Articles | Volume 9, issue 7
Geosci. Model Dev., 9, 2563–2587, 2016

Special issue: Paleoclimate Modelling Intercomparison Project phase 4 (PMIP4)...

Geosci. Model Dev., 9, 2563–2587, 2016

Model experiment description paper 29 Jul 2016

Model experiment description paper | 29 Jul 2016

Transient climate simulations of the deglaciation 21–9 thousand years before present (version 1) – PMIP4 Core experiment design and boundary conditions

Ruza F. Ivanovic1, Lauren J. Gregoire1, Masa Kageyama2, Didier M. Roche2,3, Paul J. Valdes4, Andrea Burke5, Rosemarie Drummond6, W. Richard Peltier6, and Lev Tarasov7 Ruza F. Ivanovic et al.
  • 1School of Earth & Environment, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
  • 2Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
  • 3Earth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
  • 4School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK
  • 5Department of Earth and Environmental Sciences, Irvine Building, University of St. Andrews, St. Andrews, KY16 9AL, UK
  • 6Department of Physics, University of Toronto, 60 St George Street, Toronto, Ontario, Canada M5S 1A7
  • 7Department of Physics and Physical Oceanography, Memorial University of Newfoundland and Labrador, St. John's, NL, Canada A1B 3X7

Abstract. The last deglaciation, which marked the transition between the last glacial and present interglacial periods, was punctuated by a series of rapid (centennial and decadal) climate changes. Numerical climate models are useful for investigating mechanisms that underpin the climate change events, especially now that some of the complex models can be run for multiple millennia. We have set up a Paleoclimate Modelling Intercomparison Project (PMIP) working group to coordinate efforts to run transient simulations of the last deglaciation, and to facilitate the dissemination of expertise between modellers and those engaged with reconstructing the climate of the last 21 000 years. Here, we present the design of a coordinated Core experiment over the period 21–9 thousand years before present (ka) with time-varying orbital forcing, greenhouse gases, ice sheets and other geographical changes. A choice of two ice sheet reconstructions is given, and we make recommendations for prescribing ice meltwater (or not) in the Core experiment. Additional focussed simulations will also be coordinated on an ad hoc basis by the working group, for example to investigate more thoroughly the effect of ice meltwater on climate system evolution, and to examine the uncertainty in other forcings. Some of these focussed simulations will target shorter durations around specific events in order to understand them in more detail and allow for the more computationally expensive models to take part.

Short summary
This manuscript presents the experiment design for the PMIP4 Last Deglaciation Core experiment: a transient simulation of the last deglaciation, 21–9 ka. Specified model boundary conditions include time-varying orbital parameters, greenhouse gases, ice sheets, ice meltwater fluxes and other geographical changes (provided for 26–0 ka). The context of the experiment and the choices for the boundary conditions are explained, along with the future direction of the working group.