Modelling the Northern Hemisphere ice sheets during the interglacial MIS-13

• Main Authors: Yin, Qiuzhen, Berger, A., Ganopolski, A., Goelzer, H., Guo, Z.T., Huybrechts, P.
• Other Authors: UCL - SST/ELI/ELIC - Earth & Climate
• Format: Conference Object
• Language: Ndonga
• Published: 2015
• Subjects: Greenland; Ice Sheet
• Online Access: http://hdl.handle.net/2078.1/168508

MIS-13 is observed to be the coolest interglacial of the past 800,000 years in southern high latitudes and its CO2 concentration is about 40 ppmv lower than during more recent interglacials. The benthic δ18O records also indicate larger continental ice sheets and/or cooler deep ocean during MIS-13. These data let assume that ice sheets other than on Greenland might have existed in the Northern Hemisphere (NH) during this interglacial. This is however questioned by the fact that diverse proxy records suggest MIS-13 to be as warm as or warmer than other interglacials in the NH. Here we investigate the NH ice sheets configuration during MIS-13 through a modelling approach involving two climate models and two ice sheet models. The stand-alone NHISM ice sheet model is forced by precipitation and temperature fields provided by transient simulations made with the model LOVECLIM. These 50,000-year long transient simulations cover the whole peak of MIS-13.1 and take into account changes in CO2 concentration, insolation and ice sheets (provided by the CLIMBER-SICOPOLIS climate-ice sheet coupled model). LOVECLIM-NHISM and CLIMBER-SICOPOLIS give similar results although small differences exist. Interestingly, both pairs of models simulate no significant additional ice sheets in the NH at the two sub-peaks MIS-13.11 and -13.13. This means that the effect of a lower CO2 concentration is counterbalanced by higher summer insolation when NH summer occurs at perihelion. However, a non-negligible Scandinavian ice sheet is simulated during the stadial MIS-13.12. During this stadial, the NH summer occurring at aphelion (like today) allows the lower CO2 concentration to initiate an additional ice sheet in the NH. These modelling results show the response of climate and NH ice sheets to different combinations of insolation and CO2, and highlight the importance and necessity of obtaining direct and regional proxies for reconstructing the paleo-history of ice sheets.