Are paleoclimate model ensembles consistent with the MARGO data synthesis? 1RIGC/JAMSTEC, Yokohama Institute for Earth Sciences, Yokohama, Japan
22 Aug 2011
2MARUM – Center for Marine Environmental Science and Department of Geosciences, University of Bremen, Germany
3AORI, University of Tokyo, Japan
Received: 10 Feb 2011 – Published in Clim. Past Discuss.: 01 Mar 2011Abstract. We investigate the consistency of various ensembles of climate model
simulations with the Multiproxy Approach for the Reconstruction of the
Glacial Ocean Surface (MARGO) sea surface temperature data synthesis. We
discover that while two multi-model ensembles, created through the
Paleoclimate Model Intercomparison Projects (PMIP and PMIP2), pass our simple
tests of reliability, an ensemble based on parameter variation in a single
model does not perform so well. We show that accounting for observational
uncertainty in the MARGO database is of prime importance for correctly
evaluating the ensembles. Perhaps surprisingly, the inclusion of a coupled
dynamical ocean (compared to the use of a slab ocean) does not appear to
cause a wider spread in the sea surface temperature anomalies, but rather
causes systematic changes with more heat transported north in the Atlantic.
There is weak evidence that the sea surface temperature data may be more
consistent with meridional overturning in the North Atlantic being similar
for the LGM and the present day. However, the small size of the PMIP2
ensemble prevents any statistically significant results from being obtained.
Revised: 05 Jul 2011 – Accepted: 22 Jul 2011 – Published: 22 Aug 2011
Citation: Hargreaves, J. C., Paul, A., Ohgaito, R., Abe-Ouchi, A., and Annan, J. D.: Are paleoclimate model ensembles consistent with the MARGO data synthesis?, Clim. Past, 7, 917-933, doi:10.5194/cp-7-917-2011, 2011.