Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 10, 1453-1471, 2014
http://www.clim-past.net/10/1453/2014/
doi:10.5194/cp-10-1453-2014
© Author(s) 2014. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
31 Jul 2014
Evolution of the large-scale atmospheric circulation in response to changing ice sheets over the last glacial cycle
M. Löfverström1,3, R. Caballero1,3, J. Nilsson1,3, and J. Kleman2,3 1Department of Meteorology, Stockholm University, Stockholm, Sweden
2Department of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, Sweden
3Bolin Center for Climate Research, Stockholm University, Stockholm, Sweden
Abstract. We present modelling results of the atmospheric circulation at the cold periods of marine isotope stage 5b (MIS 5b), MIS 4 and the Last Glacial Maximum (LGM), as well as the interglacial. The palaeosimulations are forced by ice-sheet reconstructions consistent with geological evidence and by appropriate insolation and greenhouse gas concentrations. The results suggest that the large-scale atmospheric winter circulation remained largely similar to the interglacial for a significant part of the glacial cycle. The proposed explanation is that the ice sheets were located in areas where their interaction with the mean flow is limited. However, the LGM Laurentide Ice Sheet induces a much larger planetary wave that leads to a zonalisation of the Atlantic jet. In summer, the ice-sheet topography dynamically induces warm temperatures in Alaska and central Asia that inhibits the expansion of the ice sheets into these regions. The warm temperatures may also serve as an explanation for westward propagation of the Eurasian Ice Sheet from MIS 4 to the LGM.

Citation: Löfverström, M., Caballero, R., Nilsson, J., and Kleman, J.: Evolution of the large-scale atmospheric circulation in response to changing ice sheets over the last glacial cycle, Clim. Past, 10, 1453-1471, doi:10.5194/cp-10-1453-2014, 2014.
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