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
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....