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

南极洲西部的地球表面正在以极高的速度上升，这是对冰盖质量卸载的反应。本研究（1）提高了使用全球定位系统（GPS）测量地表隆起的空间覆盖范围和精度;（2）使用地震学探测地球深部结构。这些观测结果将被整合到一个最先进的三维冰盖模型中，以模拟南极西部冰盖过去和未来的行为，并评估其脆弱性。项目结果将允许评估西南极冰盖的变化率及其对全球海平面上升加速贡献的时间框架，预计这将对美国海岸线产生放大影响。该研究计划通过技术进步和国际合作伙伴关系，建立并利用了对自主观测基础设施的先前投资。该项目的存档开放获取数据将促进一系列研究，这些研究将增进对南极大陆及其冰盖覆盖的基本了解。该项目将通过实地工作、研讨会和在线资源库利用的暑期学校，培训和指导一批跨学科的极地科学家。 将对POLENET-ANET自主全球定位系统和地震网络进行重新配置，以获取侧重于阿蒙森湾周围的高分辨率现场数据，从而捕捉冰盖迅速变化的区域内空间变化的地壳运动和地球结构。模式和规模的横向变化，地幔温度，粘度和岩石圈弹性厚度的分辨率，以确定该系统所需的将建立从地震学研究纳入新的仪器足迹。 绝对地幔粘度值将使用高精度GPS时间序列的地壳运动数据以及南极西部冰盖（WAIS）表面质量平衡和冰史信息独立确定。 在地幔粘度变化在短的空间尺度和基岩地形下的冰盖是复杂的，是假设为西南极洲，积极和消极的反馈之间的冰盖和固体地球可能会发生，通过提高或降低接地线和减少或增加主要出口冰川下的逆行床坡度，以稳定或不稳定的冰动力。对三维地球结构的新约束将被纳入创新的三维冰川均衡调整（GIA）模型和气候-冰冻圈-固体地球系统的耦合模型。 这些先进的模型受到本项目获得的新观测的限制，将模拟WAIS过去和未来的演变，以改进对南极洲西部不断变化的冰量的估计，确定WAIS可能因持续的地球变形而稳定的地方，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响评审标准。

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.