The Relationship between Climate and Ice Rheology at Dome C, East Antarctica

Pettit/0948247该奖项支持了一个研究南极洲东部EPICA Dome C冰芯站点附近冰的结构与气候之间关系的项目。这项工作建立在西南极洲Siple Dome正在进行的研究的基础上，并利用与欧洲科学家的合作以及进入Dome C钻孔进行声速测量。 该项目的智力价值在于，更好地了解结构如何保存过去的气候信息，可以改进冰芯站点附近的冰流模型和冰芯数据（特别是古积累）的解释，并且它可能使我们能够直接从结构数据中提取气候信息。 此外，由于冰的变形对晶体的取向很敏感，冰的流动模式对结构也很敏感。因此，冰川和间冰期冰之间的结构变化可以影响冰的变形方式和冰盖结构的发展。 冰穹C遗址对于回答这些问题特别重要，因为冰芯显示了八个冰川循环的证据，而不仅仅是在西普尔冰穹或格陵兰遗址发现的一个。 这项研究将增进对声速数据与结构之间的代用关系的了解;将有助于利用这些数据、现有冰芯化学性质和现有及新的薄片数据、改进的表面应变数据和钻孔变形数据，模拟冰期与间冰期之间结构变化造成的冰流模式;并将有助于更好地了解正反馈机制，通过对几个气候转变和相关的结构变化进行重点研究，增强结构（和相应的流变学）的可变性。 将测量钻孔压缩波声速，这将补充格陵兰和西南极已有的钻孔声速数据。 这将是东南极洲的第一次声速测量，也是第一次对一个以上的冰期/间冰期过渡进行测量。 该项目最终将有助于更好地解释冰芯记录，用于古气候研究和冰流历史，这两者都与冰在气候系统中的作用这一更广泛的问题有关。该项目还将加强古气候和冰盖建模界的国际合作。该项目将部分支持阿拉斯加大学费尔班克斯的一名研究生，他目前正在研究包括各向异性在内的冰模型，并将通过博士后职位支持一名年轻科学家的成长。这篇文章将获得与EPICA科学家合作研究气候结构关系的重要经验。艾琳佩蒂特是活跃在现场科学教育的高中生，本科生，教师和成人。该项目将有助于支持冰上女孩项目的持续发展和加强，该项目鼓励年轻妇女探索科学和自然世界。

Pettit/0948247This award supports a project to study of the relationship between fabric and climate for the ice near the EPICA Dome C ice core site, East Antarctica. The work builds on an ongoing study at Siple Dome, West Antarctica and takes advantage of collaborations with European scientists and access to the Dome C borehole to make measurements of sonic velocity. The intellectual merit of the project is that a better understanding of how fabric preserves past climate information can improve models of the ice flow near ice core sites and the interpreta-tion of ice core data (particularly paleo-accumulation), and it may allow us to extract climate information directly from fabric data. In addition, because ice deformation is sensitive to the orientation of crystals, ice flow patterns are sensitive to the fabric. Thus, variations in the fabric between glacial and interglacial ice can affect how ice deforms and how fabric in the ice sheet develops. The Dome C site is particularly important for answering these questions, because the ice core shows evidence of eight glacial cycles, not just one as found at Siple Dome or the Greenland sites. The research will improve the understanding of the proxy relationship between sonic-velocity data and fabric; will help to model the pattern of ice flow caused by the fabric variation between glacial and interglacial time periods using these data, existing ice core chemistry and existing and new thin section data, improved surface strain data, and borehole deformation data; and will help to better understand the positive feedback mechanism that enhances fabric (and corresponding rheological) variability through a focused study of several climate transitions and the associated fabric changes. Borehole compressional-wave sonic-velocity will be measured which will complement the sonic-velocity data that already exist for boreholes in Greenland and West Antarctica. These will be the first sonic-velocity measurements in East Antarctica and the first measurements that extend for more than a single glacial/interglacial transition. The project will ultimately contribute to better interpretation of ice core records for both paleoclimate studies and for ice flow history, both of which connect to the broader questions of the role of ice in the climate system. This project will also strengthen the international collaborations within the paleoclimate and ice sheet modeling communities. This project will partially support a graduate student at the University of Alaska Fairbanks who is currently working on modeling ice including anisotropy and it will support the growth of a young scientist through a Post-Doc position. This Post Doc will gain important experience collaborating with the EPICA scientists in studying the climate-fabric relationship. Erin Pettit is active in field-science education for high school students, under-graduates, teachers, and adults. This project will help support the continued development and enhancement of Girls on Ice a program that encourages young women to explore science and the natural world.