Last Deglaciation Core Experiment Design

Contacts: Ruža Ivanović, Lauren Gregoire, Didier Roche

Go back to the main working group page.
Please note this page is a work in progress and is not ready for discussion yet.

Proposal

Following wide consultation over the past year, this is our first-draft proposal for the last deglaciation core simulation. Please use the 'Discussion' section below to comment on the proposal and make suggestions for ammendments.

21-9 ka

All core simulations must span this time-period. Use:

A spun-up LGM climate simulation to initialise the simulation.
This should have been set up as per the Last Glacial Maximum (LGM) working group requirements and recommendations.

Orbital parameters as per Berger & Loutre (1991)[1].

Greenhouse gases:

CO2 from Lüthi et al. (2008)[2] on the timescale of Veres et al. (2013)[4]. 1) The high resolution Marcott et al. (2014)[5] record could be used for an alternative simulation to the core, but not for the core.

CH4 from Loulergue et al. (2008)[3] on the timescale of Veres et al. (2013)[4].

N2O from Sowers et al. (2003)[6]

Ice sheets: Choice of either ICE6G_C[7-8] or Lev Tarasov's global reconstruction of ice sheet evolution.
Whichever is chosen for the LGM should be kept for the whole simulation.
[See the last deglaciation ice sheets page for more information on the ice sheets.]

Meltwater: no meltwater in the core. 2) Global meltwater fluxes that are consistent with the ice sheet reconstructions will be provided for alternative simulations to the core, but must not be used for the core.

Other boundary conditions: keep as per the LGM.

26-21 ka

For those who wish to begin their simulation from before the PMIP LGM, use:

Orbit as per Berger & Loutre (1991)[1] for this time period.

All other boundary conditions as per the PMIP LGM Working Group.

Some points to discuss

Please think about the following points and add any comments on these or any other aspects of the experiment design to the discussion section below: [Topics will be added here as they are raised below or by email.]

Should the core experiment use the Marcott et al. (2014)[5] CO2 records?
For example, these newer data are higher resolution than Lüthi et al. (2008)[2], but are restricted to 23-9 ka. Therefore more consistency may be be gained from using the older Lüthi et al. (2008)[2] CO2 records, if longer simulations are planned by groups. Also, CH4 and N2O data are not yet available in such high resolution.

References

Berger, A. & Loutre, M. F. Insolation values for the climate of the last 10 million years. Quat. Sci. Rev. 10, 297–317 (1991).

Lüthi, D. et al. High-resolution carbon dioxide concentration record 650,000–800,000 years before present. Nature 453, 379–382 (2008).

Loulergue, L. et al. Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years. Nature 453, 383–386 (2008).

Veres, D. et al. The Antarctic ice core chronology (AICC2012): an optimized multi-parameter and multi-site dating approach for the last 120 thousand years. Clim Past 9, 1733–1748 (2013).

Marcott, S. A. et al. Centennial-scale changes in the global carbon cycle during the last deglaciation. Nature 514, 616–619 (2014).

Sowers, T., Alley, R. B. & Jubenville, J. Ice Core Records of Atmospheric N2O Covering the Last 106,000 Years. Science 301, 945–948 (2003).

Argus, D. F., Peltier, W. R., Drummond, R. & Moore, A. W. The Antarctica component of postglacial rebound model ICE-6G_C (VM5a) based on GPS positioning, exposure age dating of ice thicknesses, and relative sea level histories. Geophys. J. Int. ggu140 (2014).

Peltier, W. R., Argus, D. F. & Drummond, R. Space geodesy constrains ice age terminal deglaciation: The global ICE-6G_C (VM5a) model. J. Geophys. Res. Solid Earth 2014JB011176 (2015).

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