Session: Glacial Climates (LGM, Last deglaciation, Ice sheet uncertainties, Glacial-interglacial cycles)
Author: Chuncheng Guo / email@example.com / Uni Research Climate, and Bjerknes Centre for Climate Research
Co-author: Kerim Nisancioglu, Department of Earth Science, University of Bergen, and Bjerknes Centre for Climate Research;
Mats Bentsen, Uni Research Climate, and Bjerknes Centre for Climate Research;
Ingo Bethke, Uni Research Climate, and Bjerknes Centre for Climate Research;
Zhongshi Zhang, Uni Research Climate, and Bjerknes Centre for Climate Research;
With recent model developments at the Bjerknes Centre for Climate Research (Norway), a new and efficient Norwegian Earth System Model (NorESM) version with 2-degree atmosphere and 1-degree ocean has been configured for paleo-modelling. Here we present fully coupled climate simulations of a pre-industrial control run and a MIS3 experiment at 38 ka BP, both integrated for 2000 years . We will discuss the large scale climate features of MIS3 relative to today, including ocean overturning circulation, surface temperatures, and atmospheric circulation patterns. We focus on the climatic conditions in the Arctic Ocean and Nordic Seas and discuss ocean circulation, vertical stratification and sea ice conditions. Simulated surface temperature during MIS3 is globally colder except in the periphery of the North Atlantic subpolar gyre region; AMOC is slightly stronger compared to modern day, with a deeper penetration of NADW; MIS3 also exhibits a stronger and more contracted subpolar gyre. Additional sensitivity experiments with freshwater input mimicking ice rafting events from the large land based ice sheets are also analysed. Preliminary results from these sensitivity experiments show a significant difference in ocean and sea ice response as well as Greenland temperature to freshwater input from the Laurentide versus the Fennoscandian ice sheets.