Detection of Crystal Orientation Fabrics near the Ross/Amundsen Sea Ice-flow Divide and at the Siple Dome Ice Core Site using Polarimetric Radar Methods

该合同支持在Ross/Amundsen海冰流分界线附近使用地面雷达测量来研究织物的项目，该分界线将钻探一个深冰芯。晶体在冰中的排列（晶体取向织物）对冰的变形有重要影响。当冰变形时，产生各向异性织物，这反过来又影响进一步的变形。测量冰结构的变化可以帮助揭示冰的变形历史，并指出冰在未来将如何变形。冰芯提供了确定织物垂直剖面的机会，但织物的水平变化仍然未知。用破冰雷达进行遥感是在大范围内做到这一点的唯一方法。初步结果表明，建立的极化方法可以检测织物的水平各向异性程度及其方向，即使它们是几乎垂直对称的织物。结合冰的变形历史，我们对冰结构的首次测绘将有助于模拟未来冰芯地点附近的冰流。该项目将培养一名研究生，并为两名本科生提供实地和实验室研究经验。该项目将有助于正在进行的南极西部冰盖计划，以更好地了解冰盖对全球海平面上升的影响。该项目还支持美国和日本科学家之间的国际合作。

This award supports a project to investigate fabrics with ground-based radar measurements near the Ross/Amundsen Sea ice-flow divide where a deep ice core will be drilled. The alignment of crystals in ice (crystal-orientation fabric) has an important effect on ice deformation. As ice deforms, anisotropic fabrics are produced, which, in turn, influence further deformation. Measurement of ice fabric variations can help reveal the deformation history of the ice and indicate how the ice will deform in the future. Ice cores provide opportunities to determine a vertical fabric profile, but horizontal variations of fabrics remain unknown. Remote sensing with ice-penetrating radar is the only way to do that over large areas. Preliminary results show that well-established polarimetric methods can detect the degree of horizontal anisotropy of fabrics and their orientation, even when they are nearly vertical-symmetric fabrics. In conjunction with ice deformation history, our first mapping of ice fabrics will contribute to modeling ice flow near the future ice core site. The project will train a graduate student and provide research experiences for two under graduate students both in field and laboratory. The project will contribute to ongoing West Antarctic ice sheet program efforts to better understand the impact of the ice sheet on global sea level rise. This project also supports an international collaboration between US and Japanese scientists.