2022-04-18 ペンシルベニア州立大学(PennState)
研究者らは、強い潮流活動により、接地線での水による破壊、すなわちハイドロフラクチャリングが促進され、雪解け水の湖が迅速に、しばしばわずか数日で排水されることを見いだした。この急速な排水により、水がさらに溜まって棚氷に広がるのを防ぐことができ、水圧破砕により崩壊の可能性が高まります。研究チームは、大規模な湖の排水を引き起こす可能性のある潮汐を初めて観測し、その結果をGeophysical Research Lettersに報告した。
＜関連情報＞
- https://www.psu.edu/news/earth-and-mineral-sciences/story/strong-tides-vanishing-lakes-may-prove-beneficial-antarctic-ice/
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL095661
アメリー棚氷のグラウンディングゾーンにおける超氷河湖の繰返し潮汐による水砕現象 Repeated Tidally Induced Hydrofracture of a Supraglacial Lake at the Amery Ice Shelf Grounding Zone
Luke D. Trusel,Zhuolai Pan,Mahsa Moussavi
Geophysical Research Letters First published: 25 March 2022
https://doi.org/10.1029/2021GL095661
Abstract
Surface melting and lakes are common to Antarctic ice shelves, and their existence and drainages have been invoked as a precursor for ice shelf collapse. Here, we present satellite observations over 2014–2020 of repeated, rapid drainages of a supraglacial lake at the grounding zone of Amery Ice Shelf, East Antarctica. Post-drainage imagery in 2018 reveals lake bottom features characteristic of rapid, vertical lake drainage. Observed lake volumes indicate drainages are not associated with a threshold meltwater volume. Instead, drainages typically coincide with periods of high daily tidal amplitude, suggesting hydrofracture is assisted by tidally forced ice flexure inherent to the ice shelf grounding zone. Combined with observations of widespread grounding zone lake drainages on Amery, these findings indicate ice shelf meltwater accumulation may be inhibited by grounding zone drainage events, thus representing a potential stabilizing mechanism despite enhanced melting common to these regions.
