CAREER: Cross-Instrument Synthesis of Antarctic Radar Sounding Observations

地球的地质记录表明，巨大的冰盖导致了海平面上升的速度比今天观察到的要高得多。尽管如此，目前南极冰盖的一些部分正在整体上失去质量，并以更快的速度减少。将这些最近和正在进行的变化放在地质历史速率的背景下，并预测几十年至数百年后的未来，主要挑战之一是难以观察冰盖下的条件和过程。虽然卫星观测可以在冰川集水区到冰盖的范围内跟踪冰面的速度和海拔，但机载探冰雷达一直是评估冰下这种规模的条件的唯一方法。这些雷达观测是从20世纪60年代末开始的，但由于使用了许多不同的仪器，很难跟踪冰层下条件随时间的变化。该项目将开发在这些测量之间进行交叉比较所需的技术工具和方法，从而为跟踪和了解关键的冰下环境的变化提供机会。与该项目的研究和学生培训交织在一起的是一项外展教育努力，通过与国家科学奥林匹克运动会的合作，为初中生和高中生提供更好的资源，并增加对地球物理、冰川学和遥感主题的接触。冰盖雷达探测是冰川学科学的强大工具，具有广泛的适用性，涉及广泛的冰冻圈问题和过程。在整个西南极冰盖收集了广泛的空间和时间覆盖范围的雷达探测数据，包括多次调查提供跨越几十年时间或整个集水区冰盖扇区的观测的地区。然而，实现南极现有雷达探空观测的科学潜力的一个主要障碍是缺乏专门为跨仪器解释开发的分析方法。该项目旨在通过开发一套处理和解释技术来直接解决充分利用南极集体雷达探测记录的这些障碍，以便能够综合利用从非相干到相干、单通道到条带成像以及从数字雷达探测仪到光学记录雷达探测仪等各种系统收集的雷达探测数据集。这些方法将在两个目标地区进行评估：阿蒙森海滨和锡普尔海岸。该项目产生的所有前期和后处理探测数据将公开托管，供更广泛的研究社区使用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Earth's geologic record shows that the great ice sheets have contributed to rates of sea-level rise that have been much higher than those observed today. That said, some sectors of the current Antarctic ice sheet are losing mass at large and accelerating rates. One of the primary challenges for placing these recent and ongoing changes in the context of geologically historic rates, and for making projections decades to centuries into the future, is the difficulty of observing conditions and processes beneath the ice sheet. Whereas satellite observations allow tracking of the ice-surface velocity and elevation on the scale of glacier catchments to ice sheets, airborne ice-penetrating radar has been the only approach for assessing conditions on this scale beneath the ice. These radar observations have been made since the late 1960s, but, because many different instruments have been used, it is difficult to track change in subglacial conditions through time. This project will develop the technical tools and approaches required to cross-compare among these measurements and thus open up opportunities for tracking and understanding changes in the critical subglacial environment. Intertwined with the research and student training on this project will be an outreach education effort to provide middle school and high school students with improved resources and enhanced exposure to geophysical, glaciological, and remote-sensing topics through partnership with the National Science Olympiad.The radar sounding of ice sheets is a powerful tool for glaciological science with broad applicability across a wide range of cryosphere problems and processes. Radar sounding data have been collected with extensive spatial and temporal coverage across the West Antarctic Ice Sheet, including areas where multiple surveys provide observations that span decades in time or entire cross-catchment ice-sheet sectors. However, one major obstacle to realizing the scientific potential of existing radar sounding observations in Antarctica is the lack of analysis approaches specifically developed for cross-instrument interpretation. This project aims to directly address these barriers to full utilization of the collective Antarctic radar sounding record by developing a suite of processing and interpretation techniques to enable the synthesis of radar sounding data sets collected with systems that range from incoherent to coherent, single-channel to swath-imaging, and digital to optically-recorded radar sounders. The approaches will be assessed for two target regions: the Amundsen Sea Embayment and the Siple Coast. All pre- and post-processed sounding data produced by this project will be publically hosted for use by the wider research community.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.