Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
© Author(s) 2006. This work is licensed under the
Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License.
04 Sep 2006
Review status
This discussion paper has been under review for the journal Climate of the Past (CP). The manuscript was not accepted for further review after discussion.
Modelling ocean circulation, climate and oxygen isotopes in the ocean over the last 120 000 years
R. Marsh1, M. P. L. M. Smith1, E. J. Rohling1, D. J. Lunt2, T. M. Lenton3,4, M. S. Williamson3,4,*, and A. Yool1 1National Oceanography Centre, University of Southampton, UK
2Bristol Research Initiative for the Dynamic Global Environment (BRIDGE), School of Geographical Sciences, University of Bristol, UK
3School of Environmental Sciences, University of East Anglia, UK
4Tyndall Centre, University of East Anglia, UK
*now at: Quantum Information Group, University of Leeds, UK
Abstract. A new Earth System Model of Intermediate Complexity, GENIE-1, is used to simulate the most recent glacial-interglacial cycle by prescribing orbital forcing, atmospheric CO2 concentration, and the time evolution of ice sheet extent and orography. A series of experiments investigates uncertainty in the amplitude, frequency and location of prescribed meltwater pulses (MWPs) associated with Heinrich events in the North Atlantic and layers enriched in ice rafted debris around Antarctica. Associated with each MWP is a flux into the ocean of very light glacial oxygen isotope ratios, which serve as a tracer of the melt water. Additionally accounted for are temperature-related changes in the fractionation of stable oxygen isotopes between water and calcite. Modelled forwards from 120 000 years ago, simulated oxygen isotope records can thus be directly compared with measurements in calcite taken from International Marine Global Change Study (IMAGES) and Ocean Drilling Program (ODP) sediment cores at three locations representative of the North and South Atlantic, and the South Pacific. During the period of simulation corresponding to Marine Isotope Stage 3, the best agreement between the simulated oxygen isotope record in the North Atlantic and core measurements is found in the experiment that includes MWPs around Antarctica as well as into the North Atlantic. This challenges previous assumptions about the dominant role of northern ice sheets in glacial sea-level variability.

Citation: Marsh, R., Smith, M. P. L. M., Rohling, E. J., Lunt, D. J., Lenton, T. M., Williamson, M. S., and Yool, A.: Modelling ocean circulation, climate and oxygen isotopes in the ocean over the last 120 000 years, Clim. Past Discuss., 2, 657-709, doi:10.5194/cpd-2-657-2006, 2006.
R. Marsh et al.
Interactive discussionStatus: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version      Supplement - Supplement
RC S453: 'Referee comment', Anonymous Referee #2, 12 Oct 2006 Printer-friendly Version 
RC S492: 'Review', Anonymous Referee #1, 20 Oct 2006 Printer-friendly Version 
AC S616: 'Author Comment on Review 2', Robert Marsh, 23 Nov 2006 Printer-friendly Version 
AC S620: 'Author Comment on Review 1', Robert Marsh, 23 Nov 2006 Printer-friendly Version 
EC S910: 'Editor decision', Nanne Weber, 05 Mar 2007 Printer-friendly Version 
R. Marsh et al.
R. Marsh et al.


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