英国利兹大学Surawy-Stepney Trystan团队发现了与思韦茨冰川冰舌受损有关的周期性动态变化。这一研究成果于2023年1月9日发表在国际顶尖学术期刊《自然—地球科学》上。
研究小组展示了来自2015年开始的卫星观测的6年冰速记录，显示了横跨冰舌的两个大量级(约30-45%)和穿过冰舌的速度变化周期的延长(约1 - 2年)。小组利用自动化的、基于深度学习的方法从卫星图像中提取高分辨率裂缝图，详细描述了冰舌剪切边缘裂缝发育增加和随后再固结的时期，这些时期与观测到的速度变化相吻合。
以BISICLES冰原模型为主题的逆建模表明，冰速的变化可以用这些观测到的破裂空间格局的变化来解释。这项研究提供了南极洲西部压裂和动态变率之间直接耦合的进一步证据，但表明压裂增加和相关速度变化在一到两年的时间尺度上是可逆的。研究结果显示，在时间尺度上，破裂并不一定会导致冰川加速度的正反馈，破坏过程的建模对于准确预测南极冰盖的演变非常重要。
据了解，思韦茨冰川的稳定性和动态性取决于其海洋末端的结构性质;然而，人们对于浮冰冰舌上那些变量之间的关系知之甚少。
附：英文原文
Title: Episodic dynamic change linked to damage on the thwaites glacier ice tongue
Author: Surawy-Stepney, Trystan, Hogg, Anna E., Cornford, Stephen L., Davison, Benjamin J.
Issue&Volume: 2023-01-09
Abstract: The stability and dynamics of Thwaites Glacier depend on the structural properties of its marine terminus; however, the relationship between these variables on the floating ice tongue is poorly understood. Here we present a six-year record of ice speed, derived from satellite observations starting in 2015, showing two large-magnitude (approximately 30–45%) and prolonged (approximately one to two years) cycles of speed variation across the ice tongue. Using an automated, deep learning-based method of extracting high-resolution fracture maps from satellite imagery, we detail periods of increasing fracture development and subsequent reconsolidation in the ice tongue shear margin that coincide with the observed speed changes. Inverse modelling using the BISICLES ice-sheet model indicates that the variation in ice speed can be accounted for by these observed changes to the spatial pattern of fracturing. This study provides further evidence of direct coupling between fracturing and dynamic variability in West Antarctica but indicates that increased fracturing and associated speed changes are reversible on one- to two-year timescales. We suggest that fracturing does not necessarily lead to positive feedback with glacier acceleration on these timescales and that damage process modelling is important for accurately predicting the evolution of the Antarctic Ice Sheet.
DOI: 10.1038/s41561-022-01097-9
Source: https://www.nature.com/articles/s41561-022-01097-9