法国蔚蓝海岸大学Boughanemi Alexandre课题组近日的研究揭示了Andrade和Burgers流变学对南极冰川均衡调整模拟的影响。相关论文于2024年3月8日发表在《大地测量与地球动力学》杂志上。

研究基于Andrade和Burgers粘弹性流变学，而不是常见的Maxwell流变学，以模拟南极GIA引起的变形。Love数和Green's函数形式用于计算过去和现在，冰体变化引起的径向表面位移和重力变化。研究人员考虑一个地球模型，其弹性性质和径向结构是由初步参考地球模型和两个粘度剖面平均出来的，以解释最近发表的关于当前冰量变化的结果。

研究使用的三种流变定律对地球时间响应的影响不同，导致比两种粘度结构引起的差异更小。在地表质量变化开始后的100-1000年间，Maxwell和Burgers流变学之间的差异最大。结果表明，Andrade和Burgers流变仪可以使地球能够在十年到百年的时间尺度上做出反应，比Maxwell多出10米。仅考虑最近冰体的变化，由Burgers和Andrade流变学得出的变形率比Maxwell流变学估计的变形率大几倍。

据悉，冰体的变化使地球变形并改变其重力场，这一过程被称为冰川均衡调整(GIA)。由于过去和现在冰体变化的累积效应、过去冰体变化的未知历史以及地球力学特性的不确定性，南极洲的GIA仍然缺乏约束。

附：英文原文

Title: Effects of Andrade and Burgers rheologies on glacial isostatic adjustment modeling in Antarctica

Author: Boughanemi Alexandre, Anthony Memin

Issue&Volume: 2024/03/08

Abstract: Variations in ice mass deform the Earth and modify its gravity field, a process known as Glacial Isostatic Adjustment (GIA). GIA in Antarctica remains poorly constrained due to the cumulative effect of past and present ice-mass changes, the unknown history of the past ice-mass change, and the uncertainties on the mechanical properties of the Earth. This paper investigates the effect of using Andrade and Burgers viscoelastic rheologies, rather than the commonly used Maxwell rheology, to model GIA-induced deformation in Antarctica. The Love number and Green's function formalism are used to compute the radial surface displacements and the gravity changes induced by the past and present ice-mass changes. We consider an Earth model whose elastic properties and radial structure are averaged from the Preliminary Reference Earth Model and two viscosity profiles to account for the recently published results on the present ice-mass changes. Using the three rheological laws affects the temporal response of the Earth differently, leading to smaller discrepancies than those induced by the two viscosity structures. The differences are the largest between Maxwell and Burgers rheologies during the 100–1000 years following the beginning of the surface-mass change. Results show that using the Andrade and Burgers rheologies allows the Earth to respond on decennial to centennial time scales, up to 10 m more than Maxwell. Considering only the recent ice-mass changes, the deformation rates derived from Burgers and Andrade rheologies are several times larger than those estimated by Maxwell rheology.

DOI: 10.1016/j.geog.2023.12.008

Source: https://www.sciencedirect.com/science/article/pii/S167498472400017X