Collaborative Research: Ice Core Studies Reconstructing Greenland Climate During the Eemian and Beyond

这一三个机构合作项目的主要目标是了解格陵兰冰盖(GIS)在伊米亚时期(大约13万至11.5万年前，地球历史上最后一个主要间冰期)和紧接其之前的冰川消融(“终止期2”)期间的范围和演变。地理信息系统是在多个时间尺度上影响海平面、北极和全球气候的重要因素。需要在过去气候变化的背景下了解其动态，但由于12.3万年前之前没有连续的冰芯记录，关于最后一个冰期之前地理信息系统的足迹、体积和海拔的信息很少。在伊米亚时期，地理信息系统的规模可能只有现在的一半，导致海平面“过度”上升约3米。描述地理信息系统在冰川终止2和伊米亚冰川期间的演变将提高我们对其动态的理解，并增强我们预测未来几个世纪海平面上升的能力。以前钻探的冰芯底部确实存在较老的冰，但从这些较老的冰中提取年代和气候信息受到阻碍，因为它受到地层干扰，在许多情况下，受到土壤或基岩物质的污染。这些研究人员提出了几种新的方法来测定这些受干扰和/或“脏”的冰的日期，并提取有关气候和冰盖范围的信息。调查人员将结合他们新的测量和其他可用的数据，在2号终点站和埃米安期间开发更完整的地理信息系统历史。他们将与冰盖模型师合作，调查Eemian数据为模型提供的约束，并提高它们的预测能力。这些努力有可能提高我们预测地理信息系统对未来几十年至几个世纪海平面上升的贡献的能力。教育和外联活动包括培训两名研究生，将这项研究纳入暑期教师充实方案，为研究生和博士后举办系列讲座，并通过新闻媒体传播结果。

The primary goal of this collaborative project between three institutions is to understand the extent and evolution of the Greenland Ice Sheet (GIS) during the Eemian period (roughly 130,000 to 115,000 years ago, the last major interglacial period in Earth's history) and the deglaciation immediately preceding it ("Termination 2"). The GIS is an important agent influencing sea level, and Arctic and global climate, on multiple timescales. Its dynamics need to be understood in the context of past climate changes, but there is little information available about the footprint, volume, and elevation of the GIS prior to the last ice age due to the absence of continuous ice core records prior to 123,000 years ago. During the Eemian, the GIS was perhaps half its present size, contributing on the order of 3 m to "excess" sea level rise. Characterizing the evolution of the GIS during glacial termination 2 and the Eemian would improve our understanding of its dynamics, and enhance our ability to make projections of sea level rise during the coming centuries. Older ice does exist at the bottoms of previously drilled ice cores, but the extraction of age and climate information from this older ice is hampered by the fact that it is stratigraphically disturbed and, in many cases, contaminated with soil or bedrock material. These investigators propose several novel methods to date this disturbed and/or "dirty" ice and to extract information on climate and ice sheet extent. The investigators will combine their new measurements and other available data to develop a more complete history of the GIS during termination 2 and the Eemian. They will work with ice sheet modelers to investigate the constraints that the Eemian data provide for the models and improve their predictive capability. These efforts have the potential to improve our ability to predict the contribution of the GIS to sea-level rise in the coming decades to centuries. Educational and outreach activities include the training of two graduate students, inclusion of this research in summer teacher enrichment programs, a lecture series for graduate students and postdocs, and communication of the results through the news media.