Pre-industrial and mid-Pliocene AGCM simulation with NorESM-L

Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Abstract In the Pliocene Model Intercomparison Project (PlioMIP), two sets of experiments are suggested. One includes a reference and a mid-Pliocene experiment run with atmosphere general circulation models (AGCM experiments, referred to as Experiments I), the other includes a pre-industrial and a mid-Pliocene experiment run with coupled 5 ocean-atmosphere general circulation models (AOGCM experiments, referred to as Experiment II). In this paper, we describe the AGCM experiments with the atmosphere model in the low resolution version of the Norwegian Earth System Model (NorESM-L), and also assess the potential uncertainties in analyzing mid-Pliocene climate anomalies , due to choosing SST fields for the reference experiment. We carry out a mid-10 Pliocene experiment, a control experiment forced by the modern SST fields, and a pre-industrial experiment forced by the monthly SST fields from HadISST averaged between 1879 and 1900. Our experiments illustrate that the simulated mid-Pliocene global annual mean SAT is 17.1 • C. It is 2.5 • C warmer than the control experiment, but 2.7 • C warmer than the pre-industrial experiment. We find that the uncertainties in 15 analyses of mid-Pliocene climate anomalies are small on a global scale, but still large on a regional scale. On the regional scale, these uncertainties should be noticed and assessed in future PlioMIP studies.