The Drygalski Ice Tongue in East Antarctica stretches 90 km into the Ross Sea and influences the local ocean circulation, and persistence of the Terra Nova Bay Polynya. We examine the controls on the size of this floating ice body by comparing the propagation of six large fractures on the ice tongue's northern side using 21 years of Landsat imagery with hydrostatic ice thickness maps and strain rate calculations. We also apply a subglacial hydrology model to estimate the location and discharge from subglacial channels over the grounding line and compare these with basal channels identified along the ice tongue using remote sensing and airborne radar data. Our results suggest that large fractures are inhibited from full-width propagation by thicker ice between basal channels. We hypothesize that only once the ice tongue thins towards the terminus, can fractures propagate and cause large calving events. This suggests an important relationship between the melting of floating ice from subglacial and ocean sources and the expansion of fractures that lead to ice tongue calving.

中文翻译：

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Drygalski冰舌稳定性受裂谷形成和冰形态的影响

南极洲东部的 Drygalski Ice Tongue 延伸到罗斯海 90 公里，影响当地的海洋环流和 Terra Nova Bay Polynya 的持久性。我们通过使用 21 年的 Landsat 图像与静水冰厚度图和应变率计算来比较冰舌北侧六个大型裂缝的传播，来检查对这个浮冰体大小的控制。我们还应用冰下水文模型来估计接地线上冰下通道的位置和流量，并将这些与使用遥感和机载雷达数据沿冰舌识别的基底通道进行比较。我们的研究结果表明，基底通道之间较厚的冰抑制了大裂缝的全宽度扩展。我们假设只有当冰舌向终点变薄时，裂缝才会传播并导致大的产犊事件。这表明冰下和海洋来源的浮冰融化与导致冰舌崩解的裂缝扩大之间存在重要关系。