result in a weakening of the AMOC. Three source regions for ice sheet surges occur during these simulations: from the Laurentide ice sheet through Hudson Strait, from the Laurentide ice sheet northward directly to the Arctic ocean, and from the Fennoscandian ice sheet into the Norwegian Sea. The characteristic climate response shows a large dependence on the surge location.&lt;/p&gt;&lt;p&gt;The simulated changes in strength of the AMOC are except for millennial-scale reduction events only moderate. However, during glacial periods, brine release is the central process for deep water formation in both hemispheres, in contrast to the Holocene. dDuring the deglaciation the ventilation of the deep ocean is strongly reduced, leading to a strong increase of the simulated deep water ages. This effect lasts longest in the deep North Pacific and extends in some simulations into the Holocene.&lt;/p&gt;

Laurentide ice-sheet instability during the last deglaciation

2015 ◽  
Vol 8 (7) ◽  
pp. 534-537 ◽  
Author(s):  
David J. Ullman ◽  
Anders E. Carlson ◽  
Faron S. Anslow ◽  
Allegra N. LeGrande ◽  
Joseph M. Licciardi
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Last Deglaciation ◽  
The Last Deglaciation

scholarly journals Near-constant retreat rate of a terrestrial margin of the Laurentide Ice Sheet during the last deglaciation

Geology ◽  
2021 ◽  
Author(s):  
Thomas V. Lowell ◽  
Meredith A. Kelly ◽  
Jennifer A. Howley ◽  
Timothy G. Fisher ◽  
Peter J. Barnett ◽  
...  
Keyword(s):  
Bayesian Modeling ◽  
Gradual Increase ◽  
Ice Core ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Last Deglaciation ◽  
Last Glacial Period ◽  
The Last Deglaciation ◽  
Temperature Records ◽  
The Last Glacial

The Laurentide Ice Sheet (LIS) was the largest ice sheet during the last glacial period. An accurate representation of its behavior during the last deglaciation is critical to understanding its influence on and response to a changing climate. We use 10Be dating and Bayesian modeling to track the recession of the southwest sector of the Labrador Dome of the LIS along an ~500-km-long transect west of Lake Superior during the last deglaciation. This transect reflects terrestrial ice-margin retreat and crosses multiple moraine sets, with the southwestern part of the transect deglaciated by ca. 19 ka and the northeastern part deglaciated by ca. 10 ka. The predominant behavior of the ice margin during this interval is near-constant retreat with retreat rates varying between ~59 m/a and 38 m/a. The moraine sets mark standstills and/or readvances that in total constitute only ~17% of the retreat interval. The spatial and temporal pattern of ice-margin retreat tracked here differs from existing reconstructions that are based on using isochrons to define ice-margin positions. Acknowledging the uncertainties associated with the modeled ages of ice-margin retreat, we suggest that the overall retreat pattern is consistent with forcing by a gradual increase in Northern Hemisphere, high-latitude summer insolation. The pattern of ice-margin retreat is inconsistent with Greenland ice-core temperature records, and thus these records may not be suitable to drive models of the LIS.

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