Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/cp-2017-143
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
27 Nov 2017
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Climate of the Past (CP).
Oceanic forcing of the Eurasian Ice Sheet on millennial time scales during the Last Glacial Period
Jorge Alvarez-Solas1,2, Rubén Banderas1,2, Alexander Robinson1,2,3,4, and Marisa Montoya1,2 1Dpto. Astrofísica y Ciencias de la Atmósfera; Facultad de Ciencias Físicas; Universidad Complutense de Madrid (UCM)
2Instituto de Geociencias (UCM-CSIC), Madrid, Spain
3Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany
4Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Greece
Abstract. The last glacial period (LGP; ca. 110–10 ka BP) was marked by the existence of two types of abrupt climatic changes, Dansgaard-Oeschger (D/O) and Heinrich (H) events. Although the mechanisms behind these are not fully understood, it is generally accepted that the presence of ice sheets played an important role in their occurrence. While an important effort has been made to investigate the dynamics and evolution of the Laurentide Ice Sheet (LIS) during this period, the Eurasian Ice Sheet (EIS) has not received much attention, in particular from a modeling perspective. However, meltwater discharge from this and other ice sheets surrounding the Nordic Seas is often implied as a potential cause of ocean instabilities that lead to glacial abrupt climate changes. Thus, a better understanding of its variations during the LGP is important to understand its role in glacial abrupt climate changes. Here we investigate the response of the EIS to millennial-scale climate variability during the LGP. We use a hybrid, three-dimensional, thermomechanical ice-sheet model that includes ice shelves and ice streams. The model is forced offline through a novel perturbative approach that includes the effect of both atmospheric and oceanic variations and provides a more realistic treatment of millennial-scale climatic variability than conventional methods. Our results show that the EIS responds with enhanced iceberg discharges in phase with interstadial warming in the North Atlantic. Separating the atmospheric and oceanic effects demonstrates the major role of the ocean in controlling the dynamics of the EIS on millennial time scales. While the atmospheric forcing alone is only able to produce modest iceberg discharges, warming of oceanic surface waters leads to much higher rates of iceberg discharges as a result of relatively strong basal melting within the margins of the ice sheet. Together with previous work, our results provide a consistent explanation for the timing of the responses of the LIS and the EIS to glacial abrupt climate changes.

Citation: Alvarez-Solas, J., Banderas, R., Robinson, A., and Montoya, M.: Oceanic forcing of the Eurasian Ice Sheet on millennial time scales during the Last Glacial Period, Clim. Past Discuss., https://doi.org/10.5194/cp-2017-143, in review, 2017.
Jorge Alvarez-Solas et al.
Jorge Alvarez-Solas et al.
Jorge Alvarez-Solas et al.

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Short summary
The last glacial period was marked by the existence of of abrupt climatic changes. It is generally accepted that the presence of ice sheets played an important role in their occurrence. While an important effort has been made to investigate the dynamics and evolution of the Laurentide Ice Sheet during this period, the Eurasian Ice Sheet (EIS) has not received much attention. Here we investigate the response of the EIS to millennial-scale climate variability. We use a hybrid 3D ice-sheet model.
The last glacial period was marked by the existence of of abrupt climatic changes. It is...
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