A late-glacial high-resolution site and source temperature record derived from the EPICA Dome C isotope records (East Antarctica)

Abstract

The timing and synchronisation of Greenland and Antarctic climate events that occurred during the last glacial period are still under 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 (ND and N 18 O) in the recently drilled EPICA Dome C ice core, East Antarctic plateau. Using a simple isotopic model, site (vT site ) and source (vT source ) temperatures are extracted from the initial 50-yr highresolution isotopic records, taking into account the changes in seawater isotopic composition. The deuterium isotope variability is very similar to the less precise ND 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 vT site and vT source 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 (vT source -vT site ) with the non-sea-salt calcium and sodium records suggests a secondary influence of atmospheric transport changes on aerosol variations. ß

Dust-climate couplings over the past 800,000 years from the EPICA Dome C ice core

“…The lifetime of the particles is primarily constrained by wet deposition 23,28 and therefore by water content and temperature. As an example, along a pathway 4-6 km high and with a mean temperature of about -40 uC (conditions similar to those observed over Antarctica), a temperature reduction by 5 uC, associated with a similar change of sea surface temperature over the Southern Ocean 29 , reduces the saturation water vapour pressure to about half. Under such premises, a two-dimensional model 28 obtained an increase in dust flux to Antarctica of up to a factor of 5.…”

A brief history of ice core science over the last 50 yr

“…This link has further been confirmed for polar snow Petit et al, 1991;Ciais and Jouzel, 1994); its use for extracting information about moisture sources was developed in the eighties (Jouzel et al, 1982;White et al, 1988;Dansgaard et al, 1989;Johnsen et al, 1989). Since then, δD and δ 18 O are quite systematically measured in order to provide such additional information from ice cores drilled in both Antarctica (Jouzel et al, 1982;Vimeux et al, 1999Vimeux et al, , 2002Cuffey and Vimeux, 2001;Stenni et al, 2001Stenni et al, , 2003Stenni et al, , 2010Uemura et al, 2004Uemura et al, , 2012 and Greenland (Masson- Jouzel et al, 2007b), where deuterium excess is also used as a marker of rapid climatic changes .…”

Ranges of moisture-source temperature estimated from Antarctic ice cores stable isotope records over glacial–interglacial cycles

“…Source and site climatic information can therefore be extracted from ice core δD and d records, using a linear regression model based on the Rayleigh distillation isotopic model and/or more sophisticated models Cuffey and Vimeux, 2001;Stenni et al, 2001Stenni et al, , 2010. This dual isotope approach allows corrections to site temperature estimates for moisture source effects.…”