Session: Warm Climates (Mid-Holocene, Last interglacial, Deep-time, Pliocene)
Author: Chuncheng Guo / firstname.lastname@example.org / 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;
Zhongshi Zhang, Uni Research Climate, and Bjerknes Centre for Climate Research;
Following PMIP3 protocols, we performed four 1000-year long time slices of the Last Interglacial (LIG) simulations (130, 125, 120, 115 ka BP) with a recently developed efficient version of the Norwegian Earth System Model (2-degree atmosphere; 1-degree ocean). We will present large-scale features of the simulated LIG climates, with more focus on the ocean and sea ice dynamics in the North Atlantic and Arctic region. Comparison of our model results with SST proxy data shows reasonable agreement. Early LIG (130 and 125 ka) feature a stonger AMOC and less Antarctic Bottom Water (AABW), whereas late LIG feature a weaker AMOC and more ABWW. Late LIG features more Arctic sea ice in the model, which rejects more salt and leads to a higher SSS in the Arctic. More sea ice also results in higher sea ice export through the Fram Strait and the Denmark Strait. Higher SSS in the Arctic can be exported to the Nordic Seas and the North Atlantic, which counteracts the effects that more sea ice export leads to a fresher sea surface. The net effect is a freshening pattern along the Greenland coast and more saline pattern in the Baffin Bay and the North Atlantic.