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洲Siple Dome深冰芯的气候历史和物理特性，开发基于气泡数密度的新古气候技术，并提高美国快速准确分析冰芯物理特性的能力。来自南极西部的Siple Dome冰芯正在产生重要的古气候洞察，但由于大冰流对古气候记录的影响，已被证明比一些冰芯更难解释。因此，不依赖于冰流校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，因为它保存了积雪转化为冰的过程中平均温度和积累率的信息。我们将专注于对冰流和冰芯历史解释至关重要的薄片特征，如c轴组构，并将使用我们一直在开发的指标，如颗粒伸长和c轴取向之间的相关性，以获得更多信息。为了快速、准确地实现这一点，并为未来的项目做准备，我们建议升级Wilen建造并安置在国家冰芯实验室的自动CAXIS织物分析仪。拟议活动的学术价值包括改进了对一个重要区域的古气候条件的估计，增进了对新的古气候研究工具的了解，更好地了解了冰流及其与物理性质的联系，以及为美国在国家冰芯实验室进一步研究冰芯物理性质提供了更好的工具。拟议活动产生的更广泛影响包括更好地了解突然的气候变化和冰流，这最终应该有助于政策制定者，以及提高美国分析冰芯的能力。这项拟议的研究将有助于两位有前途的年轻科学家的研究。研究结果将被纳入课程和公众宣传，每年至少惠及数百或数千人。

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.