Recent geologic and modeled evidence suggests that the grounding line of the Siple Coast of the West Antarctic Ice Sheet (WAIS) retreated hundreds of kilometers beyond its present position in the middle to late Holocene and readvanced within the past 1.7 ka. This grounding line reversal has been attributed to both changing rates of isostatic rebound and regional climate change. Here, we test these two hypotheses using a proxy-informed ensemble of ice sheet model simulations with varying ocean thermal forcing, global glacioisostatic adjustment (GIA) model simulations, and coupled ice sheet-GIA simulations that consider the interactions between these processes. Our results indicate that a warm to cold ocean cavity regime shift is the most likely cause of this grounding line reversal, but that GIA influences the rate of ice sheet response to oceanic changes. This implies that the grounding line here is sensitive to future changes in sub-ice shelf ocean circulation.

最近的地质和模拟证据表明，西南极冰盖西普莱海岸 (WAIS) 的接地线在全新世中后期向后退缩了数百公里，并在过去 1.7ka 内重新前进。这种接地线逆转归因于均衡回弹速率的变化和区域气候变化。在这里，我们使用具有不同海洋热强迫的冰盖模型模拟、全球冰川均衡调整 (GIA) 模型模拟以及考虑这些过程之间相互作用的冰盖-GIA 耦合模拟来测试这两个假设。我们的结果表明，从温暖到寒冷的洋腔状态转变是这种接地线反转的最可能原因，但 GIA 影响冰盖对海洋变化的响应速率。这意味着这里的接地线对冰下架海洋环流的未来变化很敏感。