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Article
Simulated climate conditions in Europe during the MIS 3 stadial
| Authors: |
Kjellström, E., Brandefelt, J., Näslund, J.-O., Smith, B., Strandberg, G., Voelker, A.H.L., Wohlfarth, B. |
| Document Type: |
Article |
| Pubstate: |
Accepted |
| Journal: |
Boreas |
| Volume: |
39
doi: 10.1111/j.1502-3885.2010.00143.x |
| Year: |
2010 |
AbstractMarine Isotope Stage 3 (MIS 3), which is the interval between 60 and 30 ka before present (BP), was characterized by oscillations between stadial and interstadial climates. This work is an effort to simulate climate conditions in Europe during a stadial in MIS 3 with state-of-the-art climate models. The models are: a fully coupled atmosphere-ocean global climate model (AOGCM), and a regional atmospheric climate model (RCM) that is used to dynamically downscale results from the global model to a higher horizontal resolution allowing for a more detailed investigation of the climate conditions over Europe. The vegetation in Europe is simulated off-line by a state-of-art dynamic vegetation model (DVM) forced by the climate from the RCM. The resulting vegetation is compared to the a priori vegetation used in the first simulation. In a subsequent step the RCM is rerun to yield a new climate that is more consistent with the vegetation. Forcing conditions for the simulations include orbital forcing, land-sea distribution, ice sheet configuration, and atmospheric greenhouse gas concentrations representative for 44 ka BP i.e. Greenland Stadial (GS) 12. The results show a cold climate on the global scale with a global annual mean surface temperature that is more than 5°C colder than the modern climate. This is still significantly warmer than what the same model system yields for the Last Glacial Maximum (LGM). Regionally, in northern Europe, the climate is much colder than today but also significantly warmer than during the LGM. The simulated climate is compared to proxy-based palaeo-data for sea-surface temperature. The comparison shows that the results are in broad agreement with available proxy data albeit with a possible cold bias in parts of the North Atlantic in summer. Given a prescribed restricted MIS 3 ice sheet configuration, with large ice free regions in Sweden and Finland, the AOGCM and RCM model simulations produce a cold and dry climate which is in line with such an ice sheet configuration during MIS 3 at the time of GS12. The simulated temperature climate, with prescribed ice-free conditions in south-central Fennoscandia, is favourable for development of permafrost growth but does not allow local ice sheet formation as all snow melts during summer.
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