The impact of the North American glacial topography on the evolution of the Eurasian ice sheet over the last glacial cycle

Johan Liakka, Marcus Löfverström, Florence Colleoni

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Modeling studies have shown that the continental-scale ice sheets in North America and Eurasia in the last glacial cycle had a large influence on the atmospheric circulation and thus yielded a climate distinctly different from the present. However, to what extent the two ice sheets influenced each others' growth trajectories remains largely unexplored. In this study we investigate how an ice sheet in North America influences the downstream evolution of the Eurasian ice sheet, using a thermomechanical ice-sheet model forced by climate data from atmospheric snapshot experiments of three distinctly different phases of the last glacial cycle: the Marine Isotope Stages 5b, 4, and 2 (Last Glacial Maximum - LGM). Owing to the large uncertainty associated with glacial changes in the Atlantic meridional overturning circulation, each atmospheric snapshot experiment was conducted using two distinctly different ocean heat transport representations. Our results suggest that changes in the North American paleo-topography may have largely controlled the zonal distribution of the Eurasian ice sheet. In the MIS4 and LGM experiments, the Eurasian ice sheet migrates westward towards the Atlantic sector - largely consistent with geological data and contemporary ice-sheet reconstructions - due to a low wave number stationary wave response, which yields a cooling in Europe and a warming in northeastern Siberia. The expansion of the North American ice sheet between MIS4 and the LGM amplifies the Siberian warm anomaly, which limits the glaciation there and may therefore help explain the progressive westward migration of the Eurasian ice sheet in this time period. The ocean heat transport only has a small influence on the stationary wave response to the North American glacial topography; however, because temperature anomalies have a smaller influence on an ice sheet's ablation in a colder climate than in a warmer one, the impact of the North American glacial topography on the Eurasian ice-sheet evolution is reduced for colder surface conditions in the North Atlantic. While the Eurasian ice sheet in the MIS4 and the LGM experiments appears to be in equilibrium with the simulated climate conditions, the MIS5b climate forcing is too warm to grow an ice sheet in Eurasia. First-order sensitivity experiments suggest that the MIS5b ice sheet was established during preceding colder stages.

Original languageEnglish (US)
Pages (from-to)1225-1241
Number of pages17
JournalClimate of the Past
Volume12
Issue number5
DOIs
StatePublished - May 25 2016
Externally publishedYes

ASJC Scopus subject areas

  • Global and Planetary Change
  • Stratigraphy
  • Palaeontology

Fingerprint

Dive into the research topics of 'The impact of the North American glacial topography on the evolution of the Eurasian ice sheet over the last glacial cycle'. Together they form a unique fingerprint.

Cite this