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

泰勒/0944191该奖项支持一个项目，该项目旨在帮助建立WAIS分水岭冰芯的深度-年龄年表以及堆积史和冰动学史。深度-年龄关系、堆积史和冰动学史是耦合的。需要一个准确的年龄尺度来利用冰流模型来推断积累率和冰厚度变化的历史。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。积累史也是计算大气中冰中杂质浓度所必需的，这是气候的一个重要特征。冰层厚度变化的历史也是理解WAIS稳定性的基础。WAIS Divide冰芯项目的主要目标是调查温室气体对气候的强迫作用、气候变化的启动以及西南极冰盖(WAIS)的稳定性。准确的年龄标准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年来每年确定的深度-年龄关系。这将通过测量冰芯电导率的变化来完成，这是由化学季节变化引起的。我们希望使用这种方法能够分辨出距今40,000年前的年度地层(深度3,000米)。第二个目标是在核心寻找可能危及古气候记录的地层扰动。不规则的分层将通过测量垂直平面上穿过岩芯的冰的电导率来识别。第三个目标是得出整个核心的初步年表。对于更深的冰，我们将使用冰流模型在已知的年龄标记之间进行插补，例如确定的火山层和甲烷气体年代学的连接点。第四个目标是与积累史和冰盖厚度同时得出一个精确的年代学。冰流模型和所有可用的数据将被用来形成一个反问题，在这个问题中，我们推断出最合适的积累和冰层厚度的历史，以及对不确定性的估计。然后，与这些首选历史相关联的流动模型产生对年表的最佳估计。这项研究直接促进了西南极冰盖倡议的主要目标。该项目将通过对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。该项目将使国家冰芯实验室提供测量冰芯电导率的仪器，供其他研究人员在其他项目中使用。所有合作者都致力于促进多样性，目前参与了科学推广活动，大多数人参与了本科教育。外展将通过定期安排在威斯康星州大学举办的社区和K-12外展活动、讲座和私人投资机构的通俗写作以及通过我们各自的新闻办公室来实现。

Taylor/0944191This 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.