Session: Benchmarking & cross-cutting Group 1 (Isotope modelling, COMPARE)
Author: André Paul / firstname.lastname@example.org / MARUM, University of Bremen
Co-author: Michal Kucera, MARUM, University of Bremen;
Takasumi Kurahashi-Nakamura, MARUM, University of Bremen;
Stefan Mulitza, MARUM, University of Bremen;
Matthias Prange, MARUM, University of Bremen;
The quantification of model performance in simulations of past climate conditions requires both suitable paleo-data and skill assessment methods.
We employ the results of multiple simulations by the NCAR Community Climate System Model version 3 (CCSM3) as well as ocean state estimates by the MIT general circulation model (MITgcm), which feature different states of the Atlantic Meridional Overturning Circulation (AMOC) during the Last Glacial Maximum (LGM): shallower and weaker, stronger and deeper, stronger but shallower. The corresponding ocean circulation and climate is compared to paleoceanographic sea-surface and deep-ocean temperature reconstructions and, in the case of the MITgcm, oxygen and carbon isotopes. We use different summary diagrams (e.g., the so-called Taylor and target diagrams) to display the degree of consistency between the models and the paleo-data and we find, for example, that a more stratified Atlantic Ocean and shallower AMOC during the LGM are consistent with most paleo-data and that the sign and magnitude of a modern model bias may strongly affect a simulation of a different climate state.
Finally, we point out how our study contributes to the COMPARE (Comparing Ocean Models to Paleo-ARchivEs) working group.