Articles | Volume 12, issue 3
Clim. Past, 12, 749–767, 2016
Clim. Past, 12, 749–767, 2016

Research article 23 Mar 2016

Research article | 23 Mar 2016

Arctic sea ice simulation in the PlioMIP ensemble

Fergus W. Howell1, Alan M. Haywood1, Bette L. Otto-Bliesner2, Fran Bragg3, Wing-Le Chan4, Mark A. Chandler5, Camille Contoux6, Youichi Kamae7, Ayako Abe-Ouchi4,8, Nan A. Rosenbloom2, Christian Stepanek9, and Zhongshi Zhang10 Fergus W. Howell et al.
  • 1School of Earth and Environment, University of Leeds, Leeds, UK
  • 2National Center for Atmospheric Research, Boulder, CO, USA
  • 3School of Geographical Sciences, University of Bristol, Bristol, UK
  • 4Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
  • 5Columbia University – NASA/GISS-E2-R, New York, NY, USA
  • 6Aix-Marseille Université, CNRS, IRD, CEREGE UM34, Aix en Provence, France
  • 7Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
  • 8Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
  • 9Alfred Wegener Institute – Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
  • 10Bjerknes Centre for Climate Research, Bergen, Norway

Abstract. Eight general circulation models have simulated the mid-Pliocene warm period (mid-Pliocene, 3.264 to 3.025 Ma) as part of the Pliocene Modelling Intercomparison Project (PlioMIP). Here, we analyse and compare their simulation of Arctic sea ice for both the pre-industrial period and the mid-Pliocene. Mid-Pliocene sea ice thickness and extent is reduced, and the model spread of extent is more than twice the pre-industrial spread in some summer months. Half of the PlioMIP models simulate ice-free conditions in the mid-Pliocene. This spread amongst the ensemble is in line with the uncertainties amongst proxy reconstructions for mid-Pliocene sea ice extent. Correlations between mid-Pliocene Arctic temperatures and sea ice extents are almost twice as strong as the equivalent correlations for the pre-industrial simulations. The need for more comprehensive sea ice proxy data is highlighted, in order to better compare model performances.

Short summary
Simulations of pre-industrial and mid-Pliocene Arctic sea ice by eight GCMs are analysed. Ensemble variability in sea ice extent is greater in the mid-Pliocene summer, when half of the models simulate sea-ice-free conditions. Weaker correlations are seen between sea ice extent and temperatures in the pre-industrial era compared to the mid-Pliocene. The need for more comprehensive sea ice proxy data is highlighted, in order to better compare model performances.