Intermittent structural weakening and acceleration of the Thwaites Glacier Tongue between 2000 and 2018
Intermittent structural weakening and acceleration of the Thwaites Glacier Tongue between 2000 and 2018
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DOI：
10.1017/jog.2020.20
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发表时间：
2020-06-01
影响因子：
3.4
通讯作者：
Gudmundsson, G. H.
中科院分区：
文献类型：
--
作者：
Miles, B. W. J.;Stokes, C. R.;Gudmundsson, G. H.
斯韦茨冰川终点的不断变化的条件将对确定其未来几十年对海平面的贡献率至关重要。在这里，我们使用遥感观测调查最近的变化（2000-2018年）的结构和速度的思韦茨冰川及其浮动的舌头。我们发现，在此期间，思韦茨冰川的主干加速了38%，而其以前完整的浮动舌头已经过渡到一个较弱的混杂断裂的冰山由海冰。然而，在整个观测期间，结构弱化和加速的速率并不均匀，我们确定了两个快速加速和结构弱化的时期（2006-2012; 2016-2018），由结构完整的剪切边缘边界的减速和重新推进时期（2012-2015）分开。这些加速/减速的时间强烈表明与可变海洋强迫的联系。弱化的舌头现在有一些依赖于陆地固定海冰的结构完整性和易受陆地固定冰持久性的变化。未来陆地固定海冰的减少可能来自气候的变化和/或即将从Thwaites海湾移走的B-22 A冰山。这种变化可能对冰舌的完整性和未来的冰川流量产生重要影响。
Evolving conditions at the terminus of Thwaites Glacier will be important in determining the rate of its future sea-level contribution over the coming decades. Here, we use remote-sensing observations to investigate recent changes (2000-2018) in the structure and velocity of Thwaites Glacier and its floating tongue. We show that the main trunk of Thwaites Glacier has accelerated by 38% over this period, while its previously intact floating tongue has transitioned to a weaker melange of fractured icebergs bounded by sea ice. However, the rate of structural weakening and acceleration was not uniform across the observational period and we identify two periods of rapid acceleration and structural weakening (2006-2012; 2016-2018), separated by a period of deceleration and re-advance of the structurally-intact shear margin boundary (2012-2015). The timing of these accelerations/decelerations strongly suggests a link to variable ocean forcing. The weakened tongue now has some dependency on landfast sea ice for structural integrity and is vulnerable to changes in landfast ice persistency. Future reductions in landfast sea ice could manifest from changes in climate and/or the imminent removal of the B-22A iceberg from the Thwaites embayment. Such changes could have important implications for the integrity of the ice tongue and future glacier discharge.