Quantifying West Antarctic mantle viscosity via precise GPS measurement of Earth's response to surface mass balance anomalies

通过精确的 GPS 测量地球对表面质量平衡异常的响应来量化西南极地幔粘度

• 批准号: NE/R002029/1
• 负责人: Michael Bentley
• 金额: $ 80.07万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR002029%2F1
• 关键词: Quantifying; West; Antarctic; mantle; viscosity

Satellite measurements of ice sheet change are necessary to understand and help predict sea level rise, but are contaminated by a phenomenon known as Glacial Isostatic Adjustment (GIA). GIA is a form of ongoing solid Earth deformation in response to previous ice sheet mass changes. It can in principle be measured wherever we have access to bedrock, but this is not the case for much of Antarctica and therefore (and also for reasons of practicability) we require physically-based mathematical models of GIA. These models must be calibrated and validated, which can be done with the aid of precise measurements of Earth deformation made using continuous GPS receivers sited on bedrock.Continuous GPS data are therefore crucial to the determination of past and present ice mass change across Antarctica and the quantification of feedbacks between ice dynamics and solid Earth deformation. A fundamental property that must be quantified in such studies is the rheology of the solid Earth (its deformational response to forces acting on it). The Earth's mantle shows viscous behaviour over longer timescales but behaves elastically in the short term (as observed e.g. by the passage of seismic waves), a phenomenon known as viscoelasticity. Recent studies have demonstrated that there are large spatial variations in mantle viscosity across Antarctica, but at present the magnitude of such variations is not known. We propose to pioneer a new approach to determining spatially-variable mantle viscosity that involves analysing the viscoelastic response of the solid Earth to episodic surface mass balance (SMB) anomalies across Antarctica. Our approach makes use of the fact that in regions where the magnitude of surface mass change is well known, observations of the accompanying solid Earth response allow the quantification of the rheological properties of the Earth.In order to achieve our goal we require access to high-precision, long-duration GPS records. Fortunately there is already an extensive GPS network in West Antarctica, which although erected piecemeal via a series of NERC-funded projects (and equivalent overseas grants), now has the potential to deliver such records over the next few years. We therefore propose to overhaul the existing GPS network that lies within the remit of UK logistical support in Antarctica; we will extend the time series at a strategic subset of the existing sites, and transmit all data to open access servers via satellite. The resulting step change in precision and data accessibility will enable us to achieve our scientific goals and at the same time will benefit the international scientific community: the provision of open access GPS time series for West Antarctica will contribute to emerging data inversion activities and make it possible to ground-truth ice mass balance estimates delivered by the multi-million-dollar Gravity Recovery and Climate Experiment (GRACE) Follow-on mission, which is due for launch in 2017.

冰片变化的卫星测量对于理解和帮助预测海平面上升是必要的，但被称为冰川等静态调节（GIA）的现象污染。 GIA是一种响应先前的冰盖质量变化的持续固体变形的形式。原则上可以在我们可以使用基岩的任何地方来测量它，但是对于南极洲的大部分地区来说，情况并非如此（也是出于实用性的原因），我们需要基于物理的GIA数学模型。这些模型必须进行校准和验证，这可以借助于位于基岩上的连续GPS接收器进行的精确测量的地球变形进行，因此，连续的GPS数据对于确定南极洲的过去和现在的冰质量变化至关重要。在此类研究中必须量化的基本特性是固体的流变学（其对作用于其作用的力的变形反应）。地球的地幔在更长的时间尺度上表现出粘性行为，但在短期内（如通过地震波的通过，这是一种被称为粘弹性的现象）的弹性行为。最近的研究表明，整个南极的地幔粘度存在很大的空间变化，但目前尚不清楚这种变化的幅度。我们建议开拓一种新的方法来确定空间可变的地幔粘度，该粘度涉及分析固体大地对整个南极洲的固体表面质量平衡（SMB）异常的粘弹性响应。我们的方法利用了以下事实：在表面质量变化的区域中，众所周知，对伴随的固体响应的观察可以量化地球的流变特性。为了实现我们的目标，我们需要访问高级，长期的GPS记录。幸运的是，西南极西部已经有一个广泛的GPS网络，尽管该网络通过一系列NERC资助的项目（以及等效的海外赠款）零碎，但现在有可能在未来几年内提供此类记录。因此，我们建议对南极后勤支持范围内的现有GPS网络进行大修；我们将在现有站点的战略子集中延长时间序列，并将所有数据传输到通过卫星打开访问服务器。精确和数据可访问性的结果变化将使我们能够实现我们的科学目标，同时将使国际科学界受益：为西南极西部的开放访问GPS时间序列提供将有助于新兴的数据反演活动，并有可能在启动时，可以在2017年启动时估计，以启动的竞争估计，以启动较高的估计（GREGE），以适用于GREGE（GREGE），以下是遵循的效果，以下是遵循的效果，以下是遵循的效果，以下任务是遵循的。

项目成果

Supplementary material to "Antarctic ice sheet paleo-constraint database"

“南极冰盖古约束数据库”的补充材料

• DOI: 10.5194/essd-2022-398-supplement
• 发表时间: 2022
• 作者: Lecavalier B

A commercial finite element approach to modelling Glacial Isostatic Adjustment on spherical self-gravitating compressible earth models

在球形自重力可压缩地球模型上模拟冰川等静压调整的商业有限元方法

• DOI: 10.1093/gji/ggad354
• 发表时间: 2023
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Huang P

The Influence of Sediments, Lithosphere and Upper Mantle (Anelastic) With Lateral Heterogeneity on Ocean Tide Loading and Ocean Tide Dynamics

• DOI: 10.1029/2022jb025200
• 发表时间: 2022-11
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Pingping Huang;R. Sulzbach;V. Klemann;Yoshiyuki Tanaka;H. Dobslaw;Z. Martinec;Maik Thomas

Antarctic ice sheet paleo-constraint database

南极冰盖古约束数据库

• DOI: 10.5194/essd-2022-398
• 发表时间: 2022
• 作者: Lecavalier B

A global, spherical finite-element model for post-seismic deformation using <i>Abaqus</i>

用于震后变形的全局球形有限元模型

• DOI: 10.5194/gmd-15-2489-2022
• 发表时间: 2022
• 期刊: Geoscientific Model Development
• 影响因子: 5.1
• 作者: Nield G