PlioMIP1 simulations with CESM1(CAM4) [CCSM4] and CESM1.2(CAM5)

The CESM PlioMIP1 project, completed by Bette Otto-Bliesner, Ran Feng, Esther Brady, and Nan Rosenbloom, is a set of published simulations to understand mid-Pliocene climate variability, similarities and dissimilarities with pre-Industrial, and model skills in simulating this period. One experiment contributes to the Pliocene Model Intercomparison Project phase 1 (PlioMIP1). The rest are sensitivity experiments branched from the PlioMIP1 experiment. These sensitivity experiments quantify mid-Pliocene climate responses to closure of the Bering Strait, closure of the Canadian Arctic Archipelago Straits, variations of CO2, variations of orbital forcings, absence of the western Antarctic Ice Sheet, and changes in tropospheric aerosol conditions.

All simulations are performed with the atmosphere-ocean-land-sea ice coupled CESM1 at the nominal 1-degree latitude/longitude. Except for experiments designed to understand responses to aerosol changes (used CAM5.3), the rest of experiments use the CAM4 version of the atmospheric model. 

Further details are provided in the papers below:

  • Rosenbloom, N.A., B. L. Otto-Bliesner, E. C. Brady, and P. J. Lawrence, 2013:  Simulating the mid-Pliocene Warm Period with the CCSM4 model. Geosci. Model Dev., 6, 549-561.
  • Otto-Bliesner, B.L., A. Jahn, R. Feng, E.C. Brady, A. Hu, and M. Lofverstrom, 2017: Amplified North Atlantic warming in the late Pliocene by changes in Arctic gateways. Geophysical Research Letters, 44, 957-964.
  • Feng, R., B.L. Otto-Bliesner, T.L. Fletcher, C.R. Tabor, A.P. Ballantyne, and E.C. Brady, 2017: Amplified Late Pliocene terrestrial warmth in northern high latitudes from greater radiative forcing and closed Arctic Ocean gateways. Earth and Planetary Science Letters, 466, 129-138.
  • Feng, R., B. Otto-Bliesner, Y. Xu, E. Brady, T. Fletcher, and A. Ballantyne, 2019: Contributions of aerosol-cloud interactions to mid-Piacenzian seasonally sea ice-free Arctic Ocean. Geophysical Research Letters.

We kindly ask that you reference the appropriate paper(s) and acknowledge the PaleoclimateWG and computing resources from NSF / NCAR CISL when presenting results based on these simulations in either oral or written form. 

Project Details

  • Simulation Names:
    • b40.plio.FV1.003ext (CCSM4)
    • b.e12.B1850CN.f09_g16.plio.002 (CESM1.2 w/CAM4)
    • b40.plio.FV1.003bsc_ext (CCSM4 w/Bering St. Closed)
    • b.e12.B1850CN.f09_g16.plioCA.001 (CESM1.2-CAM4 w/Canadian Archipelago closed)
    • b.e12.B1850CN.f09_g16.plioCA_BSC (CESM1.2-CAM4 w/Canadian Archipelago and BS closed)
    • b.e12.B1850CN.f09_g16.pliolCO2.001 (CESM1.2-CAM4 w/CO2=350)
    • b.e12.B1850CN.f09_g16.pliohCO2.001(CESM1.2-CAM4 w/CO2=450)
    • b.e12.B1850CN.f09_g16.pliohorb.001 (CESM1.2-CAM4 w/NH July Max Insolation)
    • b.e12.B1850CN.f09_g16.pliolorb.001 (CESM1.2-CAM4 w/NH July Min Insolation)
    • b.e12.B1850CN.f09_g16.pliohorb.3159.001 (CESM1.2-CAM4 w/ NH Ann Max Insolation
    • b.e12.B1850CN.f09_g16.plio_cam1850 (CESM1.2-CAM5 w/CAM5.3 PI emissions)
    • b.e12.B1850CN.f09_g16.plio_cam2000 (CESM1.2-CAM5 w/CAM5.3 yr2000 emissions)
  • Model Versions: CESM1(CAM4, ie.CCSM4) and CESM1.2(CAM5)
  • Resolution: 0.9x1.25_gx1v6 (nominal 1o grid)
  • Years: varies
  • Ensemble Size: one each 
  • Time Frequencies Saved: Monthly, Daily [atm,ocn,ice], and 6-hourly [atm]
  • Machine: NWSC:Cheyenne and Yellowstone

Data Acquisition

The PlioMIP1 simulations are available on the NWSC computing storage at /glade/collections/cdg/data/CESM1-CCSM4_mid-Pliocene and NCAR's Climate Data Gateway (CDG) here

For CDG downloads (


Diagnostics for the PlioMIP1 simulations can be found here