Collaborative Research: Establishing the Chronology and Histories of Accumulation and Ice Dynamics for the WAIS Divide Core

该奖项支持了一个项目，该项目旨在帮助建立WAIS Divide冰芯的深度年龄年代学以及积累和冰动力学的历史。深度-年龄关系与堆积历史和冰动力是耦合的。利用冰流模型推断冰积速率和冰厚变化的历史需要一个精确的年龄尺度。反过来，需要积累速率历史来计算冰的年龄差，以确定被困气体的年龄。积累历史也需要计算被困在冰中的杂质的大气浓度，这是气候的一个重要特征。冰厚变化的历史也是理解WAIS稳定性的基础。南极西部冰原分界冰芯项目的主要目标是调查温室气体对气候的影响、气候变化的开始以及南极西部冰原的稳定性。准确的年龄尺度是实现这些目标的基础。该项目的第一个目标是建立过去40,000年来每年解决的深度-年龄关系。这将通过测量沿冰芯电导率的变化来完成，这是由化学的季节性变化引起的。我们期望使用这种方法能够解析距今4万年的年层（3000米深）。第二个目标是在地核中寻找可能破坏古气候记录的地层扰动。不规则的分层将通过测量冰的电导率在一个垂直的计划通过核心来识别。第三个目标是推导出整个核心的初步年表。对于较深的冰，我们将使用冰流模型在已知的年龄标记之间进行插值，例如确定日期的火山层和甲烷气体年代学的结合点。第四个目标是推导出与积累史和冰盖厚度同时发生的精确年表。冰流模型和所有可用的数据将用于制定一个反问题，在这个反问题中，我们推断最合适的积累历史和冰厚度，以及对不确定性的估计。与这些首选历史相关联的流模型然后产生对时间顺序的最佳估计。这项研究直接有助于实现南极西部冰盖倡议的主要目标。该项目将通过一名博士生和几名本科生的教育和培训，帮助培养下一代科学家。这个项目将为国家冰芯实验室提供测量冰芯电导率的仪器，供其他研究人员用于其他项目。所有合作者都致力于促进多样性，目前参与科学推广，大多数参与本科教育。外展将通过定期在华盛顿大学举办的社区和K-12外展活动、pi的演讲和流行写作以及我们各自的新闻办公室来完成。

This award supports a project to help to establish the depth-age chronology and the histories of accumulation and ice dynamics for the WAIS Divide ice core. The depth-age relationship and the histories of accumulation and ice dynamics are coupled. An accurate age scale is needed to infer histories of accumulation rate and ice-thickness change using ice-flow models. In turn, the accumulation-rate history is needed to calculate the age difference of ice to determine the age of the trapped gases. The accumulation history is also needed to calculate atmospheric concentrations of impurities trapped in the ice and is an important characteristic of climate. The history of ice-thickness change is also fundamental to understanding the stability of the WAIS. The primary goals of the WAIS Divide ice core project are to investigate climate forcing by greenhouse gases, the initiation of climate changes, and the stability of the West Antarctic Ice Sheet (WAIS). An accurate age scale is fundamental for achieving these goals. The first objective of this project is to establish an annually resolved depth-age relationship for the past 40,000 years. This will be done by measuring variations in electrical conductivity along the ice core, which are caused by seasonal variations in chemistry. We expect to be able to resolve annual layers back to 40,000 years before present (3,000 m depth) using this method. The second objective is to search for stratigraphic disturbances in the core that would compromise the paleoclimate record. Irregular layering will be identified by measuring the electrical conductivity of the ice in a vertical plan through the core. The third objective is to derive a preliminary chronology for the entire core. For the deeper ice we will use an ice-flow model to interpolate between known age markers, such as dated volcanic horizons and tie points from the methane gas chronology. The fourth objective is to derive a refined chronology simultaneously with histories of accumulation and ice-sheet thickness. An ice-flow model and all available data will be used to formulate an inverse problem, in which we infer the most appropriate histories of accumulation and ice-thickness, together with estimates of uncertainties. The flow model associated with those preferred histories then produces the best estimate of the chronology. The research contributes directly to the primary goals of the West Antarctic Ice Sheet Initiative. The project will help develop the next generation of scientists through the education and training of one Ph.D. student and several undergraduate students. This project will result in instrumentation for measuring the electrical conductivity of ice cores being available at the National Ice Core Lab for other researchers to use on other projects. All collaborators are committed to fostering diversity and currently participate in scientific outreach and most participate in undergraduate education. Outreach will be accomplished through regularly scheduled community and K-12 outreach events at UW, talks and popular writing by the PIs, as well as through our respective press offices.