Oxygen isotope and palaeotemperature records from six Greenland ice-core stations: Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIP

Authors

  • Sigfus J. Johnsen,

    Corresponding author
    1. The Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen, Denmark
    2. Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland
    • Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
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  • Dorthe Dahl-Jensen,

    1. The Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen, Denmark
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  • Niels Gundestrup,

    1. The Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen, Denmark
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  • Jørgen P. Steffensen,

    1. The Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen, Denmark
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  • Henrik B. Clausen,

    1. The Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen, Denmark
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  • Heinz Miller,

    1. Alfred Wegener Institute, Bremerhaven, Germany
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  • Valerie Masson-Delmotte,

    1. Laboratoire des Sciences du Climat et de l'Environnement, UMR CEA-CNRS 1572, CEA Saclay, Orme des Merisiers 91191 Gif sur Yvette, France
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  • Arny E. Sveinbjörnsdottir,

    1. Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland
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  • James White

    1. Institute of Alpine and Arctic Research and Department of Geological Sciences, University of Colorado, Boulder, USA
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Abstract

Oxygen isotope variations spanning the last glacial cycle and the Holocene derived from ice-core records for six sites in Greenland (Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIP) show strong similarities. This suggests that the dominant influence on oxygen isotope variations reflected in the ice-sheet records was regional climatic change. Differences in detail between the records probably reflect the effects of basal deformation in the ice as well as geographical gradients in atmospheric isotope ratios. Palaeotemperature estimates have been obtained from the records using three approaches: (i) inferences based on the measured relationship between mean annual δ18O of snow and of mean annual surface temperature over Greenland; (ii) modelled inversion of the borehole temperature profile constrained either by the dated isotopic profile, or (iii) by using Monte Carlo simulation techniques. The third of these approaches was adopted to reconstruct Holocene temperature variations for the Dye 3 and GRIP temperature profiles, which yields remarkably compatible results. A new record of Holocene isotope variations obtained from the NorthGRIP ice-core matches the GRIP short-term isotope record, and also shows similar long-term trends to the Dye-3 and GRIP inverted temperature data. The NorthGRIP isotope record reflects: (i) a generally stronger isotopic signal than is found in the GRIP record; (ii) several short-lived temperature fluctuations during the first 1500 yr of the Holocene; (iii) a marked cold event at ca. 8.2 ka (the ‘8.2 ka event’); (iv) optimum temperatures for the Holocene between ca. 8.6 and 4.3 ka, a signal that is 0.6‰ stronger than for the GRIP profile; (v) a clear signal for the Little Ice Age; and (vi) a clear signal of climate warming during the last century. These data suggest that the NorthGRIP stable isotope record responded in a sensitive manner to temperature fluctuations during the Holocene. Copyright © 2001 John Wiley & Sons, Ltd.

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