Collaborative Research: Combined Physical Property Measurements at Siple Dome

该奖项支持一项为期两年的合作努力，以更全面地了解南极深冰芯的气候历史和物理特性，开发一种基于气泡数密度的新古气候技术，并提高美国快速准确地分析冰芯物理特性的能力。来自南极洲西部的简单穹窿冰芯提供了重要的古气候信息，但由于对古气候记录的大冰流影响，证明比一些冰芯更难解释。因此，不依赖于冰流修正的古气候指标将是有价值的。气泡数密度提供了一个这样的指标，因为它保留了公司转变为冰的平均温度和积累速率的信息。我们将重点关注对冰流和冰芯历史解释很重要的薄切片特征，如c轴结构，并将使用我们一直在开发的指标，如晶粒伸长率与c轴方向之间的相关性，以获得额外的信息。为了快速准确地实现这一目标，并为未来的项目做准备，我们建议升级Wilen建造并存放在国家冰芯实验室的自动轴织物分析仪。拟议活动的智力价值包括改进对重要地区古气候条件的估计，改进对新的古气候研究工具的理解，更好地了解冰流及其与物理性质的联系，以及在国家冰芯实验室为美国进一步研究冰芯物理性质提供更好的仪器。拟议的活动所产生的更广泛的影响包括更好地了解气候突变和冰流，这最终将有助于政策制定者，以及提高美国分析冰芯的能力。拟议的研究将有助于两位有前途的年轻科学家的研究。研究结果将纳入课程和公共宣传，每年至少有数百或数千人参加。

This award supports a two-year collaborative effort to more fully understand the climatic history and physical properties of the Siple Dome, Antarctica deep ice core, to develop a new paleoclimatic technique based on bubble number-density, and to improve the U.S. capability to analyze ice-core physical properties rapidly and accurately. The Siple Dome ice core from West Antarctica is yielding important paleoclimatic insights, but has proven more difficult than some cores to interpret owing to the large iceflow effects on the paleoclimatic record. Paleoclimatic indicators that do not rely on iceflow corrections thus would be of value. The bubble number-density offers one such indicator, because it preserves information on mean temperature and accumulation rate during the transformation of firn to ice. We will focus on thin-section characteristics that are important to ice flow and the interpretation of the ice-core history, such as c-axis fabrics, and will use indicators that we have been developing, such as the correlation between grain elongation and the c-axis orientation, to gain additional information. To achieve this quickly and accurately, and to prepare for future projects, we propose to upgrade the automatic caxis- fabric analyzer that Wilen has built and housed at the National Ice Core Laboratory. The intellectual merit of the proposed activity includes improved estimates of paleoclimatic conditions in an important region, improved understanding of a new paleoclimatic research tool, greater understanding of ice flow and of linkages to physical properties, and a better instrument for further U.S. research in ice-core physical properties at the National Ice Core Laboratory. The broader impacts resulting from the proposed activity include providing better understanding of abrupt climate change and of ice flow, which eventually should help policy-makers, as well as an improved U.S. capability to analyze ice cores. The proposed research will assist the studies of two promising young scientists. Results of the research will be incorporated into courses and public outreach reaching at least hundreds or thousands of people per year.