Collaborative Research: Synthesis of Thwaites Glacier Dynamics: Diagnostic and Prognostic Sensitivity Studies of a West Antarctic Outlet System

该合同支持一项为期三年的研究，该研究使用一套现有的数值模型，结合现有的和国际极地年（IPY）提出的数据集，分离影响西南极洲阿蒙森海海湾（ASE）的Thwaites冰川（TG）的基本物理过程。四种不同的模型将被用来探讨河口几何形状、冰架支撑、基底应力分布、地表物质平衡、地表气候和内陆动力扰动对热重变化的影响。这种特殊的模型集合非常适合这项研究的广泛性质，因为它们结合了应力场（浅冰和大陆架流）、系统几何（1-d和2-d平面视图和流线；深度集成和深度依赖）和质量-动量-能量耦合（机械和热机械）的有效和互补简化。这些模型将通过数据集（包括冰厚、地表高程、基底地形、冰面速度和位场的区域图）和地球物理数据分析（包括提高地表高程的空间分辨率、改进地热通量的区域估计、地表冰的冰下界面特征以及地表冰和浮冰之间的地表区过渡）进行约束和验证。该研究的智力价值集中在NSF冰川学计划的几个重点领域，包括：冰动力学、数值模拟和冰盖遥感。此外，该研究直接解决了以下国家科学基金会的具体目标：“研究冰川快速流动的物理学，重点是冰川床的过程”；“冰架稳定性研究”；以及“冰动力和气候变化之间反馈的识别和量化”。这项研究的广泛影响将有助于回答未来冰盖稳定性和海平面变化的社会相关问题。这项研究还将有助于两位年轻研究人员的早期职业发展，并将有助于直接参与研究的研究生和本科生的教育，研究结果将纳入课程和非正式报告中。

This award supports a three-year study to isolate essential physical processes affecting Thwaites Glacier (TG) in the Amundsen Sea Embayment (ASE) of West Antarctica using a suite of existing numerical models in conjunction with existing and International Polar Year (IPY)-proposed data sets. Four different models will be utilized to explore the effects of embayment geometry, ice-shelf buttressing, basal-stress distribution, surface mass balance, surface climate, and inland dynamic perturbations on the present and future dynamics of TG. This particular collection of models is ideally suited for the broad nature of this investigation, as they incorporate efficient and complementary simplifications of the stress field (shallow-ice and shelf-stream), system geometry (1-d and 2-d plan-view and flowline; depth-integrated and depth-dependent), and mass-momentum energy coupling (mechanical and thermo-mechanical). The models will be constrained and validated by data sets (including regional maps of ice thickness, surface elevation, basal topography, ice surface velocity, and potential fields) and geophysical data analyses (including increasing the spatial resolution of surface elevations, improving regional estimates of geothermal flux, and characterizing the sub-glacial interface of grounded ice as well as the grounding-zone transition between grounded and floating ice). The intellectual merit of the research focuses on several of the NSF Glaciology program's emphases, including: ice dynamics, numerical modeling, and remote sensing of ice sheets. In addition, the research directly addresses the following specific NSF objectives: "investigation of the physics of fast glacier flow with emphasis on processes at glacier beds"; "investigation of ice-shelf stability"; and "identification and quantification of the feedback between ice dynamics and climate change". The broader impacts of this research effort will help answer societally relevant questions of future ice sheet stability and sea-level change. The research also will aid in the early career development of two young investigators and will contribute to the education of both graduate and undergraduate students directly involved in the research, and results will be incorporated into courses and informal presentations.