A COMPARISON OF THE PRESENT AND LAST INTERGLACIAL IN SIX A NTARCTIC ICE CORES V. Masson-Delmotte, D. Buiron, A. Ekaykin, M. Frezzotti, H. Gallée, J. Jouzel, G. Krinner, A.Landais, H. Motoyama, H. Oerter, K. Pol, D. Pollard, C. Ritz, E. Schlosser, L.C. Sime, H. Sodemann, B. Stenni, R. Uemura, F. Vimeux LSCE and LGGE, France - AARI, Russia - ENEA, U. Trieste, Italy - NIPR and U. Ryukyus, Japan - AWI, Germany - Penn State, USA - U. Innsbruck, Austria - BAS, UK - NILU, Norway What can be the causes for regional differences in Antarctic stable isotope records? What are the differences between the current and last interglacial?

Masson-Delmotte et al, PNAS, 2010 EPICA Dome C Greenland C ONTEXT Different orbital contexts : excentricity, phase between precession and obliquity Different deglacial contexts and early interglacial bipolar seesaw

Masson-Delmotte et al, CP, in press D RILLING S ITES Seasonality of sea ice and « continentality » Ice flow thinning

Masson-Delmotte et al, CP, in press O RIGIN OF M OISTURE AND P RECIPITATION S EASONALITY Moisture origins : larger seasonality for the coastal sites (Taylor Dome and TALDICE) Difference between precipitation weighted temperature and annual mean temperature (ERA40) : larger bias for the inland sites

Masson-Delmotte et al, CP, in press S TABLE I SOTOPE R ECORDS ON EDC3 AGE SCALE Site-specific trends Common to the current and last interglacial Abrupt drop in  18 O during glacial inception at EDML and TALDICE (increased sea ice cover?)

Masson-Delmotte et al, CP, in press C OMMON S IGNALS (EOF ANALYSIS ) First EOF : temperature history Second EOF : elevation changes No trivial relationship with the orbital context

Masson-Delmotte et al, CP, in press S ITE S PECIFIC R ESIDUALS Main possible causes : Precipitation intermittency To assess with climate model simulations with isotopes (difficult in response to orbital forcing alone) See the poster of Louise Sime Site elevation changes Qualitatively consistent with ice sheet model outputs; Suggests larger elevation changes than simulated.

Pol et al, EPSL, 2010; CP, 2010; in prep 20 YR RESOLUTION ANALYSES IN EPICA D OME C Frequency (1/ky) Age (ky BP) Period (ky)  variability high variability Transition Running standard Deviation over 3ky Running standard Deviation over 3ky Holocene MIS5 (Resampled every 20y) Age (ky BP) Frequency (1/ky) Period (ky) Age (ky BP) MIS1 MIS5.5 Centered δD ‰ Signal ‰ minus trend Centered δD ‰ Signal ‰ minus trend High variability  variability Transition  variability  variability  variability  variability Larger variance during MIS5.5 Significant changes in variance Shifts in multi-centennial to millennial periodicities MIS1 MIS5.5

C ONCLUSIONS AND P ERSPECTIVES Differences between the current and last interglacial in Antarctica - Changes in mean state (common to 6 ice cores in East Antarctica) - Changes in variability (at Dome C) : variance level, power spectrum Mechanisms responsible for these changes poorly understood - climate models show very small response to orbital forcing - importance of changes in past ice sheet geometry (WAIS+EAIS) - ocean dynamics, natural (solar, volcanic) forcings (not documented for MIS5.5) Differences between ice core records - long term: changes in ice sheet topography - short term: precipitation intermittency, moisture origin (links with sea ice cover) Perspectives: - comparisons with climate and ice sheet model results - new information on MIS5.5 may come from the NEEM and WAIS ice cores