Collaborative Research: Investigating Ice Sheet - Solid Earth Feedbacks in West Antarctica: Implications for Ice Sheet Evolution and Stability

合作研究：调查冰盖 - 南极洲西部的固体地球反馈：对冰盖演化和稳定性的影响

• 批准号: 1744852
• 负责人: Richard Aster
• 金额: $ 18.19万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1744852&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigating; Ice; Sheet

The earth's surface in West Antarctica is rising at extremely high rates in response to unloading of ice sheet mass. This research (1) improves the spatial coverage and accuracy of measurements of surface uplift using the Global Positioning System (GPS) and (2) probes the structure of the deep earth using seismology. These observations will be integrated into a state-of-the-art, 3-D ice sheet model to simulate the past and future behavior of the West Antarctic Ice Sheet and assess its vulnerability. Project results will allow assessment of the West Antarctic Ice Sheet's rate of change and the time frame for its accelerating contribution to global sea-level rise, which is predicted to have an amplified impact for U.S. coastlines. This research program builds on and leverages prior investments in autonomous observational infrastructure through technological advances and international partnerships. Archived open-access data from the project will facilitate a range of studies that will advance basic knowledge of the Antarctic continent and its ice sheet cover. The project will train and mentor an interdisciplinary cohort of polar scientists through field work, workshops, and a summer school leveraged by an online resource library. The POLENET-ANET autonomous GPS and seismic network will be reconfigured to acquire higher-resolution in situ data focused around the Amundsen Embayment to capture spatially varying crustal motions and Earth structure in a region where the ice sheet is rapidly changing. The pattern and scale of lateral variations in mantle temperature, viscosity, and lithospheric elastic thickness at the resolution necessary to characterize this system will be established from seismological studies incorporating the new instrumentation footprint. Absolute mantle viscosity values will be independently determined using crustal motion data from high-precision GPS time series together with West Antarctic Ice Sheet (WAIS) surface mass balance and ice history information. Where mantle viscosity varies over short spatial scales and bedrock topography below the ice sheet is complex, as is hypothesized for West Antarctica, both positive and negative feedbacks between the ice sheet and the solid earth may occur, acting to stabilize or destabilize ice dynamics by raising or lowering the grounding line and reducing or increasing retrograde bed slopes below major outlet glaciers. New constraints on 3-D Earth structure will be built into innovative 3-D glacial isostatic adjustment (GIA) models and coupled models of climate-cryosphere-solid Earth systems. These advanced models, constrained by the new observations obtained in this project, will simulate the past and future evolution of the WAIS to improve estimates of changing ice mass in West Antarctica, establish where the WAIS may be stabilized by ongoing Earth deformation, and reduce uncertainties in projections of future sea level change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

南极西部的地球表面以极高的速度上升，以响应冰盖质量的卸载。这项研究（1）使用全球定位系统（GPS）提高了表面隆升测量的空间覆盖范围和准确性，并（2）使用地震学探测了深层地球的结构。这些观察结果将集成到最先进的3-D冰盖模型中，以模拟西南极冰盖的过去和未来行为并评估其脆弱性。项目的结果将允许评估西南极冰盖的变化速度和加速对全球海平面上升的贡献的时间范围，预计这对美国海岸线产生了放大的影响。该研究计划通过技术进步和国际伙伴关系建立并利用了对自动观察基础设施的先前投资。该项目的存档开放访问数据将有助于一系列研究，这些研究将提高南极大陆及其冰盖覆盖的基础知识。该项目将通过现场工作，研讨会和在线资源库利用的暑期学校来培训和指导跨学科科学家的跨学科队列。 Polenet-Anet自主GP和地震网络将被重新配置，以获取围绕Amundsen胚胎的高分辨率原位数据，以捕获冰盖迅速变化的区域中的空间变化的地壳运动和地球结构。地幔温度，粘度和岩石圈弹性厚度在表征该系统所必需的分辨率下的横向变化的模式和尺度将从结合新仪器足迹的地震研究中确定。 绝对地幔粘度值将使用来自高精度GPS时间序列的地壳运动数据与南极冰盖（WAIS）表面质量平衡和冰历史信息独立确定。 地幔粘度在冰盖下方的短空间尺度和基岩地形上有所不同，这是复杂的，对于南极西部的西部，可能会发生冰盖和固体地球之间的积极和负面反馈，以稳定或降低接地或降低逆流或增加逆流式玻璃鞋的稳定或降低冰层动态，以使冰稳定或破坏冰的动态。对3-D地球结构的新约束将内置在创新的3-D冰川等静态调整（GIA）模型和气候 - 晶层固体地球系统的耦合模型中。 These advanced models, constrained by the new observations obtained in this project, will simulate the past and future evolution of the WAIS to improve estimates of changing ice mass in West Antarctica, establish where the WAIS may be stabilized by ongoing Earth deformation, and reduce uncertainties in projections of future sea level change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts审查标准。

项目成果

P- and S-wave velocity structure of central West Antarctica: Implications for the tectonic evolution of the West Antarctic Rift System

西南极洲中部的纵波和横波速度结构：对西南极裂谷系统构造演化的启示

• DOI: 10.1016/j.epsl.2020.116437
• 发表时间: 2020
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Lucas, Erica M.;Soto, David;Nyblade, Andrew A.;Lloyd, Andrew J.;Aster, Richard C.;Wiens, Douglas A.;O'Donnell, John Paul;Stuart, Graham W.;Wilson, Terry J.;Dalziel, Ian W.
• 通讯作者: Dalziel, Ian W.

Seismicity and Pn Velocity Structure of Central West Antarctica

南极洲中西部的地震活动和 Pn 速度结构

• DOI: 10.1029/2020gc009471
• 发表时间: 2021
• 期刊: Geosystems
• 作者: Lucas, Erica M.;Nyblade, Andrew A.;Lloyd, Andrew J.;Aster, Richard C.;Wiens, Douglas A.;O'Donnell, John Paul;Stuart, Graham W.;Wilson, Terry J.;Dalziel, Ian W. D.;Winberry, J. Paul
• 通讯作者: Winberry, J. Paul

The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: Insights into tectonic structure and geothermal heat flow

• DOI: 10.1016/j.epsl.2019.06.024
• 发表时间: 2019-09
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: J. O’Donnell;G. Stuart;A. Brisbourne;K. Selway;Yingjie Yang;G. Nield;P. Whitehouse;A. Nyblade;D. Wiens;R. Aster;S. Anandakrishnan;A. Huerta;T. Wilson;J. P. Winberry

Mapping Crustal Shear Wave Velocity Structure and Radial Anisotropy Beneath West Antarctica Using Seismic Ambient Noise

• DOI: 10.1029/2019gc008459
• 发表时间: 2019-11
• 期刊: Geochemistry
• 影响因子: 3.7
• 作者: J. O’Donnell;A. Brisbourne;G. Stuart;C. Dunham;Y. Yang;G. Nield;P. Whitehouse;A. Nyblade;D. Wiens;S. Anandakrishnan;R. Aster;A. Huerta;A. Lloyd;T. Wilson;J. Winberry

Heterogeneous upper mantle structure beneath the Ross Sea Embayment and Marie Byrd Land, West Antarctica, revealed by P-wave tomography

• DOI: 10.1016/j.epsl.2019.02.013
• 发表时间: 2019-05
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: A. White-Gaynor;A. Nyblade;R. Aster;D. Wiens;P. Bromirski;P. Gerstoft;R. Stephen;S. Hansen;T. Wilson;I. Dalziel;A. Huerta;J. Paul Winberry;S. Anandakrishnan