Evaluation of PMIP2 and PMIP3 simulations of mid-Holocene climate in the Indo-Pacific, Australasian and Southern Ocean regions

Authors

Duncan Ackerley, Monash University
Jessica M. Reeves, University of Ballarat, Federation University AustraliaFollow
Cameron Barr, University of Adelaide
Helen C. Bostock, National Institute of Water and Atmospheric Research, New Zealand
Kathryn Fitzsimmons, Max Planck Institute for Evolutionary AnthropologyFollow
Michael-Shawn Fletcher, University of Melbourne
Chris Gouramanis, National Univeristy of Singapore
Helen V. McGregor, University of WollongongFollow
Scott D. Mooney, University of New South WalesFollow
Steven J. Phipps, University of New South Wales, University of TasmaniaFollow
John Tibby, University of AdelaideFollow
Jonathan Tyler, University of Adelaide, University of Oxford

RIS ID

114606

Publication Details

Ackerley, D., Reeves, J., Barr, C., Bostock, H., Fitzsimmons, K., Fletcher, M., Gouramanis, C., McGregor, H., Mooney, S., Phipps, S. J., Tibby, J. & Tyler, J. (2017). Evaluation of PMIP2 and PMIP3 simulations of mid-Holocene climate in the Indo-Pacific, Australasian and Southern Ocean regions. Climate of the Past, 13 (11), 1661-1684.

Abstract

This study uses the "simplified patterns of temperature and effective precipitation" approach from the Australian component of the international palaeoclimate synthesis effort (INTegration of Ice core, MArine and TErrestrial records - OZ-INTIMATE) to compare atmosphere-ocean general circulation model (AOGCM) simulations and proxy reconstructions. The approach is used in order to identify important properties (e.g. circulation and precipitation) of past climatic states from the models and proxies, which is a primary objective of the Southern Hemisphere Assessment of PalaeoEnvironment (SHAPE) initiative. The AOGCM data are taken from the Paleoclimate Modelling Intercomparison Project (PMIP) mid-Holocene (ca. 6000 years before present, 6 ka) and pre-industrial control (ca. 1750 CE, 0 ka) experiments. The synthesis presented here shows that the models and proxies agree on the differences in climate state for 6 ka relative to 0 ka, when they are insolation driven. The largest uncertainty between the models and the proxies occurs over the Indo-Pacific Warm Pool (IPWP). The analysis shows that the lower temperatures in the Pacific at around 6 ka in the models may be the result of an enhancement of an existing systematic error. It is therefore difficult to decipher which one of the proxies and/or the models is correct. This study also shows that a reduction in the Equator-to-pole temperature difference in the Southern Hemisphere causes the mid-latitude westerly wind strength to reduce in the models; however, the simulated rainfall actually increases over the southern temperate zone of Australia as a result of higher convective precipitation. Such a mechanism (increased convection) may be useful for resolving disparities between different regional proxy records and model simulations. Finally, after assessing the available datasets (model and proxy), opportunities for better model-proxy integrated research are discussed.

Grant Number

ARC/FT140100286