Joint inversion estimate of regional glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE Project REGINA)
Joint inversion estimate of regional glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE Project REGINA)
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DOI：
10.1093/gji/ggx368
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发表时间：
2017-12
影响因子：
2.8
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
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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
根据卫星重力测量和卫星测高确定南极冰盖物质平衡的一个主要不确定性是对冰川均衡调整(GIA)造成的固体地球持续变形的鲜为人知的修正。尽管在对整个上一个冰川周期的冰盖演化以及这些载荷变化引起的基岩变形进行一致模拟方面取得了很大进展，但由于缺乏对大陆下冰盖过去的范围和厚度以及地幔流变性的观测约束，GIA的正演模型仍然不明确。作为正演模型GIA的另一种选择，我们从多个空间大地观测中估计GIA：GRACE、Envisat/ICESat和GPS。利用卫星观测对当前和过去地表质量(冰质量)变化和固体地球过程的不同敏感性，我们基于对圆盘载荷强迫的粘弹性响应函数来估计GIA。根据对南极岩石圈厚度和地幔粘度变异性的估计，计算并分配了粘弹性响应函数。我们将我们的GIA估计值与已发表的GIA校正值进行了比较，并评估了它在从GRACE和卫星测高确定南极冰块平衡方面的影响。特别关注的是南极洲西部的阿蒙森海地区，那里的全球定位系统测量到了几厘米/年的隆升速度。我们表明，这种抬升大部分是由于西南极低粘性上地幔的存在，导致了对最近冰荷载变化的快速粘弹性反应。本文件介绍了第二份也是最后一份材料，总结了在欧洲航天局资助的一项研究--Regina(www.regina-Science ence.eu)--内开展的工作。
A major uncertainty in determining the mass balance of the Antarctic ice sheet from measurements of satellite gravimetry, and to a lesser extent satellite altimetry, is the poorly known correction for the ongoing deformation of the solid Earth caused by glacial isostatic adjustment (GIA). Although much progress has been made in consistently modelling the ice-sheet evolution throughout the last glacial cycle, as well as the induced bedrock deformation caused by these load changes, forward models of GIA remain ambiguous due to the lack of observational constraints on the ice sheet's past extent and thickness and mantle rheology beneath the continent. As an alternative to forward modelling GIA, we estimate GIA from multiple space-geodetic observations: GRACE, Envisat/ICESat and GPS. Making use of the different sensitivities of the respective satellite observations to current and past surface mass (ice mass) change and solid Earth processes, we estimate GIA based on viscoelastic response functions to disc load forcing. We calculate and distribute the viscoelastic response functions according to estimates of the variability of lithosphere thickness and mantle viscosity in Antarctica. We compare our GIA estimate with published GIA corrections and evaluate its impact in determining the ice mass balance in Antarctica from GRACE and satellite altimetry. Particular focus is applied to the Amundsen Sea Sector in West Antarctica, where uplift rates of several cm/yr have been measured by GPS. We show that most of this uplift is caused by the rapid viscoelastic response to recent ice-load changes, enabled by the presence of a low-viscosity upper mantle in West Antarctica. This paper presents the second and final contribution summarizing the work carried out within a European Space Agency funded study, REGINA, (www.regina-science.eu).