Collaborative Research: EAGER: A Dual-Band Radar for Measuring Internal Ice Deformation: a Multipass Ice-Penetrating Radar Experiment on Thwaites Glacier and the McMurdo Ice Shelf

合作研究：EAGER：用于测量内部冰变形的双波段雷达：在思韦茨冰川和麦克默多冰架上进行的多通道穿冰雷达实验

• 批准号: 2027579
• 负责人: Knut Christianson
• 金额: $ 8.19万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2027579&HistoricalAwards=false
• 关键词: Collaborative; Research; EAGER; Dual; Band

This project will develop a new ice-penetrating radar system that can simultaneously map glacier geometry and glacier flow along repeat profiles. Forecasting an ice-sheet’s contribution to sea level requires an estimate for the initial ice-sheet geometry and the parameters that govern ice flow and slip across bedrock. Existing ice-sheet models cannot independently determine this information from conventional observations of ice-surface velocities and glacier geometry. This introduces substantial uncertainty into simulations of past and future ice-sheet behavior. Thus, this new radar capability is conceived to provide the needed data to support higher-fidelity simulations of past and future ice-sheet behavior and more accurate projections of future sea level.The new radar system will integrate two existing radars (the multi-channel coherent radio-echo depth sounder and the accumulation radar) developed by the Center for the Remote Sensing of Ice Sheets, as well as adding new capabilities. An eight-element very high frequency (VHF; 140-215 MHz) array will have sufficient cross-track aperture to swath map internal layers and the ice-sheet base in three dimensions. A single ultra high frequency (UHF; 600-900 MHz) antenna will have the range and phase resolution to map internal layer displacement with 0.25-mm precision. The VHF array will create 3D mappings of layer geometry that enable measurements of vertical velocities by accounting for spatial offsets between repeat profiles and changing surface conditions. The vertical displacement measurement will then be made by determining the difference in radar phase response recorded by the UHF antenna for radar profiles collected at the same locations at different times. The UHF antenna will be dual-polarized and thus capable of isolating both components of complex internal reflections. This should enable inferences of ice crystal orientation fabric and widespread mapping of ice viscosity. Initial field testing of the radar will occur on the McMurdo Ice Shelf and then progress to Thwaites Glacier, Antarctica. The dual-band radar system technology and processing algorithms will be developed with versatile extensible hardware and user-friendly software so that this system will serve as a prototype for a future community radar system.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.

该项目将开发一种新的冰穿透雷达系统，可同时绘制冰川几何形状和冰川流动沿着重复剖面图。预测冰盖对海平面的影响需要估计初始冰盖的几何形状和控制冰流和滑过基岩的参数。现有的冰盖模型无法从常规的冰面速度和冰川几何形状观测中独立地确定这些信息。这给过去和未来冰盖行为的模拟带来了很大的不确定性。因此，这一新的雷达能力被设想为提供所需的数据，以支持对过去和未来冰盖行为的更高保真度的模拟以及对未来海平面的更准确的预测。新的雷达系统将整合由冰盖遥感中心开发的两个现有雷达（多通道相干无线电回波测深仪和累积雷达），并增加新的能力。 一个八单元甚高频（VHF; 140-215 MHz）阵列将有足够的跨跟踪孔径，以三维方式测绘内部层和冰盖基底。单个超高频（UHF; 600-900 MHz）天线将具有范围和相位分辨率，以0.25 mm的精度绘制内部层位移。VHF阵列将创建层几何形状的3D映射，通过考虑重复剖面之间的空间偏移和不断变化的表面条件来测量垂直速度。然后，将通过确定由UHF天线记录的雷达相位响应的差异来进行垂直位移测量，以获得在不同时间在相同位置收集的雷达剖面。超高频天线将是双极化的，因此能够隔离复杂内部反射的两个分量。 这应该能够推断冰晶的取向结构和广泛的冰粘度映射。雷达的初步实地测试将在麦克默多冰架进行，然后前往南极洲的思韦茨冰川。该双波段雷达系统技术和处理算法将采用通用的可扩展硬件和用户友好的软件进行开发，因此该系统将作为未来社区雷达系统的原型。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。