Iceberg calving of Thwaites Glacier, West Antarctica: Full-Stokes modeling combined with linear elastic fracture mechanics
Iceberg calving of Thwaites Glacier, West Antarctica: Full-Stokes modeling combined with linear elastic fracture mechanics
复制标题
西南极洲思韦茨冰川的冰山崩解：富斯托克斯模型与线弹性断裂力学相结合
DOI：
10.5194/tc-11-1283-2017
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
H. Seroussi
中科院分区：
文献类型：
--
作者：
H. Yu;E. Rignot;M. Morlighem;H. Seroussi
抽象的。西南极洲的思韦茨冰川（TG）在过去几十年中一直在失去质量并迅速退缩。在这里，我们提出了一个二维流带全斯托克斯（FS）模型的粘性流与线弹性断裂力学（LEFM）理论模型决口传播和冰破裂相结合的产犊动力学的研究。我们比较的结果与高阶（HO）和浅架近似（SSA）模型与LEFM耦合。我们发现，FS/LEFM产生的表面和底部裂缝是一致的分布的深度和宽度的表面和底部裂缝观察到的美国宇航局的冰桥行动雷达测深仪和激光高度计，而HO/LEFM和SSA/LEFM不产生裂缝是一致的意见。我们将这种差异归因于接地线附近冰的非流体静力条件，这有助于裂缝的形成，并由FS模型解释，但不由HO或SSA模型解释。我们发现，当预先存在的表面裂缝，冰架缩短或冰架前被削弱时，产犊是增强。底切的作用取决于产犊事件的时间尺度。对于产犊速度快的冰川，这种现象比产犊速度慢的冰川更为突出。延伸到较短冰架的冰川比形成较长冰架的冰川更容易发生崩解，特别是当冰锋后退到接近接地线区域时，这会导致对崩解事件的正反馈。我们的结论是，FS/LEFM组合产生了很大的改进，在捕获的应力场附近的冰川的接地线约束决口形成和冰山崩解。
Abstract. Thwaites Glacier (TG), West Antarctica, has been losing mass and retreating rapidly in the past few decades. Here, we present a study of its calving dynamics combining a two-dimensional flow-band full-Stokes (FS) model of its viscous flow with linear elastic fracture mechanics (LEFM) theory to model crevasse propagation and ice fracturing. We compare the results with those obtained with the higher-order (HO) and the shallow-shelf approximation (SSA) models coupled with LEFM. We find that FS/LEFM produces surface and bottom crevasses that are consistent with the distribution of depth and width of surface and bottom crevasses observed by NASA's Operation IceBridge radar depth sounder and laser altimeter, whereas HO/LEFM and SSA/LEFM do not generate crevasses that are consistent with observations. We attribute the difference to the nonhydrostatic condition of ice near the grounding line, which facilitates crevasse formation and is accounted for by the FS model but not by the HO or SSA models. We find that calving is enhanced when pre-existing surface crevasses are present, when the ice shelf is shortened or when the ice shelf front is undercut. The role of undercutting depends on the timescale of calving events. It is more prominent for glaciers with rapid calving rates than for glaciers with slow calving rates. Glaciers extending into a shorter ice shelf are more vulnerable to calving than glaciers developing a long ice shelf, especially as the ice front retreats close to the grounding line region, which leads to a positive feedback to calving events. We conclude that the FS/LEFM combination yields substantial improvements in capturing the stress field near the grounding line of a glacier for constraining crevasse formation and iceberg calving.
影响因子：
2.9
作者：
G. Durand;O. Gagliardini;T. Zwinger;E. L. Meur;R. Hindmarsh
通讯作者：
G. Durand;O. Gagliardini;T. Zwinger;E. L. Meur;R. Hindmarsh
使用有限元模拟评估冰架裂缝的严重性
DOI：
10.5194/tc-6-973-2012
发表时间：
2012
期刊：
The Cryosphere
影响因子：
--
作者：
Müller;Humbert
通讯作者：
Humbert
影响因子：
5.2
作者：
Cook, S.;Rutt, I. C.;James, T. D.
通讯作者：
James, T. D.