Abstract. The S27 ice core, drilled in the Allan Hills Blue Ice Area of East Antarctica, is located in Southern Victoria Land ~80 km away from the present-day northern edge of the Ross Ice Shelf. Here, we utilize the reconstructed accumulation rate of S27 covering the Last Interglacial (LIG) period between 129 and 116 thousand years before present (ka) to infer moisture transport into the region. The accumulation rate is based on the ice age-gas age differences calculated from the ice chronology, which is constrained by the stable water isotopes of the ice, and an improved gas chronology based on measurements of oxygen isotopes of O₂ in the trapped gases. The peak accumulation rate in S27 occurred at 128.2 ka, near the peak LIG warming in Antarctica. Even the most conservative estimate yields a six-fold increase in the accumulation rate in the LIG, whereas other Antarctic ice cores are typically characterized by a glacial-interglacial difference of a factor of two to three. While part of the increase in S27 accumulation rates must originate from changes in the large-scale atmospheric circulation, additional mechanisms are needed to explain the large changes. We hypothesize that the exceptionally high snow accumulation recorded in S27 reflects open-ocean conditions in the Ross Sea, created by reduced sea ice extent and increased polynya size, and perhaps by a southward retreat of the Ross Ice Shelf relative to its present-day position near the onset of LIG. The proposed ice shelf retreat would also be compatible with a sea-level high stand around 129 ka significantly sourced from West Antarctica. The peak in S27 accumulation rates is transient, suggesting that if the Ross Ice Shelf had indeed retreated during the early LIG, it would have re-advanced by 125 ka.

中文翻译：

---

在最后一次冰间期早期，增强了向南极洲维多利亚州土地的水分输送：对南极西部冰盖稳定性的影响

摘要。S27冰芯在南极东部的艾伦希尔斯蓝色冰区钻探，位于维多利亚南部土地上，距现今的罗斯冰架北缘约80公里。在这里，我们利用S27的重建累积速率覆盖了当前（ka）之前129至11.6万年之间的最后一个冰期（LIG）时期，以推断水分向该区域的传输。累积速率是根据冰年代学计算出的冰龄-天然气年龄差异（受冰的稳定水同位素限制）和基于O ₂氧同位素测量的改进的气体年代学在被困的气体中。S27的峰值累积速率出现在128.2 ka，接近南极LIG升温峰值。即使是最保守的估计，LIG中的累积速率也会增加六倍，而其他南极冰芯的特征通常是冰川与冰川之间的差异为二至三倍。虽然S27累积速率增加的部分原因必须来自大规模大气环流的变化，但还需要其他机制来解释这一大变化。我们假设S27中记录的异常高的积雪反映出罗斯海的开放海洋条件，这是由于海冰面积减少和波利尼亚面积增加，以及可能是罗斯冰架相对于其当前位置向南撤退而造成的接近LIG发作的时间。拟议的冰架撤退行动还将与明显来自西极南极的大约129 ka的海平面高位相适应。S27蓄积速率的峰值是短暂的，这表明如果Ross冰架确实在LIG早期确实退缩，那么它将会提前125 ka。