Optical Fabric and Fiber Logging of Glacial Ice

冰川的光学织物和光纤测井

• 批准号: 1142173
• 负责人: Ryan Bay
• 金额: $ 34.84万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1142173&HistoricalAwards=false
• 关键词: Optical; Fabric; Fiber; Logging; Glacial

1142010/TalghaderThis award supports a project to combine the expertise of both glaciologists and optical engineers to develop polarization- preserving optical scattering techniques for borehole tools to identify changes in high-resolution crystal structure (fabric) and dust content of glacial ice. The intellectual merit of this work is that the fabric and impurity content of the ice contain details on climate, volcanic activity and ice flow history. Such fabric measurements are currently taken by slicing an ice core into sections after it has started to depressurize which is an extremely time-intensive process that damages the core and does not always preserve the properties of ice in its in-situ state. In addition the ice core usually must be consumed in order to measure the components of the dust. The fabric measurements of this study utilize the concept that singly-scattered light in ice preserves most of its polarization when it is backscattered once from bubbles or dust; therefore, changes to the polarization of singly-backscattered light must originate with the birefringence. Measurements based on this concept will enable this program to obtain continuous records of fabric and correlate them to chronology and dust content. The project will also develop advanced borehole instruments to replace current logging tools, which require optical sources, detectors and power cables to be submerged in borehole fluid and lowered into the ice sheet at temperatures of -50oC. The use of telecommunications fiber will allow all sources and detectors to remain at the surface and enable low-noise signal processing techniques such as lock-in amplification that increase signal integrity and reduce needed power. Further, fiber logging systems would be much smaller and more flexible than current tools and capable of navigating most boreholes without a heavy winch. In order to assess fabric in situ and test fiber-optic borehole tools, field measurements will be made at WAIS Divide and a deep log will also be made at Siple Dome, both in West Antarctica. If successful, the broader impacts of the proposed research would include the development of new analytical methods and lightweight logging tools for ice drilling research that can operate in boreholes drilled in ice. Eventually the work could result in the development of better prehistoric records of glacier flow, atmospheric particulates, precipitation, and climate forcing. The project encompasses a broad base of theoretical, experimental, and design work, which makes it ideal for training graduate students and advanced undergraduates. Collaboration with schools and classroom teachers will help bring aspects of optics, climate, and polar science to an existing Middle School curriculum.

1142010/talghaderthis奖支持一个项目，旨在结合冰川学家和光学工程师的专业知识，以开发极化 - 为钻孔工具保存光散射技术，以识别高分辨率晶体结构（织物）和冰川冰的灰尘含量的变化。这项工作的智力优点在于，冰的结构和杂质含量包含有关气候，火山活动和冰流历史的细节。 这种织物测量目前是通过将冰芯切成部分后通过将冰芯切成抑制作用来进行的，这是一个非常耗时的过程，损坏了核心，并且并不总是在其现场状态下保留冰的性质。此外，通常必须消耗冰芯才能测量灰尘的组成部分。这项研究的织物测量结果利用了冰中单散射光的概念，当它从气泡或灰尘中反向散射时，可以保留其大部分极化。因此，单一散射光的极化的变化必须起源于双折射。基于此概念的测量将使该程序能够获得织物的连续记录，并将其与年代和灰尘含量相关联。该项目还将开发高级钻孔仪器，以取代当前的记录工具，这些工具需要光源，探测器和电源电缆浸入钻孔流体中，并在-50OC的温度下将其降低到冰盖中。电信光纤的使用将使所有源和检测器都保留在表面上，并启用低噪声信号处理技术，例如锁定扩增，以增加信号完整性并降低所需的功率。此外，与当前工具相比，纤维记录系统将要小得多，更灵活，并且能够在大多数钻孔的情况下导航而没有重绞车。为了评估原位和测试纤维钻孔工具，将在WAIS Divide进行现场测量，并且还将在南极西部的Siple Dome上进行深层对数。如果成功的话，拟议的研究的更广泛影响将包括开发新的分析方法和用于冰钻研究的轻量级日志记录工具，以在冰上钻孔的钻孔进行操作。 最终，这项工作可能导致冰川流动，大气颗粒，降水和气候强迫的更好史前记录的发展。 该项目涵盖了理论，实验和设计工作的广泛基础，这使其非常适合培训研究生和高级本科生。与学校和课堂老师的合作将有助于将光学，气候和极地科学的各个方面带入现有的中学课程。