Rapid retreat of Thwaites Glacier in the pre-satellite era
Rapid retreat of Thwaites Glacier in the pre-satellite era
复制标题
前卫星时代思韦茨冰川快速退缩
DOI：
10.1038/s41561-022-01019-9
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发表时间：
2022
影响因子：
18.3
通讯作者：
Anderson, John B.
中科院分区：
文献类型：
--
作者：
Graham, Alastair G. C.;Wåhlin, Anna;Hogan, Kelly A.;Nitsche, Frank O.;Heywood, Karen J.;Totten, Rebecca L.;Smith, James A.;Hillenbrand, Claus-Dieter;Simkins, Lauren M.;Anderson, John B.
了解斯韦茨冰川的近代历史，以及控制其持续退缩的过程，是预测南极对未来海平面上升的贡献的关键。特别令人担忧的是，冰川接地区在未来几十年内可能如何演变，因为它受到海底测深高点的稳定。在这里，我们使用部署在思韦茨冰川冰锋的自主水下航行器的地球物理数据，记录过去从海底海角撤退的海底印记。我们展示了在斯韦茨冰川比今天更先进的时候，潮汐抬升和沉降机制每天形成的后退沉积脊的模式。在5.5个月的时间里，Thwaites接地区以每年>2.1公里的速度后退-是2011年至2019年期间卫星在接地区最快后退部分观察到的速度的两倍。我们的研究结果表明，在过去的两个世纪里，斯韦茨冰川发生了持续的快速退缩脉冲。在不久的将来，当接地区从海底的稳定高点迁移回来时，可能会出现类似的快速撤退脉冲。
Understanding the recent history of Thwaites Glacier, and the processes controlling its ongoing retreat, is key to projecting Antarctic contributions to future sea-level rise. Of particular concern is how the glacier grounding zone might evolve over coming decades where it is stabilized by sea-floor bathymetric highs. Here we use geophysical data from an autonomous underwater vehicle deployed at the Thwaites Glacier ice front, to document the ocean-floor imprint of past retreat from a sea-bed promontory. We show patterns of back-stepping sedimentary ridges formed daily by a mechanism of tidal lifting and settling at the grounding line at a time when Thwaites Glacier was more advanced than it is today. Over a duration of 5.5 months, Thwaites grounding zone retreated at a rate of >2.1 km per year—twice the rate observed by satellite at the fastest retreating part of the grounding zone between 2011 and 2019. Our results suggest that sustained pulses of rapid retreat have occurred at Thwaites Glacier in the past two centuries. Similar rapid retreat pulses are likely to occur in the near future when the grounding zone migrates back off stabilizing high points on the sea floor.