OGS (Istituto Nazionale di Oceanografia e Geofisica Sperimentale), Borgo Grotta Gigante 42/c, 34010, Sgonico, TS, Italy.
Department of Geoscience and Remote Sensing, Delft University of Technology (TUDelft), Delft, Netherlands.
Sci Rep. 2018 May 8;8(1):7196. doi: 10.1038/s41598-018-25664-6.
The Barents Sea Ice Sheet was a marine-based ice sheet, i.e., it rested on the Barents Sea floor during the Last Glacial Maximum (21 ky BP). The Bjørnøyrenna Ice Stream was the largest ice stream draining the Barents Sea Ice Sheet and is regarded as an analogue for contemporary ice streams in West Antarctica. Here, the retreat of the Bjørnøyrenna Ice Stream is simulated by means of two numerical ice sheet models and results assessed against geological data. We investigate the sensitivity of the ice stream to changes in ocean temperature and the impact of grounding-line physics on ice stream retreat. Our results suggest that the role played by sub-shelf melting depends on how the grounding-line physics is represented in the models. When an analytic constraint on the ice flux across the grounding line is applied, the retreat of Bjørnøyrenna Ice Stream is primarily driven by internal ice dynamics rather than by oceanic forcing. This suggests that implementations of grounding-line physics need to be carefully assessed when evaluating and predicting the response of contemporary marine-based ice sheets and individual ice streams to ongoing and future ocean warming.
巴伦支海冰盖是一种海基冰盖，即在末次冰盛期（21 千年前），它位于巴伦支海海底。比约恩约伦纳冰流是从巴伦支海冰盖流出的最大冰流，被认为是当代西南极洲冰流的类似物。在这里，通过两种数值冰盖模型模拟了比约恩约伦纳冰流的后退，并根据地质数据对结果进行了评估。我们研究了冰流对海洋温度变化的敏感性以及海底物理对冰流后退的影响。我们的结果表明，海底融化的作用取决于模型中如何表示海底物理。当在冰流模型中应用穿过海底的冰通量的解析约束时，比约恩约伦纳冰流的后退主要是由内部冰动力学驱动的，而不是海洋强迫驱动的。这表明，在评估和预测当代海基冰盖和个别冰流对当前和未来海洋变暖的响应时，需要仔细评估海底物理的实现。
