Two Interglacials: Scientific Objectives and Experimental Designs for CMIP6 and PMIP4 Holocene and Last Interglacial Simulations
Bette L. Otto-Bliesner,Pascale Braconnot,Sandy P. Harrison,Daniel J. Lunt,Ayako Abe-Ouchi,Samuel Albani,Patrick J. Bartlein,Emilie Capron,Anders E. Carlson,Andrea Dutton,Hubertus Fischer,Heiko Goelzer,Aline Govin,Alan Haywood,Fortunat Joos,Allegra N. Legrande,William H. Lipscomb,Gerrit Lohmann,Natalie Mahowald,Christoph Nehrbass-Ahles,Jean-Yves Peterschmidt,Francesco S.-R. Pausata,Steven Phipps,and Hans Renssen
Institute for Marine and Antarctic Studies, Uinversity of Tasmania, Hobart, Tasmania 7001, Australia
Department of Earth Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands
Department of Environmental and Health Studies, University College of Southeast Norway, 3800 Bø i Telemark, Norway
Abstract. Two interglacial epochs are included in the suite of paleoclimate simulations in the present phase of the Coupled Model Intercomparison Project (CMIP6). Equilibrium simulations of the mid-Holocene (midHolocene, 6000 years before present) and the Last Interglacial (lig127k, 127,000 years before present) are designed to examine the impact of changes in orbital forcing at times when atmospheric greenhouse gas levels were similar to those of the preindustrial period and the continental configurations were almost identical to modern. These simulations test our understanding of the interplay between radiative forcing and atmospheric circulation, and the connections among large-scale and regional climate changes giving rise to phenomena such as land-sea contrast and high-latitude amplification in temperature changes, and responses of the monsoons, as compared to today. They also provide an opportunity, through carefully designed additional sensitivity experiments as part of the Paleoclimate Modeling Intercomparison Project (PMIP4), to quantify the strength of atmosphere, ocean, cryosphere, and land-surface feedbacks. Sensitivity experiments are proposed to investigate the role of freshwater forcing in triggering abrupt climate changes within interglacial epochs. These feedback experiments naturally lead to a focus on climate evolution during interglacial periods, which will be examined through transient experiments. Analyses of the sensitivity simulations will also focus on interactions between extratropical and tropical circulation, and the relationship between changes in mean climate state and climate variability on annual to multi-decadal timescales. The comparative abundance of paleoenvironmental data and of quantitative climate reconstructions for the Holocene and Last Interglacial make these two epochs ideal candidates for systematic evaluation of model performance, and such comparisons will shed new light on the importance of external feedbacks (e.g., vegetation, dust) and the ability of state-of-the-art models to simulate climate changes realistically.
This preprint has been retracted.
How to cite. Otto-Bliesner, B. L., Braconnot, P., Harrison, S. P., Lunt, D. J., Abe-Ouchi, A., Albani, S., Bartlein, P. J., Capron, E., Carlson, A. E., Dutton, A., Fischer, H., Goelzer, H., Govin, A., Haywood, A., Joos, F., Legrande, A. N., Lipscomb, W. H., Lohmann, G., Mahowald, N., Nehrbass-Ahles, C., Peterschmidt, J.-Y., Pausata, F. S.-R., Phipps, S., and Renssen, H.: Two Interglacials: Scientific Objectives and Experimental Designs for CMIP6 and PMIP4 Holocene and Last Interglacial Simulations, Clim. Past Discuss. [preprint], https://doi.org/10.5194/cp-2016-106, 2016.
Received: 16 Oct 2016 – Discussion started: 25 Oct 2016