Quantifying the sensitivity of post-glacial sea level change to laterally varying viscosity
Quantifying the sensitivity of post-glacial sea level change to laterally varying viscosity
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DOI：
10.1093/gji/ggy184
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发表时间：
2018-08-01
影响因子：
2.8
通讯作者：
Lau, Harriet C. P.
中科院分区：
文献类型：
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作者：
Crawford, Ophelia;Al-Attar, David;Lau, Harriet C. P.
我们提出了一种计算冰川均衡调整（GIA）测量值与地球黏度结构和冰盖历史的导数的方法。这些导数或核，量化了测量值对潜在模型参数的线性化灵敏度。伴随方法用于在具有一系列线性或非线性粘弹性流变的横向非均质地球模型中有效地计算理论上精确的灵敏度核。我们首先提出了一种计算时域GIA的新方法，与拉普拉斯域中更常见的公式相反，它非常适合连续变化的地球模型和伴随方法的使用。基准测试结果表明，我们的公式与以前的方法非常一致。我们通过一系列相对于球对称背景模型的数值计算来说明以这种方式计算的核的潜在应用。灵敏度的复杂空间格局并不直观，这是第一次对这种效应进行高效、准确的量化。
We present a method for calculating the derivatives of measurements of glacial isostatic adjustment (GIA) with respect to the viscosity structure of the Earth and the ice-sheet history. These derivatives, or kernels, quantify the linearized sensitivity of measurements to the underlying model parameters. The adjoint method is used to enable efficient calculation of theoretically exact sensitivity kernels within laterally heterogeneous earth models that can have a range of linear or nonlinear viscoelastic rheologies. We first present a new approach to calculate GIA in the time domain, which, in contrast to the more usual formulation in the Laplace domain, is well suited to continuously varying earth models and to the use of the adjoint method. Benchmarking results show excellent agreement between our formulation and previous methods. We illustrate the potential applications of the kernels calculated in this way through a range of numerical calculations relative to a spherically symmetric background model. The complex spatial patterns of the sensitivities are not intuitive, and this is the first time that such effects are quantified in an efficient and accurate manner.