The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica
The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica
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南极洲西部岩石圈厚度横向变化对冰川均衡调整的影响
DOI：
10.1093/gji/ggy158
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发表时间：
2018
影响因子：
2.8
通讯作者：
Nield G
中科院分区：
文献类型：
--
作者：
Nield G
由于冰消历史和地球流变学的不确定性，南极洲冰川均衡调整（GIA）预测的差异持续存在。在许多GIA研究中采用的地球模型由仅在径向上变化的参数定义，并代表全球平均地球结构（称为一维地球模型）。过度简化实际地球结构会导致模型预测在地球参数与全球平均值显著不同的地区（如南极洲西部）出现偏差。我们调查的横向变化在岩石圈厚度GIA在南极洲进行两个实验，使用不同的流变学方法来定义3-D地球模型，包括岩石圈厚度的空间变化的影响。第一个实验定义了一个弹性岩石圈的厚度空间变化推断地震研究。我们比较结果，从这个3-D模型与1-D地球模型，具有统一的岩石圈厚度定义为3-D岩石圈厚度的平均值。不考虑冰消历史和岩石圈下地幔粘度，我们发现较高的梯度，现今的隆升速率（即更高的振幅和更短的波长）在西南极洲时，使用3-D模型，由于薄于1-D平均岩石圈普遍在这一地区。第二个实验使用地震推断的温度作为幂律流变学的输入，从而使岩石圈具有粘性结构。模拟岩石圈的幂律流变学的结果是相当于一个更薄的岩石圈模型的行为，它导致更高的振幅和更短的波长变形相比，第一个实验。我们的结论是，在GIA模型中忽略岩石圈厚度的空间变化将导致预测的峰值隆起和沉降偏低，在西南极洲。这对冰盖建模研究具有重要意义，因为从更现实的3-D模型预测的更陡的隆起梯度可能会促进南极洲西部海洋接地区域的稳定性。包括岩石圈厚度的横向变化，至少达到分别考虑西南极洲和东南极洲的水平，对于捕获短波长变形是重要的，它有可能提供更好的拟合全球定位系统观测以及改进重力恢复和气候实验数据的GIA校正。
Differences in predictions of Glacial Isostatic Adjustment (GIA) for Antarctica persist due to uncertainties in deglacial history and Earth rheology. The Earth models adopted in many GIA studies are defined by parameters that vary in the radial direction only and represent a global average Earth structure (referred to as 1-D Earth models). Oversimplifying the actual Earth structure leads to bias in model predictions in regions where Earth parameters differ significantly from the global average, such as West Antarctica. We investigate the impact of lateral variations in lithospheric thickness on GIA in Antarctica by carrying out two experiments that use different rheological approaches to define 3-D Earth models that include spatial variations in lithospheric thickness. The first experiment defines an elastic lithosphere with spatial variations in thickness inferred from seismic studies. We compare the results from this 3-D model with results derived from a 1-D Earth model that has a uniform lithospheric thickness defined as the average of the 3-D lithospheric thickness. Irrespective of the deglacial history and sublithospheric mantle viscosity, we find higher gradients of present-day uplift rates (i.e. higher amplitude and shorter wavelength) in West Antarctica when using the 3-D models, due to the thinner-than-1-D-average lithosphere prevalent in this region. The second experiment uses seismically inferred temperature as an input to a power-law rheology, thereby allowing the lithosphere to have a viscosity structure. Modelling the lithosphere with a power-law rheology results in a behaviour that is equivalent to a thinner lithosphere model, and it leads to higher amplitude and shorter wavelength deformation compared with the first experiment. We conclude that neglecting spatial variations in lithospheric thickness in GIA models will result in predictions of peak uplift and subsidence that are biased low in West Antarctica. This has important implications for ice-sheet modelling studies as the steeper gradients of uplift predicted from the more realistic 3-D model may promote stability in marine-grounded regions of West Antarctica. Including lateral variations in lithospheric thickness, at least to the level of considering West and East Antarctica separately, is important for capturing short-wavelength deformation and it has the potential to provide a better fit to Global Positioning System observations as well as an improved GIA correction for the Gravity Recovery and Climate Experiment data.
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DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
Z. Martinec;D. Wolf
通讯作者：
D. Wolf
冰盖-地球-海平面耦合模型中南极冰盖的变化：对地球粘弹性特性的敏感性
DOI：
--
发表时间：
2017
期刊：
影响因子：
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作者：
D. Pollard;N. Gomez;R. DeConto
通讯作者：
R. DeConto
DOI：
--
发表时间：
2014
期刊：
--
影响因子：
--
作者：
D. Argus;W. Peltier;R. Drummond;A. Moore
通讯作者：
D. Argus;W. Peltier;R. Drummond;A. Moore
影响因子：
5.3
作者：
Nield, Grace A.;Barletta, Valentina R.;Berthier, Etienne
通讯作者：
Berthier, Etienne
影响因子：
2.8
作者：
I. Sasgen;A. Martín‐Español;A. Horvath;V. Klemann;E. Petrie;B. Wouters;M. Horwath;R. Pail;J. Bamber;P. Clarke;H. Konrad;M. Drinkwater
通讯作者：
I. Sasgen;A. Martín‐Español;A. Horvath;V. Klemann;E. Petrie;B. Wouters;M. Horwath;R. Pail;J. Bamber;P. Clarke;H. Konrad;M. Drinkwater