Advanced Microstructural Characterization of Polar Ice Cores

该奖项支持一个全面表征冰芯微观结构的项目，特别是杂质的微观结构位置、晶粒取向和应变梯度。这项工作将补充光学观察，电导率测量，以及由其他人进行的可溶性离子和气体含量的精确，详细的测量。将测量到十亿分之几的可溶性离子和气体的浓度与光学测定的冰芯年层结构和稳定同位素数据联系起来，使人们能够对几个极地冰芯的颗粒、微量气体和杂质的浓度和深度/年龄分布建立大量的认识。几个小组进行的冰芯研究对我们对古气候的理解和预测未来气候变化的能力做出了巨大贡献。这项工作将建立在该领域以前的测量和技术发展的基础上，并将重点放在表征冰芯的新技术上。这项工作将使用扫描电子显微镜（SEM）结合x射线能量色散光谱（EDS）和共聚焦扫描光学显微镜结合拉曼光谱（RS）来确定杂质的微观结构位置，并将这些信息与几个极地冰芯的深度/年龄、杂质类型和浓度相关联。所提出的工作的更广泛的影响是，对杂质位置的了解，加上颗粒方向（c轴和a轴）和颗粒错误方向信息，将使古气候学家能够更好地解释冰芯数据，使其他科学家能够理解和模拟天然冰盖的物理和机械特性。这项工作的其他更广泛的影响是，这项工作将被执行，并导致博士生的教育。在项目结束时，以及从课程中获得的知识，研究生将具有使用扫描电子显微镜，x射线微分析，共聚焦扫描显微镜，拉曼光谱和离子色谱制备和表征冰芯样品的经验。研究结果将发表在期刊上，在会议上展示，并放在网页上。

Baker/0738975This award supports a project to fully characterize the microstructure in ice cores, in particular the microstructural locations of impurities, grain orientations and strain gradients. This work will complement the optical observations, electrical conductivity measurement, and precise, detailed measurements of the soluble ion and gas contents that are performed by others. Linking the concentrations of soluble ions and gases, measured to a few parts per billion, to the optically determined annual layer structure and the stable isotope data in ice cores has enabled a great deal to be established about the concentrations and depth/age distributions of particles, trace gases and impurities for several polar ice cores. Ice core studies carried out by several groups contribute immensely to our understanding of paleoclimate and, to our ability to predict future climate change. The work will build on previous measurements and technique development in this area, as well as focusing on new techniques to characterize ice cores. The work will use both scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDS) and confocal scanning optical microscopy coupled with Raman spectroscopy (RS) to determine the microstructural locations of impurities and correlate this information with depth/age, and impurity type and concentration for several polar ice cores. The Broader Impacts of the proposed work are that knowledge of the location of impurities coupled with the grain orientation (both c- and a-axis) and grain misorientation information will allow paleoclimatologists to better interpret ice core data and other scientists to understand and model the physical and mechanical properties of natural ice sheets. Other Broader Impacts of the work are that the work will be performed and lead to the education of a Ph.D. student. At the end of the project, as well as the knowledge gained from coursework, the graduate student will have experience in ice core specimen preparation and characterization using scanning electron microscopy, x-ray microanalysis, confocal scanning microscopy, Raman spectroscopy and ion chromatography. Results from the research will be published in refereed journals, presented at conferences, and placed on a web page.