Ocean-Ice Interaction in the Amundsen Sea Sector of West Antarctica

The Office of Polar Programs, Antarctic Integrated and System Science Program has made this award to support an interdisciplinary study of the effects of the ocean on the stability of glacial ice in the most dynamic region the West Antarctic Ice Sheet, namely the Pine Island Glacier in the Amundsen Sea Embayment. The collaborative project builds on the knowledge gained by the highly successful West Antarctic Ice Sheet program and is being jointly sponsored with NASA. Recent observations indicate a significant ice loss, equivalent to 10% of the ongoing increase in sea-level rise, in this region. These changes are largest along the coast and propagate rapidly inland, indicating the critical impact of the ocean on ice sheet stability in the region. While a broad range of remote sensing and ground-based instrumentation is available to characterize changes of the ice surface and internal structure (deformation, ice motion, melt) and the shape of the underlying sediment and rock bed, instrumentation has yet to be successfully deployed for observing boundary layer processes of the ocean cavity which underlies the floating ice shelf and where rapid melting is apparently occurring. Innovative, mini ocean sensors that can be lowered through boreholes in the ice shelf (about 500 m thick) will be developed and deployed to automatically provide ocean profiling information over at least three years. Their data will be transmitted through a conducting cable frozen in the borehole to the surface where it will be further transmitted via satellite to a laboratory in the US. Geophysical and remote sensing methods (seismic, GPS, altimetry, stereo imaging, radar profiling) will be applied to map the geometry of the ice shelf, the shape of the sub ice-shelf cavity, the ice surface geometry and deformations within the glacial ice. To integrate the seismic, glaciological and oceanographic observations, a new 3-dimensional coupled ice-ocean model is being developed which will be the first of its kind. NASA is supporting satellite based research and the deployment of a robotic-camera system to explore the environment in the ocean cavity underlying the ice shelf and NSF is supporting all other aspects of this study. Broader impacts: This project is motivated by the potential societal impacts of rapid sea level rise and should result in critically needed improvements in characterizing and predicting the behavior of coupled ocean-ice systems. It is a contribution to the International Polar Year and was endorsed by the International Council for Science as a component of the 'Multidisciplinary Study of the Amundsen Sea Embayment' proposal #258 of the honeycomb of endorsed IPY activities. The research involves substantial international partnerships with the British Antarctic Survey and the University of Bristol in the UK. The investigators will partner with the previously funded 'Polar Palooza' education and outreach program in addition to undertaking a diverse set of outreach activities of their own. Eight graduate students and one undergraduate as well as one post doc will be integrated into this research project.美国国家科学基金会（National Science Foundation, NSF）极地项目办公室（Office of Polar Programs）南极综合系统科学项目（Antarctic Integrated and System Science Program）已授予本奖项，以支持一项跨学科研究，探究海洋对西南极冰盖（West Antarctic Ice Sheet）最具动态性的区域——阿蒙森海盆（Amundsen Sea Embayment）的松岛冰川（Pine Island Glacier）——冰体稳定性的影响。本协作项目基于此前极具影响力的西南极冰盖研究项目所积累的知识，由美国国家航空航天局（National Aeronautics and Space Administration, NASA）联合资助。近期观测表明，该区域存在显著的冰量流失，其规模相当于当前海平面上升增量的10%。此类变化在沿海区域最为显著，并快速向内陆蔓延，凸显出海洋对该区域冰盖稳定性的关键影响。尽管目前已有大量遥感与地面观测仪器，可用于表征冰面与内部结构（变形、冰流、消融）的变化，以及下伏沉积物与岩石基底的形态，但尚未有成功部署的观测仪器，可用于监测漂浮冰架下方海洋空腔的边界层过程——而该区域正是快速消融发生的场所。研究团队将研发并部署可通过冰架钻孔（冰层厚度约500米）投放的创新型微型海洋传感器，以自动获取至少三年的海洋剖面观测数据。这些传感器的数据将通过冻结在钻孔内的导电电缆传输至地面，再经由卫星转发至美国的实验室。研究将采用地球物理与遥感方法（地震、全球定位系统（GPS）、测高（altimetry）、立体成像（stereo imaging）、雷达剖面测量（radar profiling）），绘制冰架几何形态、冰架下空腔形态、冰面几何形态以及冰川内部变形情况。为整合地震、冰川学与海洋学观测数据，团队正开发一款全新的三维冰-海洋耦合模型，此类模型尚属同类首创。其中，NASA负责支持卫星相关研究以及部署机器人摄像系统，以探索冰架下方海洋空腔的环境；NSF则负责资助本研究的其余所有环节。 更广泛影响：本项目的研究动机源于海平面快速上升可能带来的社会影响，其研究成果将为表征与预测冰-海洋耦合系统的行为提供亟需的改进方案。本项目是国际极地年（International Polar Year, IPY）的贡献项目之一，已获国际科学理事会（International Council for Science）认可，作为“阿蒙森海盆多学科研究”提案（编号258）的组成部分，纳入经批准的IPY活动“蜂巢计划”。本研究与英国南极调查局（British Antarctic Survey）以及英国布里斯托大学（University of Bristol）建立了深度国际合作。研究团队将与此前已获资助的“极地狂欢（Polar Palooza）”教育与外展项目展开合作，同时自行开展一系列多样化的外展活动。本项目将吸纳8名研究生、1名本科生及1名博士后研究人员参与。