A late-glacial high-resolution site and source temperature record derived from the EPICA Dome C isotope records (East Antarctica)Earth and Planetary Science Letters, Vol. 217, p. 183-195, 2003
Department of Geological, Environmental and Marine Sciences, University of Trieste, Via E. Weiss 2, 34127 Trieste, Italy.
J. Jouzel, V. Masson-Delmotte, O. Cattani and S. Falourd
IPSL/Laboratoire des Sciences du Climat et de l'Environnement, UMR CEA-CNRS 1572, CEA Saclay, L'Orme des Merisiers, 91191 Gif-sur-Yvette, France.
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
E. Castellano and R. Udisti
Department of Chemistry, Scientific Pole, University of Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Fi), Italy.
S.J. Johnsen and J.P. Steffensen
Geofysisk Afdeling, Niels Bohr Instituttet for Astronomi, Fysik og Geofysik, Københavns Universitet
A. Longinelli and E. Selmo
Department of Earth Sciences, University of Parma, Parco Area delle Scienze 157/A, 43100 Parma, Italy.
Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Département des Sciences de la Terre et de l'Environnement, Université Libre de Bruxelles, Avenue F.D. Roosevelt 50, B-1050 Brussels, Belgium.
The timing and synchronisation of Greenland and Antarctic climate events that occurred during the last glacial period are still debate, as is the magnitude of temperature change associated with these events. Here we present detailed records of local and moisture-source temperature changes spanning the period 27-45 kyr BP from water stable isotope measurements (δD and δ18O) in the recently drilled EPICA Dome C ice core, East Antarctica plateau. Using a simple isotopic model, site (ΔTsite) and source (ΔTsource) temperatures are extracted from the initial 50-yr high-resolution isotopic records, taking into account the changes in seawater isotopic composition. The deuterium isotope variability is very similar to the less precise δD record from the Vostok ice core, and the site temperature inversion leads to a temperature profile similar to the classical palaeothermometry method, due to compensations between source and ocean water corrections. The reconstructed ΔTsite and ΔTsource profiles show different trends during the glacial: the former shows a decreasing trend from the warm A1 event (38 kyr BP) toward the Last Glacial Maximum, while the latter shows increasing values from 41 to 28 kyr BP. The low-frequency deuterium excess fluctuations are strongly influenced by obliquity fluctuations, controlling the low- to high-latitude temperature gradients, and show a remarkable similarity with a high-resolution southeast Atlantic sea surface temperature record. A comparison of the temperature profiles (site and source) and temperature gradient (ΔTsource-ΔTsite) with the non-sea-salt calcium and sodium records suggests a secondary influence of atmospheric transport changes on aerosol variations.