Hata Shuntaro, Kawamata Moto, Doi Koichiro
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan.
Creative Research Institution, Hokkaido University, Sapporo, Japan.
Sci Rep. 2023 Nov 27;13(1):20619. doi: 10.1038/s41598-023-47522-w.
The liquid water around the Antarctic Ice Sheet plays a key role in modulating both the vulnerability of ice shelves to hydrofracturing and ice discharge from outlet glaciers. Therefore, it needs to be adequately constrained for precise future projections of ice-mass loss and global sea-level rise. Although glacial lake outburst floods (GLOFs) pose one of the greatest risks in glacierized mountainous regions, any long-term monitoring of Antarctic ice-marginal lakes and their associated potential for GLOFs has been neglected until recently owing to the limited number of such events reported in Antarctica. Here we present direct evidence of repeated GLOFs from Lake Kaminotani-Ike, an ice-sheet-dammed lake in East Antarctica, via an analysis of historical aerial photographs and recent satellite data. Two GLOFs occurred in 1969-1971 and 2017, with discharge volumes of (8.6 ± 1.5) × 10 and (7.1 ± 0.4) × 10 m, respectively, making them two of the largest GLOFs in Antarctica. A southerly oceanward pathway beneath the ice sheet is the most likely drainage route of these GLOF events based on the available surface- and bed-elevation datasets. Furthermore, the 2017 event occurred during the austral winter, thereby implying the possibility of year-round active subglacial networks in Antarctica. Our results highlight that studies on Antarctic ice-marginal lakes provide an opportunity to better understand Antarctic hydrological processes and emphasize the need for both detailed monitoring of ice-marginal lakes and detailed surveying of the subglacial environments of the Antarctic Ice Sheet.
南极冰盖周围的液态水在调节冰架对水力破裂的脆弱性以及从出口冰川的冰排放方面起着关键作用。因此，为了精确预测未来的冰量损失和全球海平面上升，需要对其进行充分的限制。尽管冰川湖突发洪水（GLOFs）是冰川化山区最大的风险之一，但由于南极洲报告的此类事件数量有限，直到最近，对南极冰缘湖泊及其相关GLOFs可能性的任何长期监测都被忽视了。在这里，我们通过对历史航空照片和近期卫星数据的分析，提供了来自东极洲一个冰盖堰塞湖——上谷谷池湖反复发生GLOFs的直接证据。两次GLOFs分别发生在1969 - 1971年和2017年，排放量分别为(8.6 ± 1.5)×10和(7.1 ± 0.4)×10立方米，使其成为南极洲最大的两次GLOFs。根据现有的地表和床面高程数据集，冰盖下方朝南向海洋的路径是这些GLOF事件最可能的排水路线。此外，2017年的事件发生在南半球冬季，这意味着南极洲可能存在全年活跃的冰下网络。我们的结果强调，对南极冰缘湖泊的研究为更好地理解南极水文过程提供了一个机会，并强调了对冰缘湖泊进行详细监测以及对南极冰盖冰下环境进行详细勘查的必要性。
