Glaciological and climatic significance of Hercules Dome, Antarctica: An optimal site for deep ice core drilling

Abstract

We present glaciological and climatological characteristics of Hercules Dome, Antarctica (86°S, 105°W), which demonstrate its potential as a deep ice core site. Annual layering in δD ratios from a 72 m ice core collected by the US‐ITASE 2002 traverse indicate accumulation rates of 0.16–0.20 m/yr ice equivalent over the last 300 years. Age control from stratigraphy seen in the radio‐echo sounding data collected during the same traverse suggests a rate of 0.09–0.11 m/yr averaged over the past 18,000 years. Ice stratigraphy also indicates that the ice divide position has been stable through at least this period. Comparison of satellite‐derived temperature anomalies with atmospheric reanalysis data show that the site is sensitive to the two dominant patterns of climate variability in the high‐latitude Southern Hemisphere. Climate proxy data from a deep ice core at Hercules Dome would be indicative of changes in Pacific Southern Hemisphere climate variability and may provide new information on rapid climate change events in Antarctica. The sensitivity of the site and the combination of relatively high accumulation rates, low temperatures (mean annual −35°C to −40°C), and simple ice flow suggest that Hercules Dome is an ideal site for a future deep ice core.