Isotope-Enabled Deglacial Slice Simulations with iCESM1.2: From 21 ka to Pre-Industrial (~3 ka Intervals)

This suite of isotope-enabled deglacial slice simulations was performed by Jiang Zhu as part of a collaboration between the University of Michigan (PI: Prof. Chris Poulsen) and the University of Arizona (PI: Prof. Jess Tierney). The simulations span from the Last Glacial Maximum (LGM, 21 ka) to the preindustrial era, with time slices at approximately 3 ka intervals: 21 ka, 18 ka, 16 ka, 14 ka, 12 ka, 9 ka, 6 ka, 3 ka, and preindustrial.

Two additional water-hosing experiments were conducted for 16 ka and 12 ka to represent the Heinrich and Younger Dryas events, respectively. The simulations incorporate changes in orbital parameters, greenhouse gas concentrations, and ice sheet configurations (based on ICE-6G reconstructions). Additional vegetation forcings, such as a Green Sahara, were implemented for 9 ka and 6 ka experiments.

These simulations were designed both to provide model priors for a paleoclimate data assimilation effort led by Prof. Jess Tierney and to investigate LGM climate forcings, feedbacks, and the role of vegetation in the Holocene Temperature Conundrum. Many boundary and initial condition files were generously provided by Dr. Pedro DiNezio.

Further details and background information can be found in the papers below:

  • Tierney, J. E., Zhu, J., King, J., Malevich, S. B., Hakim, G. J., & Poulsen, C. J. (2020). Glacial cooling and climate sensitivity revisited. Nature, 584(7822), 569–573. https://doi.org/10.1038/s41586-020-2617-x
  • Osman, M. B., Tierney, J. E., Zhu, J., Tardif, R., Hakim, G. J., King, J., & Poulsen, C. J. (2021). Globally resolved surface temperatures since the Last Glacial Maximum. Nature, 599(7884), 239-244. https://doi.org/10.1038/s41586-021-03984-4
  • Zhu, J., & Poulsen, C. J. (2020). LGM climate forcing and ocean dynamical feedback and their implications for estimating climate sensitivity. Climate of the Past Discussions, 2020, 1-24. https://doi.org/10.5194/cp-17-253-2021
  • Thompson, A. J., Zhu, J., Poulsen, C. J., Tierney, J. E., & Skinner, C. B. (2022). Northern Hemisphere vegetation change drives a Holocene thermal maximum. Science advances, 8(15), eabj6535. https://doi.org/10.1126/sciadv.abj6535

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

Project Details

  • Simulation Names:
    • b.e12.B1850C5.f19_g16.iPI.01: piControl
    • b.e12.B1850C5.f19_g16.iPI.01.21kaGaI: piControl with LGM GHG and Ice-sheet forcings
    • b.e12.B1850C5.f19_g16.iPI.01.21kaGHG: piControl with LGM GHG forcing
    • b.e12.B1850C5.f19_g16.iPI.01.21kaICE: piControl with LGM Ice-sheet forcing
    • b.e12.B1850C5.f19_g16.iPIx2.01: piControl with abrupt 2CO2
    • b.e12.B1850C5.f19_g16.i03ka.01: 3ka
    • b.e12.B1850C5.f19_g16.i06ka.03: 6ka with orbital forcing and a green Sahara and Northern Hemisphere
    • b.e12.B1850C5.f19_g16.i06ka.04: 6ka with orbital forcing
    • b.e12.B1850C5.f19_g16.i09ka.01: 9ka with a green Sahara
    • b.e12.B1850C5.f19_g16.i12ka.01: 12ka
    • b.e12.B1850C5.f19_g16.i12ka.02: 12ka extension
    • b.e12.B1850C5.f19_g16.i12ka_WH025a.01: 12ka with 0.25 Sv meltwater discharged into the Northern North Atlantic
    • b.e12.B1850C5.f19_g16.i14ka.01: 14ka
    • b.e12.B1850C5.f19_g16.i16ka.01: 16ka
    • b.e12.B1850C5.f19_g16.i16ka_WH025a.01: 16ka with 0.25 Sv meltwater discharged into the Northern North Atlantic
    • b.e12.B1850C5.f19_g16.i18ka.01: 18ka
    • b.e12.B1850C5.f19_g16.i21ka.03: LGM
    • b.e12.B1850C5.f19_g16.i21ka.03.0kaGaI: LGM with piControl GHG and Ice-sheet forcings
    • b.e12.B1850C5.f19_g16.i21ka.03.0kaGHG: LGM with piControl GHG forcing
    • b.e12.B1850C5.f19_g16.i21ka.03.0kaICE: LGM with piControl Ice-sheet forcing
  • Simulation Length: variable (900 years, 150 years, ...)
  • Model Version: iCESM1.2
  • Resolution: 1.9x2.5 (nominal 2° atmosphere/land)
  • Time Frequencies Saved: Monthly
  • Machine: NWSC Cheyenne
  • Compsets: B1850

Data Acquisition

The LGM and PI simulations are  available on the NWSC computing storage at:

/glade/campaign/cesm/community/palwg/iCESM1.2-DeglacialSlice

The data is also accessible via the Globus Guest Collection:

https://app.globus.org/file-manager?origin_id=878a2402-ee76-42a9-b035-a206dc43775f&origin_path=%2F

Contact

Please direct questions/comments about this page to:

Jiang Zhu

Project Scientist

email