Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.470 IF 3.470
  • IF 5-year value: 4.009 IF 5-year
    4.009
  • CiteScore value: 3.45 CiteScore
    3.45
  • SNIP value: 1.166 SNIP 1.166
  • IPP value: 3.28 IPP 3.28
  • SJR value: 1.929 SJR 1.929
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 64 Scimago H
    index 64
  • h5-index value: 43 h5-index 43
Volume 12, issue 8
Clim. Past, 12, 1601–1617, 2016
https://doi.org/10.5194/cp-12-1601-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Clim. Past, 12, 1601–1617, 2016
https://doi.org/10.5194/cp-12-1601-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 03 Aug 2016

Research article | 03 Aug 2016

The role of basal hydrology in the surging of the Laurentide Ice Sheet

William H. G. Roberts1,2, Antony J. Payne2, and Paul J. Valdes1 William H. G. Roberts et al.
  • 1BRIDGE, School of Geographical Sciences, University of Bristol, Bristol, UK
  • 2Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, UK

Abstract. We use the Glimmer ice sheet model to simulate periodic surges over the Laurentide Ice Sheet during the Last Glacial Maximum. In contrast to previous studies we use the depth of water at the base of the ice sheet as the switch for these surges. We find that the surges are supported within the model and are quite robust across a very wide range of parameter choices, in contrast to many previous studies where surges only occur for rather specific cases. The robustness of the surges is likely due to the use of water as the switch mechanism for sliding. The statistics of the binge–purge cycles resemble observed Heinrich events. The events have a period of between 10 and 15 thousand years and can produce fluxes of ice from the mouth of Hudson Strait of 0.05 Sv – a maximum flux of 0.06 Sv is possible. The events produce an ice volume of 2.50  ×  106 km3, with a range of 4.30  ×  106–1.90  ×  106 km3 possible. We undertake a suite of sensitivity tests varying the sliding parameter, the water drainage scheme, the sliding versus water depth parameterisation and the resolution, all of which support the ice sheet surges. This suggests that internally triggered ice sheet surges were a robust feature of the Laurentide Ice Sheet and are a possible explanation for the observed Heinrich events.

Publications Copernicus
Download
Short summary
There are observations from ocean sediment cores that during the last ice age the Laurentide Ice Sheet, which sat over North America, periodically surged. In this study we show the role that water at the base of an ice sheet plays in these surges. We show that with a more realistic representation of water drainage at the base of the ice sheet than usually used, these surges can still occur and that they are triggered by an internal ice sheet instability; no external trigger is needed.
There are observations from ocean sediment cores that during the last ice age the Laurentide Ice...
Citation