Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/cp-2018-26
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
03 Apr 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Climate of the Past (CP).
Arctic warming induced by the Laurentide ice sheet topography
Johan Liakka1 and Marcus Lofverstrom2 1Nansen Environmental and Remote Sensing Center, Bjerknes Centre for Climate Research, Thormøhlensgate 47, Bergen 5006, Norway
2National Center for Atmospheric Research, 3090 Center Green Dr., 80301, Boulder, Colorado, USA
Abstract. It is well known that ice sheet-climate feedbacks are essential for realistically simulating the spatio-temporal evolution of continental ice sheet over glacial-interglacial cycles. However, many of these feedbacks are dependent on the ice sheet thickness, which is poorly constrained by proxy data records. For example, height estimates of the Laurentide Ice Sheet (LIS) topography at the Last Glacial Maximum (LGM; ~ 21,000 years ago) vary by more than 1 km between different ice-sheet reconstructions. In order to better constrain the LIS elevation it is therefore important to understand how the mean climate is influenced by elevation discrepancies of this magnitude. Here we use an atmospheric model coupled to a slab-ocean model to analyze the LGM surface temperature response to a broad range of LIS elevations (from 0 to over 4 km). We find that raising the LIS topography induces a widespread surface warming in the Arctic region, amounting to approximately 1.5 °C per km elevation increase, or about 6.5 °C for the highest LIS. The warming is attributed to an increased northward energy flux by atmospheric stationary waves, reinforced by surface albedo and water vapor feedbacks, which account for about two-thirds of the total temperature response. These results suggest a positive feedback between continental-scale ice sheets and the Arctic temperatures that may help constrain LIS elevation estimates for the LGM and explain differences in ice distribution between the LGM and earlier glacial periods.
Citation: Liakka, J. and Lofverstrom, M.: Arctic warming induced by the Laurentide ice sheet topography, Clim. Past Discuss., https://doi.org/10.5194/cp-2018-26, in review, 2018.
Johan Liakka and Marcus Lofverstrom
Johan Liakka and Marcus Lofverstrom
Johan Liakka and Marcus Lofverstrom

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