Details

Autor(en) / Beteiligte

• Goursaud, Sentia
• Holloway, Max
• Sime, Louise
• Wolff, Eric
• Valdes, Paul
• Steig, Eric J.
• Pauling, Andrew

Titel

Antarctic Ice Sheet Elevation Impacts on Water Isotope Records During the Last Interglacial

Ist Teil von

• Geophysical research letters, 2021-03, Vol.48 (6), p.n/a

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2021

Link zum Volltext

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• Changes of the topography of the Antarctic Ice Sheet (AIS) can complicate the interpretation of ice core water stable isotope measurements in terms of temperature. Here, we use a set of idealized AIS elevation change scenarios to investigate this for the warm Last Interglacial (LIG). We show that LIG δ18O against elevation relationships is not uniform across Antarctica and that the LIG response to elevation is lower than the preindustrial response. The effect of LIG elevation‐induced sea ice changes on δ18O is small, allowing us to isolate the effect of elevation change alone. Our results help to define the effect of AIS changes on the LIG δ18O signals and should be invaluable to those seeking to use AIS ice core measurements for these purposes. Especially, our simulations strengthen the conclusion that ice core measurements from the Talos Dome core exclude the loss of the Wilkes Basin at around 128 kyr. Plain Language Summary The Last Interglacial (LIG) period (116,000–130,000 years ago) was globally ∼0.8 °C warmer than today at its peak, with substantially more warming at the poles. It is a valuable analog for future global temperature rise, especially for understanding rates and sources of polar ice melt and subsequent global sea level rise. Records of water stable isotopes from Antarctic ice cores have been crucial for understanding past polar temperature during the LIG. However, we currently lack a framework for estimating how changes in the ice sheet elevation, alongside sea ice feedbacks, affect these water stable isotopes. To address this, we examine the effect of the Antarctic Ice Sheet (AIS) elevation on water stable isotopes, using an ensemble of climate simulations where we vary the AIS elevation. We observe that (i) water stable isotope values lower with increasing AIS elevation following linear relationships and (ii) the effect of sea ice induced by AIS elevation is small so the effect of AIS elevation can be isolated. Finally, this study provides appropriate elevation‐water stable isotope gradients for the reconstruction of the AIS topography using ice cores. Key Points The relationship of δ18O against elevation at 128 kyr is not uniform across Antarctica The effect of the elevation can be isolated from that due to sea ice change Ice core results appear to unequivocally exclude the loss of the Wilkes Basin at around 128 kyr