Response of interglacial climate to insolation and CO2 during the past 800,000 years

• Main Authors: Yin, Qiuzhen, Berger, Andre, 2015 INQUA Congress
• Other Authors: UCL - SST/ELI/ELIC - Earth & Climate
• Format: Conference Object
• Language: Ndonga
• Published: 2015
• Subjects: Sea ice
• Online Access: http://hdl.handle.net/2078.1/168502

The climate of nine interglacials of the past 800,000 years has been simulated with both snapshot and transient experiments using the model LOVECLIM. These simulations allow to investigate the relative contributions of insolation and CO2 to the intensity and duration of each interglacial as well as the differences between the interglacials at global and regional scales. The transient simulations which cover a full range of precession, obliquity and eccentricity allow to investigate the response of different climate variables at different latitudes to these three astronomical parameters. The results show that the relative contribution of insolation and CO2 on the warmth intensity varies from one interglacial to another. They also show that CO2 plays a dominant role on the variations of the global annual mean temperature and the southern high latitude temperature and sea ice, whereas, insolation plays a dominant role on the variations of monsoon precipitation, vegetation and of the northern high latitude temperature and sea ice. The results also show that, compared to today, the past interglacials are warmer during boreal summer and cooler during boreal winter leading to a warmer annual mean with varying length for different interglacials. The warm interval of MIS-11 is the longest, confirming its long duration as found in proxy records. The long duration of MIS-11 is related to a particular combination of eccentricity, obliquity and precession as well as to a high CO2 concentration. The transient simulations allow also to look for past interglacial analogues for the whole MIS-1 and its natural future. As far as the variations in both annual and seasonal temperatures are concerned, MIS-19 is the best analogue of MIS-1 and its natural near future. The differences between the simulated seasonal behaviour of the past interglacials highlight the importance of seasonal climate reconstruction and therefore the necessity to obtain seasonal proxies.