Wallis Benjamin J, Hogg Anna E, Meredith Michael P, Close Romilly, Hardy Dominic, McMillan Malcolm, Wuite Jan, Nagler Thomas, Moffat Carlos
School of Earth and Environment, University of Leeds, Leeds, UK.
British Antarctic Survey, Cambridge, UK.
Nat Commun. 2023 Nov 28;14(1):7535. doi: 10.1038/s41467-023-42970-4.
Ice dynamic change is the primary cause of mass loss from the Antarctic Ice Sheet, thus it is important to understand the processes driving ice-ocean interactions and the timescale on which major change can occur. Here we use satellite observations to measure a rapid increase in speed and collapse of the ice shelf fronting Cadman Glacier in the absence of surface meltwater ponding. Between November 2018 and December 2019 ice speed increased by 94 ± 4% (1.47 ± 0.6 km/yr), ice discharge increased by 0.52 ± 0.21 Gt/yr, and the calving front retreated by 8 km with dynamic thinning on grounded ice of 20.1 ± 2.6 m/yr. This change was concurrent with a positive temperature anomaly in the upper ocean, where a 400 m deep channel allowed warm water to reach Cadman Glacier driving the dynamic activation, while neighbouring Funk and Lever Glaciers were protected by bathymetric sills across their fjords. Our results show that forcing by warm ocean water can cause the rapid onset of dynamic imbalance and increased ice discharge from glaciers on the Antarctic Peninsula, highlighting the region's sensitivity to future climate variability.
冰动力变化是南极冰盖质量损失的主要原因，因此了解驱动冰 - 海洋相互作用的过程以及可能发生重大变化的时间尺度很重要。在这里，我们利用卫星观测来测量在没有地表融水积水的情况下，卡德曼冰川前沿冰架的速度快速增加和崩塌。在2018年11月至2019年12月期间，冰速增加了94±4%（1.47±0.6千米/年），冰流量增加了0.52±0.21亿吨/年，崩解前沿后退了8千米， grounded ice的动态变薄速度为20.1±2.6米/年。这一变化与上层海洋的正温度异常同时发生，一条400米深的通道使温暖海水到达卡德曼冰川，驱动了动态激活，而邻近的芬克冰川和利弗冰川则受到其峡湾中测深槛的保护。我们的结果表明，温暖海水的强迫作用会导致南极半岛冰川迅速出现动态失衡并增加冰流量，突出了该地区对未来气候变化的敏感性。
