Our ability to improve prognostic modeling of the Greenland Ice Sheet relies on understanding the long-term relationships between climate and mass flux (via iceberg calving) from marine-terminating tidewater glaciers (TWGs). Observations of recent TWG behavior are widely available, but long-term records of TWG advance are currently lacking. We present glacial geomorphological, sedimentological, archaeological, and modeling data to reconstruct the ~20 km advance of Kangiata Nunaata Sermia (KNS; the largest tidewater glacier in southwest Greenland) during the first half of the past millennium. The data show that KNS advanced ~15 km during the 12th and 13th centuries CE at a rate of ~115 m a−1, contemporaneous with regional climate cooling toward the Little Ice Age and comparable to rates of TWG retreat witnessed over the past ~200 years. Presence of Norse farmsteads proximal to KNS demonstrates their resilience to climate change, manifest as a rapidly advancing TWG in a cooling climate. The results place limits on the magnitude of ice-margin advance and demonstrate TWG sensitivity to climate cooling as well as warming. These data combined with our grounding-line stability analysis provide a long-term record that validates approaches to numerical modeling aiming to link calving to climate.

中文翻译：

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格陵兰潮水冰川在挪威人定居时代迅速推进

我们改进格陵兰冰盖预测模型的能力依赖于了解气候与终止海洋的潮水冰川 (TWG) 的质量通量（通过冰山崩解）之间的长期关系。对近期 TWG 行为的观察可以广泛获得，但目前缺乏 TWG 进展的长期记录。我们提供了冰川地貌、沉积学、考古学和建模数据，以重建 Kangiata Nunaata Sermia（KNS；格陵兰西南部最大的潮水冰川）在过去千年的前半段前进约 20 公里。数据显示，在公元 12 世纪和 13 世纪期间，KNS 以约 115 ma-1 的速度前进了约 15 公里，与区域气候向小冰河时代降温的同时，与过去约 200 年见证的 TWG 撤退速度相当. 靠近 KNS 的北欧农庄的存在证明了它们对气候变化的适应能力，表现为在冷却气候中快速推进的 TWG。结果限制了冰缘推进的幅度，并证明了 TWG 对气候变冷和变暖的敏感性。这些数据与我们的接地线稳定性分析相结合，提供了长期记录，验证了旨在将产犊与气候联系起来的数值建模方法。