Crevasses as Indicators of Surge Dynamics in the Bering Bagley Glacier System, Alaska: Numerical Experiments and Comparison to Image Data Analysis
Crevasses as Indicators of Surge Dynamics in the Bering Bagley Glacier System, Alaska: Numerical Experiments and Comparison to Image Data Analysis
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裂缝作为阿拉斯加白令巴格利冰川系统涌动动力学的指标：数值实验以及与图像数据分析的比较
DOI：
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
U. Herzfeld
中科院分区：
文献类型：
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作者：
T. Trantow;U. Herzfeld
海平面上升预测中最大的不确定性来源之一是冰川加速，其中浪涌现象是最不了解的类型。2011-2013年阿拉斯加白令巴格利冰川系统（BBGS）的涌动为研究大型复杂冰川系统中的涌动现象提供了难得的机会。一个激增的结果在整个冰川系统广泛的裂缝复杂化许多传统的技术用于研究冰川动力学。在本文中，我们利用裂缝作为一种手段，调查最近BBGS浪涌通过数值模拟和地质统计数据分析。根据结构冰川学的原理，通过应用于Landsat-7数据的地质统计学方法获得基于图像的裂缝特征，并辅以空中实地观测。在建模方面，开发了BBGS的3-D全斯托克斯有限元模型，并应用于研究最近激增期间的冰动力学和表面结构。采用von Mises准则来模拟冰川表面的裂缝，其方向沿着最大主拉应力轴。为了便于评估模型和数据导出的决口特性，引入了三种不同的比较方法。模型数据比较的总体一致性表明，该模型能够代表峰值加速度期间的BBGS系统。基于裂隙的方法也被用来优化模型中的基底滑动参数和von Mises应力阈值。结果进一步表明，床面地形是模拟涌浪过程的一个重要约束。
One of the largest sources of uncertainty in sea level rise prediction is glacial acceleration, of which the surge phenomenon is the least understood type. The surge of the Bering Bagley Glacier System (BBGS), Alaska, in 2011–2013 has provided a rare opportunity to study the surge phenomenon in a large and complex glacier system. A surge results in widespread crevassing throughout the glacier system complicating many traditional techniques used to study glacier dynamics. In this paper, we utilize crevassing as a means to investigate the recent BBGS surge through numerical modeling and geostatistical data analysis. Following the principles of structural glaciology, image‐based crevasse characterizations are obtained through geostatistical methods applied to Landsat‐7 data, supplemented by airborne field observations. On the modeling side, a 3‐D full‐Stokes finite element model of the BBGS is developed and applied to investigate ice dynamics and surface structures during the recent surge. A von Mises criterion is adopted to simulate crevassing at the glacier surface, oriented along the axes of maximum principal tensile stress. To facilitate evaluation of model‐ and data‐derived crevasse characteristics, three different comparison methods are introduced. General agreement in the model‐data comparisons indicates that the model has the ability to represent the BBGS system during peak acceleration. The crevasse‐based approach is also employed to optimize the basal sliding parameter and the von Mises stress threshold in the model. Results further indicate that bed topography is an important constraint in modeling the surge process.
根据 CryoSat-2 高度计数据绘制大型山地冰川时空图：白令冰川涌动期间的表面高程和高程变化（2011 年至 2014 年）
影响因子：
3.4
作者：
Trantow, T.;Herzfeld, U. C.
通讯作者：
Herzfeld, U. C.