A comparison of different ways of dealing with isostasy: examples from modelling the Antarctic ice sheet during the last glacial cycle
A comparison of different ways of dealing with isostasy: examples from modelling the Antarctic ice sheet during the last glacial cycle
复制标题
处理均衡的不同方法的比较：末次冰期期间南极冰盖建模的示例
作者：
E. Le Meur;P. Huybrechts
基岩均衡响应对冰盖动力学具有很强的控制作用，因此在冰盖模型中总是要考虑到基岩均衡响应。本文回顾了通常用于冰盖建模社区处理基岩响应的各种方法，并将其与更复杂的全地球模型进行了比较。这些基岩处理，共五个，再加上一个三维的热力学冰盖模型在相同的强迫条件下，模拟南极冰盖在末次冰期循环。模拟的输出进行比较的基础上的时间依赖行为的总冰量和平均基岩海拔在周期和目前的上升率在南极洲。这一比较证实了考虑岩石圈弹性弯曲的必要性，以产生现实的基岩模式。它还证明了固有的缺陷的扩散方程在模拟地幔内的复杂变形。然而，当特征参数在其不确定性范围内变化时，单个方法内的差异通常与各种方法之间的差异具有相同的数量级。本概述最后试图指出这些方法的主要优点和缺点，并根据具体的建模要求确定哪一个是最合适的。
The bedrock isostatic response exerts a strong control on ice-sheet dynamics and is therefore always taken into account in ice-sheet models. This paper reviews the various methods normally used in the ice-sheet modelling community to deal with the bedrock response and compares these with a more sophisticated full-Earth model. Each of these bedrock treatments, five in total, is coupled with a three-dimensional thermomechanical ice-sheet model under the same forcing conditions to simulate the Antarctic ice sheet during the last glacial cycle. The outputs of the simulations are compared on the basis of the time-dependent behaviour for the total ice volume and the mean bedrock elevation during the cycle and of the present rate of uplift over Antarctica. This comparison confirms the necessity of accounting for the elastic bending of the lithosphere in order to yield realistic bedrock patterns. It furthermore demonstrates the deficiencies inherent to the diffusion equation in modelling the complex deformation within the mantle. Nevertheless, when characteristic parameters are varied within their range of uncertainty, differences within one single method are often of the same order as those between the various methods. This overview finally attempts to point out the main advantages and drawbacks of each of these methods and to determine which one is most appropriate depending on the specific modelling requirements.