VELOCITY AND STRESS-FIELDS IN GROUNDED GLACIERS - A SIMPLE ALGORITHM FOR INCLUDING DEVIATORIC STRESS GRADIENTS
VELOCITY AND STRESS-FIELDS IN GROUNDED GLACIERS - A SIMPLE ALGORITHM FOR INCLUDING DEVIATORIC STRESS GRADIENTS
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DOI：
10.3189/s002214300001621x
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发表时间：
1995-01-01
影响因子：
3.4
通讯作者：
BLATTER, H
中科院分区：
文献类型：
--
作者：
BLATTER, H
一个新的和有效的算法计算三维应力和速度场在地面冰川包括偏应力梯度的作用。在冰质量比方面采用一阶一致近似，给出了五个应力分量和三个速度分量的八个场方程以及相应的边界条件。将局部冰厚映射到单位上的坐标变换）。用中心有限差分近似水平方向的导数，得到五个常微分方程和三个代数方程。这允许使用的线的方法，开始与指定的应力和速度分量在基地的集成，和一个简单的迭代过程收敛迅速。该算法可以用于广泛的应力应变率关系，只要应变只取决于偏应力和剪应力和温度。敏感性试验，使用合成和现实的冰的几何形状显示正常偏应力的速度分量的解决方案，甚至冰盖的相关性。应力场和速度场可能与广泛使用的浅冰近似值有很大的偏差。
A new and efficient algorithm for computing the three-dimensional stress and velocity fields in grounded glaciers includes the role of deviatoric stress gradients. A consistent approximation of first order in the aspect of ratio of the ice mass gives a set of eight field equations for the five stress and and three velocity components and the corresponding boundary conditions. A coordinate transformation mapping the local ice thickness on to unit). and approximating the derivatives in the horizontal direction by centred finite-differences yields five ordinary differential and three algebraic equations. This allows use of the method of lines, starting the integration with prescribed stress and velocity components at the base, and a simple iteration procedure converges rapidly.The algorithm can be used for a wide range of stress-strain-rate relations, as long as strain only depends on deviatoric and shear stresses and on temperature. Sensitivity tests using synthetic and realistic ice geometries show the relevance of normal deviatoric stresses in the solutions for the velocity components even for ice sheets. Stress and velocity fields may deviate substantially from the widely used shallow-ice approximation.