Abstract
ABSTRACTDocumenting past changes in the East Antarctic surface mass balance is important to improve ice core chronologies and to constrain the ice-sheet contribution to global mean sea-level change. Here we reconstruct past changes in the ratio of surface mass balance (SMB ratio) between the EPICA Dome C (EDC) and Dome Fuji (DF) East Antarctica ice core sites, based on a precise volcanic synchronization of the two ice cores and on corrections for the vertical thinning of layers. During the past 216 000 a, this SMB ratio, denoted SMBEDC/SMBDF, varied between 0.7 and 1.1, being small during cold periods and large during warm periods. Our results therefore reveal larger amplitudes of changes in SMB at EDC compared with DF, consistent with previous results showing larger amplitudes of changes in water stable isotopes and estimated surface temperature at EDC compared with DF. Within the last glacial inception (Marine Isotope Stages, MIS-5c and MIS-5d), the SMB ratio deviates by up to 0.2 from what is expected based on differences in water stable isotope records. Moreover, the SMB ratio is constant throughout the late parts of the current and last interglacial periods, despite contrasting isotopic trends.
Highlights
In the context of global warming and sea-level rise, changes in the mass balance of the ice sheets must be carefully monitored, understood and anticipated, as they could become the main contributor of sea-level rise in the coming centuries (Church and others, 2013)
The lowest values of the synchro-based SMBEDC/SMBDF ratio (0.7) are reached for MIS 5d–5c, while the lowest values of the δDice profiles are reached at the Last Glacial Maximum (LGM)
Our study suggests that the vertical thinning functions evaluated by ice flow models at European Project for Ice Coring in Antarctica (EPICA) Dome C (EDC) and Dome Fuji (DF) are valid for the depth range covered here
Summary
In the context of global warming and sea-level rise, changes in the mass balance of the ice sheets must be carefully monitored, understood and anticipated, as they could become the main contributor of sea-level rise in the coming centuries (Church and others, 2013). The SMB in Antarctica is a function of the surface elevation of the ice sheet (e.g. Takahashi and others, 1994; Krinner and Genthon, 1999) and is affected by the redeposition of snow by wind (Gallée and others, 2012). The Antarctic plateau, accumulation is driven by maritime intrusions and snowfall events, and by clear sky condensation, possibly related to boundary layer dynamics. It may be affected by exchanges of water vapor between surface snow and the surrounding air (Hoshina and others, 2014).
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