A multi-model CMIP6 study of Arctic sea ice at 127 ka: Sea ice data compilation and model differences
- 1British Antarctic Survey, Cambridge, UK [four first names are joint first authors]
- 2Laboratoire des Sciences du Climat et de l’Environnement,Institut Pierre Simon Laplace, Université Paris-Saclay, CEA Saclay, L'Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
- 3Departement des sciences de la Terre et de l'atmosphere, Universite du Quebec, Montreal, Canada
- 4Department of Meteorology, University of Reading, Reading, UK
- 5Alfred Wegener Institute, Bremerhaven, Germany
- *A full list of authors appears at the end of the abstract
The Last interglacial (LIG) is a period with increased summer insolation at high northern latitudes, which results in strong changes in the terrestrial and marine cryosphere. Understanding the mechanisms for this response via climate modelling and comparing the models’ representation of climate reconstructions is one of the objectives set up by the Paleoclimate Modelling Intercomparison Project for its contribution to the sixth phase of the Coupled Model Intercomparison Project. Here we analyse the results from 12 climate models in terms of Arctic sea ice. The mean pre-industrial to LIG reduction in minimum sea ice area (SIA) reaches 59% (multi-model mean LIG area is 2.21 mill. km2, compared to 5.85 mill. km2 for the PI), and the range of model results for LIG minimum sea ice area (from 0.02 to 5.65 mill. km2) is larger than for PI (from 4.10 to 8.30 mill. km2). On the other hand there is little change for the maximum sea ice area (which is 12 mill. km2 for both the PI and the LIG, with a standard deviation of 1.04 mill. km2 for PI and 1.21 mill. km2 for LIG). To evaluate the model results we synthesize LIG sea ice data from marine cores collected in the Arctic Ocean, Nordic Seas and northern North Atlantic. South of 78oN, in the Atlantic and Nordic seas, the LIG was seasonally ice-free. North of 78oN there are some discrepancies between sea ice reconstructions based on dinocysts/foraminifers/ostracods and IP25: some sites have both seasonal and perennial interpretations based on the same core, but different indicators. Because of the conflicting interpretations it is not possible for any one model to match every data point in our data synthesis, or say whether the Arctic was seasonally ice-free. Drivers for the inter-model differences are: different phasing of the up and down short-wave anomalies over the Arctic ocean, associated with differences in model albedo; possible cloud property differences, in terms of optical depth; LIG ocean circulation changes which occur for some, but not all, LIG simulations. Finally we note that inter-comparisons between the LIG simulations, and simulations with moderate CO2 increase (during the transition to high CO2 levels), may yield insight into likely 21C Arctic sea ice changes using these LIG simulations.
6The University of Tokyo, Japan 7Department of Atmospheric Sciences, University of Washington, US 8National Center for Atmospheric Research, Boulder, US 9CSIRO Oceans and Atmosphere, Hobart, TAS, Australia 10NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway 11Climate Change Research Centre, The University of New South Wales, Sydney, Australia 12Institute of Geography, Russian Academy of Science, Moscow, Russia 13Department of Earth Science, University of Bergen, Bjerknes Centre for Climate Research, Allégaten 41, 5007, Bergen, Norway 14Centre for Earth Evolution and Dynamics, University of Oslo, Oslo, Norway 15University College London, UK 16Chinese Academy of Sciences, Beijing, China 17Institute of Numerical Mathematics, Russian Academy of Sciences, Moscow, Russia 18Department of Physical Geography, Stockholm University, Stockholm, Sweden 19Department of Atmospheric Science, School of Environmental Studies, China University of Geoscience (Wuhan), Wuhan, China 20CSIRO Oceans and Atmosphere, Aspendale, VIC, Australia *The first four authors equally contributed to the manuscript
How to cite: Sime, L., Kageyama, M., Sicard, M., Guarino, M.-V., de Vernal, A., Schroeder, D., Stein, R., and Malmierca-Vallet, I. and the Ayako Abe-Ouchi6, Cecilia Bitz7, Pascale Braconnot1, Esther Brady8, Matthew A. Chamberlain9, Danny Feltham4, Chuncheng Guo10, Gerrit Lohmann5, Katrin Meissner11, Laurie Menviel11, Polina Morozova12, Kerim H. Nisancioglu13,14, Bette Otto-Bliesner8, Ryouta : A multi-model CMIP6 study of Arctic sea ice at 127 ka: Sea ice data compilation and model differences, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8628, https://doi.org/10.5194/egusphere-egu2020-8628, 2020.
