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 Zhang10Fergus W. Howell et al. 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
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
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
Correspondence: Fergus W. Howell (eefwh@leeds.ac.uk)
Received: 02 Mar 2015 – Discussion started: 07 Apr 2015 – Revised: 09 Mar 2016 – Accepted: 10 Mar 2016 – Published: 23 Mar 2016
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.
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.
Simulations of pre-industrial and mid-Pliocene Arctic sea ice by eight GCMs are analysed....
